princeton reverb high frequency squeal

[oahu]

hello.

build a princeton reverb clone, and it worked, sounded good, but only for 3 hours...

now everything i get is a high frequency squeal, when i switch it on...

i thought, it might be the tubes, but i used different ones, same thing again. so what can this be?

greetings from vienna

[oahu]

it's gone...

after some seconds the squeal was gone, and i hit some caps with the plastic side of a screw-driver, to see, if there is a bad solder-joint. nothing. sounds like it should again. the voltages read like they should too...

then i turned the amp off, waited a few minutes and turned it on again. no squealing...

what was that? any ideas? hope it don't appear again...

[TD_Madden]

maybe try swapping the leads on pin three of the 6V6s?

[oahu]

many thanks

hello.

i will do this, if this noise ever comes again. for now it works without any problems. (I've played it about 3 hours today, no squealing...) and it sounds just great.

i've changed some tubes around. i also plan to get a mercury magnetics output transformer (are they really that good?), and a celestion alnico gold speaker (any experience with those?)... we'll see..

greetings from vienna

[gearfixer]

Check the reverb solder and cable conections had the same thing on my PR build.

[oahu]

thanks again

i've checked all that. what i think is, it was the input-jack, that didn't ground, as this noise was there, when nothing was plugged in, but i could not reproduce it, anyway... (see geofex... oh well..)

played the amp for 4 hours since this happened. nothing... no squeal... we'll see.

if it is something else, i'll let you know...

greetings from vienna...

[oahu]

celestion alnico gold vs. jensen c12q

hello everybody.

i got my celestion alnico gold 50w speaker now.

it's nice, when played at high volume. the clean range is not that good.

but for the princeton-clone the jensen C12Q sounds better to me, clean and on fullume. (oh well, the jensen is just 1/8 the price of the celestion!!!).

i also printed the data sheets of the 2 speakers.

who needs to know the voice coil inductance at 1kHz? if you don't know that, its 0.62 mH. ah! yes...

anyway, the amp is sounding great now...

greetings from vienna