MXL V67 transformer update

[Gus]

I installed the relamed V67 transformer in one of my V67s. This microphone had its caps upgraded and the filter network disconnected. It helped a little. It sound better to my ears but I think it is still limited by the capsule.

I think the relam was more of an upgrade than the cap changes.

 

[rafafredd]

Please, Gus, change the topic name...

V76 makes me think about telefunken mic preamp...

But nice info about the transformer relam!

 

[NewYorkDave]

I haven't been following the microphone threads, but I own a V67G and I'd love to hear about these upgrades. Can you point me to the appropriate threads or other sources of info? Thanks.

 

[Gus]

My mistake I had the numbers backwards.

I sent Chris a 2:1 transformer from the V67 He relamed it with Mu metal. I have had it for some time I just got about to installing it.

In the microphone meta there is thread showing one of my V67s with a KM84 circuit and a lundal 1636 10:1 as the output

The one today I replaced the input cap with 1000pf polystyrene this is a very important place in the circuit because of the big voltage difference. the 4.7uf ouput tant was replaced with a 4.7uf PET I had. the cap between the fet and the pnp was changed to a > value polypro. The .47uf cap off the drain was disconnected it modulates the filter network hanging off the 330k capsule supply.

I had the KM84 circuit one and the transformer lam cap upgrade one side by side today after adjusting for gain they sound alot alike. I have V69ms (cap upgrades) mxl1006s and 2001s (test and learn on microphones)

It seems I can only get so far with that 32mm capsule and grills. The same grill styles start to sound the same when what ever circuit behind it is at its limits with good parts, tube or transistor except headroom and low voltage B+ tube circuit about 100V.

One of the best v67 mods I did was a 100V 6021 u47 type circuit with the u47 bias set up. Look close at a u47 the 29ohm resistor causes the microphone to be more of a fixed bias because of the helper current via the dropping resistor to the fil to the 29ohm path. Now look close at the squre microphone I use a red led and a helper resistor off of the fill supply to fix the bias it is bypassed by a 1,500uf cap this allows the fil to be change without bias shifting

Tim H has a nice schematic of the v67 and 2001 (the gain is differnt in the fet stage set via two resistors ) I have hand drawn schematics of alot of the china microphones.

Tims schematic looks better.

FWIW I just finished relaming a nady tcm1050 transformer with .006 inch mu what a pain from now on its .014 inch. Hope to install that soon. The two 1050s I have are reworked circuits again the stock china transformers suck and the 32mm is not the best design capsule IMO.

 

[Flatpicker]

I?d swap out C2 with a polystyrene, C4 and C8 with a Panasonic HVs, and C6 with the best quality film cap you can fit in there.

Next, order some sample lams from Mag Metals and re-laminate the transformer. The number is:
Part Description: 2425 EE
Grade/Gauge: 8414
Quality: Superperm

 

[CJ]

FYI:
S o w t e r -mag metals
L u n d a l - mag metals
nickel only.
For M6, L goes to England as magmet does not carry M6 anymore, at leastt that's what I heard.
Temple is a name that has come up for M6, but I can't find their website.
any guesses on where J e n s i n gets their lams? I bet I could make a prety good guess!
So it seems we are stuck with a single souce for lams. Other companies exist, but nowhere near the product line of magmet.
Talking with Kev C I learned that the break in period of 100 hours for transformers is onlly for the amorphous cores. Really neat stuff. Super thin, 1 mil, and hard to work with. Since the material is so thin, you need a bigger core as air between the layers makes for a bigger build.
cj

 

[Gus]

I think it is

http://www.tempel.com/

 

[CJ]

Awesome Gus! I had it spelled wrong.
:guinness:

 

[roberflas]

Hello to all, I´m a new user, and I want to thank you for this forum, I`m really impressed with your electronics level.
But there is a few errors in the V67 scheme, I have some corrections to it for anybody
But I don´t know how put it on this post
please if anyone can help me ...[/img]

 

[Flatpicker]

Hi and welcome!

You could just copy the link to the post. That should work.

 

[roberflas]

But the image is in my computer, no link to my images folder, or i don´t know.

 

[roberflas]

Ok, I just send to you in e-mail message
Thank you

 

[roberflas]

I think that the FET circuit is a classic design from neuman U87i, in two weeks souters send me a transformer 1:7, and after change all caps i will make a modification to put the xformer trough 1uF cap (c6 Substitud) and eliminate the second stage (pnp transistor). In this way is more same U87 stage.
What do you think at this respect?

 

[Flatpicker]

I've never owned a V67 - I drew mine up from a hand drawn schematic I got from Gus about two years ago. However, I could have made a mistake or two.

Gus - does this look like yours? If not, maybe there are two versions of this mic?

 

[usernamebob]

does anyone know where to order samples on the website.. I had trouble finding it..

 

[usernamebob]

hey.. sorry to bring up such an old thread.. but I'm curious to try this mod on a couple of V67's I've got..

can anyone point me in the right direction as to where to get the laminate samples from.. and how to install them?

 

[Flatpicker]

Hi bob,
If you will check my first post in this thread you will find the exact part number needed to order lams (ask for samples and they should send you enough to do one mic). I don't have Mag Metals phone number, so you'll need to google them up or look in CJ's Transformer META. I think there were other threads about this as well explaining how to change the lams, so look in the Microphone META and read all the "MXL" threads. The transformer re-lam info might be in the Transformer META as well - you'll just have to look and see. I never got around to doing this, but probably would if someone donated me an MXL67, haha. :wink:

 

[Gus]

I would look at other parts in that circuit If you read the thread it did not make a big difference. Hint the of the circuit is an EF. The relam might even "hurt" the sound.

The best cost effective mod for that microphone is maybe changing three caps and even then it might not sound like you want with say an acoustic guitar. For that microphone I don't think removing the inside grill is a good mod unless you are doing a completely different circuit and want a different sound.

A MXLV67 is it own thing I think I have 9 of them 4 stock and the others worked on, part changes, grill and total circuit changes. Good to learn on.

No I am not going to post the caps and and not going to post a circuit. You should try things, there is a lot in the metas, make up your own mind.

If you have few pick a control and leave it stock and compare to changes you make.

 

[tommypiper]

I put in Scott Dorsey's mod and it made a big difference. I plan to put in the Royer tube mod on a second one, some day. I think both those mods would get you more mileage than replacing caps and the transformer.

FWIW, I spoke to a head MXL honcho at the AES in San Francisco, and he said he thought the V67 was their best sounding mic and he thought it was because of the grill. I know it's not thought of as a great capsule, but it has something.

 

[craigmorris74]

It certainly does have something. It's a different beast than the rest of the Chinese flock, and it make sense that it could most easily be made into something really cool. I've really thought of sticking one of these cardariod only screw on heads and a decent transfomer on this thing (which seems to have a decent body and grill) and see what happens!