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Time for some music
Ha! I was waiting for you to say that, Magura!
The speaker project is up next. I need to order a ton of capacitors and then start making some saw dust with the router next... The days seem too short for all of the projects I need to finish
Eric
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Magura: Right now, my nicest speakers are a pair of small bookshelf speakers that I built a few years ago (the HATT design by Tony Gee). I have listened a few times with this speaker, but with only one working Aleph-X amp, there isn't much to evaluate just yet. I can't say much beyond "it sounds nice" right now... Its killing me that its taking so long to get things together!
ggetzoff: I picked up my IRFP240s years ago here when someone was selling matched sets. The only place that I know has them now is here: IRFP240 (200V 20A 150W) Power Mosfets - Buy Online @ AmpsLab All of the usual places (newark, digikey, mouser, mci, allied) have been sold out for a long time now - don't know why, though.
Eric
ggetzoff: I picked up my IRFP240s years ago here when someone was selling matched sets. The only place that I know has them now is here: IRFP240 (200V 20A 150W) Power Mosfets - Buy Online @ AmpsLab All of the usual places (newark, digikey, mouser, mci, allied) have been sold out for a long time now - don't know why, though.
Eric
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Hi William,
Thanks! When I discovered I had the wrong scope setting and then saw the new traces after fixing the setting, I figured I had finally nailed it... I'm still waiting on my larger transformer to see if that reduces my hum problem. I'm also working on building the remaining two amps - I just love all of that metal drilling and tapping.
I can't wait to get two amps up and running to do some actual listening!
Eric
Thanks! When I discovered I had the wrong scope setting and then saw the new traces after fixing the setting, I figured I had finally nailed it... I'm still waiting on my larger transformer to see if that reduces my hum problem. I'm also working on building the remaining two amps - I just love all of that metal drilling and tapping.
I can't wait to get two amps up and running to do some actual listening!
Eric
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I'm working on building my second amp now (it'll take a few more days given my schedule of things). For this one, I've increased heatsinking by 50% (6 sinks instead of 4) and switched to a 1500va transformer instead of the 750va I had for the first one.
I finished the power supply last night and used it to power my first amp. Using a CRC with 70,000uF caps, a 0R2 resistor and then 220,000uF cap, I get 5mV of ripple. The bad news is that the new transformer buzzes slightly as well. Thermistors help reduce the buzz and DC blockers seem to have no effect at all. Overall, the buzz is much less than with the 750va, so I don't think it will be noticeable once the amp is finished and enclosed.
I finished the power supply last night and used it to power my first amp. Using a CRC with 70,000uF caps, a 0R2 resistor and then 220,000uF cap, I get 5mV of ripple. The bad news is that the new transformer buzzes slightly as well. Thermistors help reduce the buzz and DC blockers seem to have no effect at all. Overall, the buzz is much less than with the 750va, so I don't think it will be noticeable once the amp is finished and enclosed.
Just in case anyone needs a good PSU cap recommendation:
Digi-Key - P6671-ND (Manufacturer - ECO-S1VA223EA)
Great price, in stock, and they sound great; I just can't imagine spending the big bucks for a "salon" cap like a Nichicon FG.
Digi-Key - P6671-ND (Manufacturer - ECO-S1VA223EA)
Great price, in stock, and they sound great; I just can't imagine spending the big bucks for a "salon" cap like a Nichicon FG.
Hi there, anyone could drop quick look to my changed aleph-x ?
I mainly want to copy aleph 2 performance
its 25.5-26V rails 12Amps
24x irfp 240 per channel, source resistors 0.5ohm (1A per fet) it will also have spare option(may use later) with wired but not conected extra 8 mosfets (total in this case 32fets /16Amps) and changed toroid taps down to 20v.
I did some changes and would like to see if amp will operate well enought
changes-
1)output current limit resistors changed from 100 to 170ohms (r13/r35) which value in range 120-170 I should choose to operate circuit safely in accident shorted outputs
r17 changed to 10kohm ( according to original aleph2)
r15/r32 1.5k
r14/r31 3kohm
local fedback resitors for input fets 20kohm
output to ground 100ohms
r16/r30 200kohm (for bigger input sensitivity)
I want also to remoove 2 of input protection diodes , like in Graeme ax100, but on his schematic i see that he is also added 4,7uf input(which I do not use) caps together with 100kohm ressitor
(just before any part- from input to gnd) what this resitor does? and can I remoove r21 (3ohms) and reposition input protection with 2 zenner diodes?
thanks in advance for any input
I mainly want to copy aleph 2 performance
its 25.5-26V rails 12Amps
24x irfp 240 per channel, source resistors 0.5ohm (1A per fet) it will also have spare option(may use later) with wired but not conected extra 8 mosfets (total in this case 32fets /16Amps) and changed toroid taps down to 20v.
