6L6GC/EL34 SE Stereo Design

[Sch3mat1c]

Ah, now your posts appear (between John's and my last post). Looks nice!

Tim

 

[Sch3mat1c]

Re: Questions

So, what do you suggest I do to the exposed aluminum of the chassis to keep it clean? I'd rather not have to take it all apart and sand and spray ... and so on. Any ideas????

Aluminum itself is generally pretty corrosion-resistant, how much depends on what alloy of course. You don't really have to do anything to it, of course if you want a different color or finish, you'll have to take it apart.

im

 

[bartr0n]

Hey, got a serious question. I'm using a Hammond 270HX and it runs very hot and hums a bit. Is this normal? I've read that it is normal for it to run a little warm. I know that I am within power ratings, and I shouldn't be pulsing it too hard if that's what's happening (for a CLC filter). Any ideas on this?

Also, my standby switch has shorted in some way so that it is always on now. It measures to spec with a DMM (10 Meg Ohm off resistance???), but the amp is now on in either direction. It had a rating of 1Kv peak. Any recommendations for a replacement? Just has to fit a 1/2" hole.

Also, any directions to learn about global neggative feedback? I'm having a hard time looking it up. Thnx.

-=Bart=-

 

[Sch3mat1c]

Very hot = ? Does it pass the 10-second test (try holding your finger on it for 10s), does it boil water, is it glowing red?

Hmmm, 270HX, 550VCT 200mA plus heater windings, unless your first C is extremely large and fed with an SS rect., it should be more than adequate. It should run maybe luke-warm with the load that I think you have on there.

I have a 269AX running at 65mA (it's rated for 100 but that's FWCT, not FWB rect. which is half), which is over the published limit, and it just passes the 10-second test. Hammond does good work, although the PTs might hum a bit (my 272BX does).

Tim

 

[Positron]

10 megs.

is too low. It should measure infinity.

The switch is bad. I think Allied Electronics has some switches that are rated higher voltage, but don't quote me on that.

 

[fdegrove]

Hi,

is too low. It should measure infinity.

Yes.

I usually put a snubber across the contacts, they'll last for ever that way....

Unless there's something else wrong with the amp; if you have a leaky cap then that can cause excess current draw too causing all kinds of odd things exactly as you describe them.

Cheers,