Wtb wood cabinets

MarkWComer

MarkWComer

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rollcentre said:
I'm looking for a couple original wood cabs for my PL400s

Thanks !
Keith
Click to expand...
They don’t pop up often on ebay, a rare item. I think you may be better off getting cabinetry equipment and DIY, then you’d have some to sell.

A few threads here mention the need for the bias circuit to have some heat for it to work properly, excess cooling isn’t necessary a good thing, but excess heat hasn’t been discussed regarding those wooden cabs, don’t know if that might be a problem…
 
Gepetto

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MarkWComer said:
They don’t pop up often on ebay, a rare item. I think you may be better off getting cabinetry equipment and DIY, then you’d have some to sell.

A few threads here mention the need for the bias circuit to have some heat for it to work properly, excess cooling isn’t necessary a good thing, but excess heat hasn’t been discussed regarding those wooden cabs, don’t know if that might be a problem…
Click to expand...

Clarification: Excess cooling of the chassis insides is not recommended as this causes the bias transistor to be faked out thinking that the heatsinks are running cooler than reality and thus will set the bias voltage too high for the actual conditions. The bias voltage will go down as the amp heat sinks heat up and that is normal and the way you want it to work.

Adequate to very good cooling of the heatsink fins is a good thing, this keeps the output transistors cool and the bias transistor will properly track that temperature.

The wooden case does not violate any of the above but it can trap the heat generated by the heat sinks more than when they are operating in free air..
 
R

rollcentre

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MarkWComer said:
They don’t pop up often on ebay, a rare item. I think you may be better off getting cabinetry equipment and DIY, then you’d have some to sell.

A few threads here mention the need for the bias circuit to have some heat for it to work properly, excess cooling isn’t necessary a good thing, but excess heat hasn’t been discussed regarding those wooden cabs, don’t know if that might be a problem…
Click to expand...
I've been considering that. I have a couple I snagged from my local vintage stereo shop earlier this year and I'm glad I did now. I could use those as a go-by. They seem incredibly simple to make, but I know nothing about cabinetry. If I go that route I would also like to make some for my early SAE mark stuff. They seem pretty similar to the PL style cabinets , and even more uncommon.
 
R

rollcentre

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Gepetto said:
Clarification: Excess cooling of the chassis insides is not recommended as this causes the bias transistor to be faked out thinking that the heatsinks are running cooler than reality and thus will set the bias voltage too high for the actual conditions. The bias voltage will go down as the amp heat sinks heat up and that is normal and the way you want it to work.

Adequate to very good cooling of the heatsink fins is a good thing, this keeps the output transistors cool and the bias transistor will properly track that temperature.

The wooden case does not violate any of the above but it can trap the heat generated by the heat sinks more than when they are operating in free air..
Click to expand...
Thanks Joe, I have added a couple 120v muffin fans and wired them in series to slow them down, my question is, would it be beneficial in any way to put the metal strips back on the amp that cover the output transistors? I have the covers off for now and the fans blowing right on the transistors
 
Gepetto

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rollcentre said:
Thanks Joe, I have added a couple 120v muffin fans and wired them in series to slow them down, my question is, would it be beneficial in any way to put the metal strips back on the amp that cover the output transistors? I have the covers off for now and the fans blowing right on the transistors
Click to expand...
Those covers prevent shock hazard since there is 160 to 210 VDC between adjacent columns where the transistor cases are live. They do nothing one way or another for cooling
 
MarkWComer

MarkWComer

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Gepetto said:
Clarification: Excess cooling of the chassis insides is not recommended as this causes the bias transistor to be faked out thinking that the heatsinks are running cooler than reality and thus will set the bias voltage too high for the actual conditions. The bias voltage will go down as the amp heat sinks heat up and that is normal and the way you want it to work.

Adequate to very good cooling of the heatsink fins is a good thing, this keeps the output transistors cool and the bias transistor will properly track that temperature.

The wooden case does not violate any of the above but it can trap the heat generated by the heat sinks more than when they are operating in free air..
Click to expand...
Copy that, message acknowledged!
 
mr_rye89

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I have a PL400 series 1 case, it’s crap but have a look anyways. You can have it for shipping if you want it. I don’t know where the missing chunk went.

On a related note, how much are these cases worth?
 

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WOPL Sniffer

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mr_rye89 said:
I have a PL400 series 1 case, it’s crap but have a look anyways. You can have it for shipping if you want it. I don’t know where the missing chunk went.

On a related note, how much are these cases worth?
Click to expand...

I got offered $175 for a nice one which is on my soon to be WOPL'd 400 II, and I also got the wood side panels which just screw to the sides of the amp which is cool..
 
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