mxl v67 mic mods?

[changeng]

can someone point me in a direction to get a v67 modified and if you know, what are the differences before and after?

thanks!

[Minion]

There are a Few Mods that you can do to that Mic,

You can do a Simple Capacitor mod which means changeing all of the Capacitors to Low leakage types of the Electro"s and bypassedwith High quality Poly"s....thit mod tends to produce a much richer low end and a crisper less brittle high end.....

The other mod you can do is a Capsule Mod which is to change the Condenser Capsule, there are many capsules you can use for this Mod, a Common one is to use a Peluso capsule which will give a dramitic increase in sound quality....

The last mod is to do a Transformer mod which also increases the signal output and give a much warmer sound, a Common transformer to use for this mod is a Cinemag or a Lundahl......

I know someone who you can send your mic to who will do any or all of these mods to your mic...His name is Dave Thomas and he lives in Vancouver BC Canada, and he has modded probably hundreds of mics but I warn you that these mods can be quite expensive, probably as much or more than what you paid for the mic it"s self......

If you PM me with your e-mail address I can send you the Contact info for him.....
I could probably easilly do the Capsule and Capacitor mod but not the Transformer mod unless I had a wireing diagram.....


If you got the Peluso capsule and the Cinemag transformer and the Capacitor mod it would be a Totally different mic...It wouldn"t sound like a $200 mic anymore it would sound like a $2000 mic and would be a Fully Pro piece of equipment.....


Cheers

[Docmattic]

do you know where to find tutorials on doing this yourself?

[Jim Williams]

Replace the input cap off the capsule with a MIT .001 uf PPMFX. Replace the jfet with a J305 from Siliconix. Replace the electrolytics with Panasonic FM. Bypass the signal electrolytics with a Wima .01 uf MKP-2.

Jim Williams
Audio Upgrades

[kriista]

I'm with docmattic on this one,

is there a tutorial for this sort of thing,

ive done my share of soldering and the like, but recapping and mods are something beyond my understanding

i have a v67m that ive been looking to upgrade (dont want to do the dorsey mod though), by upgrading just components and not gutting the whole thing

knowing where to get the parts would be a big help too

thanks

Rodrigo

[Docmattic]

yeh ^^ thats what i was thinking....

is it very involved or quite basic?

[craigmorris74]

Replacing the caps is easy. You might just have to be creative about how you bend them, as sometimes the replacement caps are larger. The Peluso capsule should be easy enough to wire in, just make sure that you write down how the orginal capsule was wired. The transformer replacement might be the trickiest thing. Somtimes it's best to silicone glue the replacement in the original transformer housing.
If you have decent soldering skills all this won't be too bad. Just make sure you don't have to keep unsoldering components, as the PCB trances will eventually lift.

Here's what I'd do:
Replace the caps first. You might find that mic suitable after that. It will change the sound significantly.
Then try to replace the capsule. The newer 67 capsules MXL used have been dodgy.
Finally, replace the transformer. The stock transformer isn't too bad, but a Cinemag will be better.

Craig

[kriista]

What kind of impact does changing the transformer have?
or relamming it for that matter?

i read , i believe on the prodigy-pro forum that relaming or changing the transformer could actually have a detrimental effect on the v67 due to the quirky way it was designed (im paraphrasing from memory here)

im definately looking to recap mine, and i was entertaining relamming(to be honest, i dont even know what that means yet), or changing the transformer, until i read what i mentioned above at the prodigy-pro forum

[ulysses]

