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#31
19th April 2012
Old 19th April 2012
  #31
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Recording Tools MC-900 is not a Kel Song Sparrow

< REMOVED BY MODERATOR > my experience with the Recording Tools Mic's: this German co knows mic design & looks to be Oktava affiliated... and at this price must be China parts or made in... but is smiles from most other chinese branded mic's, and is unique to doing mic design right. the Ribbon mic... is the best i have used in it's class ... and the MC-520... will leave a drum sample as 2 overheads dry... it will speak for it's self. as far as the MC-900 even tho the body and color is similar... it is it's own design and not a Kel clone at all, unlike the Song Sparrow, the 900 is transformer balanced and has 2 sputtered diagrams... but single pattern... a different mic altogether.

Kel microphones, are lovely mic's and priced right... hope to try them in the studio soon... looks' like lots of Chinese mechanical mic's parts floating around from brand to brand... i know Recording Tools is redesigning a mini mount to go with the 900... and sorry but i do have one suggestion for Recording Tools please replace the driver in your headphones for the Superlux HD-662 driver... and you will have an unmistakable winner... this can needs to be able to take just a little more push... super design very nice at moderate volumes. http://static.gearslutz.com/board/im...milies/lol.gif

here is Yonrico Scott doing a sample for AudioHipster on two spaced pair MC-520 dry. Cheers Doyen http://static.gearslutz.com/board/im.../leapfroga.gif
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File Type: mp3 MC-520 STEREO DRUMS.mp3 (4.81 MB, 252 views)
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#32
19th April 2012
Old 19th April 2012
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Quote:
has 2 sputtered diagrams... but single pattern...

OK




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#33
19th April 2012
Old 19th April 2012
  #33
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Quote:
Originally Posted by Kelly Dueck View Post
I don't know where this copy of our Song Sparrow comes from or who made it --- though I can guess -- but we have already begun to take action to protect our interests.

I have also found copies of our HM-1x on a couple of Chinese sites.

We are in the process of moving some of our production to Canada now. Which to be honest is what I've wanted to be able to afford to do all along. But that's a discussion for another day.

As for modding the little MCA mic it's easy to do but remember you can go a long long way with good song arrangement, good instruments and mic placement -- even creative mic placement.

Good for you, Kelly; I also wish you the best dealing with the cloners.
As I mentioned earlier, I already own a very fine KEL HM7u, and I prefer that my cash goes to support quality builders and designers instead of pirate clones. I hope you can beat the capsule makers at their own game with local production; I'd pay extra for that.

The Recording Tools mics are likely decent because they are copying a design someone else already tested out - KEL, etc. They don't have to research or proof the product, they just flat out copy. The exterior of that mic pictured, at least, is a straight clone. They also bothered to use decent components, instead of the cheapest, and why not? They have no R&D cost! They can afford to do that and still have huge margins. I'm sure these RT mics are made in Asia too, probably in some chop shop by kids at pennies a day. Yeah, the shengke factory probably has shitty work conditions too, but at least it's a known facility that can be put under pressure to improve, unlike the chop shops. It happened to Apple...
#34
19th April 2012
Old 19th April 2012
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Ok, back to the SP1.

Let's make this more fun. I'm going to do a write up of the easiest physical mods, in complete process, as a starting point, step by step. It'll take a bit of time; I'll try to add more pictures too. We can expand the thread to include other models that are similar, like the MXL gear.

If you're not interested in soldering, electronics, or theory, go buy a clone. If you'd like to learn what makes these mics worth cloning, stick around and let's get our hands dirty...


also, I think we scared away the OP; that or else he's in finals..
#35
19th April 2012
Old 19th April 2012
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Quote:
Originally Posted by Boschen View Post
Good for you, Kelly; I also wish you the best dealing with the cloners.
As I mentioned earlier, I already own a very fine KEL HM7u, and I prefer that my cash goes to support quality builders and designers instead of pirate clones. I hope you can beat the capsule makers at their own game with local production; I'd pay extra for that.

