Modded SCT2000/Nady TCM-1050/GT-2B Frequency Question

[Maliq]

Hi Folks,
this group seems to always be my last hope shoortly before i loose my minds when it comes to modding and microphones.

I'm still no expert when it comes to electronics and modding but i think i researched alot those last years and builded some gear like different EQ's, preamps, mic upgrading (as far as i could) and other stuff like 2 x Sound Skulptor Mp 5.66 Tube pres  which are my go to preamps in the studio.

Back to my problem. My "Baby" as i call my favorite microphone is a modded sct 2000/Nady TCM-1050/GT-2B. I only use it for vocal recordings, female and mostyl rap/singing type vocals.

C9 / C10 / C6 Removed, capsule changed to a Maiku K47 and changed the OT to a Advanced Audio BV08 Dual Bobbing.
Tube is a Goldpin EH 6072a Tube.

C8 to a 400V 1uF and one time also with a 2uF 250V Cap

Change Z5 and Z6 (D5 & D6) in the power supply from 72v Zeners to 62v zener diodes.

I put it up against a Neumann TLM-103, and against the Slate VMS, i kept my "Baby" and returned the Neumann and Slate.
My "Mic" sounds warmer and smoother, and not so "bassy" then the TLM103. I've used my Motu M4 Audio Preamps to test it in a blind shoutout and of course my Mp566 tube preamp which i always used to record Vocals in the Studio.

I might be spoiled by this mic but what bothers me alot is the "Esses" and "Shhsss". I need to use one deesser first to reduce Frequencys around 6,1Khz (very sharp "ess") around 6dB. Then after adding my mix chain, which is basically a neve and pultec vst plus some compression (not much) i need to do some manual deessing again (about 6db again) a deesser would make the vocal to "dull" at this point. The sharp frequencys range from 3.8khz up to 6,3khz

My (maybe stupid) question is, can a solder joint, or to much tubes in the chain cause this problem? Can i change a component, since the K47 is allready the smoothest capsule. It can also be my voice of course and i simply have to live with it!!!

Somehow i can remember i recorded with a similar modded mic, just a AA Ak47 capsule and a more simple GZT 6.5:1 OT from 3U Audio. I think i've not changed the PSU voltage back then and i used a more simple SPL Goldmike. The vocals sounded very nice and also smooth allready.. sometimes i start to regret my updates with more expensive stuff.

Anyway, maybe some of you got an idea, if you need pictures i can upload some from the mic.
I wonder how my mic compares to a Diy D-47 Mic... damn so many questions

Lately i thought about to buy a AT 4060 Tube mic but maybe i regret this also...

All the best and thanks guys.

 

[RuudNL]

Without a schematic it is difficult to tell what  C6, C8, C9 and C10 are, or do in the circuit.
With a schematic it would be a lot easier to give a useful advise to improve this microphone.

 

[doqmemory]

This should be the same as the Apex 460 circuit, according to Recording Hacks http://recordinghacks.com/microphones/Nady/TCM1050. 

I applied (most of) the "Fox mini mod" http://www.foxaudioresearch.ca/The460secret.htm on my Apex 460B (I left the original transformer in) and put a 3U Audio M7 in it http://3uaudio.com/cp.asp?id=696 and the sibilance problems are gone.  BTW, I also have the same M7 in my D-47FET DIY and is sounds great there, too.  These two microphones are still quite different, though.  I like them both on my voice (male, high baritone), but YMMV.

You might try the 3U Audio M7 (this sounds like a commercial).

 

[Wordsushi]

I'll second what doqmemory said. It's the Apex 460 circuit. I did pretty much the same thing. GT-2B, Fox mini-mod, Guosheng's killer 3U M7, plus a nice tube from Bowie. The M7 really tames the sibilance and gives it a nice vintage-y roundness.

I also de-soldered the stock tube and put in a tube socket, which required a bit of finessing. To fit the adjusted length of the tube+socket, I also had to remove the transformer cover, which involved de-soldering the transformer and re-seating it just under the PCB. The stock pin holes in the tube pcb are a bit smaller in diameter than the spacing of a 9 pin tube socket so I had to also bend those socket pins in a bit to get them to fit. It was a bit of a process, but it worked and I love the way the mic sounds now.

 

[Maliq]

Thanks alot, that looks interesting. I kinda fixed the problem but I'll take a look into those mods and i gotta say the 3U Audio M7 looks promising, someone know how much it is? I allready bough a few parts from 3U Audio. good company !

Regards

 

[Wordsushi]

The most recent price I received on the 3u W7 was $180 US. With all the current global economic flux, I suppose it's always best to just email Guosheng directly to ask.

