5e3 problem - low output!

[M Fowler]

Are you sure the OT is any good, sounds like a blown OT.

Low output with distorted sound?

Mark

[tsutt]

Nik, good links. I wonder now if it worth recapping the knight signal tracer i got from my dad. Looks brand new inside.

[alvarezh]

"Are you sure the OT is any good, sounds like a blown OT.

Low output with distorted sound?"

I am with you Mark.

All the best

[cbass]

If he played his guitar through it while the speaker was unhooked Then the blown OT is Likely

[alvarezh]

Badly performed transformer leads solder joints can cause the same damage as those of a loose or unhooked speaker lead.

Good weekend guys.

[ben85]

the sound coming out is very clean,not distorted.although i can't be sure for the OT,i have to tell that it seems to me that my 6V6s do not get any signal,cos as i said,they do not change color or turn more blue or something like this when i play,when i 've played in another 5e3 with the same tubes and when i was playing the 6V6s were turning blue.i don't know if i'm correct for this diagnosis though

[tsutt]

Have you measure the voltage at the plates on the 6v6's, looks like pin 3 looking at the the tubes isnt going to tell you anything.

[ben85]

i've measured it at 346v,at both tubes

[Tillydog]

... it seems to me that my 6V6s do not get any signal,cos as i said,they do not change color or turn more blue or something like this when i play...

Don't worry about this - it means nothing.

Measure the DC voltage from the chassis to every pin of every tube and post the results. Make the measurement at the tube socket. Make a note if the speaker clicks (loud or quiet) when you take each measurement (this is what you've been asked to do already). Post this information, also.

For example:

V1:
Pin
1 - 120V - click
2 - 0V - loud click
3 - 0.8V
4 - 3V
5 - 3V
6- 200V - quiet click
7 - 0V loud click
8 - 1.5V
9 - 3V

V2:
Pin
1 -
2 -

..... and so on to the 6V6s.

Post you A, B & C voltages measured at the same time (I know you have already posted some, but something may have changed, so measure them again)

[ben85]

ok,thank you Tillydog,i'll check and post later!

[ben85]

well,i checked v1 and i found:

pin

1- 172v, no click
2- 0v, no click,but loud noise
3- 1v, no click
6- 164v, quiet click
7- 0v, no click
8- 1v, no click

then i went on to check v2...

at pin 1 there was a very loud and continuous noise,even after i pulled off the probe from the pin.so, i thought i'd better ask before i continue checking.so,what's this?Also,since then,wherever i switch on stand by,this very loud noise is coming out!!!what the hell?

i also checked A, previously, at 344v and there was the same,as loud as at pin 1 at v2,noise when i tried to measure B...

[Tillydog]

....at pin 1 there was a very loud and continuous noise,even after i pulled off the probe from the pin....

It sounds like you have found a bad connection or a short circuit.

Turn the amp off, leave it for 10 minutes for the capacitors discharge (check that the A, B & C voltages are below 10V), then examine the connections in that area very carefully and re-make any that are not *perfect*. (You should not rely on the ohm meter test to decide if a connection is good. It must look good, too.)

When you're done, go back and repeat the voltage measurement and click test and post the results. Start over from the begining again, as something may have changed.

Good luck.

[martin manning]

As T-dog says, this is sounding like you still have some bad solder joints. It's common to get a buzzing sound if the input (control grid, pins 2 and 7 on 12AX7) is ungrounded, such as from a bad joint or a bad shunt contact on an input jack. Does turning the volume controls affect the noise?

[tsutt]

And make sure your connections on the tube socket are clean and not in contact with each other, which should be obvious but check them. And check for solder dross on them also.

[cbass]

SOme pics would help us catch any wiring mistakes.If there is one.