I hope this is the correct forum to ask this question. I am using a pair of F6 monoblocks to drive a pair of 5 ohm nominal speakers, 4.5 ohms minimum. The F6 sounds surprisingly good with them (I don't listen very loud). Would an Aleph 60 build drive a 5 ohm load better or worse than the F6? I am curious because I think the Aleph 60 is single ended class A, compared to push pull of the F6.
Thanks,
Alan
Thanks,
Alan
It doesn't sound like I am running into current delivery issues with the F6, at least up to a certain volume. Somewhere between medium and loud volume, the F6 will stop sounding "full" and can get a little edgy. The speakers are not very efficient. The F6 sounds really good at a medium volume, and I would like to keep a similar flavor sound flavor with a touch more power in reserve. I built a high power, low distortion class AB amp last year to drive them, which drives them cleanly at any volume I would listen, but the F6 gives a warm, full sound that I find extremely engaging. Thus I am wondering about the Aleph 60 build. I think I read somewhere that the original Aleph 60 would deliver 100 watts into 4 ohms, which I found confusing compared to the Aleph J, which is also single ended class A but delivers less power into 4 ohms than 8 ohms.
If you need power, I recommend the A2s over the A5s and 60s.
I also got an F5, a non starter into my Maggies (current hogs at 93 db/w), perhaps an F5 Turbo V3 in the future?
I've been running the A5s for a few years now, they sound very good and I've been extremely happy with them but, sometimes, they just didn't play loud enough. Just got the A2s hooked up today. Sort of like the A5s but with much better bass and the ability to play relatively "uncongested" with much better dynamics. The soundstage doesn't shrink as the volume increases.
No contest.
Into power hungry speakers, power doesn't corrupt, power is necessary.
Sure, of course, it likely sounds different (A2 vs F6) but, but, if it doesn't sound loud enough, it just doesn't sound right at all.
Compromises.
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Hi,
maybe a dumb question, but can I use the PSU of this amp for every First Watt amp with +/-25v rails without change (f.e. for the M2x)?
I use 33000uF 35v caps and the resistors are 0.27R 5watt in parallel.
I'm planning to build the PSU in a separate chassis so I can use it with different amps - if there are no changes required.
maybe a dumb question, but can I use the PSU of this amp for every First Watt amp with +/-25v rails without change (f.e. for the M2x)?
I use 33000uF 35v caps and the resistors are 0.27R 5watt in parallel.
I'm planning to build the PSU in a separate chassis so I can use it with different amps - if there are no changes required.
It should work for all of the first watt amps with dual rail +/- 24 or 25v rails.
I’ve never done the external supply for power amps, but it is suggested to put a final bank of caps in the amp chassis, too.
Many thanks Randy!
Is the (additional?) cap bank suggested even if I plan to use 7 mm2 shielded connection between amp and psu?
Is the (additional?) cap bank suggested even if I plan to use 7 mm2 shielded connection between amp and psu?
A PSU with large caps like the 33,000 uF mentioned will benefit from having smaller caps (470 to 2200 uF) in parallel to reduce supply impedance at high frequencies. Those smaller caps need to be close to the amp PCBs, inside the amp chassis.
I have the old Brian GT documents (as well as an article) on making an Aleph Mini. Maybe you could cross reference the changes between the models to the UMS chassis board and make a smaller aleph with your UMS boards. You could start with that and when you get new heatsinks/chassis, you can build the rest out. Let me know if you would like them. It would be interesting to hear the changes anyways.
The idea is to use only enough IRFP240's to keep the bias high. I had a couple of heatsinks that I built an Aleph mini on. They were about the size of yours with horizontal fins so not as efficient. It sounded really good. Not much authority in the bass but the main attraction was still there.
Pm sent. I can make a mini build doc and BOM for these boards.
Idk where I posted it now, but I ended up turning my Aleph 30 into an Aleph "20" by pulling one pair of output transistors per board, leaving two pairs per channel, and mounting the thing in a 3U 300 Dissipante chassis which previously held an F3. An Antek AN-3218 donut just barely fits. I didn't need to make any changes to the DC offset or bias, L-R channels were at 30mV and 14mV, respectively and 1.5A bias, +/- 21.8V rails loaded. I must have done a better job with grounding this time as there's almost zero hum/buzz, compared to when the Aleph 30 was in a 4U Deluxe.
The sinks of this Aleph 20 get no hotter than an ACA's. 3-5 second touch no problems.
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Very nice! Now I think I do remember seeing your post somewhere. Maybe the pass project photo thread.
