I copied most of Jim's posts in this thread for reference, but I'm not going to repost them if he's deleting them himself. He's shared generously with this board, giving far more than we ever gave back. For whatever reason, he's decided to pull back some of those contributions. That's his business; I'm sad about the loss of a respected contributor round these parts.
Got an email from Matt at Microphone parts that the 990 kit is already out. The SP-1 kit is expected to be available Oct 15. I understand there will be a price break for buying the capsule and the kit.
Yeah, not sure what the exact reason was for removing the old posts. I would prefer to see Jim continue to contribute, and I think we can encourage that by embracing this new mod.
After all, we're the target market, and while some will continue to mod on their own, others will prefer the safe path of a proven and tested kit project. I think that will include many posters to this thread. I plan on ordering the kit myself.
Funny, just after posting the link last eve, had an announcement email from microphone parts.com in my email. We're actually spreading the word ahead of the manufacturers campaign.
It will be a treat not to have to scour the bins in my local electronics supply shop, though I know I'm lucky to even have a real one near me. Instead I can get the new capsule and kit all in one. I know this will also put the mod in reach of others who wouldn't otherwise try it out.
Looking to see a revival of this thread...
Whoever gets the new kit in hand first, please report back here on your results.
Choosing between the basic kit ($49) and the advanced kit ($99) might be a good topic for discussion. The opportunities for mixing and matching just got expanded quite a bit given the choice of capsules, too.
I'm curious to see how successful the kit instructions are in making the mods a solder by the numbers matter for folks like me who ain't got a clue about the internals of the mic.
Whoo hoo! Just ordered a stereo pair of the basic kit with 47's for 2 of my 990's. When the SP-1 kits are ready I may go for the 12's or 67's with the advanced kit next time around depending on the difficulty of the first set as I am just getting back into electronics after many years.
Thanks for this thread guys!
Ok, so I ordered the kit(s) Monday, it shipped Tuesday and arrived today. That was fast, but then I am just a couple counties away from MP in northern California.
The instructions are detailed with pictures. I got the basic version of the kit(s) with RK-47 capsules. The basic kit includes 4 WIMA caps (2x .68 and 2x .01), 1 diode (no spec mentioned) and one 0 ohm resistor (jumper can be used instead), backplate lead wire, mount and screws.
The most difficult part was disassembly; pulling parts off and keeping holes clear of solder after part removal (even with a solder sucker). I only felt like I had a couple questions along the way but they were answered by looking at pics on their installation guide page (how to attach the backplate lead to the capsule for example).
Getting the capsule on the mount was a bit of a trick too getting the screw holes properly aligned. Basically it is best to start a thread of one screw then the second before completely tightening. I probably spent about 2 1/2-3 hours total from start to finish on the first mic.
The booklet has the user start with disassembling the mic body in detail, then part removal and replacement (C3 and C4 get replaced by the .68 caps with the .01's paralelled at their connections under the PCB, the diode replaces D3, R1 is replaced by the 0 ohm resistor or a jumper wire and the cap on the underside of the PCB is removed, then finally swapping the 2 & 3 pin connections for the XLR), then capsule replacement (though the booklet shows the RK12 capsule which is one reason I had some minor issues in my head only) and even the headbasket and caulk mods. Plus a suggestion to paint the body.
Not really concerned with the caulk in the body yet but I had removed the mesh layers in prep for this a while ago.
So I plugged her in (as suggested before removing extra component leads to be sure things work) and sure enough it worked! I grabbed an unmodded 990 for comparison. I recorded just a couple takes of VO to test and read some dialogue through both 990's and an AKG C 3000 (original, not the B) that I have at home (I have a couple U 87ai's at my "office" which I intend to compare as well). Compared to the stock 990 there is more of everything. The stock mic sounded hollow and fuzzy compared to the mod. The mod sounds more natural and up front. You need to get right up on it for any real plosives or sibilance. Not so for the AKG which is chock full of pops. There is more pronounced low end on the AKG which almost sounds hyped when compared to the modded 990. The RK47 seems to have a good upfront midrange with natural sounding top and bottom. The mod definitely made the mic better, but not certain that it can out class a Neumann. Definitely useable though.
I have another 990 (3 total) and 4 SP-1s that will get this treatment.
The advanced kit has more parts and allegedly can extend the low end a little more so I may go that route in the future. I got my 990's years ago for around $60 per and I got the SP's for $40 per so I am still around $200 per mic including the upgrades when all will be said and done. I can't complain about making mics I wasn't using viable and useable. Not to mention doing the work was fun.
I wish the kit were a little more instructive as to what the components swapped/removed affect in the circuitry but aside from that if you can work a soldering iron and have a basic understanding of electronics the kit is fairly ideal and easy enough.
I think MP would be smart to include a label with their kits that could be put on the mic body indicating which mod has been performed. That would help keep track of which mic has which mod and could be good advertising for MP, too. I have no plans to paint mine.
Removing the old components would seem to be the more difficult part of the whole job.
I modified mine but it doesn't sound quite "right" so I'm hoping Jim Williams will chime and tell me what I can add/do to make it as it should. Here's what I did:
Replace the 2SK170 (T3) with Siliconix J305
Replace the 2N5401 output transistors with Hitachi 2SA1084's (T1 & T2)
Replace 1G ohm resistors with Mini Mox metal oxides (R9 and R10)
Replace the 150 k resistors with 100 k Dale CMF55 (R3 & R4)
Replace the 2.2 k resistors with Dale CMF55 (R6 & R7)
Replace the .33uf output caps with 1uF stacked mylar (C3 and C4)
Replace 47uF/50V capacitor with Panasonic FR 100uF/50V (C5)
Replace 220uF/25V capacitor with Panasonic FR 330uF/25V (C6)
Replace high frequency roll-off capacitors with 470pF mono ceramic (C14 and C15)
Should I bypass the electrolytic capacitors? If so, what should I use? Should I replace the ceramic cap feeding the capsule with something else?
EDIT: holy crap, missed the post by Jim W! That photo is gold; thanks so much for sharing, Jim! We truly appreciate your input in the thread, and it's great to see your mod work.
I've been busy with some design/install, so hadn't had time to crack my mic open again for another round of mods. Sorry I hadn't had a chance to check back in earlier. Your post clarifies a couple of points for me, like why I'm now getting apx. 12.5 V at the FET, lol. As usual your posts spark new questions as well.
Here are some shots of the latest I've done, below. I'm using teflon silver wire, beefier caps, new zeners and better electrolytic caps. I'm using the schemo below, which I've revised to correspond to the markings on the SP1 boards. It's from Jim G., Zapnspark, at the Yahoo micbuilders boards, which I recently joined. I encourage others to do so as well; very informative. Let me know if you find errors in my revisions, anyone. The circled figures in pencil are my troubleshooting notes.
EDIT: Damnit, I had an EQ and a Limiter in the chain when I took those measurements. They are useless, well except for the Jabberwocky recitation. If I leave the same settings for the after test then at least it will give some sort of picture of whats going on.
Here is some before information:
As you can see my room is not even close to perfect. The Nady CM100 was included to try to take the room out of the equation.
I think it's odd (perhaps I made a mistake or there is some sort of phase issue) that the CM100 has a similar frequency response to one of the SP-1s and the other two SP-1s are similar to each other but different from the "test" mic.
FYI the CM100 is a cheap calibration microphone that is supposed to have very even response.
The audio files are me reciting from the Jabberwocky. I thought that it would be easier to do an after with that bit since I know it so well.
Singing would have been harder to recreate a similar scenario.
Let me know if you guys have any advice. I hope to do the mods this weekend...
I finished my first attempt. I got a loud feedback sound. Then I realized that I connected the capsule to the wrong leads. When I wired it correctly I get a very quiet hiss and periodic clicking.
I ordered the basic mod kit with RK47 capsule a couple of weeks ago and received it very quickly. I can't say enough good things about Matt at Microphone Parts. He is very helpful and responds very quickly to emails.
I finished the mod but I am getting a low frequency buzz that increases with volume whenever I test it with the SP1 capsule. Tried to troubleshoot some potential problems and check the solder joints but everything looks like it's set up okay. Back to the board. I guess it's better to gain the knowledge of troubleshooting something to get better than it is to have everything work on the first time.
I ordered the basic mod kit with RK47 capsule a couple of weeks ago and received it very quickly. I can't say enough good things about Matt at Microphone Parts. He is very helpful and responds very quickly to emails.
I finished the mod but I am getting a low frequency buzz that increases with volume whenever I test it with the SP1 capsule. Tried to troubleshoot some potential problems and check the solder joints but everything looks like it's set up okay. Back to the board. I guess it's better to gain the knowledge of troubleshooting something to get better than it is to have everything work on the first time.
