Finished! Kegger-designed SE EL84 monoblocks
- Thread starter Redboy
- Start date
wickedweed
Active Member
I just realized that u made the two mono blocks a mirror of the other.
apurcell22
Well-Known Member
I too am interested in seeing the schematic. Have iron, will solder!:thmbsp::yes:
apurcell22
Well-Known Member
Thanks Kegger!
Nate, any up-skirts of the completed amps?
TIA,
Al
Nate, any up-skirts of the completed amps?
TIA,
Al
apurcell22
Well-Known Member
I already have the opt's, chokes, tubes, and most of the hardware. Would only need chassis power transformers, sockets, and misc bits. How does it compare to your 2a3's?
apurcell22
Well-Known Member
What are the dimensions of those plates?
Redboy
a few good watts
They're not quite as refined as 2A3s, but I'm impressed at just how good a single ended pentode (and especially the EL84) can be. Without the 2A3s side by side for comparison, you wouldn't miss much. I had a hunch that an EL84 amp could sound very good if it was treated with the same quality components usually reserved for the "good" triodes, and that was the idea here. I'd like to upgrade a few parts still, but it has played out well so far.
Top plates are 6x14, subplates are an inch smaller.
GOYA
Super Member
The sticker on them is the same.
Yep, there's a new creation on the bench and it sounds very nice.
Kegger
R.I.P. 1/12/1966 - 6/1/2017
Sorry for the delay.. (way to long on my part) .. 
But everything is all shook out now, here is the amp and supply schematic.
Nate is running mono's so this is for 1 channel, both supply an audio circuit.
If you wanted to do a stereo amp you could use the same supply but up the
6.8uf input cap to say 33uf an drop the chokes resistance to 75ohm a piece
or use a power tranny with a bit more voltage then the 275v Nate used here.
(so however you can get say 315-330v of clean B+ is good to go)
Also Nate went with all poly caps in the supply, lately I've been building amps
with similar style supply, but generally use electrolytic's for the larger caps an
my second choke is a much smaller one followed by a larger cap, like 220-470.
Also if building the stereo amp and wanting to use 1 dual triode instead of the
2 6AU6, the 6BK7/6BQ7/6BZ7 family of tubes will drop right in the same circuit.
(the 6BK7/6BQ7/6BZ7 family of tubes are a very good fit there)
1 Last thing the EL84 here are running at a pretty good clip, if your worried for
your vintage EL84's "lasting" you may want to up the 240ohm cathode resistor
to 270ohm, the amp should sound it's best with the 240 but if yur running high
on PS voltage the 270 may be an better option, I wouldn't "worry" about it but
thought I'd mention it, running those Russian 7189 equivalent tubes your rockin.
Anyways that should about do it, if there are any questions or "alterations" ask.
-
But everything is all shook out now, here is the amp and supply schematic.
Nate is running mono's so this is for 1 channel, both supply an audio circuit.
If you wanted to do a stereo amp you could use the same supply but up the
6.8uf input cap to say 33uf an drop the chokes resistance to 75ohm a piece
or use a power tranny with a bit more voltage then the 275v Nate used here.
(so however you can get say 315-330v of clean B+ is good to go)
Also Nate went with all poly caps in the supply, lately I've been building amps
with similar style supply, but generally use electrolytic's for the larger caps an
my second choke is a much smaller one followed by a larger cap, like 220-470.
Also if building the stereo amp and wanting to use 1 dual triode instead of the
2 6AU6, the 6BK7/6BQ7/6BZ7 family of tubes will drop right in the same circuit.
(the 6BK7/6BQ7/6BZ7 family of tubes are a very good fit there)
1 Last thing the EL84 here are running at a pretty good clip, if your worried for
your vintage EL84's "lasting" you may want to up the 240ohm cathode resistor
to 270ohm, the amp should sound it's best with the 240 but if yur running high
on PS voltage the 270 may be an better option, I wouldn't "worry" about it but
thought I'd mention it, running those Russian 7189 equivalent tubes your rockin.
Anyways that should about do it, if there are any questions or "alterations" ask.
-
Attachments
Kegger
R.I.P. 1/12/1966 - 6/1/2017
They will work, you'll probably have "just enough" current to not have them do
anything ugly, the main reasons I didn't use them here are, low current and the
no local feedback they provide gives you more gain then is really "needed" here.
(with the LED try say a 100-150k FBK resistor instead of the 220K)
Experiment, try it with the LED, then with the 510ohm cathode resistor, I would
be curious what you feel sounds better to you.
anything ugly, the main reasons I didn't use them here are, low current and the
no local feedback they provide gives you more gain then is really "needed" here.
(with the LED try say a 100-150k FBK resistor instead of the 220K)
Experiment, try it with the LED, then with the 510ohm cathode resistor, I would
be curious what you feel sounds better to you.