good idea. I try to build dual monos. Its not a huge amount extra to do this, but if its class A you need a massive chassis. My last one (UGS) I can barely lift and I cant get my F5 Turbo running properly so I can leave it in the basement for now🙂
Another dual mono amp
Having thought of this ideas and read Aljordans report I decided to embark on the same dual mono pathway with my F6 and M2 amps, which were in identical chassis with almost identical power supplies (different brand same spec transformers). It has been a great success with the DPDT switch on the power rails and the earth constantly wired, no hum. The switches cost $Au28 and the amps sound more solid in the mid-range ( I use separate bass amplification), well worth the effort. One small suggestion; wire the matching amp boards on opposite sides of the two chassis so you can stack them without getting heat buildup on one side alone, cheers.
Having thought of this ideas and read Aljordans report I decided to embark on the same dual mono pathway with my F6 and M2 amps, which were in identical chassis with almost identical power supplies (different brand same spec transformers). It has been a great success with the DPDT switch on the power rails and the earth constantly wired, no hum. The switches cost $Au28 and the amps sound more solid in the mid-range ( I use separate bass amplification), well worth the effort. One small suggestion; wire the matching amp boards on opposite sides of the two chassis so you can stack them without getting heat buildup on one side alone, cheers.
Attachments
someone wise once told me that I should order PSU components in X multiples of PSU boards because, as they put it, "no one ever builds only one". Compound that with antek being out of 300 or 400va 18v transformers, noticing that they do instead have AS-2218's in stock, and this thread, and it all got me thinking.
Right now I want to build my first DIY amp from an aleph j pcb. If I build it now with dual PSU's using 2X 200VA toroids, I'm thinking I can just take out one toroid and PSU board to stuff into another 4U, whenever that itch strikes, likely for an F4.
This a rational idea? 200VA I'm assuming is more than enough for a mono build given that 300VA is plenty for a regular stereo build. Right? Anything I'm missing? /not an electronics guy
Right now I want to build my first DIY amp from an aleph j pcb. If I build it now with dual PSU's using 2X 200VA toroids, I'm thinking I can just take out one toroid and PSU board to stuff into another 4U, whenever that itch strikes, likely for an F4.
This a rational idea? 200VA I'm assuming is more than enough for a mono build given that 300VA is plenty for a regular stereo build. Right? Anything I'm missing? /not an electronics guy
if you're going to use one PSU/channel , it doesn't matter in how many cases you're going to spread it ...... electrically the same 🙂
thanks, Zen Mod. suppose I should have elaborated more.
Worth reducing the capacitance on the PSU's a little bit since now i'll have one board dedicated to each rail? Target something like 8 x 8,000-10,000uF? Or is inrush or excess? capacitance not a problem at the typical 120,000uF total each?
Also saw a post about using only one half of the diode rectification in another thread. They didnt say why they wanted to do it but from the schematic it looks like that wouldnt use both sets of capacitors? Or am I missing something / Should I not even be thinking about this?
Similarly, why not just split the PCB down the middle and use each half separately with one xformer to each rail? Feel like there must be a reason since all the mono builds I see are two full PSU boards per rail that would normall be used in a stereo configuration.
Worth reducing the capacitance on the PSU's a little bit since now i'll have one board dedicated to each rail? Target something like 8 x 8,000-10,000uF? Or is inrush or excess? capacitance not a problem at the typical 120,000uF total each?
Also saw a post about using only one half of the diode rectification in another thread. They didnt say why they wanted to do it but from the schematic it looks like that wouldnt use both sets of capacitors? Or am I missing something / Should I not even be thinking about this?