I did some changes and would like to see if amp will operate well enought
changes-
1)output current limit resistors changed from 100 to 170ohms (r13/r35) which value in range 120-170 I should choose to operate circuit safely in accident shorted outputs
r17 changed to 10kohm ( according to original aleph2)
r15/r32 1.5k
r14/r31 3kohm
local fedback resitors for input fets 20kohm
output to ground 100ohms
r16/r30 200kohm (for bigger input sensitivity)
I want also to remoove 2 of input protection diodes , like in Graeme ax100, but on his schematic i see that he is also added 4,7uf input(which I do not use) caps together with 100kohm ressitor
(just before any part- from input to gnd) what this resitor does? and can I remoove r21 (3ohms) and reposition input protection with 2 zenner diodes?
thanks in advance for any input
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Wow! Just had the opportunity to listen to two Aleph-X amps on a pair of HATT speakers (designed by Tony Gee). These are small, two-way, bookshelf speakers that I built a few years ago.
I've never heard these tiny little speakers sound so BIG before! In a less-than-ideal room (unfinished, so lots of reflective surfaces), they sounded better than I've ever heard them before.
I can't wait to get my floor-standing dipoles up and running!
Edit:
I forgot to add that my second amp used 6 instead of 4 heatsinks with CRC filter following a 1500VA transformer. Final temperature rise is 32c with larger sinks vs 51c rise with the smaller sinks - definitely a worthwhile design change. After the CRC (0.2ohms), I get 22.5v with 5mV of ripple and pulling 8.3A per side, I get 103w into 8 ohms and 113w into 4 ohms. William's spreadsheet indicates I should be able to bump bias up to almost 10A where I'd get almost 190w into 4 ohms, but this seems to be overkill right now.
A funny thing happened when I connected the PSU ground to AC ground using a diode: Absolute DC offset started near 16v and climbed from there. When I replaced the diode with a thermistor (CL-60), everything behaved as expected - Absolute DC offset starts a 9V, drops to 6V within a few seconds, and settles to 0V within 30-45mins.
I've never heard these tiny little speakers sound so BIG before! In a less-than-ideal room (unfinished, so lots of reflective surfaces), they sounded better than I've ever heard them before.
I can't wait to get my floor-standing dipoles up and running!
Edit:
I forgot to add that my second amp used 6 instead of 4 heatsinks with CRC filter following a 1500VA transformer. Final temperature rise is 32c with larger sinks vs 51c rise with the smaller sinks - definitely a worthwhile design change. After the CRC (0.2ohms), I get 22.5v with 5mV of ripple and pulling 8.3A per side, I get 103w into 8 ohms and 113w into 4 ohms. William's spreadsheet indicates I should be able to bump bias up to almost 10A where I'd get almost 190w into 4 ohms, but this seems to be overkill right now.
A funny thing happened when I connected the PSU ground to AC ground using a diode: Absolute DC offset started near 16v and climbed from there. When I replaced the diode with a thermistor (CL-60), everything behaved as expected - Absolute DC offset starts a 9V, drops to 6V within a few seconds, and settles to 0V within 30-45mins.
Last edited:
Eric I just wanted to say thanks for putting all the hard work into your site. Making it feasable for someone like me to attempt to build the Aleph-X (or two) and it possibly working. Thank you for taking the time to collect all the gold nuggets and arranging them on your site. It's been very informitive and helpful.
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Hi Guys, Thanks for sharing your kind thoughts! You are welcome! I certainly don't know as much as many others here, but I am more than happy to share what I have learned! It was my intention to create a concise and easy to follow single source of information that could get someone up and running largely on their own. I don't know that I succeed in the arena of "concise" though... Most of the content has been sourced from the two big Aleph-X threads that I followed over the years. I'm very happy to have some personal insights to share now that my own amps are up and running, rather than just organizing materials posted by others...
Eric
Eric
yes very complete article , thanks Eric, However I belive there some mismach in article about adjusting curent gain ,
change is made by ressitors r12 and r34. but I belive(from previuos Nelson post and seeing aleph schematic) its opozite- LOWERING values of r12/34 will INCREASE current provided by CCS , not increasing values. or I didnt understand description correct.
change is made by ressitors r12 and r34. but I belive(from previuos Nelson post and seeing aleph schematic) its opozite- LOWERING values of r12/34 will INCREASE current provided by CCS , not increasing values. or I didnt understand description correct.
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elviukai: Yes, something is off here... William indicated the same thing to me in an email some time ago, but I haven't been able to find where my calculations are incorrect. Following the calculations that I posted (that I think came from Edwin Dorre in one of the big threads) I reached the conclusion that lowering values decreased current gain. But then again, I wrote this section up before I was able to measure things with a scope.
Something remains incorrect in the formulas I have posted. If you (or anyone else) can help me identify the inaccuracy, I would like very much to correct it.
Thanks!
Eric
Something remains incorrect in the formulas I have posted. If you (or anyone else) can help me identify the inaccuracy, I would like very much to correct it.
Thanks!
Eric