The Recording Tools mics are likely decent because they are copying a design someone else already tested out - KEL, etc. They don't have to research or proof the product, they just flat out copy. The exterior of that mic pictured, at least, is a straight clone. They also bothered to use decent components, instead of the cheapest, and why not? They have no R&D cost! They can afford to do that and still have huge margins. I'm sure these RT mics are made in Asia too, probably in some chop shop by kids at pennies a day. Yeah, the shengke factory probably has shitty work conditions too, but at least it's a known facility that can be put under pressure to improve, unlike the chop shops. It happened to Apple...
...OK, I'm going to go out on a limb and say the Recording Tools mics are more likely not "clones" at all, but are being manufactured by the very same factory that makes the mics they resemble...if there's anything unethical going on, it's that the manufacturers in China offer up a product they develop for one client to other clients (often in other int'l territories), possibly violating any exclusivity agreements they may have with the original client...we've seen this before (often with guitars), and it's usually resolved after the fact, once the secondary products are identified...this particular manufacturer is one of the largest in China, and they have established a very good reputation for quality products, in particular, their LDC capsules...but the problem stems from the evolution of business ethics in Asian manufacturing community, and rather than turn this thread into an unnecessary discussion of such, suffice to say, these incidents seem to be less prevalent than in previous years...so, I suspect this may not be a cloning issue, but rather an exclusivity problem, and I'm confident Kelly will get it resolved to his advantage...

...another case in point, take a look at Dave Thomas' Canada based Advanced Audio microphones (many developed exclusively for Dave) and then look at Australian based Jeanne Audio mics...look familiar?...nuff said...
http://www.aamicrophones.com/index.htm
http://www.jeanneaudio.com.au/index.html

...my apologies for derailing...
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#36
19th April 2012
Old 19th April 2012
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No worries on the OT.

If shengke is selling the same base models to another builder and they are just rebranding that design and selling, then yeah, that's unethical, and no surprise. It does surprise me that shengke would match every feature of the KEL--I would have guessed that external bling details, like textured rubber rings, paint and such, had been added in some other shop somewhere. Most builders have a layer of this stuff they add or change from the base model to make the mic their own distinctive thing. If shengke is selling a base model made to KEL's specs to another builder, I guess it wouldn't be a clone, as in this case the copy is made by the manufacturer of the original... Maybe not cloning, but probably intellectual property theft.
As you pointed out, we've seen this with guitars...

.... now, weren't we modding mics or something?
#37
19th April 2012
Old 19th April 2012
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Quote:
Originally Posted by Boschen View Post
If shengke is selling the same base models to another builder and they are just rebranding that design and selling, then yeah, that's unethical, and no surprise. It does surprise me that shengke would match every feature of the KEL
...hard to know without a side-by-side comparison of the two mics' innards/circuit...body, capsule and mount certainly look to be identical...anyway, back to the soldering of bits & pieces...
#38
19th April 2012
Old 19th April 2012
  #38
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The obvious end run loophole around the "clone" mics dilema is to change out one or perhaps more components with a different spec part - or even just a part from a different component manufacturer, change the paint scheme, MAYBE (although not usually) swap out for a different body, and..... Voila. New Chinese design.....


Not.


This going on HUGE in the Chinese mic manufacturing business, and really should be no surprise to anyone who is remotely familiar with what's out there. And yes, it is DEFINITELY slowing down development of new products. US & European mic designers are not stupid. They are finally begining to realize that a happy face and contract on the other side of the ocean will not stop their builders from undercutting them. It's a mis-match of western vs. eastern culture and ethics.

Like I said earlier, my buddy in is court suing these guys constantly. And he wins 100% of the time. But it has done nothing to stop or barely even slow down the Chinese from selling his intellectual property to his competitors for their profit.

There are ways around the Chinese propensity to steal (at least that's what we call it in the US - they have a different opinion obviously), but it cuts into the profit margin of US companies, and ultimately results in higher priced mics than the $110 models discussed. The good news is - it helps bring back some jobs into the US.

Sorry for the harshness, but it's the reality of the situation.

Boschen - your writeup sounds quite interesting. It would no doubt be valuable for those attempting a mod on the sp-1. Go for it!!
#39
21st April 2012
Old 21st April 2012
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I'll be posting additional pics and notes on this process as I'm able, so you'll see more being added to this thread over time.

Please note that the mods have already deleted some portions of this discussion; lets try to keep this on the topic of SP1 mods, and use this thread as a place to compile useful info on that subject.

Step-by-Step:

THE MCA SP1 PUSSYWILLOW MOD SUITE:

Consisting of: headbasket mod, FET to capsule cap replacement, capsule replacement, cardioid / omni switch install.