 

[till]

Thanks alot, that looks interesting. I kinda fixed the problem but I'll take a look into those mods and i gotta say the 3U Audio M7 looks promising, someone know how much it is? I allready bough a few parts from 3U Audio. good company !

Regards

How did You solve the problem? I have the same mic and i wanted to do the mods You described. Can You give me an advice?
Best Regards
Till

 

[McIrish]

Completely off the main subject...
The OP asked about getting a AT4060 and wondering if they would regret it. I have a AT4060 and I also have multiple U47 (ish) mics and have had some real U48 mics in the studio from time to time. The AT4060 sounds nothing like a U47. It has a much airier sound and lacks the big lower mids of a U47. It is not one of my favorite vocal mics. OK.. back to the topic.
BTW, I have the TCM-1050 and did all the mods and installed a Beesneez M7 (that may be defective, I think there is some contamination under the diaphragm). So far I don't care for it so it sits on the shelf. I've thought about getting a different capsule for it. As I said, my M7 may be defective. I have a BN K7 in a different mic and love it, so Ben does make very nice capsules.

 

[evil grill]

This should be the same as the Apex 460 circuit, according to Recording Hacks Nady TCM1050 | RecordingHacks.com.

I applied (most of) the "Fox mini mod" The 460 Mini-Mod on my Apex 460B (I left the original transformer in) and put a 3U Audio M7 in it 3U Audio Microphones,Condenser Microphones and the sibilance problems are gone. BTW, I also have the same M7 in my D-47FET DIY and is sounds great there, too. These two microphones are still quite different, though. I like them both on my voice (male, high baritone), but YMMV.

You might try the 3U Audio M7 (this sounds like a commercial).

So no changes to B+ needed? Can't find a schematic.
I have a 3U M7 that I want to use for a tube microphone.

 

[doqmemory]

So no changes to B+ needed? Can't find a schematic.
I have a 3U M7 that I want to use for a tube microphone.

One of the changes is to replace one of the zener diodes in the power supply to lower the B+ voltage closer to 120V.

 

[evil grill]

One of the changes is to replace one of the zener diodes in the power supply to lower the B+ voltage closer to 120V.

As I suspected! Thanks!

 

[Migs 31]

So no changes to B+ needed? Can't find a schematic.
I have a 3U M7 that I want to use for a tube microphone.

Hey @evil grill
I took a screenshot long time ago on the Advanced Audio forum (can no longer open that page!)
Concerning this very same type of mod by a member called "lizardville". See pic (red circle).

Also inspiring : t.bone SCT2000 (Apex 460) - U47 mod with both halves of the tube in parallel

I went a completely different way and butchered the poor thing and made it into a Franken-Mic.
Sounds really really nice now... Might still have a schemo. lying somewhere?

M

 

[mattrico]

Funnily enough I just went looking for that exact page before I saw this thread, and it seems the AA forums are now closed. How annoying.
I also posted a couple of years ago in the other link you shared, and didn't get much response, and also didn't get anywhere with that mic so I abandoned it. In a strange irony though I've just bought an SCT2000 and am attempting this whole thing again, although this time the mic seems better built than that old Soundart I had, and the tube is socketed. So I've already swapped the tube for an old mullard 12AT7 I bought a couple of years ago, and I've got my 3U K47 capsule ready to go in too (though now I'm thinking I should've bought an M7 instead). Still wondering about this whole "tube in parallel" thing, I'm keen to try it but don't want to fry my mic, so don't want to just connect those tube pins without being absolutely sure nothing else needs to happen in the mic before switching it on.
Otherwise, thinking I'll just cut C6, C7, C9 and C10, and put a decent cap on C8. And I probably should replace the transformer too while I'm at it

Hey @evil grill
I took a screenshot long time ago on the Advanced Audio forum (can no longer open that page!)
Concerning this very same type of mod by a member called "lizardville". See pic (red circle).

Also inspiring : t.bone SCT2000 (Apex 460) - U47 mod with both halves of the tube in parallel

I went a completely different way and butchered the poor thing and made it into a Franken-Mic.
Sounds really really nice now... Might still have a schemo. lying somewhere?

M

 

[Migs 31]

.... put a decent cap on C8. And I probably should replace the transformer too while I'm at it

Ok for a »better » C8.
Not sure something wrong with that transformer. Don’t change parts just for the fun of it. Think what you want to achieve first and see.

12AT7 asked for a different cathode resistor on mine. Can’t remember exact value now.

Ask questions first. That’s what the forum is there for.

