Any Suggestion on Upgrade and Mod on the NADY TCM1050??

Any Suggestion on Upgrade and Mod on the NADY TCM1050??
It has a Solder on 12au7 or At7 .... But Not Important ,, All the Parts in the Mic are CHINA , and the Resistor are Chipping off in it :sad:
Need to do a Overhaul ASAP , So might as well make it better
Thanks!!!

Hang tight. Marik and Gus will be here shortly...

Great Thanks :sad:

[quote author="Adky"]Any Suggestion on Upgrade and Mod on the NADY TCM1050??
It has a Solder on 12au7 or At7 [/b][/quote]

Yeah, this cruel habit to solder tubes...
Adky, you have an earlier version of this Nady. The later ones use sockets and different hardware, in addition to about 10mm longer body.
I have modified both of those, and they have same schematics. I 'reversed' it, but cannot find where I put it, maybe Gus has it.
Here what I did. First of all, unsolder the tube and put a socket. The regular one won't work here. I used pins--contact Kevin Carter--he has them, and will understand what do you mean. I changed the tube for 6072 GE 5 star. The input stage of the shematics is a C24 clone (one half)directly coupled to CF, with unusually high value of cathode resistor in CF--278K. They did it because the value of resistor that high, raised the impedance of the tube, and at the same time lowered the bias, and thus they could use cheap off shelf 1:10 output transformer. I changed the trafo for LL1550, connected as 1:4, and lowered the value of cathode resistor to 72K. I used Caddock resistors. In the place of bypass electro cap use Black Gate. Also, you can try experimenting without it, at all and see if you like the sound. In addition, I removed inernal screens of the grill, leaving only outside, thicker mesh. After these mods the mic sounded very good.
Let's hope Gus will chime in later--he did something different.

Great Idea!!!! Seams a lot of work.......
You mean I still can fit Socket in it or I need a Different kind of Socket Alike Solutions??
Thanks Marik!!! I am still waiting for more idea and opinion before I actually jump on it.... btw: with all that changes do I need to Mod the PSU as well?? :roll:
Adky

[quote author="Adky"]
You mean I still can fit Socket in it or I need a Different kind of Socket Alike Solutions??

btw: with all that changes do I need to Mod the PSU as well?? :roll:
Adky[/quote]

It is a socket alike. It looks like a little tube with inner diameter exactly like this of a tube pin. You will need to slightly enlarge holes in the PCB to fit, and then solder 9 these little tubes individually. Make sure you align them straight. Another solution would be using subminiatures (like 5840, 6111, 6021) and soldering them directly to contacts on PCB. That what Gus did, I think. The 6111 and 6021 are twin triodes, so you could use them as a direct coupled CF, as well, if you wish, and then use lower transformer ratio. It is just personal preference, and sound you are seeking for.

I did not change PSU for this modification. Looking inside, it seems that it could use better parts, though.

Socket kind of like a IC socket nice machine pin one.
But much bigger to fit the .029" tube pin.
look for "KevinC" on this board he will help you!

I've got some pictures of the individual tube pin sockets that can be purchased at K&K Audio:





The stock new TCM-1050 (with a tube socket and slightly longer dimension) sounds a bit better than the old one stock. The new one has better capacitors already. So upgrading the capacitors is a small-but-simple improvement you can make without changing the circuit.

Marik worked on this microphone for me, and we listened to it carefully before and after. The greatest improvement in sound (though the circcuit was also changed, so I don't know the contribution of every step or component) was due to the transformer change.

Here's a picture of the components in the modified microphone:



For those of you reading this and thinking about buying a TCM-1050 just to modify, you might consider the Generis GT-2 mic found on eBay under ADK Tube Mic at about $100 less than the current price of the Nady. The Generis has no shockmount and has a 6-micron diaphragm versus the 3-micron of the TCM-1050, but is otherwise probably about the same, although I was told buy the owner of ADK microphones that they are not made in the same factory. Also, the Nady shipped some (old-style, I think) TCM-1050's with wrinkled diaphragms, so be aware of that if you are looking at used mics.(Just getting some old information onto the new board.)