With thanks to Jim Williams for his input and willingness to share his mod process! Jim performs a much more elaborate and involved mod on this mic, from which I've lifted the most easily performed elements. In time, I plan to add the more esoteric and difficult parts of Jim's mods to this thread, and perform them myself on my own SP1.
I heartily recommend anyone interested in Jim's work or his fine products to contact him here:
http://www.audioupgrades.com/

Tools:
>Safety glasses
>Power drill, combo metal bits
>File, a rat-tail type if possible
>Soldering iron, solder,
>Jeweler's screwdriver set
>Vise or clamp
>Scissors, wire strippers
>Awl, pick
>Needle nose pliers

Pussywillow Mod BOM (bill of materials, to be expanded as mod complexity increases):

EDIT: corrected a couple of errors

>.001 uf polystyrene or polypropylene film cap --- for replacing the existing capsule to FET cap - apx. $2 USD.
I think this Vishay Orange Drop polypro cap will work; still need confirmation.
Mouser link:
http://www.mouser.com/ProductDetail/...PmS%2fpVgBI%3d

>SPST or SPDT sub miniature toggle switch --- for cardioid / omni toggle mod - apx. $2 USD.
Mouser link:
http://www.mouser.com/ProductDetail/...JdmBEencVCw%3d

The toggle switch linked to above is similar to the one I used, though a slightly different size. Look for the smallest toggle you can find, sub-miniature style. You can use either a SPST or SPDT; if you use the latter, just use two of the three solder terminals. You could also use a submini push button switch, or a slider switch instead of the toggle. I opted for something that would mount in a simple round through-hole application. You'd have to cut a square hole for a slider, far more difficult. More on this later...

DISCLAIMER:
Please take reasonable safety precautions.
WEAR EYE PROTECTION WHEN SOLDERING.
Did you get that?
Ok.

Before you work on the mic, discharge any static by grounding your body. Wear a strap for static if you need one.

Schemo:



EDIT: New schemo, from the page linked to in an earlier post; the schemo now matches the PCB layout on the SP1 stock mic.

You shouldn't even need this to do the mods below, but it's a helpful reference for us to use in discussion. You will find that the PCB boards of the SP1 are labeled with markers, i.e. C1, C2, R1, R2, etc. These are printed on the PCBs, so you can find the part on the mic corresponding to the schemo.

>Get at the Guts:
To disassemble the mic, unscrew the two base pieces, and the metal shell will slide off the chassis to reveal the two circuit boards. Unscrew the two screws on the underside of the headbasket, that hold the headbasket onto the chassis. Take care not to lose the holding tab on the front screw. Now carefully remove the headbasket. This all should take about 5 minutes. Set the exposed capsule and chassis aside in a safe place. Keep in mind that in the pics below, I've already performed this mod suite, so the guts may not exactly resemble yours; i.e., the toggle switch and extra wire for the omni capsule.



PCB #1:


Ok, see the FET on PCB 1 above? At the left top on the board, the black thing labeled T3. It's Q1 on the MXL schemo, in about the middle of things. To the right is the input from the mic capsule, where the white wires are soldered onto the PCB. On the left is the blue wire to ground.



PCB#2:


This is the second PCB; the toggle switch is an option I added when I replaced the capsule.


>Removing the Headbasket Lining:
The basket has three layers of mesh; the outer layer, and two inner layers. The thinner inner layers are soldered to the outer mesh at several points along the inner seams of the headbasket. To remove the mesh, start work at some point away from a solder seam; use a pick, awl or pointed tool to work a part of the inner mesh free. When you've lifted up a part of the mesh, use scissors to lever it up and start cutting. I found it easiest to cut most of the mesh away from the inner seams, then use pilers to pull the remaining bits out from under the solder points and seam. Any remaining bits of mesh can be snipped away or bent under the seams so they don't show. It doesn't have to be perfect; just get those inner layers ripped out as much as you can. Don't leave any jagged bits to catch on your fingers or the capsule. Below is a shot of the basket with the inner layers removed.




>Capsule to FET Cap Replacement:
The capacitor between the capsule and the FET is ripe for replacement on this mic; Jim recommends a polystyrene replacement capacitor. We talked about values for those earlier in the thread. The cap is sandwiched between the two PCB boards, out of sight. To access this part of the circuit, you have to take off PCB1, the one with the FET on it. The PCBs are screwed onto the chassis with two screws. Remove these, and the wires will permit you to lift up the PCB and access the cap we're replacing. You should have enough slack to do this without having to unsolder the wiring, if you're careful. Below is a shot of the cap after replacement; my leads are a bit long, try to keep yours shorter:



Be careful not to heat up the solder points more than needed to remove the old cap and solder on the new one. Also, don't touch the FET component, as you might give it a jolt of static--I've found them to be forgiving, but I've heard this warning before. You can use de-solder braid to remove the old solder points if you want. I found the old cap lifted off easily once the solder points are heated enough. Use care during this step. You should only have to apply the iron for a few seconds to melt the solder. You should apply new solder to the joint, instead of re-heating and re-using the old dollop of solder, another reason using a de-soldering braid is a good thing.

>Next, replacing the stock capsule with an RK47.