If I were going to modify a V67, I would dig out the back issue of Recording Magazine (what was, it, Sept 2002? I don't remember) and read Scott Dorsey's article about the V67. It is a tutorial on how to modify the V67 into a useful microphone. His mod involves removing the output transformer and the original circuitboard and replacing them with a circuitboard of his design, which uses an elegant circuit he calls The Schoeps Circuit because that's where he first saw it. There are two transistors and one FET in this circuit, it's very elegant and simple. You can make your own circuitboard using his layout, have a circuitboard made for you, or buy one from him (I don't know if he still has any left, but knowing him he probably has hundreds). The information is all in the article.
I went to Mars Music (rest in pieces you rat bastards) back at that time to buy a pair of V67s with the intention of performing these mods. But instead of V67s, they had a bunch of V57s which, lo and behold, already had basically this circuit installed in them. Apparently Scott had sent this suggestion to MXL and suggested they improve their microphones (and save money) by getting the terrible and inconsistent transformer out of there. They heeded his advice at almost exactly the same time his article ran in Recording. So if you go to the store and look at any of these Shanghai mikes (of any brand), be sure to unscrew the body and have a look at the circuitboard. My V57s also have a 2nd circuitboard with a DC-DC converter to raise the capsule polarizing voltage, but other than that the circuit is pretty much the same. I haven't gotten around to upgrading the components yet, but I think even with crappy components the circuit is much better than the V67's. On the other hand, some people like the stock V67's fuzzies on some vocals.
So call up Recording and get them to find the back issue with this article in it, and pay the $6 or whatever it is for a copy. Two months prior to this issue, Scott wrote another article about cheap condenser mike electronics in general. Read these two articles and you'll learn a lot. Don't ask Scott to send you a scan of the article though, he won't. Buy the back issue and encourage Recording to keep publishing this good stuff!

[kriista]

ok, after a few hours research heres what ive been able to dig up:

cinemag doesnt offer a drop in transformer replacement
but you can order laminate samples and just do it yourself

i have a part# , but i lost the link, ill edit it in once i find it


im still fuzzy on the recapping portion of the upgrade as most peoples suggestions are geared to people who know what theyre talking about (i dont)

for example, i dont know what this means

"You can do a Simple Capacitor mod which means changeing all of the Capacitors to Low leakage types of the Electro"s and bypassedwith High quality Poly"s...."

low leakage types?, bypassed with poly's?

or

"Replace the electrolytics with Panasonic FM"

panasonic FM?,


i think the v67 is a target 1st mod for alot of people, and its a hard nut to crack into(modding mics),
perhaps someone whos done the recapping mods could post part #s or something more concrete that i can call a company up with to order

the closet thing to that i found on some other board and goes as follows:

(i didnt copy/paste the author of the posts name, so appologies in advance for not citing it)

OK. For this you will need:

1) 1000pF polystyrene capacitor
1) .47nF Metal Film, metalized Polyester, or good film capacitor.

Do NOT use ceramic or tantalium caps!!

If you open the mic, you'll see it has 2 circuit boards, back to back. Unscrew the board that does NOT have the leads from the capsule soldered to it. Carefully move it to the side trying not to pull two hard on the wires that connect it to the other board. On the back of the other board, you will see a spall capacitor mounted to the stand-offs for the capsule. Replace this one with the 1000pF polystyrene.

(the author suggested .22nF at first, but a few other people suggested .47 after and he agreed)

i also read that lining the inside of the body with leukoplast tape reduces some of the resonance of the body itself
seems like a simple enough non electrical mod

, so thats all i was able to find out so far, not very definative

im also curious as to the jfet mod mentioned a few posts earlier, thats the first time i saw a non dorsey/royer recapping/relamming suggestion
is that just a quiter component?


rodrigo

[Minion]

Originally Posted by kriista

im still fuzzy on the recapping portion of the upgrade as most peoples suggestions are geared to people who know what theyre talking about (i dont)

for example, i dont know what this means

"You can do a Simple Capacitor mod which means changeing all of the Capacitors to Low leakage types of the Electro"s and bypassedwith High quality Poly"s...."

low leakage types?, bypassed with poly's?

or

"Replace the electrolytics with Panasonic FM"

panasonic FM?,

rodrigo

The Capacitor mod is basicly just replaceing all (Or most) of the Capacitors with high quality Capacitors.... The Panasonic FM Caps are High quality low leakage Electrolytics so these would be a Good choice for replaceing the Electrolytics....

Bypassing Caps is just putting another cap in Paralell with the first cap but to add these were there weren"t any before would be a bit too tricky for a Newbie DIYer and if you use a Good Cap in the First place then there should be no need to bypass it so you shouldn"t really have to concern yourself with that.....

