Cheap and expensive is so relative
I don't mind paying 15-20$ per output device for example what might be necessary here with B.B., and it's reasonable price for me, but some might think that's way too expensive. So is there any idea what price range this will be, then we can consider is that "too expensive"? I like your approach on this one too.
Hello Builders,
Since I do not build at the present on a regular basis, I take the opportunity to download from the threads, the important posts related to the building and testing in Word documents, so I do not have to hunt through all the verbage to find what I need. It also guards against loosing info if something happens to the website.
Since this thread was getting long and involved up to 3 different builds, I made 3 different documents (AKSA 20W, AKSA 20W 4OHM, AKSA Big Boy. You can modify these to your liking. PM me with your email address if you would like the 3 doc's. I will endeavor to send them as promptly as I can.
Regards,
Myles
Since I do not build at the present on a regular basis, I take the opportunity to download from the threads, the important posts related to the building and testing in Word documents, so I do not have to hunt through all the verbage to find what I need. It also guards against loosing info if something happens to the website.
Since this thread was getting long and involved up to 3 different builds, I made 3 different documents (AKSA 20W, AKSA 20W 4OHM, AKSA Big Boy. You can modify these to your liking. PM me with your email address if you would like the 3 doc's. I will endeavor to send them as promptly as I can.
Regards,
Myles
AKSA Alpha Amps - 20W - 20Wx4R - BigBoy
Hi X,
Since all the .doc files contain pics & images, I think they are all to large to upload. Website is not letting me upload. The one Alpha 20 file is 18.2 MB. The max file size quoted onsite for zip files is 976 KB, which seems small.
Any suggestions.
MM
Hi X,
Since all the .doc files contain pics & images, I think they are all to large to upload. Website is not letting me upload. The one Alpha 20 file is 18.2 MB. The max file size quoted onsite for zip files is 976 KB, which seems small.
Any suggestions.
MM
Hmm.. maybe resemble your images to 800x600 as JPGs. There really should be anything that graphic intensive - other than an image of the PCB render or photo of the PCB in high res as it shows all the vias. They add a lot of non-compressible content. So trick is to reduce resolution to not show each via. At large files like that you can’t email it even. Only way is to host on a file share like google drive. Etc.
Cheap and expensive is so relative
I like your approach on this one too.
JPS64 just shared with me his master plan for the controller board for the BB (or other amp). We had a nice meeting to discuss projects and future builds over dinner and drinks in Darmstadt. It looks like when all is said and done on this smart controller with ePaper screen, micro-controller, etc will still be a very reasonable BOM cost of under 40 Euro. It is quite impressive what JPS64 has in mind and he is careful to separate all the analog and digital grounds. The VU meter is tricky, because we are asking an inherently noisy digital ciricuit to "touch" a clean ultr-low noise analog circuit. So care has to be used here to make this a reality without killing the sound. It is in the works and I am finding out the the current smart connectors on the BB amp's PWM controller boards need this smart main controller to be complete.
So for now, I am testing with the COTS fan controller. I am looking forward to building this remarkable amp as soon as I get back to the lab.
He brought me a huge bag of goodies too, X-mas came way early this year
(F6 Nitrous, M2 tribute, Pass HPA, ACA, MoFo, and F6 stereo PSU). Lot's of possibilities there and of course, all done with super layouts complete with spade connectors and a billion vias Thank you JPS64 for taking the hour and a half drive to meet with me
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Hi X,
Had 2 people send me a PM with their emails. I have separated the Alpha 20 thread into 6 separate doc's that can be pasted back together. The Alpha 20-4R and the Alpha Big Boy are small enough to combine in one email. So 7 emails. I have requested these 2 people to email me if they receive everything OK. Not so tuff to do it this way.
Myles
Had 2 people send me a PM with their emails. I have separated the Alpha 20 thread into 6 separate doc's that can be pasted back together. The Alpha 20-4R and the Alpha Big Boy are small enough to combine in one email. So 7 emails. I have requested these 2 people to email me if they receive everything OK. Not so tuff to do it this way.