Last edited by Boschen; 30th April 2012 at 02:47 AM.. Reason: updated schemo
#40
21st April 2012
Old 21st April 2012
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Continued:

>Capsule Replacement with an RK47

First, you'll need a new capsule. I got mine at microphone-parts.com, their RK47:

RK-47 Microphone Capsule | K47 | Microphone Parts

I got one for just under $100 on sale. Order the larger round base mount, which will fit into the SP1. In the shot below, you can see the new base at rear right, the round one. The base at left is other other type, which was also included with the capsule. This capsule arrives ready to go; you have to install the ground wire onto the ring, but the capsule is pre-wired on both sides.

To remove the old capsule, take off the headbasket. Now unscrew the screws holding the white plasic base onto the chassis to free the capsule. Snip off the hot and ground wires, leaving tails on the PCB so you can see which wire went to which terminal. Red is the input, black is ground. These wires go to the same points on the PCB pictured in the guts post above. In that photo, the new capsule is installed, with white input wires, and a blue ground wire.
Below is the stock capsule being removed:




Once the old capsule is gone, you'll have to mod the base mount before we fit on the new capsule. Shave off the nubs on the base of the plastic mount, so the base sits evenly. You may also have to carve away a bit of soft rubber on the mount edges to let it sit flat around the baseplate screw clamps. When you've carved it up so the mount fits firmly and solidly, screw it down to the plate. Now you install the capsule onto the mount. First screw the ground ring onto the capsule's outer copper ring, under the base, so it has solid contact. Now you're going to screw the capsule onto the mount from below. Be freaking careful not to touch the damn capsule coating! This part takes a very light touch. It's easier if you get one screw in a few threads, then work on the other, then tighten both down.

Once the capsule is mounted, separate out the front and back capsule wires, and trim them back to a proper length, leaving enough wire to work with. Feed the wires, front, back, and ground, down the holes in the baseplate. Now solder the capsule and ground wires to the PCB-- the capsule wires go to the input solder point (red wire in above photo), ground wire to the ground (black in above photo). You can opt to use just the front wire, if you only want cardioid. If you want the omni toggle option, keep enough slack on the rear capsule wire to allow wiring it to a SPDT toggle switch. What I did was solder the front and back capsule wires on, then I snipped the rear wire, and inserted the switch where the wire was cut. Leave enough slack! More on that switch next. Here's the new capsule and mount installed on the backplate. The ground wire isn't visible, it's in back of the post.



>Next: adding a card / omni toggle switch...
#41
21st April 2012
Old 21st April 2012
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Wow thanks for the extra deets on the mod! Will definitely come in handy!
#42
22nd April 2012
Old 22nd April 2012
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I wanted to give you thumbs up yesterday, but didn't want to disturb any continuation in your posts.
I guess it's safe to do it now.






Henk
#43
22nd April 2012
Old 22nd April 2012
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Quote:
Originally Posted by Boschen View Post




>Capsule to FET Cap Replacement:
The capacitor between the capsule and the FET is ripe for replacement on this mic; Jim recommends a polystyrene replacement capacitor. We talked about values for those earlier in the thread. The cap is sandwiched between the two PCB boards, out of sight. To access this part of the circuit, you have to take off PCB1, the one with the FET on it. The PCBs are screwed onto the chassis with two screws. Remove these, and the wires will permit you to lift up the PCB and access the cap we're replacing. You should have enough slack to do this without having to unsolder the wiring, if you're careful. Below is a shot of the cap after replacement:




>.
I didn't want to interrupt, either. Fantastic. Clear.

Is there a part number somewhere for a recommended cap at Digikey or Mouser or other place?
#44
22nd April 2012
Old 22nd April 2012
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Thank you, gentlemen!

The replacement cap above is a 1000pf / .001uf polypropylene, IIRC... /// EDIT: Corrected value and type, it's polystyrene.
I think it appears on the MXL schemo above as C130, rated at 680pf. I added a Mouser link in the BOM I edited in above, but we should have someone more experienced to confirm that cap will be correct for the circuit, as I haven't used that exact part.

I had to go hunting through the copious bins of my local electronics supply shop (thank god there's one around here), for the replacement cap for my SP1. Being somewhat ignorant of cap markings, and converting pf and uf values, I installed an incorrect value first, and the mic didn't work, so I had to try a couple of others until I got it right. I'd like to avoid that mistake for you all, so anyone who can confirm that part will work, please let us know for certain.

I'm going to add a BOM (bill of materials) to the above posts, listing the components required. As the thread expands to include the more difficult mods, a BOM will be even more help. Half the work in modding these things is figuring out exactly what parts you need to use; a BOM removes that obstacle.
Keep in mind that if you do the pussywillow mod suite described above, then later decide to go back and mod other elements of the circuit, this will involve some backtracking. The full mod will require you to de-solder and remove all the wires from the PCBs, so they can be completely removed from the chassis and components can be easily desoldered and replaced. Then you have to re-do the wiring, and reassemble the chassis. Not a big deal with this mic, though some may prefer the 'whole hog' approach, and do the more elaborate mods from the get go.