The one I built had point-to-point wiring for the PS supply, cheap resistors on that circuit, wooden bottom to the chassis, no real provisions for transformer snubbing etc. Against all odds, it was quiet. I also built it with IRFP150's which is the equivalant of two IRFP240's. That probably brought the distortion down a bit
The new UMS boards look so much better and much more practical. I built mine as cheap as possible to be a garage amp thinking it was am old design etc. Now I am planning another one for my main system! I was surprised to say the least. I shut my other amps off for a while and just let this little thing cook the house.
You know what would be neat is if HIfi 2000 made a mini UMS case where mini amps could be made. Something the size of the Vfet case. I think this amp was only 10-15 watts or so and it was great.
The one I built had point-to-point wiring for the PS supply, cheap resistors on that circuit, wooden bottom to the chassis, no real provisions for transformer snubbing etc. Against all odds, it was quiet. I also built it with IRFP150's which is the equivalant of two IRFP240's. That probably brought the distortion down a bit
The new UMS boards look so much better and much more practical. I built mine as cheap as possible to be a garage amp thinking it was am old design etc. Now I am planning another one for my main system! I was surprised to say the least. I shut my other amps off for a while and just let this little thing cook the house.
You know what would be neat is if HIfi 2000 made a mini UMS case where mini amps could be made. Something the size of the Vfet case. I think this amp was only 10-15 watts or so and it was great.
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Wow, the point-to-point work is pretty amazing. I tend to have so many issues when building that I make everything modular. I was thinking of making an amp with a front and back wooden panel as well, just heat sinks, top & bottom lids would be metal. I have some salvaged sinks drilled out to mount 2SK180's in but it remains to be seen if they can dissipate the power without fans. I'll have to pick a design with a relatively low bias.
Modular is a great approach. I build a lot of my cases out of wood both preamps and amps. I am surprised to say that I haven't had a noisy amp yet. I thought I was going to have to get creative with the shielding. Even just a nice piece of wood on the front of a case dresses things up a bit.
The little Aleph was comprised of the most wood yet was particularly quiet. Wood bottom, front and the top was just galvanized mesh painted black. I suspect the Aleph circuit may just be a quiet one.
You do lose a little bit of the cooling ability though as the wood insulates a bit. So you would want to have your heatsinks be a bit larger than typical.
The little Aleph was comprised of the most wood yet was particularly quiet. Wood bottom, front and the top was just galvanized mesh painted black. I suspect the Aleph circuit may just be a quiet one.
You do lose a little bit of the cooling ability though as the wood insulates a bit. So you would want to have your heatsinks be a bit larger than typical.
Hi! Please can you explane me the reason of C6 (1nF) and its iteration on sound performances?
Thanks in advance.
Antonio
https://www.diyaudio.com/community/threads/aleph-choice.3176/
C104 on the Aleph 3 schematic is C6 on the "Classic Aleph" PCBs.
From Papa himself:
C104 on the Aleph 3 schematic is C6 on the "Classic Aleph" PCBs.
From Papa himself:
I finished these Aleph 2's about a month ago for a friend. Randy's boards are easy to use and very straight forward. Mosfets were well matched and the 9610's being harris parts are icing on the cake.
I went the bolt-it-together approach trying to keep things as simple as possible. The only holes that I had to drill were opening up the holes for the transformers and the holes for the rectifier bolts. Otherwise no machine work. Not something I am used to.
I have the heatsinks between 25-30 degrees celsius above ambient.
The amp sounds terrific. A nice large weighty sound with a little warmth and sugar on top. Reasonably detailed while not being a fast amp with sharp edges. One of the Pass sounds that I have come to love. Before these, I had only heard Aleph Mini which was only around 18 watts. Going off of memory, I hear a lot of similarities with the Aleph 2's being a lot better overall.
A big thank you to Randy and Mr Pass! 🙂
Attached are a few pictures. Don't mind the state of the floor and trim. This is an 1840's farm house that is in the middle of a remodel.
I went the bolt-it-together approach trying to keep things as simple as possible. The only holes that I had to drill were opening up the holes for the transformers and the holes for the rectifier bolts. Otherwise no machine work. Not something I am used to.
I have the heatsinks between 25-30 degrees celsius above ambient.
The amp sounds terrific. A nice large weighty sound with a little warmth and sugar on top. Reasonably detailed while not being a fast amp with sharp edges. One of the Pass sounds that I have come to love. Before these, I had only heard Aleph Mini which was only around 18 watts. Going off of memory, I hear a lot of similarities with the Aleph 2's being a lot better overall.
A big thank you to Randy and Mr Pass! 🙂
Attached are a few pictures. Don't mind the state of the floor and trim. This is an 1840's farm house that is in the middle of a remodel.
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