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6L6/5881/EL34 SEUL integrated amplifier

76.18.70.175
Posted on June 27, 2015 at 16:19:05
krankkall
Audiophile

Posts: 296
Location: New Mexico
Joined: April 5, 2014
 A multiple option SEUL power tube amp, with a Russian 6N1P driver tube, and a Hitachi 5AR4 rectifier tube.
Edcor GXSE15-3.5K-8 OPT transformers.
315 DC plate voltage (including cathode resistor voltage drop) with 65ma of cathode current, and power dissipation at 20 watts.
Biased a little cool, but still well within the ballpark.
It has the ability to use 6L6GB/6L6WGB/6L6GC/5881/EL34 power tubes.
Right now, I am using a pair of NOS SED/Winged C EL34 power tubes.
F&T electrolytic caps in the power supply, a 4.5H/200ma Stancor choke, and a pair of yellow cased 0.22uf/400Vdc Pyramid PIO coupling caps.
Sounds quite nice using an old late 80's Magnavox CDB460 as a source.
Speakers are homebrew 70's E-V SPC8 full range drivers (95db eff.@ 1W) in ported 1.1cf cabinets.
Didn't blow up, so I'm a happy camper at the moment.

Steve











 

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RE: 6L6/5881/EL34 SEUL integrated amplifier, posted on June 27, 2015 at 16:46:46
drlowmu
Manufacturer

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

I would place the cores so they face the tubes, not the open windings.

I'd have given a little more space between the iron and the tubes, so fields do not interact. Otherwise, very nice effort and care is displayed.

Underside shot ??

Jeff Medwin

 

RE: 6L6/5881/EL34 SEUL integrated amplifier, posted on June 27, 2015 at 16:53:20
krankkall
Audiophile

Posts: 296
Location: New Mexico
Joined: April 5, 2014
 Appreciate the advice!

Aluminum chassis size is 17" x 8" x 3".
Using a 12" x 2 1/4" turret board, things got a mite....tight....under that chassis.
Yeah, the power and rectifier tubes are closer to the iron, than I would have liked.
I'm fan cooling the chassis top, to keep the temps down.

Steve

 

Its a Cinch !!, posted on June 27, 2015 at 17:10:31
drlowmu
Manufacturer

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



Hi,

A turret board forces you to place parts away from the tube sockets, and use wire lengths ( bad ) to connect most everything.

Cinch makes a 5 terminal strip, only $1.46 at Newark, Model C-56U, which I often use in many places in my tube amps. VERY handy piece, a favorite, and you can place parts, connect them, right to tube socket pins.

Next build, TRY them.

Jeff Medwin

 

RE: Its a Cinch !!, posted on June 27, 2015 at 17:31:30
krankkall
Audiophile

Posts: 296
Location: New Mexico
Joined: April 5, 2014
 I've been using turret board for years in guitar and hifi amplifiers.
LOL.....of course, even an old dog like myself, can learn a few 'new' tricks, right?

Steve

 

RE: Its a Cinch !!, posted on June 27, 2015 at 17:44:06
unclestu
Dealer

Posts: 5851
Joined: April 13, 2010
 for economy of parts, look inside a Quicksilver amp. Hardwired, usually most wiring is simply the component leads themselves.

Or that solid state phono section in a wooden box (can't remember the name od the designed) . Everything was point to point using only the leasd of the individual components. It was like a giant three dimensional puzzle.

 

RE: Its a Cinch !!, posted on June 27, 2015 at 22:21:22
drlowmu
Manufacturer

Posts: 9730
Location: East of Kansas City
Joined: January 10, 2005
 I'm older than you !! This is HIGH FIDELITY !!!

Jeff Medwin

 

RE: 6L6/5881/EL34 SEUL integrated amplifier, posted on June 28, 2015 at 09:23:36
krankkall
Audiophile

Posts: 296
Location: New Mexico
Joined: April 5, 2014
 I used three NOS Johnson ceramic octal tube sockets.
They look great....but....were tighter than an old virgin on her wedding night!?
I ended up breaking the guide pin on a Shuguang 6L6CG power tube.
Electrically, it was fine though.
I CAREFULLY swapped out the Shuguang 6L6GC tubes, for a pair of NOS SED/Winged C EL34 tubes.
IMHO, the Shuguang 6L6GC tubes sounded much two dimensional, almost like a solid state amp??
But the Winged C EL34 tubes?

Like my Cats say......purrfect!

Steve

 

RE: 6L6/5881/EL34 SEUL integrated amplifier, posted on June 29, 2015 at 08:19:25
REL54
Audiophile

Posts: 1944
Location: Virginia Coast
Joined: January 3, 2003
 With the voltage you have (315) you can also use the 6L6G tubes in addition to the ones you've listed.. Some of the 6L6Gs are very very nice. When ever you get a chance you might want to give them a try.

cheers,
roN

 

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