This mod is such fun, takes little time and cash to accomplish, and yields great results; hard to go wrong!

Still pending: adding a toggle switch for omni / cardioid mode.... once that's up, we'll have the basic PW mod suite ready to go, and it'll be time to step up to the more complex mods to the circuit itself!
#45
22nd April 2012
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The BOM would be great to figure how what it might cost to go all the way or just a part of it.

And for the less knowledgeable like me, gives us a clear roadmap to follow.
#46
22nd April 2012
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Cost for the pussywillow mod suite:

$50 - stock SP1 mic
$100 - replacement RK47 capsule
$5-10 - toggle and replacement capacitor, shipped

If you go the whole hog in upgrading the circuit, total cost is likely to run about 170$, maybe $150 if you have a local supplier for components, instead of shipping from Mouser or Digikey. For this you get a mic with omni & card patterns, great electronics & capsule, and a wonderful sound. Considering that a CAD m179 costs about as much, I would say it's a good deal, provided you enjoy doing this kind of mod work, and enjoy using a mic you worked on yourself. The basic mod can be done in less than two hours, so even at my professional rate (80$/ hr), I only have about $310 value invested in one of these mics. I feel they are well worth that investment of time.

Jim W. has stated that the fully upgraded SP1 mics compare very well with high end models costing much more. Based on the tests I've done after performing only the basic mods, I have every reason to believe Jim's assertions. He designed the Rode NT1 and NT2, after all, and has some experience in these matters.
#47
23rd April 2012
Old 23rd April 2012
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Thanks for the cost estimates too. I was wondering how much that would be. For now I'm just starting with the headbasket and the circuit. I'll look into replacing the capsules after that.

Very well done with the documentation here, I'll try and post picks of my progress too.
#48
23rd April 2012
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>Adding an omni / cardioid toggle switch:

Thanks to Jim Williams for suggesting this particular mod!

Adding a toggle switch to the rear capsule wire allows you to switch your replacement RK47 capsule from cardioid to omni mode. The RK47 comes with both sides of the capsule wired, and the ground wire and ring loose in the box. After you've mounted the capsule (see above post), take the wire from the rear of the capsule, and insert the toggle between the rear capsule and the PCB#1 input solder point (see above posts). So you'll have the wire from the rear capsule going down into the body of the mic, where you solder it to the switch. Then solder a wire from the second leg of the switch to the PCB input. The stock RK47 wires are plenty long enough to cut the rear capsule wire in half, and have enough to reach both sides, from capsule to switch to input on PCB#1.

You have leeway on where you want to mount the switch. I did the easiest thing; I drilled a hole through the back of the mic shell, opposite and slightly lower than the cardioid symbol on the front of the mic. There's lots of room under there to fit the toggle in, and many ways you could do it. First I drilled a small pilot hole, then I drilled another just smaller than what I needed, and used a file to get the hole to fit the switch threads. I used a multipurpose metal / wood bit and a Milwaukee driver, then a rat-tail file. Be careful not to drill the hole too large; size the bit to match the shaft of the toggle, then file it out to just fit the threads.

I installed a through-hole toggle switch, but I could have used a slider switch, or a PCB mount, or a push button style. A sub miniature on/off push button with a round through-hole mount would have been better, but my local supplier didn't have one. A rotary switch would work too--you could mount the switch to the PCB or chassis so the end of the knob just sits flush with the shell, instead of sticking out, like mine. I may replace my toggle with something more low profile if it seems to be an issue during use.

The switch pictured below is an SPDT sub miniature toggle. An SPST will also work.
SPDT= SINGLE POLE DOUBLE THROW.
SPST= SINGLE POLE SINGLE THROW.
Give it a google if you need clarification.
There are additional pictures above in the thread of the mic with the switch in place. You can use a SPST toggle, but my local supplier only had an SPDT in sub mini size. If you use the SPDT, just solder to two of the terminals, and the switch will function as an SPST on / off. In the pics below, that's what I've done. The SPDT is intended to switch between two different wires and a common, you see? But if nothing is soldered to the third terminal, it functions as an off switch.



Below is a closer shot of the terminals, lower center. I'm only using two terminals of the SPDT.