Similarly, why not just split the PCB down the middle and use each half separately with one xformer to each rail? Feel like there must be a reason since all the mono builds I see are two full PSU boards per rail that would normall be used in a stereo configuration.
well , I'm not following you there ...
channel demands dual rail , you make dual rail rectifier and cap bank .... how you are going to do that physically is irrelevant , as long is properly routed
approach with separate secondaries and dedicated bridge per secondary , so GND established after the bridges - is better in cases where rail load isn't symmetrical , and then you can have some xformer buzz and ringing ; that's more often than we think
only with OS where are used strictly complementary parts , having equal xconductance/beta , so halves are equally sharing current - we have equal loading of rails
channel demands dual rail , you make dual rail rectifier and cap bank .... how you are going to do that physically is irrelevant , as long is properly routed
approach with separate secondaries and dedicated bridge per secondary , so GND established after the bridges - is better in cases where rail load isn't symmetrical , and then you can have some xformer buzz and ringing ; that's more often than we think
only with OS where are used strictly complementary parts , having equal xconductance/beta , so halves are equally sharing current - we have equal loading of rails
Sorry for the confusion, let me try again. And if this isnt the right thread, I can move to the power supply thread, but my intent here is to investigate building a dual PSU supplied alpeh J in a single enclosure now, that I may be able to split up down the road into dual/switchable monoblocks as was done in the original post.
Going in assumptions:
Will use two antek as-2218 transformers and two complete/separate diyaudio universal psu boards all inside one enclosure.
Hopefully that was a little more clear. Really appreciate the help.
Going in assumptions:
Will use two antek as-2218 transformers and two complete/separate diyaudio universal psu boards all inside one enclosure.
- Should I reduce the capacitance on each PSU board from the recommended 8x15000uF for a typical stereo build, and if so, should I go roughly half of that with something like 8X8-10000uF? Asking this question due to reading other threads about in-rush and "excess" capacitance.
- Each PSU board has a "left" and "right" side intended to be used to feed two separate rails/channels from a single transformer with 2 secondaries. As such, since now I'll have two full PSU boards & two Transformers, one for each channel, do I need to use both left & right sides of the diode rectification on both PSU boards (4X total) or can I just use one on each (2X total)? Asking this question because I saw someone ask this in another thread where 6L6 replied with a schematic of how to do it, and it got me thinking.
- Is my assumption of needing TWO PSU boards right in the first place, or can I simply buy one PSU board, snap it in half on the provided cut, and have those feed each rail separately? Naturally I would stay with the "typical" build of using at least 4x15000uF capacitors per rail/channel. Asking this because every dual psu/mono fed single enclosure amp I've seen has TWO full PSU boards. So I must be missing something obvious or maybe not.
Hopefully that was a little more clear. Really appreciate the help.
1. you can skimp on capacitance , counting what's Pa using regularly as common PSU - 8pcs of 15mF
that is 120mf
so , say 60mF per channel
I'm using 33mF-0R1-33mF per rail , for dual mono ( so practically 4 times that)
2. I'm not overly familiar with Store Cap Bank pcbs , so someone else must chime in , to cover that
3. you can snap one pcb only if it's made as two independent entities
if you want to observe pretty much established way of making dual mono in one case , see some of builds on my blog
that is 120mf
so , say 60mF per channel
I'm using 33mF-0R1-33mF per rail , for dual mono ( so practically 4 times that)
2. I'm not overly familiar with Store Cap Bank pcbs , so someone else must chime in , to cover that
3. you can snap one pcb only if it's made as two independent entities
if you want to observe pretty much established way of making dual mono in one case , see some of builds on my blog
You need two transformers and two store PSU PCBs with the diode sections intact. Each one of those PSU assemblies will feed one amplifier channel.
1) as Zen says, you could use smaller capacitors.
2) you need two sets of diodes.
3) splitting the PCB doesn’t double it up, in this case it will make a bipolar supply into two single supplies, and that won’t work.
The amplifier boards need V+, GND, V-
1) as Zen says, you could use smaller capacitors.
2) you need two sets of diodes.
3) splitting the PCB doesn’t double it up, in this case it will make a bipolar supply into two single supplies, and that won’t work.
The amplifier boards need V+, GND, V-
About to perform this to my M2 (teabag version) and Aleph J. Cant help but feel a little silly "working on" two amps that work perfectly, but its a proven path so here I am.
One question I have before putting power to it. Answer seems obvious enough to me, but I could look at double burning amp for the 7/4 celebration.
