Thanks guys 
. I think that B.B. is best amp so far I have heard, it seems that my friend will take mine to his system. Maybe I'll have to build another one, as passive cooled..don't know, lacking motivation (and extra money) right now.
Would there be too much concentrated heat with huge passive heatsink, since we are using only two devices per amplifier?
. I think that B.B. is best amp so far I have heard, it seems that my friend will take mine to his system. Maybe I'll have to build another one, as passive cooled..don't know, lacking motivation (and extra money) right now.Would there be too much concentrated heat with huge passive heatsink, since we are using only two devices per amplifier?
You need a cpu heat pipe spreader to take the high flux of 100w/3cm^2 out to a larger area. Maybe take a CPU cooler with heat pipes and remove the fins. Then sweat braze the copper pipes to a copper plate. Then bolt the plate to a large radiator. The larger the area of spread on the pipes the better. You can also order bare heat pipes and make your own - it’s more expensive though that way.
Is this for Alpha 20 or B.B. and do you mean just populate the boards with all parts? Are you asking to have the power supply included as well?
I think the Alpha 20.
It is the cheapest of the two to build?
I’ve tried reading though all of this post, and as you know it’s a great and long post to read. But my goal is two channels and cost
Juntuin, try the B. B with taipuu loudspeakers he , sounded promising at expo, ask Mr. K if evaluation listen demo / B.B amp setup is possible with K:s schedule.
If K agrees, and all sets are promising, article could be Inc. in Hifi maailma, no much of good old discrete amp diy they published for a long time. They also have rather good measurement equipment.
University of Oulu they also got only heard not checked by me good equipment and might be helpful.
For xrk971 this could be a good proto test run, promo if all parties agrees.
And a premium build custom Noctua can be ordered they done 12 heatpipes >15000cm^2, ~ 8kg for a client so no problem there, how many channels for B. B or B. B ^XXL with custom Noctua.
A crazy idea, but as B.B is the best you owned, others will probably follow. What do you think. For better amps a small step.
Eu will ban tubes 2019 but not Ixys semis
and mature audience/mech/techs will need something to keep them occupied before or more importantly, when pension age is reached.
What do you think.
If K agrees, and all sets are promising, article could be Inc. in Hifi maailma, no much of good old discrete amp diy they published for a long time. They also have rather good measurement equipment.
University of Oulu they also got only heard not checked by me good equipment and might be helpful.
For xrk971 this could be a good proto test run, promo if all parties agrees.
And a premium build custom Noctua can be ordered they done 12 heatpipes >15000cm^2, ~ 8kg for a client so no problem there, how many channels for B. B or B. B ^XXL with custom Noctua.
A crazy idea, but as B.B is the best you owned, others will probably follow. What do you think. For better amps a small step.
Eu will ban tubes 2019 but not Ixys semis
and mature audience/mech/techs will need something to keep them occupied before or more importantly, when pension age is reached.
What do you think.
I just tried out the new Mark Johnson cap Mx (Prasi layout)for my Class A M2. Using a single 400VA trafo and one pair of external bridge rectifiers powering two independent cap Mx boards, I was able to get operation without any hum or noise. 100uV rms and 300uV rms on outputs of amps.
Might be a good choice to try for Alpha 20. I am running 1.27amp bias on each channel. Voltage dropout is about 2v and main benefit is only a pair of 10,000uF smoothing caps required per channel.
https://www.diyaudio.com/forums/sol...sy-capacitance-multiplier-58.html#post5572538
So a pair of 10mF caps is about 1/10 cost of 8 33mF caps. Cost of 4 BJTs and miscellaneous cap Mx is about $20/pair. So it’s maybe 1/2 cost of CRCRC cap bank for F6 but with better performance of -50dB ripple reduction and superior channel separation. More compact too.
