"Just as an example, placing the output coil on the PCB. "
On the new PCB I mentioned above, I have taken th e output coil and Zobel off the main board and placed on the output connector PCB for the reasons you quoted above. I moved to Zobel as well since I was afraid of noise at high frequncies getting into the grounds on the PCB - although I believe the ground layout is quite good anyway.
On the new PCB I mentioned above, I have taken th e output coil and Zobel off the main board and placed on the output connector PCB for the reasons you quoted above. I moved to Zobel as well since I was afraid of noise at high frequncies getting into the grounds on the PCB - although I believe the ground layout is quite good anyway.
If you go anywhere beyond two numbers in a table, you'll find out that copper and aluminum are very close in thermal conductivity. It would help if you would consider a practical POW: how would the required HS area change when you change the material, from aluminum to copper.
But don't rush into this, you have to do first your negative feedback homework.
Apparently, copper has 2 X the conductivity of aluminum.
In practice, air flow, cost and weight are the determining factors:
http://www.thermshield.com/ThermshieldPages/Copper_vs_Aluminum.pdf
/Hugo
In practice, air flow, cost and weight are the determining factors:
http://www.thermshield.com/ThermshieldPages/Copper_vs_Aluminum.pdf
/Hugo
That's exactly what I am saying. Numbers are different, but as different as 1000000000 to 2000000000. Double, but who cares. BTW, we are not talking about forced cooling here.
Mr Oopopa,
maybe it helps if Upupa would mention what insulator type he uses between the heatsink and the copper bar.
(who knows, it might even be a layer of high thermal conductivity graphite-epoxy.)
That would be o0popa, please.
I was thinking more like a sheet of synthetic diamond, but then the entire story with the "thermal pulse response" doesn't keep water.
Like syn08 stated, FX visual effects in amp are complete waste of time and money and none of any importance; it can only impress some enthusiastic aesthete. 
What bothers me are mediocre schematic, mid quality caps, suspicious wires, output relay (?), opamp input un/balanced amplifier (?) and a lot of other nonsenses. But watch, there are golden plated screws?!
I'm sorry, but these are typical nonsenses significant for eastern-block industry.
What bothers me are mediocre schematic, mid quality caps, suspicious wires, output relay (?), opamp input un/balanced amplifier (?) and a lot of other nonsenses. But watch, there are golden plated screws?!
I'm sorry, but these are typical nonsenses significant for eastern-block industry.
Last edited:
Mid quality in the present context of course. If you talk about gold plated screws, you would expect at least RIFA 120° caps inside: very long lifetime, Z100kHz=4mohms, ...
There's also present the worst thing common to almost all DIY amps: output relay !!!
Please DIY-ers, do make amps without this archaic solution.
Last edited:
In my life I heard many amps with top grade caps, which sound was horrible...and amp without relay ? Do you know cannon shot from 1812 ? It make amp sometimes, especially when is complement by low z caps...
That was not caps to blame but mediocre sch.
Do you know how relay contacts looks after few years? All major role players on the market skiped them long ago.
Umm, solid-state tech has no contacts. There are devces to control large currents, using our good old n-p junctons, after all. Sure, some of them might have to take a little bit of space for heatsnks, but there's no problems with contact aging. Are they in any way worse than normal relays?
Anyway, after a good amount of years, there'll be a few parts here and there that need replacng. It's only a question of how many.
Anyway, after a good amount of years, there'll be a few parts here and there that need replacng. It's only a question of how many.
Last edited:
Ohhhhhhh I have been misguided for the last 30 years doing DIY. DIY audio must not look good
And you absolutely MUST use very expensive “magic caps” (standard caps in a new oversized cans?) and resistors made of ferry hair (standard carbon resistors?) and then dip the whole circuit into snake oil for at least 24 hours before putting into a crappy chassis…….
What’s the problem here ?
DIY is about making good sounding circuits to match the commercials. Those who as I have worked with high priced commercial stuff know that not all is gold under the bonnet of a $10,000 power amp. Most use standard components, but these have been selected by their sound/price/quality relation.
I think some here are envious about Pavels skills in making great sounding amps and great looking innovative PCB layouts (got a DPA222 my self). Many here knows Pavel as a very helpful person with very few secrets. You can disagree with his way of doing things, but sometime it could be wise to “listen and learn”.
And what’s wrong with offering the circuits assembled and in a nice chassis? I know you can buy the bare PCBs and assemble them your self. As a true DIYer you can just put them in a crappy chassis
"There's also present the worst thing common to almost all DIY amps: output relay !!! "
My amp can deliver 450W into 4Ohms and peak currents of 40A. My speakers cost me $4k. I think I'll stick to using a relay on the amp output to protect my investment.
Do you have a better solution? Please show us.
(look at my words carefully: A better solution)
My amp can deliver 450W into 4Ohms and peak currents of 40A. My speakers cost me $4k. I think I'll stick to using a relay on the amp output to protect my investment.
Do you have a better solution? Please show us.
(look at my words carefully: A better solution)
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.