Basicly you would open up the Mic and Look at all of the Capacitors and write down all of the Values of the Caps and there Type( ceramic, Poly, Electrolytic ect) and then buy the same Value caps but high quality ones and maybe replace the Ceramics with Poly or metal film caps.....

If this is your first foray into doing something like this it would be good to have someone help you that has some Knowledge because if this is your first time useing a soldering iron and trying to mod something you will risk ruining your mic...



Good luck

[kriista]

Thanks for the info..

I'm fairly comfortable with a soldering iron, having built several highly complicated kits before (a theremin, and 2 kittennettik kits from ciat-lonbarde :
******//www.ciat-lonbarde.net/kittennettik/index.html )
and circuit-bending for like 8 years, its just the 'legit' type electronics theory/stuff that is beyond my understanding.

With the values/types of the caps, if I call up a place that deals with hi-fi type stuff, would they be able to suggest/offer the appropriate replacements)

(im going to see if theres a hi-fi shop in town that I can go to in person)

I've read in a few places that changing caps for a 25% higher value is something to do to avoid creating, or removing any exsisting HPFs.

So swapping out exact values, for just better quality parts is the way to go here then?


Again, thanks for the suggestions etc..

rodrigo

[Minion]

You should keep the same values , even though beefing up the Caps on the Power rails can be of benefit but without knowing which ones these are it is best to keep everything the same value....

I suppose some High Fi Audiophile type places might supply high quality caps ,You might even try a Big Electronics supply place and see what they have....I buy most of my parts off of e-bay as it is about 1/10 the price than what I pay at my local electronics shop.....

You can buy all the caps you need online from Mouser or Digikey ,Look for "Audio grade" capacitors...
Wima are popular caps for the Polly caps and you can probably replace most all of the ceramic caps with Poly caps and use the Panasonic FM or other low leakage/ESR caps for the Electrolytics.....

Cheers

[Jim Williams]

Originally Posted by ulysses

If I were going to modify a V67, I would dig out the back issue of Recording Magazine (what was, it, Sept 2002? I don't remember) and read Scott Dorsey's article about the V67. It is a tutorial on how to modify the V67 into a useful microphone. His mod involves removing the output transformer and the original circuitboard and replacing them with a circuitboard of his design, which uses an elegant circuit he calls The Schoeps Circuit because that's where he first saw it. There are two transistors and one FET in this circuit, it's very elegant and simple. You can make your own circuitboard using his layout, have a circuitboard made for you, or buy one from him (I don't know if he still has any left, but knowing him he probably has hundreds). The information is all in the article.
I went to Mars Music (rest in pieces you rat bastards) back at that time to buy a pair of V67s with the intention of performing these mods. But instead of V67s, they had a bunch of V57s which, lo and behold, already had basically this circuit installed in them. Apparently Scott had sent this suggestion to MXL and suggested they improve their microphones (and save money) by getting the terrible and inconsistent transformer out of there. They heeded his advice at almost exactly the same time his article ran in Recording. So if you go to the store and look at any of these Shanghai mikes (of any brand), be sure to unscrew the body and have a look at the circuitboard. My V57s also have a 2nd circuitboard with a DC-DC converter to raise the capsule polarizing voltage, but other than that the circuit is pretty much the same. I haven't gotten around to upgrading the components yet, but I think even with crappy components the circuit is much better than the V67's. On the other hand, some people like the stock V67's fuzzies on some vocals.
So call up Recording and get them to find the back issue with this article in it, and pay the $6 or whatever it is for a copy. Two months prior to this issue, Scott wrote another article about cheap condenser mike electronics in general. Read these two articles and you'll learn a lot. Don't ask Scott to send you a scan of the article though, he won't. Buy the back issue and encourage Recording to keep publishing this good stuff!

Or just buy a Marshall 2003, it has this circuit. Or better yet, get the MCA SP-1 for $39.99. It has the schoeps style circuit and that nice smooth 20 mm capsule, ripe for upgrades.