Nat,

Thank you for posting this pics. Yeah, looking at them I remembered that I forgot to mention that I also changed caps. From the capsule--1000pf polystirene, from anode to trafo--film cap. Caddocks are for anode and cathode resistors of the first stage. I removed from the circuit C9, C10, and C6 (bypass) caps.

I removed from the circuit C9, C10, and C6 (bypass) caps.

Click to expand...

Just out of curiosity, what did those caps do? Does anyone have the circuit drawn out?

Another advantage of the ADK Generis mic is that ADK used standard 2" tubing, so if you needed a longer mic it would be easy to substitute some of the 2" brass railing that people are using on these mic projects. The Nady mic has a larger diameter body, and I can't seem to locate any replacement tube with the same diameter.

-Scott

[quote author="scott_humphrey"]

I removed from the circuit C9, C10, and C6 (bypass) caps.

Click to expand...

Just out of curiosity, what did those caps do? Does anyone have the circuit drawn out?
[/quote]

C9 and C10 are low pass filters, and C6 is a cathode bypass.

Paging Gus and Marik...

Did either of you guys ever find the circuit diagram for this? Just to save the rest of us the trouble, if you could post the stock diagram and then each of your mods?

Thanks for the GREAT work you guys do on these mics!
Charlie

[quote author="SonsOfThunder"]Paging Gus and Marik...

Did either of you guys ever find the circuit diagram for this? Just to save the rest of us the trouble, if you could post the stock diagram and then each of your mods?

Thanks for the GREAT work you guys do on these mics!
Charlie[/quote]

Well, I never found it. I remember the audio part of the schematics. If Gus doiesn't have it, let me know and I can draw it from memory--just don't remember details of polarizing voltage part, but anyway, don't touch it.

Gus, do you have it? Email it to me and I will host it.

I just sent the 1050 schematic to Marik.

Here is the Nady 1050 schematics, Gus sent to me. Please note, there are two 0.1Mf caps--one from each secondary to ground, not shown.

http://home.comcast.net/~markfuksman/nadytcm1050.gif

Oops, the image was to big--follow the link.

I'm asking a lot of questions this morning!

What's the thinking behind removing the cathode cap? I thought this cap helped give a flatter freq response? I have added cathode bypass caps to some of my mics.

Stewart

[quote author="zebra50"]I'm asking a lot of questions this morning!

What's the thinking behind removing the cathode cap?

Stewart[/quote]

Thinking ??? What's that :?:
I prefer not to think :green:

The capsule is not especially bass friendly and sounds more top end. With stock bypass cap it sounded kinda harsh and at the time I did not have Black Gate to put instead, so I desided to go without cap at all, as it just sounded better that way. Since output is a CF, output transformer wired as 1:4, so there is still plenty of gain.

Thank you Marik and Gus for the schemo! You guys do great work here and I am interested to see more!

Peace!
Charlie

I just installed the relamed 1050 transfomer in one of my 1050s. The circuit was changed . It was lamed with .006inch (pain to work with) mu. It sounds Ok not great it looks like a 3 layer wind at 11:1. The other 1050 has a 12:1 jensen. Both modded 1050 microphones seem to be missing some of the bass the highs are OK. The stock transformer does not sound good and is mising the lows as well.

The 1050 has a 32mm 3 micron china type capsule again a 32mm limiting the sound. I did not get around to removing one or more layers of mesh.

The 1050 might be good for the body,shock mount and power supply toss the capsule and stock circuit if you want to make a Nice microphone.

Modded a little, new transformer and caps might be OK for drum overheads.
The thing is a good transformer is going to cost >$75.00 the caps are not a big deal except for one or two.

[quote author="Gus"] The stock transformer does not sound good and is mising the lows as well.
[/quote]
If lows is missing, you have overdamped output transformer.
To adjust low frequency response, change R8,
you can varies it from 20k.
(this vary current of tube, mu and then output impedance)
Also can vary output cap. It is second order system and setting
is like a woodoo without simulations.
10:1 is not intelligent to cathode follower output transformer,
use 1:1 - 4:1.
xvlk