Solder up the switch in place where you want it, hanging out the rear side of the chassis. Leave enough wire to work with, but keep things short and tidy as possible. Then put the shell partway back on, sliding the toggle up from underneath to poke out the hole you drilled. Tighten the toggle down while the shell is still not fully assembled. Don't spin the toggle, or you'll twist the wires attached to it; hold the toggle and spin the nut tight. You can leave the locknut washer inside or out. You'll have to play with the switch to make it sit in the exact orientation you want.

I'm still experimenting on putting a resistor on the switch going to ground, to reduce the audible pop when switching from omni to cardioid. Anyone with ideas, let me know. Not a big issue, as I don't plan switching patterns on the fly, but it would be a nice feature to add on.
#49
29th April 2012
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Not to muddy the discussion, but I could also use some suggestions about which capsule might be suited to female vocals?

I'm confused by bits and pieces of discussions from other threads that bring up other capsule options for the SP-1 besides the RK-47 discussed in this thread.

This post by Jim Williams makes me wonder if the R-7 might be a better choice for female vocals? Good, cheap dark condensers

Then Kidvybes has brought up the KCM capsule in other threads. KCM 35mm LARGE DUAL DIAPHRAGM CONDENSER MIC CAPSULE CAP | eBay

Or just do the capsule being discussed in this thread?

#50
29th April 2012
Old 29th April 2012
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@2manyrocks;

My best guess is that the choice of capsule should be dictated by the circuit it drives. The SP1 guts are a variation of an old schoeps circuit. A good idea might be to dig up info on the original circuit design, and see what capsules were commonly used with that.

In your link, Jim says that R7 has a darker top end, a full low end and more body in the mids, compared to the RK47. For a female with a bright voice, that might be just the thing to use. You do want to match the freq response of a mic to the voice it's recording. If the voice you have in mind needs more support in the mids and lows, and less emphasis on the highs, the R7 sounds like a good choice.

So, hells yes, put an R7 in that mother! Then post some clips for us.

I can't get much info on the KCM capsule, so it's likely another Chinese factory product. Nothing on quality control, manufacture, etc. These may be seconds, or caps that haven't been subjected to rigorous QC testing. No way to tell without info on the factory they came out of. I'd stick to caps that have been vetted by the bulk buyers like Octavamod, microphone-parts.com, and others. These folks guarantee a level of quality, and can be reached for returns, replacements, or support. Of course, no way to know unless someone buys one of these KCMs and lets us know what they find.

I'm now planning to completely gut another SP1, and work over the PCBs wholesale, per Jim's suggested specs. I'll do an update to the thread when I can gather all the bits and pieces and get started.
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Quote:
Originally Posted by Boschen View Post
I can't get much info on the KCM capsule, so it's likely another Chinese factory product. Nothing on quality control, manufacture, etc. These may be seconds, or caps that haven't been subjected to rigorous QC testing. No way to tell without info on the factory they came out of. I'd stick to caps that have been vetted by the bulk buyers like Octavamod, microphone-parts.com, and others. These folks guarantee a level of quality, and can be reached for returns, replacements, or support. Of course, no way to know unless someone buys one of these KCMs and lets us know what they find.
...the K67 capsule being offered by KCM is a 35mm Feilo capsule with a 6-micron mylar diaphragm...I do not know if these are seconds (though I tend to doubt it), but I can tell you that this same capsule/metalwork can be found in microphones ranging from the Stellar, Advanced Audio, Gauge Audio, Peluso variety all the way up to some very pricey boutique mics (which I discretely hesitate to list)...I believe Microphoneparts is also sourcing their newer RK-7 from Feilo, probably the single largest capsule manufacturer in the world...so, while I can't vouch for the eBay seller's customer service, the origin of the capsule is one of the best in Asia...

Quote:
Originally Posted by 2manyrocks View Post
Not to muddy the discussion, but I could also use some suggestions about which capsule might be suited to female vocals?
...also, historically the C12-type (edge-terminated) capsule has most often been associated with female vocals/voicing, but as Boschen points out, the circuit feeding the capsule accounts for an important element in the mic's ultimate performance characteristics...
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Thank you both for your thoughts on this. I keep making mistakes by jumping into something before I understand it well enough. So your guidance is much appreciated.
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Thanks for the dope, KV!

I didn't see any mention that the caps linked to are from Feilo. I know that factory turns out caps for plenty of US companies. For years there have been smaller knock-off shops making imitations out of Shanghai as well, apparently using Feilo-trained staff and technique, but no real testing or QC. Like you say, those caps are probably not seconds, but at that price.... maybe some outfit bought ten pallets of caps from Feilo and needed to purge them.

