you made attenuator at output, or you (properly) made variable load, which is acting as Volume control?
I use
Oh. The display I got from China, I don’t know what is type or number. But it connect with arduino by i2s protocol.
Oh. If you decide to go with nano every don’t use OLED from DIYMORE. It seem to not suit with nano every. l have try it and it work but not stable.
Yes, it is OLED. And I think it is noisy type of display, So I made it lid for 30 sec. after any setting change then turn it off. I also use nano every for this project, it work fine and I use all every I/O port of it, I wish they will have other type which small and more port. Haha
Oh. The display I got from China, I don’t know what is type or number. But it connect with arduino by i2s protocol.
Oh. If you decide to go with nano every don’t use OLED from DIYMORE. It seem to not suit with nano every. l have try it and it work but not stable.
I made it follow the service manual schematic which I suppose it is variable load right?
I just coding the controller to trick the relay as 8 bit binary sequence with a bit delay time to prevent pop noise in some step.
Ah, did not hear anything on the noisy Chinese OLED yet, but there is indeed an step up convertor from 3.3V to 12V on it.
BTW for more IO we are using a MCP23017 extender chip on the I2C bus. You see them in the resistor ladder boards.
I am busy together with my colleague Peter, he is doing all the Arduino software. We are using the Display Visions EA OLEDL128-6LWA, the one on the right and the Chinese ZJY-M242-OLED on the left.
The Display Visions being the more expensive (45 Euro's) and better one, it has no step up convertor but you need to supply the 12V yourself.
The resistor ladder boards can be coupled until 3 or 4 boards, so you can make a Dolby 5.1 or 7.1 attenuator also.
What you see now is a balanced configuration.
Excellent work tanwa, just briliant.Hello all
Is it not too late to build my own Aleph P?
Just finish it, I make it dual mono with 256 steps relay volume control by my own coding controler and I also need remote control for the preamp.
All PCB and chassis is my own design. chassis is devided in 2 partitions one for audio section and the other for the noisy part. let pictures told other things.
Hope Aleph P is not obsolete for this board.
Not quite a PASS amp yet but will hopefully be part of it.
Chances upon this (not that I was looking for an arc welder) 70 years old, beautifully designed and extremely well constructed 9KVA arc welder.
The top and the base are made of cast aluminium. Centre is 1.5mm thick sheet aluminium, finished in hammerite green.
It is a 3-phase only arc welder, on the label it says 130A@20V output, 9.2KVA, either I have to re-attend my secondary school physics class on ohm’s law or the man who did the calculation failed his maths.
I was looking at the Pass Amp 20 years ago, so this looks like a perfect low cost entry 🤣
When I hooked it up to the 3-phase supply it didn’t blow the apartment to pieces. The output measured 65Vac. Opening it up revealed that the transformer was wired to 2 phases, 450Vac across the primary, neutral not connected, 3rd phase omitted.
So I re-wired it to single phase, L1-N, 230Vac and the output fell to 41Vac. With that if I add a bridge rectifier and some electrolytic capacitors I should be able to get well over +-25Vdc.
So I ordered a Pass A5 clone today, with the +-25 Vdc I should be able to get 40W @8 ohm? to drive my Sonus Faber Concertino with 86dB sensitivity.
The reason why I chose not to build an A2 instead was I may buy a “proper” toroidal transformer later if I cannot get rid of the transformer hum later.
Found an old thread by John Biles that someone suggested that the EMF emitted by the transformer would cause Leukaemia, this is in a grounded and fully enclosed aluminium case and perhaps that itself is a Faraday’s cage? Just to be on the safe side I am going to buy a EMF tester.
Wish me luck!
Chances upon this (not that I was looking for an arc welder) 70 years old, beautifully designed and extremely well constructed 9KVA arc welder.
The top and the base are made of cast aluminium. Centre is 1.5mm thick sheet aluminium, finished in hammerite green.
It is a 3-phase only arc welder, on the label it says 130A@20V output, 9.2KVA, either I have to re-attend my secondary school physics class on ohm’s law or the man who did the calculation failed his maths.
I was looking at the Pass Amp 20 years ago, so this looks like a perfect low cost entry 🤣
When I hooked it up to the 3-phase supply it didn’t blow the apartment to pieces. The output measured 65Vac. Opening it up revealed that the transformer was wired to 2 phases, 450Vac across the primary, neutral not connected, 3rd phase omitted.
So I re-wired it to single phase, L1-N, 230Vac and the output fell to 41Vac. With that if I add a bridge rectifier and some electrolytic capacitors I should be able to get well over +-25Vdc.
So I ordered a Pass A5 clone today, with the +-25 Vdc I should be able to get 40W @8 ohm? to drive my Sonus Faber Concertino with 86dB sensitivity.
The reason why I chose not to build an A2 instead was I may buy a “proper” toroidal transformer later if I cannot get rid of the transformer hum later.
Found an old thread by John Biles that someone suggested that the EMF emitted by the transformer would cause Leukaemia, this is in a grounded and fully enclosed aluminium case and perhaps that itself is a Faraday’s cage? Just to be on the safe side I am going to buy a EMF tester.
Wish me luck!
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So far “piece” only, there are 2 other identical ones for sale in our local ads. I am trying to negotiate next “pieces”, one as the power supply for the other mono block and one for spare😉
It is quite usual to see the casings of arc welding machine made with cast aluminium. All those I have seen are uglily designed and made with sheet steel, including the larger ones from the same manufacturer Elektro-Bau AG. When laid down the handles of this model is reminiscent of power amp’s front handles.
Are welding cable good as speaker cable, I will end up with quite a few welding cable if I am successful with my negotiations.
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