Obviously the V+ and the V- of the power supply are switched, question is about "0" connection on power supply.
I assume (here we go...) that the board that is "staying" remains hooked up to power supply's "0" connection, while the board which is being transplanted in will need a wire from its connection to this "0" connection on power supply?
Next assumption is that these two connections remain attached like this, even though obviously only one board or the other is energized and they don't need that connection switched.
Sorry, I had rather look silly making sure than looking silly for cooking two perfectly working amplifiers...
Russellc
One question I have before putting power to it. Answer seems obvious enough to me, but I could look at double burning amp for the 7/4 celebration.
Obviously the V+ and the V- of the power supply are switched, question is about "0" connection on power supply.
I assume (here we go...) that the board that is "staying" remains hooked up to power supply's "0" connection, while the board which is being transplanted in will need a wire from its connection to this "0" connection on power supply?
Next assumption is that these two connections remain attached like this, even though obviously only one board or the other is energized and they don't need that connection switched.
Sorry, I had rather look silly making sure than looking silly for cooking two perfectly working amplifiers...
Russellc
I only switched + and - and left the rest wired in permanently on mine (M2X and F6) all works perfectly, enjoy.
Russellc,
Unfortunately I can't get inside my amp right now because I am in the hospital recouperating from some surgery. However, I only switched the + and - lines as well as I recall. I think I may have explained it in the beginning of the thread.
Alan
Unfortunately I can't get inside my amp right now because I am in the hospital recouperating from some surgery. However, I only switched the + and - lines as well as I recall. I think I may have explained it in the beginning of the thread.
Alan
Get well, don't worry about this now, I figured that you left that wired on the board that stayed, saw no mention from anyone about adding one for the board transplanted in....
Russellc
Russellc
Surgery complete and successful. The Amps have more ummph for sure. Soundstage seems enhanced over non mono block versions.
I built both original amps with Antek 500 VA 18 + 18 volt transformers and Teabag power supply boards with eight 33,000 uF caps.....any problems with "excessive power supply?
In deciding if "better" than stereo version, I found myself wanting to compare with original versions...now I have to wait and see if that desire wanes, usually the sign of it being all original was and more, or if I can continue to "wonder" about it until I have to build another "regular" Aleph J......
Any thoughts on "too much power supply"?
Russellc
I built both original amps with Antek 500 VA 18 + 18 volt transformers and Teabag power supply boards with eight 33,000 uF caps.....any problems with "excessive power supply?
In deciding if "better" than stereo version, I found myself wanting to compare with original versions...now I have to wait and see if that desire wanes, usually the sign of it being all original was and more, or if I can continue to "wonder" about it until I have to build another "regular" Aleph J......
Any thoughts on "too much power supply"?
Russellc
Do you have less hum than before? Other than more oomph and soundstage differences, the big thing I noticed was that any hint of ground loop was erased.
You did recheck all your test points and offsets? I don't think too much VA can hurt anything except maybe your back when you lift the amplifiers. Maybe a larger transformer radiates more crud than need be into the surrounding components, but if you don't notice any noise issues you can just say your PS is super manly.
You did recheck all your test points and offsets? I don't think too much VA can hurt anything except maybe your back when you lift the amplifiers. Maybe a larger transformer radiates more crud than need be into the surrounding components, but if you don't notice any noise issues you can just say your PS is super manly.
Yes I rechecked bias, adjusted it on Aleph J, measured it on M2. On fire up, M2 has offset of about 190 mV, which quickly settled down. Still had to be readjusted to zero, one channel ran out of adjustment range ( could be fixed with resistor adjustment.) but was down to 3 mV, so good enough.
I don't think conversion to mono block caused the elevated offset on fire up, just never measured it on fire up before.
Aleph J was re checked and adjusted. Both amps were quiet before, and still are hum free.
Liking this just fine.
Russellc
I don't think conversion to mono block caused the elevated offset on fire up, just never measured it on fire up before.
Aleph J was re checked and adjusted. Both amps were quiet before, and still are hum free.
Liking this just fine.
Russellc