300b

[snodge]

After some time and a lot of thinking I have just picked up a 300B PP amplifier. I am looking forward to receiving it and plugging it in. I have heard that they run pretty hot. Is this the case? Rgds David

[Richard]

Hi David, If yours is the WAD stereo chassis 300B pp then it runs similar to other large stereo pp amps which are running in Class A such as KT88, 6550 and EL34.

The power used is similar at around 200W. It's useful to remember that Class A means (amongst other things) that the amp is running flat out all the time regardless of how high the volume level is set and I always switched it off between listening sessions to save power and valve life.

So yes they run warm/hand hot in the same way you'd expect a couple of old tungsten 100W bulbs to warm up a space/box.

I've had all these amp types and once put a temp probe inside one and it was 48C. The 300B pp was similar to the others and didn't seem to suffer in particular and was good and reliable. Amps where, say, the mains TX seems overly hot may be down to under spec/over running the mains TX design.

[snodge]

Hi Richard, many thanks for the reply. I am looking forward to receiving the amp and wiring it in. Best regards David