Transformer options and opinions for Nady TCM1050

[McIrish]

Hi,
I picked up a used Nady TCM1050 a couple weeks ago in hopes of modding it to the point that I like it. I already put in a new capsule and did some of the electronic mods that Dave at Advanced Audio posted on. I'm think about replacing the stock transformer now but I'm not sure what will fit. Any recommendations? I'd rather not spend over $100  on a transformer. That's too close to what I paid for the mic.  ;D

 

[wlinart]

Do you really need to change the transformer? There are a lot of measurements made which prove that the stock transformer in those chinese mics isn't too bad, just do a quick search.
If you would need to change, because the ratio would be different for example, then look at these for example: Neutrik NTE10/3 (€12), 3U audio GZT-47, GZT-87 or GZT-12 (all €30), Haufe t14/1 (around €60),...
These could be better.

 

[McIrish]

I had not read anything stating the transformer was OK. I guess you are right that I should do some tests with it before simply replacing it. I was looking at the Tab BV8, the Advanced Audio BV8 or Beesnees BV08, but if the stock transformer sounds good, I might just leave it. thank you for the less expensive options. I really don't want to invest much in this but I'm always curious on how good I can make an inexpensive mic sound.

 

[wlinart]

The Tab BV8 and the Beesneez BV08 are probably better indeed. I'm not really a fan of the advanced audio transformers, but i could be better too.
But if i remember correctly, the stock transformer has a ratio of 10:1. BV8 are 6.5:1.
I'm not sure what the effect of a different ratio would be in this case. Or have you changed the circuit to accommodate the new transformer?
Anyway, if you would need something close to the original ratio: the GZT-87 would be a good option, 9.5:1

 

[kingkorg]

Stock transformer is actually phenomenal, and performs better than most "upgrades".

You really don't need to "upgrade" it. Lower ratio transformer will provide some more output if that is what you need.

I would personally love to find the source of these stock transformers, so that i can use them instead of available "boutique" stuff.

GZT transformers have way higher THD level 30-100hz than stock, and i can't call them upgrade by any means compared to stock, which is like four times larger in size than GZT.

 

[wlinart]

Stock transformer is actually phenomenal, and performs better than most "upgrades".

You really don't need to "upgrade" it. Lower ratio transformer will provide some more output if that is what you need.

I would personally love to find the source of these stock transformers, so that i can use them instead of available "boutique" stuff.

GZT transformers have way higher THD level 30-100hz than stock, and i can't call them upgrade by any means compared to stock, which is like four times larger in size than GZT.

Yes, the stock ones are very nice.
I've used the GZT ones a few times, and i actually like them. Maybe i just like more THD

 

[ln76d]

Matija - did you measured GZT transformers THD? All the types of GZT?  Or circuit THD with installed transformer?

McIrish - same as the guys stated, original transformers are really good. This is the last thing which i would change in that microphone. Better concern on messy circuit, which is horrible, and definately change the tube if it's original chinese 12ax7.

 

[kingkorg]

I tried gzt 11:1 and 6.5:1.
I didn't say they were bad, but THD is codsiderably higher.

I tried them in circuits, u47 and c12 style. Of course you need to be very close to the maximum spl to notice that distortion.

On vocals, guitars, room mics etc, there is no way one can push mic so far, so GZT will work great, however stock will handle those extreme levels better.

 

[McIrish]

Matija - did you measured GZT transformers THD? All the types of GZT?  Or circuit THD with installed transformer?

McIrish - same as the guys stated, original transformers are really good. This is the last thing which i would change in that microphone. Better concern on messy circuit, which is horrible, and definately change the tube if it's original chinese 12ax7.

This is all very good to know.  I did do some of the circuit mods: Removed C6, C7, C9, C10. I ordered a different cap for C8 as well. I'm not sure what tube it is using currently. I'll have to investigate. The mic is not noisy at this point. It actually sounds very good with Beesneez M7 capsule in it. I'm pretty surprised. I wish they had left a bit more space so a socket could be installed for the tube. Overall, it's a pretty nice mic that I'm sure I can find a use for.

 

[kingkorg]

If you remove transformer shield, there should be enough place for tube socket.

A member here came up with another solution. He placed the socket on the other side of pcb, so that tube pins go through pcb into the socket. I hope you get what i mean.

 

[McIrish]

I completely understand what you mean. Interesting idea. I will have to have a look at how I might do that. I would imagine that removing the transformer shield might not be a great idea. I will look at the socket first.

 

[Gus]

With a good soldering iron soldering in tubes is not that hard

Back in the mid 2000s? someone posted about using individual sockets for the pins in a 1050. The type like discreet opamps use.

 

[ln76d]

Or just drill the bigger hole in the top of the shield can and install rubber grommet. Then you will be able to install socket.
Anyway, there's pretty hard to remove these tubes, PCB is double sided.
Personally i would build just new circuit with much better tube than any 12a.7 family.
Simple plate follower, with 6s6b-v is really good choice for the mikes with limited space inside.