Tube types for the TNC series mics - what you using?

[TimS]

Hi All,
Does anyone know (or is there a thread that documents) the types of tubes that are in the TNC Group Buy mics?
I have a 1200 and the 6802T and was wondering what type of tubes are in these mics. I've opened them up and they only China 12AX7B.

Has anyone who purchased these mics swapped out the tubes for something a little more boutique?
If so, what have you found the makes these tube mics shine.. NOS GE's, RCA, Telefunken, Mullard..
Tim..

 

[antichef]

I'm using a RCA 6AK5 in the ACM-900, and I think it sounds better than the stock chinese 6j1

I'm still using the stock tube in the ACM-310 (is that a 6j1b?)

I put a GE 12AT7 in my ACM-6802T, and thought it sounded better. Later, Marik extensively modified the mic (different capsule (Peluso PK47), different transformer (TF BV314) and different circuit), and recently I've been using an old GE 12AU7, and a NOS Mullard 12AU7 in it - both sound good, but this particular Mullard is just a tad noiser than this particular GE - they have a slightly different sound, so it's nice to go back and forth. I actually store a bunch of tubes in the flight cases so I can swap them out.

I don't have a 1200.

 

[Weasel9992]

I'm still using the stock tubes in my 1200's. I'll replace it soon, but it's way down the priority list.

Frank

 

[yrdbrd]

replaced the 12AX7 in my ACM-1200 with a Tung Sol 5751 and it made me
very happy... not that i wasn't happy with it stock. its just that i have a
lot of old preamp tubes and i like to tinker/tweak.
will probably replace the xformer for the same reason.

my ACM-310 is stock...
anyone know where to get this tube (6j1b) or others similar that work in
this mic? it would be cool if there was a lower gain tube that worked well in this mic.

 

[antichef]

my ACM-310 is stock...
anyone know where to get this tube (6j1b) or others similar that work in
this mic? it would be cool if there was a lower gain tube that worked well in this mic.

Over at PSW, someone was using the 310 with drums (toms, I think), and wound up just plugging straight into an analog-in port, skipping the preamp altogether

 

[dgatwood]

Over at PSW, someone was using the 310 with drums (toms, I think), and wound up just plugging straight into an analog-in port, skipping the preamp altogether

ROTFL. The problem with the 310 is that it uses a subminiature tube. There are only a very limited number of tubes you could choose for that application, and the tube isn't socketed because it isn't all that practical or useful to swap the tube anyway.

 

[zbert]

I put a JAN GE 6072 in my 1200 but what I'm really waiting for are the parts Chance talked about to do a complete mod on the mic.

 

[BudgetMC]

I've got three 1200's, and have been futzing around with the tubes a good bit.

I first tried some RCA JAN RCA 12AY7's (NOS, 1950's). I was, frankly, underwhelmed. The biggest single flaw of this mic, that I've identified is really poor transient response. Try the "key jangle" or "jingle bells" test, and all three of mine made nasty farty noises stock. And, they did the same thing with the RCA's... maybe a bit less, but nothing terribly exciting, improvement-wise. Next, I tried a JAN 12AX7... more farts! Then, I pulled out the stops and tried a NOS MUllard 4024. Big improvement! The farty transients aren't gone, but they are much improved. Overall tone of the mic seems improved, too.

I've got a batch of 1950s-1970s 12at7's that I'm going to also try. I'll let you know how they come out.

 

[TimS]

thanks for the replies so far guys..

 

[TimS]

Any ideas what the stock shipped 1200 - 12AX7a/b??
Anyone know what they are??

 

[Weasel9992]

Cheap Chinese AX7...I haven't changed mine out yet, and the more I use the mic the more I see a need to change it as soon as possible. Though I'm very interested in the possibility of a total mod too.

Frank

 

[PhilGood]

Basically the same circuit as the Apex 460. Any 12a*7 series will work, but most people prefer the 12AY7/6072A.

I have been mulling over changing the "Apex mod" to use an EF86 tube. Flatter response with better noise floor. It'll require some rewiring and a different transformer, but there are more options for big transformers using that tube. With a good capsule it really could be one hell of a mic.

 

[Yonce N Mild]

I accidentally won some NOS Russian military 12AX7 tubes on ebay recently. I'm expecting them to arrive next week. I'm looking forward to trying them out. They look pretty cool anyway they say C.C.C.P. on them and have the star logo. I've heard military grade tubes can sound too sterile but I only paid $20 for 8 of them including shipping so it can't hurt to try.

 

[dgatwood]

Basically the same circuit as the Apex 460. Any 12a*7 series will work, but most people prefer the 12AY7/6072A.

I have been mulling over changing the "Apex mod" to use an EF86 tube. Flatter response with better noise floor. It'll require some rewiring and a different transformer, but there are more options for big transformers using that tube. With a good capsule it really could be one hell of a mic.

So basically replace the capsule, replace the tube, replace the circuit, replace the transformer... what are you keeping, again?

 

[PhilGood]

So basically replace the capsule, replace the tube, replace the circuit, replace the transformer... what are you keeping, again?

No, no!

Most tube circuits operate on the same principles. You merely have to adjust some values of components and apply the right parts with the circuit. It wouldn't take much, plus its worth it since you already have a viable body to do the job. I'd bet I wouldn't even have to swap boards! The filaments use the same voltage and amperage. It wouldn't alter too much of what's already there.

I'll do a run on one mic I already have and see what the outcome is.

BTW, we pretty much do this already with the standard "Apex mod". I'd bet the result is better than good!

Anyway, the design and parts of the original mic are essentially garbage anyway. What could it hurt to re-do it completely?