• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Photo Gallery

Things are progressing nicely on my latest amp..I think I've been working on this thing for a year now! Anyway, a little eye-candy...wouldn't want to spoil it now, would I :wave2:
 

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Hey Gaz,

It's like a miniature city all aglow, I have a dim setting for the LEDs but they're still far too bright :bigeyes:

I'm not sure what to make of the sound quite yet. I've grown accustomed to my P-P 6L6 setup that has rich bass and a tubey sound, but a hum at low levels that still drives me nuts in a quiet room. That set was full octal all around.

This baby is dead quiet, and maybe a hair more powerful, despite the giant transformers (maybe someday I'll do parallel EL34s). But like Rozenblit claimed, they don't really have a tubey sound. It might even be too airy. I'm also finding that it exploits every little nuance in the source. There's no covering up a poor recording. I'll give it time and see, sometimes your ears just get worn out! ;)
 
Nina Preamp Photo

Here she is ....
Note the layout:
Heater TX at front RHS
Mains TX at rear RHS
Two 6CJ3 single damper diode rectifiers at front.
1st PSU choke behind the 6CJ3's.
Two smaller chokes (one per channel), 2nd stage
of the 2 pi, behind the 1st choke.
Signal valves are E80CC in front, 2 x E83F behind.

The red blobs are test points, 2mm sockets from Maplin which take my meter probes perfectly.
 

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EL84 Amp

My first project (built it about 5 years ago). It's a clone of a Dynaco ST35 with a beefier power supply. I'm going to build a slightly better version that is enclosed as I have a new daughter who will quicklyy grow up to be a grabby toddler...
 

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diyAudio Senior Member
Joined 2002
Hi,

I'm surprised no one has commented. It looks clean and functional.

I think the e-mail notifier decided to skip this one...If you hadn't posted I'd never noticed.

It looks great.
Nice logical layout and it's hard to go wrong with the venerable EL84/6BQ5.

I avoided this kind of persuit while I had todlers.

Better safe than sorry, sure.
A friend of mine actually raised his young daughter the danger straight away and got by just fine.

Cheers and congrats derekva,

;)
 
my DC coupled stereo OTL amplifier

This is a webcam type pic, so sorry about the sorry quality. I thought this amp would be a natural in a fireplace.....you get the heat, plus, with a mirror in back, even an orange glow:D

I've used this amp almost continuously since 1988, although I've rebuilt and upgraded the power supply - you wouldn't want to know how many corners I cut in the original version -for instance, I originally used a 1400VA toroid kit without winding any secondary, instead taking one of the primaries as a half wave rectified source for the output stages, but for the last ten years, it's got a 700VA toroid with proper homebrew secondaries for the sixteen output 6AS7G supply rails and their filaments.

It's a fully balanced all triode design (except for the DC level shifters that use pentodes as current sources and as part of the output stage bias circuit, but the signal doesn't pass through them, so they 'don't' count;))

This amp does respond down to DC, although I don't hate my speakers enough to not at least roll it off to unity gain down there. There is no servo offset control and no silicon devices anywhere in this amp except for supply rectifiers. Only negative feedback provides offset correction. I recently took it off the shelf where it had been sitting for two years & powered it up. One channel was sitting at 25mV dc and the other at about 100mV dc - hadn't been adjusted for at least four or five years & this with three fresh 6AS7G's (some had been mechanically damaged during storage) and snapped this pic after playing it for a few hours this evening.

I think this amp probably still has more than half the original tubes in it :clown:
 

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Just finished mine after 6 months or so. PSE 300b based on Audio Note Conquest. Managed to underrate the PSU Tranny though, gets too hot after a couple of hours :xeye:
The case is all fabricated 2mm ally, screw heads filled with bodyfiller and rubbed smooth. Sowter Iron. All done on the kitchen worktop :D
 

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