Myles
Cranking up the distortion?
Hugh,
Re the 20W amp, at the risk of Maty screaming "blasphemy" and being banned for eternity, mea culpa; is there a way to increase H2 to get a more tube-like sound for say, string quartet music, or just a more romantic setting. Avoiding, of course, H3 proportionally making any gains.
On my integrated, I'll tweak the bass a bit, on photographs (not the Tesla ones I sent you) I'll increase the saturation and contrast a bit so they look closer to what I see or experience.
I appreciate all the work you and X have done to create as distortion free and harmonically neutral amp as possible, and I may be totally pleased with it as is, but is it possible?
Thanks,
Scott
Hugh,
Re the 20W amp, at the risk of Maty screaming "blasphemy" and being banned for eternity, mea culpa; is there a way to increase H2 to get a more tube-like sound for say, string quartet music, or just a more romantic setting. Avoiding, of course, H3 proportionally making any gains.
On my integrated, I'll tweak the bass a bit, on photographs (not the Tesla ones I sent you) I'll increase the saturation and contrast a bit so they look closer to what I see or experience.
I appreciate all the work you and X have done to create as distortion free and harmonically neutral amp as possible, and I may be totally pleased with it as is, but is it possible?
Thanks,
Scott
I absolve you of all your sins in the Name of the Father, and of the Son and of the Holy Spirit. 
It is a very interesting question that I posed myself weeks ago but with the preamp. And that this predominance could be adjusted without much difficulty.
Preamp with H2 predominant + clean DAC with full DSP + clean poweramp
It is a very interesting question that I posed myself weeks ago but with the preamp. And that this predominance could be adjusted without much difficulty.
Preamp with H2 predominant + clean DAC with full DSP + clean poweramp
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Hi Scott,
Very good question, and I am impressed that Maty, being a Spaniard, is being a mild Inquisitor, and I'm grateful...... I have been preaching for twenty years that distortion should never be called so; it is harmonic profile, and accepting that 'distortion' is inevitable - impedance is futile after all - we need to work with it. Actually, Maty is onto me; he understands all my tricks now. I take my hat off to you, Maty!
I have spent a long time profiling harmonics from SS amps and this one has one of the closest to monotonic decrease that I have ever seen, short of a single ended triode.
So YES, and I love your photography analogy, it is apt and I use it too with my photographs of my amps! Saturation is indeed H2! There are ways of changing the ratios of H2/H3/H4 and they are perverse. The singleton input stage is one of the best, and I used this in the NAKSA, though in the SAKSA I used this still first and second stage from the ALPHA. Reason? It gives better listening sessions with BAD recordings; the NAKSA was somewhat unforgiving. Normally a LTP followed by a Lender connected VAS has H2 pretty much equal with H3, and low, but if you put a diode like the ALPHA left LTP leg you throw more current drive onto the emitter, whilst giving less voltage drive on the base. The effect is to drive the npn VAS in a hybrid of common emitter and common base; this speeds it considerably and brings up the high pole, making compensation benign and easy to achieve. The result of this is much less H5 and beyond, which improves the listening experience with bad recordings, and of course we all know that about 80% of our recordings are BAD, not just M. Jackson, which is actually recorded very nicely with lots of H2 from Quincy Jones.
So, to answer your question, yes. We can put in a pot in place of R17, the resistor in series with the 220uF on the CCS. At the 560R level, the dynamic current swings of the upper and the lower devices are close to IDENTICAL, which gives you H2 at -70dB and H3 at -79dB for +20dB output (14.14Vp into 8R; H5 is at -111dB). If you reduce the R17 to 330, the currents swings are LESS on the pmos (1.2A-1.85A) than on the nmos (0.1A-3A), and H2 is -69dB and H3 is -83dB, H5 is still at -111dB. This change of R17 does change the ratio of H2 and H3 but I prefer to set the current swings equal so you can maximise the power output.