If KCM does get their caps from Feilo, they should be on par with those found in the mic brands you mentioned.
However, KCM doesn't have a proper webpage, only myspace and facebook links, which to me is a red flag. I can't seem to get any real info on the company, their designers, or history. The links on their facebook page to their new store are dead links. There's no info on their supplier, as KCM claims to be the supplier and manufacturer. If these KCM guys are anything more than a clearinghouse, it doesn't show.
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Quote:
Originally Posted by Boschen View Post
I didn't see any mention that the caps linked to are from Feilo. I know that factory turns out caps for plenty of US companies. For years there have been smaller knock-off shops making imitations out of Shanghai as well, apparently using Feilo-trained staff and technique, but no real testing or QC. Like you say, those caps are probably not seconds, but at that price.... maybe some outfit bought ten pallets of caps from Feilo and needed to purge them.
...the 35mm K67 is now a stock capsule from Feilo/ShuaiYin (Shanghai) originally developed for Peluso (pic below right)...trust me when I tell you that even in very small quantities, that eBay seller is more than doubling his money at those prices...KCM generally sells components that appear to originate from Feilo (possibly diverted product)...check out the Advanced Audio AK67 (pic below left) on this site link, retailing for $75...same capsule (more than a few capsules pictured on this page are originating from Feilo, and others, like the RK47 and RK12 from Ningbo Shengke/TongXin)...

Large-Diaphragm Microphone Capsules
Attached Thumbnails
MCA SP-1 Mod Procedure-advanced-audio-ak67.jpg   MCA SP-1 Mod Procedure-peluso-cek367.jpg  
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Thanks KV!

...informative link

I've been impressed with my Shengke capsules from microphone-parts, so I'll probably be trying out one of the Feilo ones for comparison...

I wonder why we can't produce these products here in the US; the labor can't be that intensive for items like this, and we certainly have access to the best test equip, laser interferometry, testing chambers, etc. The prices for those items have gone down, to some degree, but still no love for a US manufactury. ...

props to Kelly; at least he seems to be trying... a bit further North...

BTW, to all; I updated the schemo in the earlier post to one from the page link below, that matches the PCB layout; one less mental backflip to perform...
Thanks to legato for the link:
http://www.nvrecording.nl/nhc/AudioT...ds/mods_en.htm
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Here's an interesting tidbit for us solder junkies; the original Schoeps circuit...
See the two pots? One for the fet and another for adjusting U8, whatever that is. Something to do with the electrical balance of the circuit?

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Quote:
Originally Posted by kidvybes View Post
...

...also, historically the C12-type (edge-terminated) capsule has most often been associated with female vocals/voicing, but as Boschen points out, the circuit feeding the capsule accounts for an important element in the mic's ultimate performance characteristics...
I emailed Microphone parts. Their suggestion is to use their RK12 for a female singer with good balance and tonality. For a female singer who is siblilant, they suggested the RK-7.
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Quote:
Originally Posted by 2manyrocks View Post
I emailed Microphone parts. Their suggestion is to use their RK12 for a female singer with good balance and tonality. For a female singer who is siblilant, they suggested the RK-7.
...good advice!...
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Quote:
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I emailed Microphone parts. Their suggestion is to use their RK12 for a female singer with good balance and tonality. For a female singer who is siblilant, they suggested the RK-7.
Nicely done!
Different capsules make for differing flavors; with this mod, you can pick your own.

I've been piecing together the next set of SP1 mods, based on info from Jim Williams' and Jim Jacobson's posts. They have been kind enough to share their knowledge in the past, but it would be nice to have a post that gathers all that info into a complete process.

Coming up, the more complicated mods, replacing more caps, transistors, resistors, and other fun.... I have another SP1 on the way, and another capsule, and I'm going to gut this mofo... we can rebuild him...
we have the RK47... he will be better... faster.... cheaper....
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Lads, we're in deep now. Below is the list I've assembled for the full mod suite. This is no pussywillow hack; we're going to strip the mic down to the PCBs, take off a load of components, stuff the naked boards with new bits, clean it up, then put it back together. Then hopefully we can use it!

This is a work in progress; the BOM and process below are still unconfirmed until I've completed a full mod myself using them, so these will be subject to edits and changes. Please don't hesitate to contribute! Most component values are drawn from Jim Williams' comments in other threads, where he generously shares info on his mods, as does Jim J. Additional info comes from the Dutch page linked to earlier in the thread, which also provided the SP-1 schematic. Thank you to Jim Williams, Jim Jacobson, and nvrecording.dl!

