LOL!
Regardless, we all know that it's an addiction with no known cure.
(I am currently making an order to make a 'universal' external PSU for my Pass/Firstwatt amps. A box with the transformer, bridge, caps, etc... so I only have to pay for/build one powersupply, and just make amp channels on heatsinks or in smaller chassis. Not having to buy a PSU for every amp means that I can try more of them! Hooray!)
See, it's not just you. 😀 😀 😀
Regardless, we all know that it's an addiction with no known cure.
(I am currently making an order to make a 'universal' external PSU for my Pass/Firstwatt amps. A box with the transformer, bridge, caps, etc... so I only have to pay for/build one powersupply, and just make amp channels on heatsinks or in smaller chassis. Not having to buy a PSU for every amp means that I can try more of them! Hooray!)
See, it's not just you. 😀 😀 😀
Yes a seperate p/s is an excellent idea.I have a set of PD's Aleph J boards assembled and waiting in the wings but I'm going to have to disassemble my F5 to put it together.Was thinking of just swapping out the pcb's and heatsinks but the last quote for heatsinks unanodised was 300GBP's talk about rip off Britain! 🙁
Ideally one case only having large heatsinks, a multitapped transformer and high enough voltage rated caps of consequent capacitance might serve for most of amp boards to try including classA, AB, Or even chip amps.
You'll end with many holes into the heatsinks though is that a problem?
If you can't stop building amps it will go cheaper.
You'll end with many holes into the heatsinks though is that a problem?
If you can't stop building amps it will go cheaper.
Yes, exactly. Nothing complicated... merely oversized (600VA transformer) with 100,000uf per rail, convenient, (Speakon connections for the power umbilical) and in a nice box to look good.
Hi guys,
Today I finally connected my new Aleph J to my main system. It would take too much time to set up in my study, so I decided to take the plunge in the main system.
It replaces my Pass Labs built Aleph 3 and runs mid/hi on my 4 Ohm Magnepan MG3a's. Not an ideal marriage, but .... SHE SINGS!
First impressions (single ended input):
I will not try to explain the differences at this stage, but just enjoy the music! After a week or so, when it is burnt in properly, I hope to be able to do some comparing and also try out the balanced inputs.
A friend of mine built a pair of Aleph 2 monoblocks for me about 6 years ago. I intended to use them in my main system because the Aleph 3 is a bit small for the power hungry Magnepans. While the 2's sound very nice, they could not match the Aleph 3 in sound quality and ended up in my study. Having just switched on the J it is interesting that I do not (yet) miss the 3.
Having built my first power amp I now plan to take the Aleph 2's apart 😀
I have already seen that some parts could do with upgrading (Silmic caps, better internal wiring, small film caps in PSU, etc). I will try to get the 2's to sound closer to the 3. Depending on how the J settles down, I might end up converting the 2's to a jfet front-end, but will need serious help from you guys if I do!
Thanks everyone, I am a very happy builder! 🙂
Albert
Today I finally connected my new Aleph J to my main system. It would take too much time to set up in my study, so I decided to take the plunge in the main system.
It replaces my Pass Labs built Aleph 3 and runs mid/hi on my 4 Ohm Magnepan MG3a's. Not an ideal marriage, but .... SHE SINGS!
First impressions (single ended input):
- Dead quiet.
- The sound is different.
- It really draws you into the music.
I will not try to explain the differences at this stage, but just enjoy the music! After a week or so, when it is burnt in properly, I hope to be able to do some comparing and also try out the balanced inputs.
A friend of mine built a pair of Aleph 2 monoblocks for me about 6 years ago. I intended to use them in my main system because the Aleph 3 is a bit small for the power hungry Magnepans. While the 2's sound very nice, they could not match the Aleph 3 in sound quality and ended up in my study. Having just switched on the J it is interesting that I do not (yet) miss the 3.
Having built my first power amp I now plan to take the Aleph 2's apart 😀
I have already seen that some parts could do with upgrading (Silmic caps, better internal wiring, small film caps in PSU, etc). I will try to get the 2's to sound closer to the 3. Depending on how the J settles down, I might end up converting the 2's to a jfet front-end, but will need serious help from you guys if I do!
Thanks everyone, I am a very happy builder! 🙂
Albert
I succeeded in stripping 1 F5 Chanel & replacing with Aleph J
Matched mosfet, jfet. ZTX critter.Here are my voltage readings
R7-4.92V
R8-8.94V (case of Zener not dropping 9.1V??)
R16-.521V
R17-.610V (??)
R18-.563V
R19-.557V
No voltage across R20/21/22/23???
Offset after 1 hour 27mV.Plays music, things which sound harsh with F5 are mellower.
Any concerns with the above???
Matched mosfet, jfet. ZTX critter.Here are my voltage readings
R7-4.92V
R8-8.94V (case of Zener not dropping 9.1V??)
R16-.521V
R17-.610V (??)
R18-.563V
R19-.557V
No voltage across R20/21/22/23???
Offset after 1 hour 27mV.Plays music, things which sound harsh with F5 are mellower.
Any concerns with the above???
that mosfet connected to R17 is somewhat off (unmatched) , but it can't be main thing for your (un)satisfaction , against F5
check AC gain of Aleph CCS , just in case
whatever , I always preferred Aleph J to F5 , at least with my spks and my ears 😉
check AC gain of Aleph CCS , just in case
whatever , I always preferred Aleph J to F5 , at least with my spks and my ears 😉
Zen, as I said things which are harsh with F5 are mellower with J.
So J at the very alpha stage suits me better than 5.
But I need to do the 2nd channel and connect them to my 2.5 spks(90db with woofers going down to 7.1 ohm -- same characteristic as the 2 ways that 6 moon reviewed the J with) to come to a conclusion
In itself are my readings any cause for concern
So J at the very alpha stage suits me better than 5.
But I need to do the 2nd channel and connect them to my 2.5 spks(90db with woofers going down to 7.1 ohm -- same characteristic as the 2 ways that 6 moon reviewed the J with) to come to a conclusion
In itself are my readings any cause for concern
sorry for miss-read from my side
just woke up , prior to that post 😉
well - if you have no better matched mosfets , just leave them as is and be 😎
that was one of the reasons why I used IRFP150 in my Babelfish J - just one pair/ch. , no matching required , lesser capacitances blahblah
no matching was main reason
just woke up , prior to that post 😉
well - if you have no better matched mosfets , just leave them as is and be 😎
that was one of the reasons why I used IRFP150 in my Babelfish J - just one pair/ch. , no matching required , lesser capacitances blahblah
no matching was main reason
Nah no more matched stuff :-(.Guess the source resistors also there as an insurance against badly matched mosfets.
The other channel will be with BC critters & some changes to the grounding scheme.
Right now RCA gnd is of the amp PCB,while IN- & out gnd is off psu gnd.
Will lift the RCA gnd off the psu gnd & see whether the buzz goes
The other channel will be with BC critters & some changes to the grounding scheme.
Right now RCA gnd is of the amp PCB,while IN- & out gnd is off psu gnd.
Will lift the RCA gnd off the psu gnd & see whether the buzz goes
Thanks, I'll do the second channel.
By the way what kind of effect will the mismatch have on sound ..I check the Vgs in circuit
one has ~100mV less than others.Worth the effort changing the pair 🙂?
Offset is fine though ~25mV
By the way what kind of effect will the mismatch have on sound ..I check the Vgs in circuit
one has ~100mV less than others.Worth the effort changing the pair 🙂?
Offset is fine though ~25mV
Is there anybody out there that knows PCB design and could design an Aleph J board for the Universal Mounting Spec?