Good luck !
M

 

[mattrico]

Thanks for the extra info. I've actually come unstuck now, replacing the capsule. I've swapped capsules in a lot of mics before, and never had this issue. I must have mucked with something because it's now giving me the attached noise. I tried swapping back to the original tube, I tried swapping back to the original capsule, I tried swapping a cap (C4) that looked a little damaged. I've tried different power supplies (I have a few on hand, for an AA CM67SE and a Nude C12), I tried different cables. I tried resoldering all the mic points. None of it fixed that noise. I'm completely lost now, so any help is appreciated!

View attachment sct2000 noise.wav

 

[Migs 31]

I must have mucked with something because it's now giving me the attached noise.
View attachment 130477

Oh!!!
I had that type of “wind shield noise” on another mic. In my case, I suspect I had contaminated the Hi Z input section of my mic. I ended up swapping the styro capacitor before the grid (1nF) and gratting dirt/flux and cleaning with a toothbrush & alcohol all the 1G/Hi Z & capsule wires section.

Careful! styro caps don’t like alcohol (I think I screwed up one like that)

The noise went away after all the cleaning.May be, or may not be your case. Specially if you have swapped capsule AND tubes.... who knows?

M

 

[mattrico]

Oh!!!
I had that type of “wind shield noise” on another mic. In my case, I suspect I had contaminated the Hi Z input section of my mic. I ended up swapping the styro capacitor before the grid (1nF) and gratting dirt/flux and cleaning with a toothbrush & alcohol all the 1G/Hi Z & capsule wires section.

Careful! styro caps don’t like alcohol (I think I screwed up one like that)

The noise went away after all the cleaning.May be, or may not be your case. Specially if you have swapped capsule AND tubes.... who knows?

M

Thanks again for your help, I did something and managed to fix it, but I'm not sure what I did that actually fixed it haha. Anyway, I checked my solder points, and realised I'd forgotten to tidy one up when I put the new capsule on, so I cleaned that up, then cleaned up the mic wire and soldered it on again. Then I figured while it was apart on the table I'd remove c9 and c10, so I did that. Then swapped C8 for a decent cap. Put it all back together and it's behaving now. It seems to have more resonant noise coming through the body now when you touch it, compared to before, though it's always going to live in a shock mount so that's not really an issue. I tested the sound and it's really good, I put it up against my AA CM67SE and it competes very easily, and sounds different enough to justify having both in the mic locker. I think I'll leave the original transformer in there and I won't touch anything else on it, I don't want to muck anything up and I'm pretty happy with the sound. I'll chuck it on some vocals in sessions I have coming up and will try and post something in here for people to hear.

 

[Migs 31]

Anyway, I checked my solder points, and realised I'd forgotten to tidy one up when I put the new capsule on, so I cleaned that up, then cleaned up the mic wire and soldered it on again.

Clean tidy soldering is always a must. Specially with mics.

Is AA CM67SE really good or soso?
Does it really compare with a U67?
Or it just has similar numbers/name?
M

 

[mattrico]

Clean tidy soldering is always a must. Specially with mics.

Is AA CM67SE really good or soso?
Does it really compare with a U67?
Or it just has similar numbers/name?
M

Having never used a U67 I can't say for sure. I did compare it to my Beesneez U87 copy, and preferred it. They are VERY similar sounding mics, but the AA just had a tiny bit more of something that the Beesneez lacked. Maybe a bit more low or low mid, I don't remember, it was a couple of years ago. But I confirmed it with an audio mate who I consider has better ears than mine. So I kept the AA and sold the BN. Considering the Beesneez is seen as a very nice and somewhat accurate U87 clone, I would have to say that the CM67SE must be in the right zone. I've used proper U87's in the past but don't have access to one these days., so I can't make any direct comparisons. What I will say though is that the CM67SE has been used on a bunch of my recordings and always came up a treat. Not only when I've used it for projects that I've mixed personally, but also for projects that have been sent on to some really good mix engineers in other countries. It's my go to for most projects, I only swap other mics in if people are after a different kind of sound, or if I find it's just not working for a particular project. I also use it as my main mic for voiceovers, for radio, tv, web etc. I'm going to try this new sct2000 for a little while, to see if I prefer it, but generally the AA mic has fit the bill quite well for that purpose.
Hope that helps!

 

[Migs 31]

Ok,
I just savagely desacrated the poor thing during the first COVID cockdown.

Kids DON’T try this (put a EF86 in the mic) at home, pins are NOT compatible with ECC83/12AX7.
I had to hack, cut traces/rewire alot.
But the mic sounds superb on ac. guitar and on vocals. I wish I had two.

First two pics are before/during mod.
Last four, are after the ugly deed.
M