There's still a puzzle piece or two to fit in here. Besides simply replacing the original components, we can get better results if we do some fiddling with the electrical balance of the circuit.
Remember the OP? (Maybe he'll pop back in someday…)
Look at 3 & 4 on Cooney's original mod list;

"3) Replace the 2 1n4148 diodes with UF4001's

4) Replace the 6.2v zener diode with either a 7.5v or 8.2v zener diode- check DC converter voltage at the UF4001's and try to achieve ~60vs" Cooney, OP

And then digest this acorn from Jim W.;

"…I up the polarization voltage from 40 to 57 volts which increases output by around 5 db..." Jim Williams.

Ok, we're trying to get more current to the mic capsule here. Why? This will increase the output, according to Jim. And here's another clue; look at the old Schoeps schematic… see the two pots in the circuit? (P1, P2). The symbol is like a rectangular resistor with a diagonal line through it. There's one pot by what could be an output transistor, and another by the resistor off the FET, R1. WTF! Why do we need a pot there? It's to change the way the current flows! The pot is just a variable resistor, right? So we can change the values of resistance at those two points in the circuit, changing the way the circuit behaves, and balancing the response of the mic. Holy shit!

Now, this feature doesn't seem to have been incorporated in the modern mic designs that copy this circuit. Our Dutch connection suggests finding the ideal balance point using a pot, measuring the value, then replacing the pot with a fixed resistor, or set of resistors of exact equal value. The process is described here:

http://www.nvrecording.nl/nhc/AudioT...ncemike_en.htm

Mod-masters like Jim seem to be using fixed resistor values which they have tested and found to work on this circuit. Changing the zener diodes is probably a part of that as well. I'm still in the process of working out that element of this mod. Anyone with more knowledge, please share! I think it's more valuable to understand why we are making changes, rather than blindly following a list.

Remember, this mod, and the BOM, have not been tested; I'm documenting this so others can learn from my mistakes, as I make them.
Now, let's mod…

SP-1 Slutz Mod BOM: BETA

THIS LIST IS UNCONFIRMED
Confirmed items will have an asterisk added *
Mouser / Digikey links pending.
PLEASE CONTRIBUTE! ... and point out my errors...

Film Capacitors:
>1 x polystyrene or polypropylene .001uf --- use MIT MultiCap
>1 x 100 uf Panasonic FR cap
>2 x 330 uf Panasonic FR caps

Electrolytic Capacitors: --- use Nichicon or Panny
>2 x 330n cap
>4 x 22n cap
>2 x 1n cap

FET / JFET:
>2 x JFET bipolar transistors Hitachi 2sa1083's, matched
>1 x FET fast J305 Siliconix

Diodes:
>7.5v or 8.2v zener diode
>2 x UF4001 diodes

Resistors:
>2 x 1 gig ohm resistors --Mini Mox 200 metal oxides

Resistors, Vishay/ Dale CMF55:
>2 x 2k2
>2 x 150k
>2 x 150 ohm matched pair
>1M
>750k
>270k
>250k
>6k05
>1k5


SP-1 Slutz Mod, Process:

Replace capsule to FET cap:
>Replace C13 capsule to FET cap
with polystyrene or polypropylene .001uf --best- MIT MultiCap

Replace JFET bipolar transistors:
>Replace he bipolars T1,T2
with Hitachi 2sa1083's, matched pair

Replace the FET:
>Replace T3, the 2sk170 FET
with a J305 from Siliconix

Replace Resistors:
>Replace R8, R9 1 gig ohm
with Mini Mox 200 metal oxides
>All other resistors to be Dale CMF55's
>R1, R2 replacements MUST be matched pair 150 ohm .5%

Replace ceramic caps with nice film caps:
>Change 47 uf 50v cap to a Panasonic FR series, 100 uf.
>Change 220 uf caps to 330 uf Panasonic FR's.
>The ouput caps (C3 and C4? Or is it C1 & C2?) are enlarged to allow 20 hz to pass and are bypassed with more MIT caps.
(From the Dutch Mod) - Replace C3, C4 each by, or connect 4,7u/63V electrolytic (NO tantalum) capacitors in parallel (the + wires connected to the bases of T1 en T2).

NEED CLARIFICATION ON ABOVE ITEM

Replace electrolytic caps:
>Replace with Panny FM electrolytics or Nichicons

Replace semiconductors:
>Change the 2 1n4148 diodes to UF4001's
>Change the 6.2v zener diode to either a 7.5v or 8.2v zener diode
>Check DC converter voltage at the UF4001's, look for ~60vs"




Ok, still a lot of shit to figure out here... the current balancing process, and which output caps to replace. There are also a few items I haven't put on the mod list process, which I've seen mentioned in other threads, such as removing certain resistors, and other things.

I'm assembling all the above components, so I can document the process of the Slutz Mod as I perform it. I mostly buy from a local supplier, but I may have to order certain bits they don't stock; I'll add purchase links as I find them, or as others contribute.
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