DC coupled 6av5/6L6

RE: DC coupled 6av5/6L6, posted on May 21, 2016 at 08:51:45
hennfarm Audiophile Posts: 535 Location: Oregon Joined: October 8, 2008	Chassis is 16x16x3.5 stainless. It previously served as some sort of hinged grease vapor catch lid on a broken chicken broaster. Found two of them behind the Koho Bistro in Eugene. JH

RE: DC coupled 6av5/6L6, posted on May 21, 2016 at 08:59:33
hennfarm Audiophile Posts: 535 Location: Oregon Joined: October 8, 2008	.

RE: DC coupled 6av5/6L6, posted on May 21, 2016 at 09:00:29
hennfarm Audiophile Posts: 535 Location: Oregon Joined: October 8, 2008	.

That's how you "repurpose" with conviction..... nt, posted on May 21, 2016 at 12:16:44
Uncle Mike	Good Job!

RE: DC coupled 6av5/6L6, posted on May 21, 2016 at 12:34:09
drlowmu Manufacturer Posts: 9730 Location: East of Kansas City Joined: January 10, 2005	Its HARD to improve upon the KISS high mu, two stage, DC amplifier. Very good basic design when running high efficiency speakers, the best possible AFAICT. The Devil is in the details. Jeff Medwin

RE: DC coupled 6av5/6L6, posted on May 21, 2016 at 12:49:45
hennfarm Audiophile Posts: 535 Location: Oregon Joined: October 8, 2008	Jeff, you sent me your paper on DC 2stg amps. Thank you. I have an 35H 185ohm input choke in the power supply that I know you will cough up a lung over. Lol. JH

RE: DC coupled 6av5/6L6, posted on May 21, 2016 at 17:30:42

drlowmu
Manufacturer

Posts: 9730
Location: East of Kansas City
Joined: January 10, 2005

JH,

That 35 HY at 185 Ohms choke is just fine !!! After the rectifier, is it choke or cap input ??

LOL. That 185 Ohm choke is placed there by you so one fine day you can spend $20.00 and put in two Triad C-40Xs, with 30 and 50 uF after each, and thus YOU get to HEAR the difference. ( Or hear Hammond's newly-designed 159ZAs, only 6 Ohms at a slightly heavy 2.5 pounds ).

Mikey Samara recently ( this year ) had a GREAT listening ( and measuring ) experience, adding a 10 Ohm C-40X on his recent Mac 30 mod.

What do you think it will sound like, when you go from 185 Ohms of Series resistances to the finals, to only 20 Ohms of series DCR ?? Mikey went from 100 Ohms to 10 Ohms, .... and he was very impressed. Isn't that so, Mr. Samara ??

Its something one NEVER forgets.... after properly experienced !!! All audio chokes to the finals need to be 20 Ohms or less in DCR.

( Instead of ten Ohm Ls, I am " mulling " over having wound for me custom 4 Ohm Ls, maybe 300 mHY, under two pounds total weight, ( low in storage ) just to HEAR that. )

Layout - I'd a placed those two RCA input jacks within 2 inches ( or less ) of the grid of the driver tube, on TOP of the chassis. Might have spaced the Output transformers behind the Finals tubes, and mainly - away from the input tube....fields radiate 'ya know !!

Voltages - Did you get 150 to 195 VDC on the plate of the 6AV5, so its in its best sounding plate VDC operating range??

Howz it sounding to you on yer 4-Pi speakers, versus other DIY builds you have done??

Very LIVELY, at even low listening levels ?? Have fun, I am !!

Put in my phono as a source on my VOTTs Friday PM, after six months exclusively of decent digital. OMG !!!! No comparison, ole' analogue rules !! Thats good, because I have about 9 to 10,000 lovely LPs at home. Bring them on . Maybe time to do a Lenco mod on my L-75 spare table.

Jeff Medwin

RE: DC coupled 6av5/6L6, posted on May 21, 2016 at 18:54:19

hennfarm
Audiophile

Posts: 535
Location: Oregon
Joined: October 8, 2008

Jeff, 6av5 is the power tube, Screen tied to plate. Driving it is a 6dj8 with ~145v plate vdc. The amp has four octal sockets, two with Eia base 6ck (6av5ga) and two sockets 7ac base pinout (6L6/kt88) It can run either type as finals. I have a 20k ohm shunting pot to juggle driver tube plate voltage and vary finals bias. I need to add some form of thd analysis to measutement tools. Still doing some A/B listening tests...JH

RE: DC coupled 6av5/6L6, posted on May 21, 2016 at 18:57:48
hennfarm Audiophile Posts: 535 Location: Oregon Joined: October 8, 2008	.

RE: DC coupled 6av5/6L6, posted on May 21, 2016 at 18:59:45
hennfarm Audiophile Posts: 535 Location: Oregon Joined: October 8, 2008	Yea that's a chicken under the table. :-)

RE: DC coupled 6av5/6L6, posted on May 21, 2016 at 19:55:13
drlowmu Manufacturer Posts: 9730 Location: East of Kansas City Joined: January 10, 2005	OK, There was a "6 something " designated tube, that is equal to half a 12AX7. I didn't check the designation, and THOUGHT ( by mistake ) that the 6AV5 was the driver, a high mu tube, low current, and a 6L6G was the finals. The amp chassis looks pretty outside in your back yard / daylight photos. Jeff

RE: DC coupled 6av5/6L6, posted on May 22, 2016 at 02:03:50
Sidewinder Audiophile Posts: 254 Joined: April 13, 2001	Nice work. Please post a schematic if possible. Regards, David

6AV6, posted on May 22, 2016 at 07:19:16

FenderLover

Close.

8^)

http://www.mif.pg.gda.pl/homepages/frank/sheets/093/6/6AV6.p

RE: DC coupled 6av5/6L6, posted on May 23, 2016 at 06:52:14
deathtube 667	Now I know why you have that moniker, LOL! The chassis was a good find.

RE: DC coupled 6av5/6L6, posted on June 25, 2016 at 15:11:34
drlowmu Manufacturer Posts: 9730 Location: East of Kansas City Joined: January 10, 2005	Looking at below deck photo.....We need to talk about wiring some. I have a few ideas that worked well for me and Drummerwill - for you to try out.... and simply listen to. Can you contact me on this. NOT COSTLY, but 'guessing - very effective !! Jeff

RE: DC coupled 6av5/6L6, posted on June 25, 2016 at 17:15:58
hennfarm Audiophile Posts: 535 Location: Oregon Joined: October 8, 2008	Nt

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DC coupled 6av5/6L6

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