Tube Repro

[jcmusic]

I am wondering why I don't see any post about this wonderful tape amp? The only titled thread is locked what's up?
Anyway for the guys that are using the Tube Repro, what tubes are you guys using or having good results with?

Jay

[Paul Birkeland]

Hello Jay,
I would highly recommend a pair of RFT EF86's, and the best 7308 you can afford (in place of the 6922).  Getting good EF86's is a bit of a crapshoot, so if you decide you want to go with mesh plate EF86's, I would buy at least 4 of the same type to make one good pair.  

The 6CM7's don't have quite the influence that the higher gain tubes have, and I have found that all the various old stock varieties have their own strengths.

-Paul

[jcmusic]

Hello Jay,
I would highly recommend a pair of RFT EF86's, and the best 7308 you can afford (in place of the 6922).  Getting good EF86's is a bit of a crapshoot, so if you decide you want to go with mesh plate EF86's, I would buy at least 4 of the same type to make one good pair. 

The 6CG7's don't have quite the influence that the higher gain tubes have, and I have found that all the various old stock varieties have their own strengths.

-Paul

Hi Paul,
Thanks for replying and for the info, I will look into the EF86's. I already have a couple nice pair of 7308's.

Jay

[jcmusic]

Has anyone noticed a difference in sound when using the balanced and unbalanced out puts on the Tube Repro?

Jay

[Doc B.]

Yes, there is a slight difference. The single ended output has one less tube gain stage and is a cap coupled output. The balanced output has that additional gain stage triode and a transformer output. I find that the single ended output is maybe a little more neutral tonally and perhaps has a bit more precise imaging if the load it is running into is acceptable high, at least 15K  (but 50K is probably better). To my ear the balanced output has a little more punch and more bass "balls", and of course it can drive loads clear down to 500ohms. I guess I ever so slightly prefer the balanced output (and my current preamp setup requires that I use it), but the differences are pretty small and it is pretty much a matter of personal taste.

[jcmusic]

Hey Dan,
Thanks alot for replying and your opinion, I was just wondering what others thoughts were on this!!! I kinda thought it was like splitting hairs myself!!!

Jay

[jcmusic]

Has anyone modded their repro with different caps or other goodies?

Jay

[Paul Birkeland]

Has anyone modded their repro with different caps or other goodies?

Jay

I have to warn severely against doing this.  Having built most of the Repro amps available in circulation, I can comment that the design is not convenient for parts swapping.  This is especially true in the EQ network where I build everything compactly and tightly to minimize any movement in shipping.  This also means that to roll EQ caps, you might have to remove eight or ten resistors in the process.

I can, however, say that Doc may be amenable to taking in a Repro for modifications.  These could include:

1.  New Front Panel color
2.  Alternate EQ capacitors/EQ modes (this will generally necessitate a new front panel for reasons mentioned above)
3.  Alternate coupling capacitors

With all that was thrown into the Repro, it is actually pretty difficult to come up with crazy ideas to make it a lot better (we discuss this quite a bit without much consensus). 

-PB

[jcmusic]

Hey Paul,
Thanks for replying it is not that I wanted to hurry up and do a mod, I was just curious if anyone had done any and what they were. I am really happy with my Repro and the sound it makes, with the right tubes in it the sound is awesome.

Jay