Very true. With a bit of work there are other pieces worth a bit, though negligible compared to the original cost.
Pcgab,
You are indeed close to first sound. Good luck! Did you end up going with the Heatsinksusa profile?
X
You are indeed close to first sound. Good luck! Did you end up going with the Heatsinksusa profile?
X
I haven't ordered them yet, I'm going to fire it up and listen with the Dell heatsinks, then figure out long-term plans.
I ran IRFs for more than 25 years running at 38W (1.4A with Vds of 27V) each, with two on a 300x100 heatsink to do 76W total.
This was an early Class A amp I'd designed in 1994 called the Glass Harmony.
This was a very nice sound, but hugely inefficient, did 152W of heat EACH CHANNEL for only 28W of heavenly Class A sound. Front end was a 6SL7 tube at B+ of 340V.
I never had a failure, and I believe the device packages at the heatsink were over 60C.
They are very tough devices, with a nice tempco and current structure which makes them more durable than bipolars in this role.
HD
This was an early Class A amp I'd designed in 1994 called the Glass Harmony.
This was a very nice sound, but hugely inefficient, did 152W of heat EACH CHANNEL for only 28W of heavenly Class A sound. Front end was a 6SL7 tube at B+ of 340V.
I never had a failure, and I believe the device packages at the heatsink were over 60C.
They are very tough devices, with a nice tempco and current structure which makes them more durable than bipolars in this role.
HD
Ha! I just pulled it out to check the batteries earlier today.
Hopefully I can get my mosfets measured in the next few days, I'm ready to listen to this bad boy on my horn system.
Get well JPS, sorry about the flu - it’s pretty bad this year. The design looks great.
One comment, I use female spade connectors with plastic sheath and they need more clearance - can you move them away from the nearby caps a bit?
Thanks,
X
PCB's came today, many thanks for the design team 🙂 they really are super nice quality.
First PCB almost stuffed now, seems that I'm missing one resistor and many caps. I used Vunce's BOM and he clearly told before that it's incomplete, just couldn't remember that anymore 😀 most important parts are there though and missing ones I can buy locally.
For R131 I used one .33ohm 5w and R132 one .12ohm 3w like Vunce, I assume they are just fine...?
First PCB almost stuffed now, seems that I'm missing one resistor and many caps. I used Vunce's BOM and he clearly told before that it's incomplete, just couldn't remember that anymore 😀 most important parts are there though and missing ones I can buy locally.
For R131 I used one .33ohm 5w and R132 one .12ohm 3w like Vunce, I assume they are just fine...?
Yes. But actually, if you use double 0.33R in parallel for R132, when you apply AC excitation, the optimal Aleph CCS tuning (via trimpots) strives to make AC voltages between R131 and R132 equal (since we want 2x the AC current in R132 vs R131). But 0.12R is fine if you have it.
Hi, question please. What type of capacitor is best used in positions C105 and C113 ( 18pf ),should I use silver mica or multilayer ceramic ?
Also why is carbon film chosen for R 113 (22k )
Regards
Also why is carbon film chosen for R 113 (22k )
Regards
Hi Juntuin,
I never released a BOM?
I referenced the schematic to make up my parts list. The values I picked for R131 & R132 are on it.
Regards,
Vunce
I might remember wrong, I picked it up many pages ago and thought it was made by you (more like yourself, only parts what you didn't have) 😕 sorry!
No problem Juntuin 🙂
It seems like not too long ago there was just about 10 pages, and now there’s over 70 pages to this thread! It can get very confusing 😕
It seems like not too long ago there was just about 10 pages, and now there’s over 70 pages to this thread! It can get very confusing 😕
Tell me about it! It's getting pain in the *** to search all the valuable information, since I'm not such a talented builder, and I need to dig all facts in this topic that I can 🙂