Triodes that would like a 10K a-a OPT? - diyAudio
Go Back   Home > Forums > Amplifiers > Tubes / Valves

Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 21st October 2007, 09:32 PM   #1
diyAudio Member
 
sorenj07's Avatar
 
Join Date: May 2006
Default Triodes that would like a 10K a-a OPT?

Are there any reasonable (price, availability) power triodes that would like a reasonably high primary impedance on such a transformer? I'd been thinking maybe the 6S19P but am open to other options such as a 6EM7 and 6BL7, though 6BL7's seem a little rare...
  Reply With Quote
Old 21st October 2007, 10:28 PM   #2
diyAudio Member
 
Join Date: Apr 2004
Location: Monroe Township, NJ
Triode wired 6V6s and close relations love 10 K trafos. See Poindexter's "Musical Machine".
__________________
Eli D.
  Reply With Quote
Old 21st October 2007, 11:51 PM   #3
diyAudio Member
 
sorenj07's Avatar
 
Join Date: May 2006
I might have to do the Musical Machine. I'd probably use some 5V6 tubes.

As for the driver tube: what would be best? The closest substitute I can think of is a 6N7S in that it has a similar gain (35 vs 47), but the 6N7S has a plate resistance of 11K versus 6.7K for the 5865. Is this likely to be an issue?
  Reply With Quote
Old 22nd October 2007, 12:18 AM   #4
diyAudio Member
 
Join Date: Apr 2004
Location: Monroe Township, NJ
The twin triode is a 5965. High gm is a consideration in a differential splitter. I think that rules the 6N7 out. Of late, Poinz has been experimenting with hand matched 6GK5s in the splitter.

BTW, "El Cheapo" owes much to Poinz's design. We went for a much lower price point. Please notice that, like the 5965, the 12AT7 is a high gm type.
__________________
Eli D.
  Reply With Quote
Old 22nd October 2007, 04:36 AM   #5
diyAudio Member
 
sorenj07's Avatar
 
Join Date: May 2006
Thanks! I think I'll actually go with 6S19P's, they offer the best price/power ratio for triodes I've seen. I've also been confirmed in my suspicion that 10K a-a actually is reasonable. If you draw the load line you'll see what I mean.

The OPT, without voltage measurements yet.

Click the image to open in full size.
  Reply With Quote
Old 22nd October 2007, 07:18 AM   #6
diyAudio Member
 
sorenj07's Avatar
 
Join Date: May 2006
I might try triode-wired 6AG7's. Looking at the datasheet for the Russian equivalent, the 6P9, things seem pretty hopeful. A 6N23P/6N1P driver stage Musical Machine-style with a negative long-tail supply seems like it should work fine, with a bit of headroom for feedback. And, if I hate the way the amp sounds after tweaking it constantly, I can always turn it into a real Musical Machine by subbing in 6V6's and a 5965.

http://tubedata.tigahost.com/tubedat.../113/6/6P9.pdf
  Reply With Quote
Old 22nd October 2007, 07:12 PM   #7
diyAudio Member
 
sorenj07's Avatar
 
Join Date: May 2006
Update! Measured the various impedances of one of the OPT's (I assume it holds true for both) and got some interesting numbers.

Click the image to open in full size.

I guess it's "Triodes that would like a 7.5K a-a OPT?" now
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
FS: two new 811 triodes Tekko Swap Meet 0 17th November 2008 11:27 AM
More triodes kmaier Tubes / Valves 4 4th July 2008 09:22 PM
LPT with low triodes? Fuling Tubes / Valves 9 4th December 2006 11:48 PM
FS: 50CA10 triodes ReinoutdV Swap Meet 6 5th September 2006 03:20 AM


New To Site? Need Help?

All times are GMT. The time now is 10:33 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2