Jim Williams
Audio Upgrades

[kriista]

ok, heres the info on the lam samples

call Mag Metals (1-800-257-8174) and order some samples of:

#2425EE8414

which is this:

Part Description: 2425 EE
Grade/Gauge: 8414
Quality: Superperm

(again, pulled from another board)

havent gotten them so ill report back when i do

im also trying to put together a definate mod guide with sound samples at each step since its been so hard to find all the info in one place

not an every option you can possibly do, but just the relam info, and cap changes with specific part #s to order etc..

ive never messed with a transformer so thatll be exciting, theres apparantly pics over here on the homerecording board, but i still havent gotten my email responses so i can post/view pics on that forum (and its been over a week)

(about halfway down the page theres some pics linked)

******//homerecording.com/bbs/showthread.php?t=124563

if someone can repost those pics here, or elsewhere that would be much appreciated

[jeff deff]

I've been doing some research on modding a v67g too. I really like the general tone of this mic for vocals but the high end, around 7k or so I'm guessing, sounds distorted. For instance sibilant consonants, like the letter "s", will sound more like a cat hissing. They lack definition. This trait earned the mic the nickname "the green dragon", because the singer described this high end distortion as sounding "scaly".

I did an extensive blind mic shootout with a singer and we picked the V67G unanimously. It definitely has a magic to it, something that causes you to fall in love in the short term.... After tracking the record though, we started to notice that this high end distortion, though subtle, became very grating and distracting.

My question, to those who have experience with mods, what element of the mic would be the biggest cause of this distortion? Is it the capsule? The FET? The caps? The transformer? I want to keep the general tone of the mic intact, but just clean up this high end grit.

I've read that the design of the grill on this mic has a big effect on the character of the sound. Also, it seems to me that the transformer plays a big part. What elements should be left alone to keep the general character intact?

Thanks to all those on this board who are so generous with their knowledge.

[alba359]

I did a search for MCA SP1 microphone. It has been discontinued.

[Jim Williams]

Pro Sound Stage and Lighting in Cypress, CA has another batch of them for $39.99.
1-800-945-9300
Get 'um while you can!

Jim Williams
Audio Upgrades

[Brent Casey]

Originally Posted by ulysses

If I were going to modify a V67, I would dig out the back issue of Recording Magazine (what was, it, Sept 2002? I don't remember) and read Scott Dorsey's article about the V67. It is a tutorial on how to modify the V67 into a useful microphone. His mod involves removing the output transformer and the original circuitboard and replacing them with a circuitboard of his design, which uses an elegant circuit he calls The Schoeps Circuit because that's where he first saw it. There are two transistors and one FET in this circuit, it's very elegant and simple. You can make your own circuitboard using his layout, have a circuitboard made for you, or buy one from him (I don't know if he still has any left, but knowing him he probably has hundreds). The information is all in the article.
I went to Mars Music (rest in pieces you rat bastards) back at that time to buy a pair of V67s with the intention of performing these mods. But instead of V67s, they had a bunch of V57s which, lo and behold, already had basically this circuit installed in them. Apparently Scott had sent this suggestion to MXL and suggested they improve their microphones (and save money) by getting the terrible and inconsistent transformer out of there. They heeded his advice at almost exactly the same time his article ran in Recording. So if you go to the store and look at any of these Shanghai mikes (of any brand), be sure to unscrew the body and have a look at the circuitboard. My V57s also have a 2nd circuitboard with a DC-DC converter to raise the capsule polarizing voltage, but other than that the circuit is pretty much the same. I haven't gotten around to upgrading the components yet, but I think even with crappy components the circuit is much better than the V67's. On the other hand, some people like the stock V67's fuzzies on some vocals.
So call up Recording and get them to find the back issue with this article in it, and pay the $6 or whatever it is for a copy. Two months prior to this issue, Scott wrote another article about cheap condenser mike electronics in general. Read these two articles and you'll learn a lot. Don't ask Scott to send you a scan of the article though, he won't. Buy the back issue and encourage Recording to keep publishing this good stuff!

