Hi!
I was looking for a nice and simple SE amp with one ECL82 per side and found two attractive circuits.
I would like ask the experts about these designs:
-are they operate in Class A?
-has any negative fead back in the circuits?
-which one is better?
Thanks and greets:
Tyimo
I was looking for a nice and simple SE amp with one ECL82 per side and found two attractive circuits.
I would like ask the experts about these designs:
-are they operate in Class A?
-has any negative fead back in the circuits?
-which one is better?
Thanks and greets:
Tyimo
Attachments
Note. Power supply removed from schema -- to dangerous to contemplate
> -are they operate in Class A?
Yes, obviously.
> -has any negative fead back in the circuits?
No. (I won't count the cathode resistor in the first one.)
> -which one is better?
They are essentially THE SAME. Draw them both in the same style: very minor differences.
One BIG difference: #1 does not show a power supply, #2 does, and the #2 power supply as drawn is a death trap!!! It shows one side of the wall-power line connected to chassis. There no indication which side is utility-ground. It is uncertain which wall-socket pin is grounded (60% of my kitchen outlets had black and white reversed). The chassis is exposed to the users at the input connector, which makes the whole hi-fi system "electrically HOT". It can kill you or your children. And as drawn, turning the power switch Off ensures that the chassis will be "hot". Do not build that power supply as shown!!!
Yes, obviously.
> -has any negative fead back in the circuits?
No. (I won't count the cathode resistor in the first one.)
> -which one is better?
They are essentially THE SAME. Draw them both in the same style: very minor differences.
One BIG difference: #1 does not show a power supply, #2 does, and the #2 power supply as drawn is a death trap!!! It shows one side of the wall-power line connected to chassis. There no indication which side is utility-ground. It is uncertain which wall-socket pin is grounded (60% of my kitchen outlets had black and white reversed). The chassis is exposed to the users at the input connector, which makes the whole hi-fi system "electrically HOT". It can kill you or your children. And as drawn, turning the power switch Off ensures that the chassis will be "hot". Do not build that power supply as shown!!!
I think I would just build the more recent of the two circuits, supply decoupling looks to be marginally better in the newer design.
If you do build the earlier one do get a power transformer with about a 180-200V secondary as well as a filament winding. You can use a bridge rectifier, bear in mind the original halfwave rectifier would have dropped significantly more voltage than a full wave bridge.
The old power supply design as previously stated is extremely hazardous to put it mildly.
Kevin
If you do build the earlier one do get a power transformer with about a 180-200V secondary as well as a filament winding. You can use a bridge rectifier, bear in mind the original halfwave rectifier would have dropped significantly more voltage than a full wave bridge.
The old power supply design as previously stated is extremely hazardous to put it mildly.
Kevin
Hi!
Giaime! Yes, you are right! I looked only the main-audio circuit section and not the whole circuit with the PSU... That PSU design was realy a "deadly joke" Thanks for the moderators that removed it from the schematic!
Kevin: Thanks! Which one do you mean: the Noel82, with coloured schem ? I would anyway build a better PSU for this amp.
Greets:
Tyimo
Giaime! Yes, you are right! I looked only the main-audio circuit section and not the whole circuit with the PSU... That PSU design was realy a "deadly joke" Thanks for the moderators that removed it from the schematic!
Kevin: Thanks! Which one do you mean: the Noel82, with coloured schem ? I would anyway build a better PSU for this amp.
Greets:
Tyimo
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