Semisouth Aleph J?

[RainfallSky]

Aleph Jupiter sounds good (or god)

There is a place for big axial capacitor on the right side.
Dimensions exactly for this one.

 

[Zen Mod]

who needs amplifier at all, besides these capacitors?

 

[Ylab]

Hi Codyt,

Do you have a part number of those big stand-off that you are using with the 3 watt resistor?

Thank you!

 

[codyt]

Hi Codyt,

Do you have a part number of those big stand-off that you are using with the 3 watt resistor?

Thank you!

Sure, they’re Millmax 8827-0-15-15-16-27-04-0. Kinda pricey for what they are, but they make tweaking those resistors a breeze.

 

[Ylab]

Sure, they’re Millmax 8827-0-15-15-16-27-04-0. Kinda pricey for what they are, but they make tweaking those resistors a breeze.

Great thank you!

 

[GnuB]

RainfallSky, I think you should include something on the board that makes it clear that it is not an original Aleph J. Perhaps something like:
Aleph J
Inspired SemiSouth
version

Looks good!

 

[peppennino]

I vote for Aleph Jupiter

 

[RainfallSky]

RainfallSky, I think you should include something on the board that makes it clear that it is not an original Aleph J. Perhaps something like:
Aleph J
Inspired SemiSouth
version

That is an interesting subject.
I think the only original is First Watt Aleph J.
There is also DIYAudio store boards with layout made by Didiet based on Nelson scheme.
My layout have only 2 transistors in output stage and also overcurrent protection excluded.
But it's still Aleph J topology no mater how named.
Also this board is not limited only by SS. And as a bonus no need to match output stage transistors.
Right now board have text lines:
"Original Aleph circuit by Nelson Pass" (circuit/topology)
"Layout by RainfallSky 2021"
"Pass Laboratories Inc. patents apply" (I copy it from my Alep JX layout. I see one patent here (US Patent # 5,710,522). But just in case. )
Maybe I should add a line "Non-commercial use only" ?
Suggestions are welcome. I don't want to upset Papa.

Looks good!

Thank you!
I am just a beginer in layout software and one of the goals was the board to look pretty.
Yet trace the best layout I can pull ofcaurse.

 

[codyt]

I think the non commercial line makes sense to include, and could probably replace the patent line

 

[RainfallSky]

Will do.

 

[RainfallSky]

Hum bucking resistors and the like, as described by Andrew Russell of Hifisonix:

http://hifisonix.com/wordpress/wp-c...B-Design-Guidlines-for-Minimizing-Hum-1-1.pdf

That being said, I have found that using a differential input solves a lot and I never seem to have a 'hum' issue. My primary source (DAC) is differential.

Even when I played with vinyl I would use the XLR outputs (transformer coupled) and never had any hum issues to deal with.:

Poseidon's Voice Narada LP Phonostage


Best,
Anand.

I read this guidelines from another thread and got nervous my V inputs are too far from each other.
So here is a new udates in attempt to improve layout.
V+ and V- input distance reduced from 160mm to 11.42mm
High current wires now can be less scattered across the amplifier case.

High current grounds now marked SPK GND (Speaker Return) and PWR GND (PSU Power Ground).
Maybe I should rename SPK GND to SPK RET, SPKR or somethin like that.

I can't find myself big flaws.
Other than small polishing I think layout more or less settled.

 

[codyt]

Looks really nice. Is the AC gain pot controlling bias? Or is it for tweaking the ‘ac gain’ of the Aleph CSS?

 

[RainfallSky]

Looks really nice. Is the AC gain pot controlling bias? Or is it for tweaking the ‘ac gain’ of the Aleph CSS?

I saved this quote of 6L6 in my notes about this pot: "Aleph CCS current gain, but also will set the output stage bias".

But he also have a fresh comment about this pot in another thread.

Remember that playing with the “bias” pot in an Aleph is actually changing the AC current gain of the Aleph Constant Current Source... in English, that means the adjustments are doing more than just changing the Iq (quiescent current, ‘bias’) of the output devices... it also changes how the CCS reacts to the load.

I.E., experiment with it, yes, but go in knowing that more Iq may not be “better”, and that the recommended starting value is the AC current gain that is the sweet spot in terms of most listener’s preference.

 

[twitchie]

Very nicely done!

 

[RainfallSky]

Thank you!

 

[Nelson Pass]

On the Aleph, if the pot is an adjustment of the resistance in series with the
capacitor, then it only adjusts the gain, not the DC bias.

 

[codyt]

I saved this quote of 6L6 in my notes about this pot: "Aleph CCS current gain, but also will set the output stage bias".

But he also have a fresh comment about this pot in another thread.

I understand. Its the pot labelled as 'bias' on the store boards. I asked because I have some boards that use a pot in place of R24, which is another way of impacting the gain of the Aleph CCS. The one labelled 'Aleph Gain' in the attached snippet.

 

[RainfallSky]

I understand. Its the pot labelled as 'bias' on the store boards. I asked because I have some boards that use a pot in place of R24, which is another way of impacting the gain of the Aleph CCS. The one labelled 'Aleph Gain' in the attached snippet.

Scheme of this board from KiCad in attach.
Pot is R22 in the scheme.

 

[codyt]

I saved this quote of 6L6 in my notes about this pot: "Aleph CCS current gain, but also will set the output stage bias".

But he also have a fresh comment about this pot in another thread.

Yep, that looks right, or at least accurate with the schematics I've seen for the store board. Either way, its the one I twiddle when I want to change the bias.

 

[Ylab]

Scheme of this board from KiCad in attach.
Pot is R22 in the scheme.

Questions: What is the reason for the parallel resistors r5/r6?