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I build my first ever amplifier as a lower voltage clone of AKSA !
Well, referring to the pdf file attached to the first post. Dropping from 35V to 20V is a factor of 1.75. So to first guess you need to reduce R3 to around 28k in order to keep the LTP current at the right level; distortion maybe a little higher, the sound a little more mellow. If you can keep the same current through the input pair you can leave R4 unchanged.
The current through the VAS needs to be maintained too, so you want to reduce the value of R5 and R6. However, this does place more stress on the bootstrap drive because it will see a lower impedance to the rail (R5). You want around 1k2 on R5 and 1k8 on R6, or for simplicity you could try 1k5 for both R5 and R6.
A little experimentation would be within the spirit of the project.
Yes, with lower PSU voltage. It built by many of friends here.
Simple, easy to build. You don't regret to built it.
Is it possible to operate this using two laptop power supply +/-19v?(one for each rail)
It can, but I'm not sure the performance is same or not. I must simulate it, first.
I think, this topology is optimal when using +-45VDC. Using higher than +-45VDC, the THD will increase significantly. Using lower than +-25VDC, will difficult to choose resistors bootstrap value (too small).
The challenge is to make THD lower as possible, but still H2 dominant.
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No, I made simulation base on Mr. Hugh Dean clue. I do not care about other version. You can compare other version with my version. Which is better?
If mine better then my conclusion about this topology is right.
Although blue led more noisy then red led, but I like the color 😀 and if I use red led, it need more the 4 led, and it too much.
I use a resistor for CCS to get more H2 distortion.
Hi, would it be possible for you to post the PCB files [board house does not accept pdf files] and a BOM?
Thanks!
i ended up building the original version and find the sound to be appealing. however, compared to VSSA the treble is not as refined- bit fatiguing, in fact.
I'm using bd140/139 for drivers. could somebody who has compared different transistors in this location chime in about the sound differences? I'm hoping the pricier 2SC4793/2SA1837 would be the fix, but from my previous experience with VSSA, slow driver transistors like 140/139 actually sounds more 'round'.
I'm using bd140/139 for drivers. could somebody who has compared different transistors in this location chime in about the sound differences? I'm hoping the pricier 2SC4793/2SA1837 would be the fix, but from my previous experience with VSSA, slow driver transistors like 140/139 actually sounds more 'round'.
The drivers and the outputs should be 30MHz devices; use different devices and the compensation changes. This in turn affects the sound quality.
Hugh
Hugh
Hi,
From the above artwork link, is it possible to only extract the traces, make them pitch black and remove the silkscreen ? I recently built an authentic AKSA 55N and I truly enjoy this amp. Since it's out of production I'd like to make a similar one using the BAKSA while etching my own PCB. Is there a PCB dimensions or reference so I can know which scale to use..
Thanks in advance,
Eric
You could try my artwork from the link below (Portuguese language, use Google Translator if necessary 🙂). Also see from post #614.
Construindo um Amplificador – SomShow Magazine
Search for the Dropbox link at the article's end. 😎
Rgds.