@carageae
I don't have anything to add here except to note that I've never bothered measuring/matching transistors except once or twice at the very beginning, and that was mainly to verify that I had no duds. The circuit will work fine with the natural "as purchased" parameter variation, i.e., with no selection.
If you aren't using my board design, you'll have to take up any build issues with whoever drew that layout.
I don't have anything to add here except to note that I've never bothered measuring/matching transistors except once or twice at the very beginning, and that was mainly to verify that I had no duds. The circuit will work fine with the natural "as purchased" parameter variation, i.e., with no selection.
If you aren't using my board design, you'll have to take up any build issues with whoever drew that layout.
@rjm : Thank you for the reply and for sharing the project of this amplifier. The layout is very similar with yours, AFAIK @Julian RO followed your files, with only minor mods, bigger pads and small design changes. Thank you @Julian RO for sharing this pair of pcb.'s and of course for the Denoiser PCB.
At this moment I listen the amp with FiiO JT1 headphones. In the image below I tested it with some cheap 8 ohms speakers.
It is by far the best detail retrieval amp I built, maybe not my first choice for entertainment listening, but for critical sessions or monitoring this seems to be my near future toy.
In the following days I will do further more tests...now it plays with jumper 1 closed and I chose open loop configuration.
My transistors are BC327/337 with hFE strictly chosen between 438-442 (I bought a lot of them from 3 stores to achieve this pairing). Maybe it couldn't be strictly necessary, but for sure it doesn't hurt. The finals are some NOS C-DIL BD139-140 from electols.com , hFE 174 all.
My power supply is a bit overkill, a symetrical Denoiser supply, followed by the onboard supply, but only as a capacity multiplier, I didn't mount the Zenners. I don't hear any noise with zero input signal.
At this moment I listen the amp with FiiO JT1 headphones. In the image below I tested it with some cheap 8 ohms speakers.
It is by far the best detail retrieval amp I built, maybe not my first choice for entertainment listening, but for critical sessions or monitoring this seems to be my near future toy.
In the following days I will do further more tests...now it plays with jumper 1 closed and I chose open loop configuration.
My transistors are BC327/337 with hFE strictly chosen between 438-442 (I bought a lot of them from 3 stores to achieve this pairing). Maybe it couldn't be strictly necessary, but for sure it doesn't hurt. The finals are some NOS C-DIL BD139-140 from electols.com , hFE 174 all.
My power supply is a bit overkill, a symetrical Denoiser supply, followed by the onboard supply, but only as a capacity multiplier, I didn't mount the Zenners. I don't hear any noise with zero input signal.
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@carageae
You may find it sounds less fatiguing if you switch out that power supply with a simple unregulated unit as originally specified. The boards have enough smoothing that regulated supplies are not needed. I find they tend to deaden the sound - I prefer just transformer + diodes.
You may find it sounds less fatiguing if you switch out that power supply with a simple unregulated unit as originally specified. The boards have enough smoothing that regulated supplies are not needed. I find they tend to deaden the sound - I prefer just transformer + diodes.