Same here on both counts. Matt is great and very responsive, but I think that there is something wrong in the instructions because I have done the mod twice and had the same result both times. He told me that he is in the process of rewriting them.
I found that it was easier to remove the wires from both PCBs then remove all of the components that need to be replaced and work from the center of the board out (so you have more room to work).
EDIT: is the low frequency buzz sound that you are getting similar to the attached M4A file?
Same here on both counts. Matt is great and very responsive, but I think that there is something wrong in the instructions because I have done the mod twice and had the same result both times. He told me that he is in the process of rewriting them.
I found that it was easier to remove the wires from both PCBs then remove all of the components that need to be replaced and work from the center of the board out (so you have more room to work).
EDIT: is the low frequency buzz sound that you are getting similar to the attached M4A file?
Hey Grovestand! Glad to know that someone else is in the same boat I am.
Yes, the sound file you attached does sound like the buzz I'm receiving but it's not phasing as much as yours. What's interesting is that I placed my thumb on the prongs where the audio input coupler capacitor was and the buzz went away. I'm wondering if I should solder this back on. All my solder joints are perfect and all wiring is up to par. Have you attached the stock capsule to the board and tested to see if audio is coming through? I am able to hear my voice but it is accompanied by the low buzz. Hmmm.
Hey Grovestand! Glad to know that someone else is in the same boat I am.
Yes, the sound file you attached does sound like the buzz I'm receiving but it's not phasing as much as yours. What's interesting is that I placed my thumb on the prongs where the audio input coupler capacitor was and the buzz went away. I'm wondering if I should solder this back on. All my solder joints are perfect and all wiring is up to par. Have you attached the stock capsule to the board and tested to see if audio is coming through? I am able to hear my voice but it is accompanied by the low buzz. Hmmm.
The phasing happens when I turn on/off the phantom power. I was nervous to leave it on for any length of time, but it doesn't phase once its gotten to full volume. I did hear some audio at one point, but i couldmt tell whether it was just clicking or what. Couldn't hurt to try putting that cap back. I hadn't thought of that!
I emailed all of this to Matt as well. I'm sure that he will help when he has some time. Please let me know if you find a solution that works.
This is an instance in which Mr. William's absence is very much missed to sort out what's going on.
Kinda worrisome from a buyer's perspective to hear there's something yet to figure out. I mean, the idea of buying the kit, is so one doesn't run into problems doing the mods.
Probably not a good guess, but neither of you guys overheated anything soldering in your mods? I didn't see any obvious overheating in the pictures.
This is an instance in which Mr. William's absence is very much missed to sort out what's going on.
Kinda worrisome from a buyer's perspective to hear there's something yet to figure out. I mean, the idea of buying the kit, is so one doesn't run into problems doing the mods.
I don't think that buying one of the kits, and using it to guide one's own mods for other mics is unethical. Perhaps, that will get a buyer out of a jam?
This is an instance in which Mr. William's absence is very much missed to sort out what's going on.
Kinda worrisome from a buyer's perspective to hear there's something yet to figure out. I mean, the idea of buying the kit, is so one doesn't run into problems doing the mods.
Probably not a good guess, but neither of you guys overheated anything soldering in your mods? I didn't see any obvious overheating in the pictures.
Mat has contacted me and pointed out a few points where the flux may be concealing some traces of solder.
I just started a new job but as soon as I have a minute of free time I am going to clip the leads and scrub the board.
I am a novice and I will say that I wish I had done a few simpler projects or kits first.
It is not difficult but there is a lot that I don't know.
He didn't seem to think that it was likely that it was a design problem.
I ordered the basic mod kit with RK47 capsule a couple of weeks ago and received it very quickly. I can't say enough good things about Matt at Microphone Parts. He is very helpful and responds very quickly to emails.
I finished the mod but I am getting a low frequency buzz that increases with volume whenever I test it with the SP1 capsule. Tried to troubleshoot some potential problems and check the solder joints but everything looks like it's set up okay. Back to the board. I guess it's better to gain the knowledge of troubleshooting something to get better than it is to have everything work on the first time.
I may be getting confused, but I took it from this that the buzz came about with attempted use of the kit?
I can't imagine there's a design problem with the kit. Mr. Williams is too much a perfectionist to let that happen.