Baah, I'm a knucklehead...
Right Channel - 0.620v
Left Channel - 0.614v
I had left my mains bulb tester in series with the mains power, and the giant incandescent bulb was sucking up most of the power, as it should be.
Removed that, went through the variac, set at 120v, and now they look right.
~Gable
Right on!! Easy Peasy zero adjustment Class A. How is the dc offset?
Music playing yet?
Bulb tester was doing its job - kept bias at 200mA a safe level for Class AB smps to prevent magic smoke. But in Class A, it’s too safe.
Haven't checked offset yet. I had just enough time on my lunch break to get those initial measurements.
May have enough time later this evening to check offset, and hopefully rock some tunes!
They're in the same room, I can move between them. I try to keep them separate, work on personal stuff during my lunch break, etc.
Off set is:
~3.9mv - right channel, input not shorted
~4.6mv - left channel, input not shorted
The move around a little, but this is stabilized after a few minutes.
First sound later tonight!
Listening to it now:
Tidal HiFi -> iPhone 7+ -> Alpha
Speakers are my bench test speakers, Tang-Band w4-1337 in non optimal bass reflex boxes.
There is a little bit of noise when no music is playing, but it's tiny. Likely the mess of wires that is the proto chassis at the moment.
Sounds class A, a definite signature I recognize. Very high frequency sounds a bit more present, but not shrill, very clear, bass is quite authoritative. Not boomy bass at all, just very well defined I guess.
A few songs in, and I am enjoying it quite a bit, I'll likely listen like this for the next few days in my office, throw lots of different music types at it.
Coltrane's 'Blue Train' album is sounding wonderful so far....
more later..
Cheers,
~Gable
Tidal HiFi -> iPhone 7+ -> Alpha
Speakers are my bench test speakers, Tang-Band w4-1337 in non optimal bass reflex boxes.
There is a little bit of noise when no music is playing, but it's tiny. Likely the mess of wires that is the proto chassis at the moment.
Sounds class A, a definite signature I recognize. Very high frequency sounds a bit more present, but not shrill, very clear, bass is quite authoritative. Not boomy bass at all, just very well defined I guess.
A few songs in, and I am enjoying it quite a bit, I'll likely listen like this for the next few days in my office, throw lots of different music types at it.
Coltrane's 'Blue Train' album is sounding wonderful so far....
more later..
Cheers,
~Gable
Attachments
Until you hear an Aleph you cannot compare it to anything else. They have a certain magic that is very, very attractive. Extremely beautiful amplifiers.
Fantastic Pcgab!!
Glad to see another ALPHA is born
My initial response to first sound was exactly the same as yours, lots of upper frequency energy, but not shrill or bright. I’m starting to think it’s just more accurate or more information I’m hearing (if that makes sense). How do you like the DIYA store soft start board? How hot are your heatsinks getting?
Rock on
Vunce
Glad to see another ALPHA is born
My initial response to first sound was exactly the same as yours, lots of upper frequency energy, but not shrill or bright. I’m starting to think it’s just more accurate or more information I’m hearing (if that makes sense). How do you like the DIYA store soft start board? How hot are your heatsinks getting?
Rock on
Vunce
Pcgab,
Congratulations on first sound! Those are generous heatsinks, temps are in 40’s?
Enjoy!
Thanks!
I didn't check temps while I was listening. I will check tomorrow, I'm planning on listening all day to give it some proper 'soak in' time.
Fantastic Pcgab!!
Glad to see another ALPHA is born
My initial response to first sound was exactly the same as yours, lots of upper frequency energy, but not shrill or bright. I’m starting to think it’s just more accurate or more information I’m hearing (if that makes sense). How do you like the DIYA store soft start board? How hot are your heatsinks getting?
Rock on
Vunce
It's the second time I've used the soft start board, both times they've worked exactly as they should out of the gate (knock on wood I don't jinx the next one!).
It must be lower distortion, as the clarity is very evident. If I have time tomorrow I'll connect the alpha to my FE126 BLH's.
I have a 100k passive volume control I may throw that between a CDP and the alpha for the next few days. Or my B1 clone, that might work better.
I need to clean up the lab though, it's a mess of parts, and the 4 compression drivers I'm putting new diaphragms in...
Yes sir.
I'm pretty sure the tiny bit of hum is from one of the many too long wires draping all over the power supply. I'll tidy them up in the next few days. The hum is really quiet. I'll see if it's present with nothing connected.
I had them connected to my iphone, just paused the play and put my ear up next to the driver. That was the only way I could hear any hum.
aleph class a amplifier harmonic graph - Google Search nothing
In the other site I only write in the open Internet, an audiophile forum, I just have write:
Imagine the magic sum: H2 predominance system (with very low noise and without nasty harmonics) + waveguide
By the way, does anyone know Nelson Pass opinion about the ALPHA, with the Aleph CSS? I suppose he must also be amazed by the harmonic profile achieved.
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