Hello all,

I would like to correct a statement made here regarding Scott Dorsey and his involvment with MXL: While working with MXL I did speak on several occaisions with Scott during the time in and around his magazine tutorial ran. However, Mr. Dorsey had absolutely no influence one way or the other regarding MXL mic circuit topology.
Furthermore, from examining the "Dorsey mod" as it is shown in the magazine article, it is very likely that any mic equipped with this circuit would be prone to distort assymetrically at far lower SPL levels than would be acceptable for a production microphone.

Sincerely,

Brent Casey
PMI Audio Group
877-563-6335

[Brent Casey]

Originally Posted by jeff deff

I've been doing some research on modding a v67g too. I really like the general tone of this mic for vocals but the high end, around 7k or so I'm guessing, sounds distorted. For instance sibilant consonants, like the letter "s", will sound more like a cat hissing. They lack definition. This trait earned the mic the nickname "the green dragon", because the singer described this high end distortion as sounding "scaly".

I did an extensive blind mic shootout with a singer and we picked the V67G unanimously. It definitely has a magic to it, something that causes you to fall in love in the short term.... After tracking the record though, we started to notice that this high end distortion, though subtle, became very grating and distracting.

My question, to those who have experience with mods, what element of the mic would be the biggest cause of this distortion? Is it the capsule? The FET? The caps? The transformer? I want to keep the general tone of the mic intact, but just clean up this high end grit.

I've read that the design of the grill on this mic has a big effect on the character of the sound. Also, it seems to me that the transformer plays a big part. What elements should be left alone to keep the general character intact?

Thanks to all those on this board who are so generous with their knowledge.

Hi Jeff,

The "biggest cause" of distortion in the V67 is the PNP emitter follower that buffers the FET.

-Brent Casey

[Wavebourn]

Hi Brent;

thank you for your comments!

Can you tell what weak points has MXL 770 that may be fixed by modifications?

I did not open it yet, but it seems to me it has some kind of equalization on high end against impact of an input capacitance of the FET that causes distortions? I don't believe that topology is so poorly designed for the production...

--Anatoliy

[Brent Casey]

Originally Posted by Wavebourn

Hi Brent;

thank you for your comments!

Can you tell what weak points has MXL 770 that may be fixed by modifications?

I did not open it yet, but it seems to me it has some kind of equalization on high end against impact of an input capacitance of the FET that causes distortions?

--Anatoliy

Hello Anatoliy,

I am sorry - I have not seen nor heard an MXL770. I parted company with MXL in 2002. In my opinion it is unlikely that equalization would be used to correct a problem like high input capacitance, because designing an eq circuit to "correct" the problem would be much more difficult than designing a good simple circuit that did not have input capacitance issue in the first place.
Outside of RF mics, such as the Sennheiser MKH 406, etc. equalization circuits in condenser microphones are unlikely, generally speaking.

I think your description of possible issue is great - 'Mic has sound in high end like eq is used to correct FET input capacitance problem'. I had to read it a couple of times, but it describes what you are hearing in terms that I can understand very well.

Regards,

Brent Casey
PMI Audio Group
877-563-6335

[Wavebourn]

Thanks Brent; I feel that I have to open the mic to see what is inside...

My second guess is, they loaded a transistor amplifier by really bad transformer. Probably that's why they decided to add -10dB and 80 Hz switches, so use cheap transformers. I still don't understand how people may get saturations on millivolts when they have 48V of a voltage in disposal, more times than plenty... It is unfair, the cpsule itself and surround sounds great!

PS: I've started searching the net and found a lot of interesting information... For example, Neumann used a tube with 10K (!) resistor in plate before the transformer, and connected it with a positive feedback to cathode... While MXL used couple of followers, one FET and one BJT... Defenitely, the devil is in details such as transformers!

[Brent Casey]

Originally Posted by Wavebourn

Thanks Brent; I feel that I have to open the mic to see what is inside...