Might be a good choice to try for Alpha 20. I am running 1.27amp bias on each channel. Voltage dropout is about 2v and main benefit is only a pair of 10,000uF smoothing caps required per channel.
https://www.diyaudio.com/forums/sol...sy-capacitance-multiplier-58.html#post5572538
So a pair of 10mF caps is about 1/10 cost of 8 33mF caps. Cost of 4 BJTs and miscellaneous cap Mx is about $20/pair. So it’s maybe 1/2 cost of CRCRC cap bank for F6 but with better performance of -50dB ripple reduction and superior channel separation. More compact too.
Attachments
Last edited:
I didn’t know an IRFP240 can handle 90w of dissipation. But apparently with copper heat spreader and cpu cooler it can. Hmmm... anyone want to try B.B. with a cheap $2 IRFP240 and IRFP9240?
https://www.diyaudio.com/forums/pass-labs/314903-mofo-inductor-options-1khz-2.html#post5247586
https://www.diyaudio.com/forums/pass-labs/314903-mofo-inductor-options-1khz-2.html#post5247586
Hi X, first post for quite a while, hope all is well with you. Winter approaches giving me more free time to continue with Alpha 20W build.
I've been following the cap multiplier discussion with great interest. I am in the position that I can use either a CRC supply or a cap multiplier, as I have ample space and large electrolytics. So I am looking for advice from yourself and other members regarding performance of either. Obviously the most important being sonic performance, which is superior of the two options?
Best regards
Alan
I've been following the cap multiplier discussion with great interest. I am in the position that I can use either a CRC supply or a cap multiplier, as I have ample space and large electrolytics. So I am looking for advice from yourself and other members regarding performance of either. Obviously the most important being sonic performance, which is superior of the two options?
Best regards
Alan
Hello Alan,
Agree, the weather change is a good thing for my DIYA also
I thought I’d chime in on the capMx/ALPHA combo.
My ALPHA BB set up utilizes a pair of capMx’s by Jason Kuetemann based on the works of MrEvil and PMI.
Simplified MrEvil / PMI Capacitance Multiplier
The combination works very good. I tried a few different conventional psu solutions (CRC, CRCRC, CRCLC) with the last being the best, but definitely most expensive and occupied the most real estate.
The capMx psu had the same performance as the CRCLC, as far as I could tell without an O’scope, but did have to be properly cooled (Mosfets and diodes).
I do want to try the same setup with my ALPHA 20, just never got to it yet.
So, when I get my BB in a proper chassis it will have a capMx as it’s psu.
Just my two cents
I haven’t tried it in an Alpha 20 yet, but the sonic quality on the M2 beats the CRCRC. Quieter and superior stereo separation which gives better imaging. Note that if you have two power transformers your stereo separation won’t be improved. I am listening right now and have not heard the M2 sound better. You have to deal with the 2v dropout though so size your trafo for higher voltage. I look forward to making another Alpha 20 to test it out.
I think a KSC1845 will work just fine there. It’s what is used for Alpha 20. I don’t think you need all the dissipation that it provides vs 1845.
Hi X,
That 'M2' cap multiplier is impressive. Could you please put up the schem again, there were a few changes...... I love Prasi's pcb too, elegant.
An IRFP240 will run with 38W and passive cooling for more than 25 years. But at 90W you'd need liquid cooling for a reasonable MTBF to avoid overheating the junctions. If you use passive cooling (my preference) you have to have either a TO264 or an ice puck device, that' HOT.
Thank you for your wonderful energy on the forum, X. You have done a huge service to the community.
HD
That 'M2' cap multiplier is impressive. Could you please put up the schem again, there were a few changes...... I love Prasi's pcb too, elegant.
An IRFP240 will run with 38W and passive cooling for more than 25 years. But at 90W you'd need liquid cooling for a reasonable MTBF to avoid overheating the junctions. If you use passive cooling (my preference) you have to have either a TO264 or an ice puck device, that' HOT.
Thank you for your wonderful energy on the forum, X. You have done a huge service to the community.
HD