Audio Asylum Thread Printer

Get a view of an entire thread on one page

FAQ / News / Events

Tube DIY Asylum

RE: 6146 Based Tubes

108.200.223.64

In Reply to: RE: 6146 Based Tubes posted by Triode_Kingdom on November 04, 2023 at 11:52:26

Funny you mentioned the 807/1625. My other DIY amps are a pair of 1625 monoblocks with a quad of 1625's in each block. I have no issue with plate caps, but I get why some folks wouldn't want them. The screens are an issue, which is why it has a regulated screen voltage setup in the safe zone.
I have never been a fan of ultraliner. If I ever get another Citation II, I would change the output to pentode, and have a full pentode amp. I've read that Stu Hegman originally wanted to make the Citation II all pentode, but was overridden for marketing reasons.
I don't get the comments about audio quality with the 6146 family. The 8552 has a lot in common sonically with the Sylvania 6550. I actually find the 8552 amps have slightly higher sound quality over the 1625, but it's not much. The amps originally had 12SN7 driver/phase splitter. After some time, swapped out the 12SN7 for 6BL7's. Both amps sounded quite a bit better. Not quite sure why this was so, but the results were not in dispute. Took the advice of a fellow DIY'er who has more diverse background than myself.
" Don't look back. Something may be gaining on you"

Satchel Paige

Edits: 11/04/23

Follow Ups:

RE: 6146 Based Tubes - Triode_Kingdom 14:23:03 11/04/23 (2)
I think the entire topology and many details would need to be revised to optimize a Citation II for pentode mode. That's one reason I own a Cit V. The signal path is configured exactly the way I like it, and my own DIY push-pull amps use the same approach (Voltage amp - LTP - Outputs). The 6BL7 is one of my go-to tubes for certain things. I usually work with existing vintage iron though, and the high filament current isn't supported by most power transformers. I use 6BL7s as direct-coupled drivers in my A2 SETs, and they perform remarkably well. You realize all this online talk about 8552s will drive prices up, right? :)
- RE: 6146 Based Tubes - PakProtector 09:56:03 11/06/23 (0)
  Try a 2-stage amp. Pentodes everywhere. Either SE input( and thus phase splitting out of the first stage) or balanced drive. In the latter the diff amp tail load can go to a resistor to ground instead of a significantly harder load like a current regulator.
  
  Go with small power tubes. EL84 is quite nice. If 6V6/6AQ5 are used a linestage with a wee bit more gain is useful. or...veritcal deflection pentodes are another group to source out of.
  
  Douglas
  Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.
- RE: 6146 Based Tubes - Freo-1 14:54:43 11/04/23 (0)
  No worries on the 8552. I've got a boatload of 6883B tubes, along with some 8552 (which are the same tube, I think). Because of the plate cap, don't see a big run on them, but one never knows? :-)
  
  I use Heyboer iron, so it's easy to spec out what is needed. Very happy with Heyboer. The 6BL7 is a great tube, and works wonderfully in both sets of power amps.
  
  Jim McShane provided a good response to the Citation II question. Would be tight in the chassis, but could still be worth looking at.
  " Don't look back. Something may be gaining on you"
  
  Satchel Paige

Post a Followup:

FAQ

Post a Message!

Forgot Password?

Moniker (Username):
Password (Optional):
	Remember my Moniker & Password (What's this?) Eat Me
E-Mail (Optional):
Subject:

Message:	(Posts are subject to Content Rules)

Optional Link URL:
Optional Link Title:
Optional Image URL:
Upload Image:
E-mail Replies:	Automagically notify you when someone responds.

To view your new posting or follow-up, click on the RELOAD or REFRESH button on your browser.

This post is made possible by the generous support of people like you and our sponsors: