Mxl v67 transformer and caps mod

[Raffertypr]

Hi guys, I´ve been reading the forum researching all the MXL V67 mods you guys have done. This month i got one as a gift (a hi end studio guy told me to take it because it had been unused for some time and he knew i could use it more) so with all the threads about modding the mic i have decided to do 3 things first:

1) A silent sky studios cap kit.

2) A transformer upgrade - advanced audio offers a BV225 Bi metal, dual bobbin transformer. 2.25:1 turns ratio. I wrote to the guys at advanced audio and they told me this transformer would work great with the mic. They told me it would drop the output 2-3db, but that it would add a bit more secondary harmonics, and recover much faster to large transient sources.

3) The classic headbasket mod.



I want to do these upgrades before changing the capsule, to hear how much the mic will improve. If i decide to use another capsule in the mic, i will use the Advanced audio AK12.

 

[Gus]

I don't think the transformer change will do much. The stock one is OK.

What is a "A silent sky studios cap kit." ?
I googled and found http://www.silentsky.net/products.html

I did not find the PDF of what is changed.

Are the changes the parts that have been written about at this forum and others over the years?

I don't see any resistors so IMO is an incomplete adjustment of the circuit. You can change more with a few resistor adjustment than with cap changes in a V67.

I would not remove the inner layer of mesh in a v67 you will ruin the grill, it becomes way to weak, it is more exposed to dirt and spit and has less electrical shielding.

I suggest you do more searching for all the threads about the V67/2001 etc that have been posted over the years.

 

[RuudNL]

I often read about removing layers of mesh from a headbasket.
Often this only causes problems, because a more 'open' headbasket will give less shielding (Faraday shield), resulting in hum when you come close to the microphone.
And once a layer of mesh is removed, it will be very difficult to put it back in!
The Neumann U87 microphone uses 3 layers of mesh, and I expect that the designers knew what they were doing!

 

[kingkorg]

I never got any improvement by removing inner mesh.

However i did get some when i removed outer mesh and used only inner. Some narrow dips in frequency response disappeared. It led to flatter, less jittered curve. However this left me with a very ugly microphone.

I don't think transformer will help either. But if you measure performance of your mic after each step you might notice some difference.

Record a drum loop a song, and pink noise at same position/level etc. from a speaker after each "upgrade" and you should be able to notice the difference if it's there.

 

[Raffertypr]

I don't think the transformer change will do much. The stock one is OK.

What is a "A silent sky studios cap kit." ?
I googled and found http://www.silentsky.net/products.html

I did not find the PDF of what is changed.

Are the changes the parts that have been written about at this forum and others over the years?

I don't see any resistors so IMO is an incomplete adjustment of the circuit. You can change more with a few resistor adjustment than with cap changes in a V67.

I would not remove the inner layer of mesh in a v67 you will ruin the grill, it becomes way to weak, it is more exposed to dirt and spit and has less electrical shielding.

I suggest you do more searching for all the threads about the V67/2001 etc that have been posted over the years.

 

[Raffertypr]

I don't think the transformer change will do much. The stock one is OK.

What is a "A silent sky studios cap kit." ?
I googled and found http://www.silentsky.net/products.html

I did not find the PDF of what is changed.

Are the changes the parts that have been written about at this forum and others over the years?

I don't see any resistors so IMO is an incomplete adjustment of the circuit. You can change more with a few resistor adjustment than with cap changes in a V67.

I would not remove the inner layer of mesh in a v67 you will ruin the grill, it becomes way to weak, it is more exposed to dirt and spit and has less electrical shielding.

I suggest you do more searching for all the threads about the V67/2001 etc that have been posted over the years.

he Caps kit i will get for my mic includes:

The following parts are included in each kit:

(2) Polypropylene Capacitors for c3 and c6
(2) Polarized Electrolytic Capacitors for c4 and c8
(2) Metal Film Capacitors for c1 and c5
(1) Polystyrene (also called "styroflex") capacitor for c2

The values are the same as the factory values.

If you have a recommendation of other things i could get let me know, but since i dont have a lot of electronics knowledge if you could guide me with type, material and voltage of the  part, great. Thank you a lot!

 

[Moby]

3) The classic headbasket mod.

Just to support other members who already notice this. Yes, removing layers will change the sound, but does "different" always means better? No. Most Hi end studio mic's use 3 layers mesh and sound great.  So,  search the sound in capsule, tube, surrounding components, transformer, body resonance, PSU design and components inside. Did I miss something?

 

[Raffertypr]

Thanks for all the input guys. I will not mod the headbasket. Will only do electronics upgrade and transformer upgrade. And if I can, i will add in the future the C12 type capsule.

