I'd like to try a push pull screen drive amp. I've been reading about George's 6AV5 amp, others' amps and the Berning EA-230. I don't know about using a FET yet, mostly because I don't want a heat sink, and have never used them.
Bottom of page:
http://tubelab.com/articles/tube-testin ... weep-tube/
Wondering if I could use a 6SN7 SRPP like Gregg's 845 driver to drive a 6FW5's screen so I wouldn't need a FET? I'd still need a phase splitter.
http://geek.scorpiorising.ca/GeeK_ZonE/ ... pic=4466.0
Of course, if anyone has a schematic...
Push pull screen drive
7 posts
• Page 1 of 1
Push pull screen drive
by DeathRex » Thu Feb 20, 2014 9:22 am
At first I wanted to be a ET. Now I are one.
-
DeathRex - KT88
- Posts: 1014
- Joined: Wed Nov 18, 2009 8:13 pm
- Location: Cortez, CO
Re: Push pull screen drive
by Geek » Thu Feb 20, 2014 11:38 pm
-= Gregg =-
Fine wine comes in glass bottles, not plastic sacks. Therefore the finer electrons are also found in glass bottles.
Fine wine comes in glass bottles, not plastic sacks. Therefore the finer electrons are also found in glass bottles.
-
Geek - KT88
- Posts: 3585
- Joined: Sun Oct 21, 2007 3:01 am
- Location: Chilliwack, British Columbia
Re: Push pull screen drive
by DeathRex » Fri Feb 21, 2014 5:51 pm
That just looks crazy. 
Never would have thought of that. 
Luckily I have several 6SJ7s. 
How much gain can you get out of that circuit, and can it swing 350 or so vpp?
I don't have any 3.3uf caps, do you remember what brand you used?
Never would have thought of that. Luckily I have several 6SJ7s. How much gain can you get out of that circuit, and can it swing 350 or so vpp?I don't have any 3.3uf caps, do you remember what brand you used?
At first I wanted to be a ET. Now I are one.
-
DeathRex - KT88
- Posts: 1014
- Joined: Wed Nov 18, 2009 8:13 pm
- Location: Cortez, CO
Re: Push pull screen drive
by Geek » Fri Feb 21, 2014 6:27 pm
I wouldn't use something so big anymore. Use 220n to 470n caps. I just had the 3.3uF on hand at the time.
I like the Panasonic ECWF series from Digikey.
Gain was about 55 or so, IIRC.
To get away with it though, you need a big transconductance tube for the top section of the mu follower (5000 uMhos+).
Cheers!
I like the Panasonic ECWF series from Digikey.
Gain was about 55 or so, IIRC.
To get away with it though, you need a big transconductance tube for the top section of the mu follower (5000 uMhos+).
Cheers!
-= Gregg =-
Fine wine comes in glass bottles, not plastic sacks. Therefore the finer electrons are also found in glass bottles.
Fine wine comes in glass bottles, not plastic sacks. Therefore the finer electrons are also found in glass bottles.
-
Geek - KT88
- Posts: 3585
- Joined: Sun Oct 21, 2007 3:01 am
- Location: Chilliwack, British Columbia
Re: Push pull screen drive
by tomlang » Fri Feb 21, 2014 7:26 pm
+1 for the Panasonic ECWF series, a great value.
-
tomlang - Posts: 192
- Joined: Sat Sep 26, 2009 8:14 pm
- Location: Augusta, GA
Re: Push pull screen drive
by DeathRex » Fri Feb 21, 2014 9:22 pm
I just got some Russian K42Y 0.47uf 500v caps. Any other caps that I'll be needing, I'll try the ECWF.
The output tubes I'm thinking of are 6FW5s, a replacement for the 6AV5GA. They seem to be octal 6JN6s, the ones that Berning used.
It seems screen drive, or dual drive, is the answer to push pull problems; lots of power when needed, but long tube life, linear, very little power used when volume is tuned down, cool running amp, small power transformer (the new ZH-230 is only 15 pounds).
Just need more drive voltage, and larger power supply capacitors.
I was thinking of doing a PPP 1625, but was having a hard time finding a power transformer to run them all. With a PP 6FW5 screen drive, I should only need a 150ma power transformer, plus a power transformer to run the rest of the amp. Probably need more current for the preamp, driver and phase splitter than for the power transformer.
The output tubes I'm thinking of are 6FW5s, a replacement for the 6AV5GA. They seem to be octal 6JN6s, the ones that Berning used.
It seems screen drive, or dual drive, is the answer to push pull problems; lots of power when needed, but long tube life, linear, very little power used when volume is tuned down, cool running amp, small power transformer (the new ZH-230 is only 15 pounds).
Just need more drive voltage, and larger power supply capacitors.
I was thinking of doing a PPP 1625, but was having a hard time finding a power transformer to run them all. With a PP 6FW5 screen drive, I should only need a 150ma power transformer, plus a power transformer to run the rest of the amp. Probably need more current for the preamp, driver and phase splitter than for the power transformer.
At first I wanted to be a ET. Now I are one.
-
DeathRex - KT88
- Posts: 1014
- Joined: Wed Nov 18, 2009 8:13 pm
- Location: Cortez, CO
Re: Push pull screen drive
by DeathRex » Mon Feb 24, 2014 9:31 am
Oh my, I don't have 8 6EJ7s, or the acerage to plant them all. Maybe I should look into FETs.
At first I wanted to be a ET. Now I are one.
-
DeathRex - KT88
- Posts: 1014
- Joined: Wed Nov 18, 2009 8:13 pm
- Location: Cortez, CO
7 posts
• Page 1 of 1
Who is online
Users browsing this forum: No registered users and 1 guest