Is my 5E3 sick ?

[Hebaton]

Thank you again. Those 4 64K resistor you refer to at the inputs do read 34K each tough. THIsis taking the reading on each one eithe side of theresistor . I see the other 64 Ks you refer to and they are not coded the same. I do beleive the input resistors on my unit are all 34K...

THanks so much for investing so much time on this, I could not start to say how much I appreciate !

P.S. on page 3 of this document you will find the references used ( R 3, 4, 5 and 6 )

[TriodeLuvr]

Based on your description of the problem, that amp has a more fundamental problem than a few resistor values. Could be the output transformer, the speaker, speaker wiring, or any number of other basic issues. That's why I asked if it distorts when you turn it up. that might provide a clue as to where the signal is being lost.

Jack

[Hebaton]

IT certainly distorts as I turn it up . In fatc when I was trying things and pushing it hard the sound went down and then off for a secound and then came back. AS for the speaker, I tryed two others and besides differences in tone and efficiency, it is very much the same.

[TriodeLuvr]

I just realized what you meant earlier. The reason your input resistors measure 34K is because each pair of 68K resistors is connected in parallel when nothing is plugged into the amp. No offense, but I think you need to find someone local who can help you troubleshoot this.

Jack

[Daviedawg]

Jack makes a fair point about getting hands on help.

Dd

[Hebaton]

Thanks all of you. I'll see if I can ship this somewhere. THere is no one "Local" at a good 100 miles around where I am.

[Hebaton]

FOr the Heck of it I removed the chassis from the cabinet and looked at the OT.
It is a Webber W041318 rated 25 watts

IS this corect ? COUld it be that It'S just a really cheap OT ?
I can source here ( in Canada ) a Hammond 1750EP said to be accurate with paper core...They also offer aversion with Bobbin core...

THose cost 4 times what the Weber costs...

[lavrgs]

A bit late but here are the typical voltages
EDIT found a voltage chart

[Hebaton]

A bit late but here are the typical voltages
EDIT found a voltage chart

O.K. now something is not right.
I went again with this chart and I now get 245v at V2 pin 1

[lavrgs]

Check grounds...and look for bad connections
Fill out the entire chart - I noticed that I missed the 17V on V2 pin 7

[Hebaton]

Just want to let all of you know I found a bad solder joint that was responsable for unstable voltage at V2 pin 1
and also decided to go with a different speaker. ThIs thing will never sound as good as some others of the type unless I go further... really considering the Hammond 1750 EP Output tranny.

Thanks to all

[JMPGuitars]

Just want to let all of you know I found a bad solder joint that was responsable for unstable voltage at V2 pin 1
and also decided to go with a different speaker. ThIs thing will never sound as good as some others of the type unless I go further... really considering the Hammond 1750 EP Output tranny.

Thanks to all

Before you replace anything as big as a transformer, make sure the rest of the amp is healthy. There was one bad joint, and from what I saw of the photos, I wouldn't be surprised if there are more. It's not terrible, but it's certainly not professional quality work. Put in the time to clean it up, and you should be happy...well, as happy as a 5E3 can make you.

[Bieworm]

I agree with Josh. If the Weber OT is not totally underspec'd or out of spec, which likely isn't the case, you'll have to be a very experienced 5E3 guy to even hear the difference with a hammond OT. Guys with that amount of OCD are also very meticulous in the build quality.
Stop worrying about the transformers and check the human/builder factor in your build. Replacing an output transformer in an existing build is not as easy as putting one in while building a new amp. Certainly not in f#@nder type amps.
Find the problems in the soldering and lead dress first...

[Hebaton]

Just want to let all of you know I found a bad solder joint that was responsable for unstable voltage at V2 pin 1
and also decided to go with a different speaker. ThIs thing will never sound as good as some others of the type unless I go further... really considering the Hammond 1750 EP Output tranny.

Thanks to all

Before you replace anything as big as a transformer, make sure the rest of the amp is healthy. There was one bad joint, and from what I saw of the photos, I wouldn't be surprised if there are more. It's not terrible, but it's certainly not professional quality work. Put in the time to clean it up, and you should be happy...well, as happy as a 5E3 can make you.

I am curious wat makes you say this is not professional work. To my inexperienced eyes, it looks well executed. Would you care to specify a little ?

[JMPGuitars]

I am curious wat makes you say this is not professional work. To my inexperienced eyes, it looks well executed. Would you care to specify a little ?

Sure. Take a close look at the solder connections. Especially on the tubes. Look at the eyelets. Now go read the solder technique thread in my signature and watch the linked videos.

The solder joints have zero mechanical connections.

Most of the solder joints don't have great coverage, and those that do are convex.

Solder joints should be smooth, and relatively shiny. They should be concave. They should have mechanical connections. Most of what I see in there is dull, clumpy, dimply, convex, etc... etc...

Also, I would get rid of that ground bus on the back of the pots. All that's doing is creating a ground loop, and negating the shielding of the pots. That's assuming the pots aren't isolated from the chassis, and they certainly don't look like they are.

The lead dress isn't impressive.

The ground lugs are on the transformer, and transformer bolts should ONLY be used for...mounting transformers.

All ground connections should serve no purpose besides being a ground connection. It looks like your power ground is also connected to a transformer lug. That's also a big no-no. It should have its own chassis connection close to where the power cable enters the chassis.

I could keep going, but I won't. Besides that I'd ditch that cord and put an IEC socket there instead.

I'm not saying you should redo the whole amp (unless you want to). But cleaning up the solder joints is the first step towards making it usable.

Thanks,
Josh

PS. Considering that terrible ground bus on the pots, and that it's also connected to the power amp ground, you should also read the "modern ground schemes" thread in my signature.