Do you guys suggest using other capsule or do you think the c12 will do great with the premium components upgrade (same compoment values but better quality) and the transformer upgrade?

 

[Icantthinkofaname]

Keep in mind that the V67 has at least some corrective EQ so you're probably not going to get that C414 sound if that's what you're looking for.

 

[Raffertypr]

While I was reading about the products on the advanced audio page, i found the ak67 capsule. The description says it has more damping holes to create a 2-3db tame on the HF of the capsule. So if this is true, those 2-3 db less + the mic de emphasis circuit should sound really good. Alao, this capsule has a little bit more pronounced low end. I think that with the higher quality caps, better transformer and this capsule the mic could achieve a great sound. It will not be overly bright, because the factory hf de emphasis + capsule smoother eq will work together

 

[Icantthinkofaname]

While I was reading about the products on the advanced audio page, i found the ak67 capsule. The description says it has more damping holes to create a 2-3db tame on the HF of the capsule. So if this is true, those 2-3 db less + the mic de emphasis circuit should sound really good. Alao, this capsule has a little bit more pronounced low end. I think that with the higher quality caps, better transformer and this capsule the mic could achieve a great sound. It will not be overly bright, because the factory hf de emphasis + capsule smoother eq will work together

I'm pretty sure a C12 style capsule will work too because those are less bright than a K67 capsule.

 

[Raffertypr]

Hi guys, updating you. The mic sounds great with the modifications, low mids sound really focused and the hi freq are not harsh. i still would like to change the capsule to a better k67 to take it to another level. The mic as is today, i think holds its own against other mics that go in the 600-800 ballpark

 

[kingkorg]

Any samples, measurements against stock?

 

[Raffertypr]

Any samples, measurements against stock?

I will record some vocals next weekend, so i hope to have something for you guy next week!

 

[Icantthinkofaname]

Hi guys, updating you. The mic sounds great with the modifications, low mids sound really focused and the hi freq are not harsh. i still would like to change the capsule to a better k67 to take it to another level. The mic as is today, i think holds its own against other mics that go in the 600-800 ballpark

You should probably just replace the capacitor responsible for the HF de-emphasis. That's what the problem is. You can spend another $100 on a better capsule, but you'll probably get better results from the C3 upgrade because the capsule isn't the problem in the mic, it's the circuit that's the problem. Unless you get a capsule that's tuned to be really flat or has built in HF de-emphasis.

 

[awedmusic]

Hi guys, I´ve been reading the forum researching all the MXL V67 mods you guys have done. This month i got one as a gift (a hi end studio guy told me to take it because it had been unused for some time and he knew i could use it more) so with all the threads about modding the mic i have decided to do 3 things first:

1) A silent sky studios cap kit.

2) A transformer upgrade - advanced audio offers a BV225 Bi metal, dual bobbin transformer. 2.25:1 turns ratio. I wrote to the guys at advanced audio and they told me this transformer would work great with the mic. They told me it would drop the output 2-3db, but that it would add a bit more secondary harmonics, and recover much faster to large transient sources.

3) The classic headbasket mod.



I want to do these upgrades before changing the capsule, to hear how much the mic will improve. If i decide to use another capsule in the mic, i will use the Advanced audio AK12.

 

[awedmusic]

This is a reply an old thread. I've had great success by changing just 3 components. Fet to J305, feedback capacitor from 220 pf to 820 pf silver mica and gate capacitor to 1000 pf polystyrene. No other changes. A and B comparison with an unmodified mic is substantial. This mod IMO gets you 90% there. Comparison to an U87i is even more telling. The modded V67 really holds its own on spoken word and acoustic guitar. The V67 Mxl will never be a U87 no matter what one does to it....just saying it sure sounds good.

 

[solowiej]

This is a reply an old thread. I've had great success by changing just 3 components. Fet to J305, feedback capacitor from 220 pf to 820 pf silver mica and gate capacitor to 1000 pf polystyrene. No other changes. A and B comparison with an unmodified mic is substantial. This mod IMO gets you 90% there. Comparison to an U87i is even more telling. The modded V67 really holds its own on spoken word and acoustic guitar. The V67 Mxl will never be a U87 no matter what one does to it....just saying it sure sounds good.

Thanks for documenting. A $5 V67 just landed on me from an estate sale and I will be following in your tracks.

 

[awedmusic]

Thanks for documenting. A $5 V67 just landed on me from an estate sale and I will be following in your tracks.

Sure. One other change that will help minimize distortion is replace the 4.7 uf tantalum capacitor with a 4.7 uf electrolytic feeding the transformer.
That's it. Don't strip out the the inner head basket.
That's all. I compared this modded v67 with all of my top mics....really surprised. I have no reservations in hanging this for a vocal session.