So, you can change H2 but changing the Pass CCS; by changing the input and VAS topology; and by using asymmetrical source resistors on the output stage of a PP Class AB amp. A 'niceness' knob is quite difficult to arrange however, and if you did, many purists would say that it's not designed correctly because it increases the distortion.
In decades in the future, people will come to understand this is an acceptable way to make a sound better than the 0.0005% monsters we used to buy in the eighties.
HD
Very good question, and I am impressed that Maty, being a Spaniard, is being a mild Inquisitor, and I'm grateful...... I have been preaching for twenty years that distortion should never be called so; it is harmonic profile, and accepting that 'distortion' is inevitable - impedance is futile after all - we need to work with it. Actually, Maty is onto me; he understands all my tricks now. I take my hat off to you, Maty!
I have spent a long time profiling harmonics from SS amps and this one has one of the closest to monotonic decrease that I have ever seen, short of a single ended triode.
So YES, and I love your photography analogy, it is apt and I use it too with my photographs of my amps! Saturation is indeed H2! There are ways of changing the ratios of H2/H3/H4 and they are perverse. The singleton input stage is one of the best, and I used this in the NAKSA, though in the SAKSA I used this still first and second stage from the ALPHA. Reason? It gives better listening sessions with BAD recordings; the NAKSA was somewhat unforgiving. Normally a LTP followed by a Lender connected VAS has H2 pretty much equal with H3, and low, but if you put a diode like the ALPHA left LTP leg you throw more current drive onto the emitter, whilst giving less voltage drive on the base. The effect is to drive the npn VAS in a hybrid of common emitter and common base; this speeds it considerably and brings up the high pole, making compensation benign and easy to achieve. The result of this is much less H5 and beyond, which improves the listening experience with bad recordings, and of course we all know that about 80% of our recordings are BAD, not just M. Jackson, which is actually recorded very nicely with lots of H2 from Quincy Jones.
So, to answer your question, yes. We can put in a pot in place of R17, the resistor in series with the 220uF on the CCS. At the 560R level, the dynamic current swings of the upper and the lower devices are close to IDENTICAL, which gives you H2 at -70dB and H3 at -79dB for +20dB output (14.14Vp into 8R; H5 is at -111dB). If you reduce the R17 to 330, the currents swings are LESS on the pmos (1.2A-1.85A) than on the nmos (0.1A-3A), and H2 is -69dB and H3 is -83dB, H5 is still at -111dB. This change of R17 does change the ratio of H2 and H3 but I prefer to set the current swings equal so you can maximise the power output.
So, you can change H2 but changing the Pass CCS; by changing the input and VAS topology; and by using asymmetrical source resistors on the output stage of a PP Class AB amp. A 'niceness' knob is quite difficult to arrange however, and if you did, many purists would say that it's not designed correctly because it increases the distortion.
In decades in the future, people will come to understand this is an acceptable way to make a sound better than the 0.0005% monsters we used to buy in the eighties.
HD
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Thank you very much for your kind words.
This amplifier could also use a DAC with full 64-bit DSP to regulate the volume instead of a preamp, so it would also be interesting to configure it as H2 predominant by changing only a resistor after finding the value that we like with a blue pot trimmer.
Maybe your Son, aka xrk971, be encouraged to do it and upload some graphics.
******** ********
I guess I am also H2 predominant: my food is just a single cookie and my arms are asymmetric too
![URL]](/community/proxy.php?image=http%3A%2F%2F%5BURL%5Dhttp%3A%2F%2Fmaty.galeon.com%2Fportada%2Fmonster2.jpg%5B%2FURL%5D&hash=61e8d0bdec364b91135e00f4ff15091c)
This amplifier could also use a DAC with full 64-bit DSP to regulate the volume instead of a preamp, so it would also be interesting to configure it as H2 predominant by changing only a resistor after finding the value that we like with a blue pot trimmer.
Maybe your Son, aka xrk971, be encouraged to do it and upload some graphics.
******** ********
I guess I am also H2 predominant: my food is just a single cookie and my arms are asymmetric too
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