My second guess is, they loaded a transistor amplifier by really bad transformer. Probably that's why they decided to add -10dB and 80 Hz switches, so use cheap transformers. I still don't understand how people may get saturations on millivolts when they have 48V of a voltage in disposal, more times than plenty... It is unfair, the cpsule itself and surround sounds great!

I don't know.
Maybe that cheap transformer has a "good" effect on the sound of the mic and there is a nonlinearity elsewhere that creates a harsh high end response. Perhaps that transformer is not even being hit hard enough to saturate before some other part of the circuit begins to distort badly...

Brent Casey

[jeff deff]

Originally Posted by Brent Casey

Hi Jeff,

The "biggest cause" of distortion in the V67 is the PNP emitter follower that buffers the FET.

-Brent Casey

Thank you Brent. Do you think that simply replacing this PNP transistor with another part would clean up the high end any? Or is it more complicated than this? Any suggestions on a replacement part?

Thanks for sharing info with a newbie mic modder.

[Wavebourn]

Originally Posted by jeff deff

Thank you Brent. Do you think that simply replacing this PNP transistor with another part would clean up the high end any? Or is it more complicated than this? Any suggestions on a replacement part?

Thanks for sharing info with a newbie mic modder.

No.

I've found in the net a modification schematic that eliminates the transformer instead of replacing it by something more expensive.

He spllitted load of the FET and used couple of emitter followers for a symmetrical output without a transformer.

Brent;

If you call harsh highs "a good effect", I don't like it.

[Brent Casey]

Originally Posted by jeff deff

Thank you Brent. Do you think that simply replacing this PNP transistor with another part would clean up the high end any? Or is it more complicated than this? Any suggestions on a replacement part?

Thanks for sharing info with a newbie mic modder.

Jeff,

Replacing the transistor will have no effect. The issue is more in the biasing of this transistor to allow for the largest achievable voltage swing. In the case of the V67, the biasing is too high and the waveform clips on the positive swing. Also, as a single device, there is only so much it can do in terms of sourcing current to drive the load.
The semiconductors in the V67 and most cheap mics are of good quality. The selection and implementation of these devices in a given circuit may be questionable however.


Brent Casey

[Brent Casey]

Originally Posted by Wavebourn

No.

I've found in the net a modification schematic that eliminates the transformer instead of replacing it by something more expensive.

He spllitted load of the FET and used couple of emitter followers for a symmetrical output without a transformer.

Brent;

If you call harsh highs "a good effect", I don't like it.

Wavebourn,
I suspect that the thing that I was saying is different from what you are thinking I am saying...

[Wavebourn]

Ok Brent, I'll open mine and see what is inside...

I understood you well, you are blaming on a singer or something else, but it is defenitely a mic. I used them before with -10db switch on, but this time wanted to get as wide as possible dynamic range so switched off -10dB and got distorted highs... I used them with Yamaha MX400-24 mixer, it has decent inputs. Now I have a rare record of one of bards from St. Petersburg, Russia, but with distorted highs...

Is there you on the picture?

--Anatoliy

[Brent Casey]

Originally Posted by Wavebourn

Ok Brent, I'll open mine and see what is inside...

I understood you well, you are blaming on a singer or something else, but it is defenitely a mic. I used them before with -10db switch on, but this time wanted to get as wide as possible dynamic range so switched off -10dB and got distorted highs... I used them with Yamaha MX400-24 mixer, it has decent inputs. Now I have a rare record of one of bards from St. Petersburg, Russia, but with distorted highs...

Is there you on the picture?

--Anatoliy

Anatoliy,

No singers are being blamed here. What I am saying is that the harsh high end may not be caused by the transformer. Perhaps there is a distortion in another part of the circuit which causes this effect.
If the MXL770 has same circuit as V67, then SPL handling is not very high. This is not the fault of the transformer - it is the PNP output transistor in the V67 which is distorting much earlier than anything else in the circuit.

It would be hard to hear distortions in the V67 due to transformer saturation because by the time the transformer cannot pass more audio, the PNP transistor before it in the circuit has already been driven right the hell into the positive rail. Do you see?


-Brent Casey