1964 Fender Vibro champ volume problem

[peteb]

the OP’s amp has a lot of corrosion. That is what you are seeing. Those solder joints have never been disturbed

hey Wally,

I agree that it could be fender soldering.

i am saying that it is below standard fender soldering practices.



thanks

pete

 

[Wally]

hey Wally,

I agree that it could be fender soldering.

i am saying that it is below standard fender soldering practices.



thanks

pete

ime, here is no problem, and I see typical Fender factory work.

 

[peteb]

ime, here is no problem, and I see typical Fender factory work.

there is a reason why the cans have four tabs. They are meant to be used.

I have soldered on two of the CE cap cans.

I too made the mistake of soldering only two tabs and thinking it was solid. It wasn’t.

two points of contact are unstable Compared to three or four.


I say the difference we are seeing in the soldering is experience level. The person soldering all four tabs is not rushing the job to meet a schedule. The person who sloppily solders two tabs is rushing the job.

 

[peteb]

The name for the tip of the high wattage soldering iron needed to solder to the chassis is a chisel tip.


besides soldering to chassis, they are commonly used in making stained glass.

 

[Wally]

@peteb, the amp in this thread proves that two tabs are secure if the solder joints are properly done. Now, could one take a hammer and whack that can and perhaps break those joints??? Maybe….but why would anyone do that.
I have seen many more than two Fenders with cap cans and have replaced a fair number of them. I have never seen a cracked solder joint on one of them…and they all certainly did not have all four tabs soldered. None of the soldered tabs in the Fenders in which I replaced the cap cans have failed to my knowledge. If your joints failed, then I suspect you need a better iron.
That said, if one wants to solder all four tabs, that is fine by me. Fender obviously gave a thumbs up in the final inspection on two amps shown in this thread with only two tabs soldered.

 

[maybeoneday]

So, job done.
I've also replaced the 2w bias resistor with the 3w and switched position with the cap.
The volume is improved a lot but still not at the same level of the 62 Fender Champ, is it normal and it will never be like the 5F1 or am I still missing something?

 

[Wally]

A 1962 Champ is a 5F1. Ime, that amp will have more ‘oomph’ because the more elaborate tone stack in the AA764BF/SF Champs neuters those amps to some extent. There may also be a difference in the speaker efficiency Depending on what speaker you have in the ‘62?? There could also be a difference in the operation of those two power tubes. In a cathode biased output, the tubes determine how much current draw occurs in the circuit.….different tubes are cooler or hotter depending on the particular tube’s operational parameters.

 

[Wally]

So, job done.
I've also replaced the 2w bias resistor with the 3w and switched position with the cap.
The volume is improved a lot but still not at the same level of the 62 Fender Champ, is it normal and it will never be like the 5F1 or am I still missing something?

Too late for this, but I would have done some cleaning of that chassis before installing that can. The oxidation and around those soldering areas needed to be removed down to fresh metal, and the solder should have flowed more thoroughly around the tabs. Done is done, though, and perhaps it is good.

 

[maybeoneday]

A 1962 Champ is a 5F1. Ime, that amp will have more ‘oomph’ because the more elaborate tone stack in the AA764BF/SF Champs neuters those amps to some extent. There may also be a difference in the speaker efficiency Depending on what speaker you have in the ‘62?? There could also be a difference in the operation of those two power tubes. In a cathode biased output, the tubes determine how much current draw occurs in the circuit.….different tubes are cooler or hotter depending on the particular tube’s operational parameters.

I see.
In the VC I have a WSG G8A and in the champ a Jensen C8N
Also on the Champ I got a CIETES as 5Y3GB and the Brimar 6V6GT as power tube and in the VC I have the JJ.

I want to post an audio about a weird sound, like a soft but firm hammer hit the VC does while warming up but it doesn't allow me

 

[Wally]

@maybeoneday, if you want to hear the difference in the power tubes, simply switch them. There may or may not be a difference. It could be an interesting experiment. I like to know how a power tube is Biasing in these little single-ended amps. There can be a wide variation in plate dissipation, and that will determine what the amp sounds.

 

[maybeoneday]

Weird sound
I hope you guys can access the file

 

[maybeoneday]

@maybeoneday, if you want to hear the difference in the power tubes, simply switch them. There may or may not be a difference. It could be an interesting experiment. I like to know how a power tube is Biasing in these little single-ended amps. There can be a wide variation in plate dissipation, and that will determine what the amp sounds.

I switched the tubes and the respective volumes stay the same, however in the Champ on B+1 there are almost 400VDC, it makes 60V more than the VC, I guess that is why the volume differences.
I'm going to clean pots, tube sockets and jacks and then close everything.

Ihave another nice curious challenge on a Deluxe Reverb, I'll open a tread for this.

Thank you everybody for your help, I've learn many things.

 

[Wally]

That is an odd noise….And unacceptable. Pull V1 to see if that stops it. I don’t think it will, but this has to be systematic. If not, then pull V2. If the noise persists, pull the power tube. I would also want to watch the B+ voltage during the occurrence of the noise. If the noise persists with only the rectifier tube in place, I would switch your other 5Y3 into this amp. Does the noise persist?

 

[peteb]

If your joints failed, then I suspect you need a better iron.

mine is a Weller SP120.

no problem there.

if there is a problem, with 120 watts, it is that there is no waiting time at all needed to heat the chassis up to melt the solder. Perhaps I could spend more time at it but once the chassis melts the solder I don’t see any need for more heat or time.

 

[maybeoneday]

CIETES 5Y3GB
JJs rectifier

I have tried 4 rectifiers (2 JJs and the one from the vibro champ). The old one from the Champ is the only one that doesn't make the weird sound.

Look how the JJs give the pick at the start and the vintage doesn't

 

[Wally]

I cannot download the JJ exercise above. Also, what is a CIETES 5Y3?
Maybe you have run into a batch of JJ 5Y3s that have a problem In the production process. Are the JJs new tubes? I have never used JJ 5Y3s. Their GZ34 has been a good tube for me. I would run a NOS 5Y3 in that VC.

 

[SnidelyWhiplash]

Older production 5Y3s are still relatively affordable & a good one will last a long time.

 

[maybeoneday]

I cannot download the JJ exercise above. Also, what is a CIETES 5Y3?
Maybe you have run into a batch of JJ 5Y3s that have a problem In the production process. Are the JJs new tubes? I have never used JJ 5Y3s. Their GZ34 has been a good tube for me. I would run a NOS 5Y3 in that VC.

These are the tubes in the champ and the CIFTES (not Cietes, sorry) 5Y3GB doesn't give the pick in the vibro champ.
I put the JJs in the Champ and works just fine.

 

[slider313]

CIFTE was a French tube manufacturer. The design looks to be RCA and was probably built under RCA shared patents.

 

[peteb]

If your joints failed, then I suspect you need a better iron.

I think I helped cause the failure by resting the chassis on a table with the tubes and filter cap can bearing all of the weight.

why would I do this?


because I saw Gerald Weber do it.