JLH/PLH PC Boards?

[Winding Man]

Does anyone know if a PCB board was made for the PLH amp?

Ta

WM

 

[Nelson Pass]

I did not make one, but I probably could.

What dimensions? Are you mounting outputs on the board?
What are the hole placements?

 

[Winding Man]

I did not make one, but I probably could.

What dimensions? Are you mounting outputs on the board?
What are the hole placements?

Hello Nelson,

I would want to mount the outputs on the board - well on the edge of the board I guess?

Mono boards and I was hoping to use the IRFP240's that I have assuming they can do the duty.
Dimensions are not critical would design the box around them...

I really dont know how you find the time to be so active in this forum and produce all the kit you do as well!

Much obliged.

WM

 

[bigfishe]

I would totally buy a PLH board.

 

[Winding Man]

I would totally buy a PLH board.

Yes I am sure the list here will grow!

Nelson one other thing I have just thought of - I would want the version with paralleled output devices i.e Fig 11 in your writeup?

Thanks again.

WM

 

[Winding Man]

O.K not growing...

Never mind Nelson clearly not worth it!

I will look at recreating JLHs bipolar endeavours instead.

WM

 

[knutn]

I am working on an all-FET version of the JLH class A, where the ouput is very similar to (OK, nearly a copy of..) the PLH amplifier. So it is a 4 transistor design. But I use split supply (plus/minus 24 V).

 

[Winding Man]

Hello,

Thanks yes I would be interested - I need the PCB foil pattern though which is why I have switched to the JLH bipolar 1969 version - I have got a foil pattern for that.

Ta

WM

 

[knutn]

Here is the schematic. I have ordered the PCBs, and as soon I receive them, I can start mounting the components before initial testing.

I plan to use a 2x18 V 500VA transformer common for the two channels. I also have two quite large heatsinks (0.3 K/W) which I plan to use. This amplifier favours high quiescent current, so maybe I can set this as high as 1.8 A...

 

[Nelson Pass]

You are perhaps missing the opportunity to adjust the balance between
the positive and negative output drives. Look at the pots on the PLH
schematic.

 

[knutn]

Yes I know what you mean. I have not quite decided yet if I am going to use a pot as done in the PLH amplifier. For the time being I have thought of using to resistors instead of the pot and then have the possibilty to change between push pull and something like halfway single ended.

 

[Winding Man]

Here is the schematic. I have ordered the PCBs, and as soon I receive them, I can start mounting the components before initial testing.

I plan to use a 2x18 V 500VA transformer common for the two channels. I also have two quite large heatsinks (0.3 K/W) which I plan to use. This amplifier favours high quiescent current, so maybe I can set this as high as 1.8 A...

This is certainly looking good to me! - Nelson can help crit the design I am not up to that - but I mean the concept and the components!

I have a pair of Conrad MF35-151.5 heatsinks rated at 0.21C/Watt and I have IRFP240s - so yes very happy with the direction this is going knutn!

Thanks

WM

 

[knutn]

Winding Man - you've got PM

 

[Winding Man]

Winding Man - you've got PM

Replied!

Yes still interested!

Ta


WM

 

[JZatopa]

I would buy a pair of PLH PCBs.

 

[Allen Newby]

Knut,

You can balance the drive on the output transistors by splitting the 0.47 ohm sense resistor into a centre tapped pair of 0.235 ohms, with the the feedback resistor R14, the bootstap capacitor C20 and the loudspeaker connected to the same point. I used this approach in the latest version of my interpretation of ZenV4 - similar topology to J Aleph.

See: http://www.diyaudio.com/forums/pass-labs/161716-aleph-current-source-mod.html

 

[knutn]

My objective was to make an all-FET JLH amplifier using the work done by Pass (the PLH amplifier). I do not doubt that the amplifier presented is very good, but a possible realization have to wait ....