Need help in identifying 2 tranformers

[Sir Ricardo]

Hello!

I have a modded Fender Deluxe Reverb.

I've been told that its power tranformer came from a Bassman. But I'm not sure. Its dimensions are about 4" x 3" x 3 1/2", and it is black.

The PT's code is:

K022814
606 2772
CSA 827

Is this a Bassman PT? Is it a 1972? How many watts?


The OT is silvery, with a black middle, is about 3 1/2" square, and has this code:

Fender
022889
606-1-24

What type (Twin, Super, Pro Reverb, etc) of amp was this OT designed for? Wattage?

Thanks much for any info and thoughts you have!

Cheers,

Richard

ps: in case your wondering why a DR has these two very large transformers, it's because it has been modified to run on 4 power tubes. Currently, the tubes are 5881s. It also has 2 60 watt 8 ohm speakers. I'm wondering if these 2 trannys can handle 4 5881s.

[slack]

I have each of those, but in two diff 1960s Bassman heads.

67 Bassman AB165:

J022814
606016
CSA TESTED

022871
606745

65 Bassman AA864:

125P7D
606-446

022889
-606-0-51

[Sir Ricardo]

Hello Slack, thanks for responding!

Are you saying both of my tranformers are from a Bassman?

If so, do you think that they are up to the task of dealing with 4 5881s?

Thanks - - Richard

[slack]

Originally Posted by Sir Ricardo

Hello Slack, thanks for responding!

Are you saying both of my tranformers are from a Bassman?

If so, do you think that they are up to the task of dealing with 4 5881s?

Thanks - - Richard

I'm saying that one of your parts is in my 65 Bassman, the other is in my 67 Bassman, as indicated above. Each a different circuit.

I'm sorry, but I'm just not qualified to respond to your other questions.

[Sir Ricardo]

Slack, thanks a lot for the info. This is great, I just posted my request a few minutes ago, and with your help I've now identified the tranformers.

Thanks again - -

Richard

[Wally]

According to the Fender Transformer Reference and Conversion charts, your Trannies are as follows:
1) #022889 is an output transformer for AB763 Twin Reverb and AB763 Dual Showman.
2) #022814 is a power transformer for BF and SF Bassman (thru AA270) amps, the AB763 and AA270 Bandmasters, and the 6G5(A) Pro amp.

[mark norwine]

also understand that 125P7D = 022814

the 125 number scheme is Leo's {pre CBS} and the 6 digit number is the CBS scheme

also..not that anyone asked...but 125Pxx...P=Power trannies; 125Axx....A = audio {output or reverb driver} trannies; 125Cxx = chokes. The number was the model, the last letter was the revision level.

so, 125P7D...pre CBS power tranny, model #7, revision "D". CBS later renamed it 022814.

anyone care? didn't think so... :)

[Sir Ricardo]

Hello Mark:

Thanks for the reference information, those tidbits of knowledge always have a way of being useful, sometimes just when you don't expect it.

Can I ask you, what do you think of my amp's tube/tranformer situation?

The MAIN question:
Is it OK to run 4 5881s, given that I've got a Bassman PT, and a Twin OT?

The guy who sold me the amp claims that he never had a problem with it, and he used it fairly regularly. I believe that as far as he knows, he is telling the truth.

If your answer is neither "absolutely yes" nor "absolutely no," but rather...."it might be OK"....under what circumstances might I run into trouble? Playing at 10 for 10 hours straight? Playing at 5 for 2 hours?

How could I tell if a problem is starting to materialize? How could I minimize the likelihood of a problem? Would pulling 2 power tubes be a good idea? I'd rather not pull any tubes, until I get to know the amp a little better (I just got it), but I could do that if I had to.

I've got the amp plugged in right now, I was playing it a few minutes ago. In comparison to my Princeton Reverb's PT, which is warm, the Deluxe's PT is much hotter. If I press the back of my fingers against it, I can only leave them there for a couple of seconds whereas with my Princeton's I can let my hand just stay on it. The DR's PT is hot. You should see these 4 tubes, they are very close to the PT, and the tubes themselves are giving off quite a bit of heat.

How hot is a PT supposed to get?

The filter cap box is warm...the OT is cool to the touch (the amp is not being played as I speak, its just sitting there with the standby on "on").


thank much for any thoughts you might have - -

cheers,

Richard

[mark norwine]

my immediate thought is "that's a lot for a P7D"...let me explain, if i may.

P7D, like any power transformer, has 2 jobs to do...1.) feed the high voltage current that provides the backbone of the amp's ability to work, and 2.) light up the tubes by supplying 6.3V to the filaments.

the P7D seems marginal for job #1, but let's focus on job #2.

In a bandmaster {non rev}, the P7D needs to light up 2 x 6L6 and 4 x 12A_7.

6L6's draw 900mA each; the "12's" draw 300mA each. The total current draw can be seen to be 3 Amps {i.e. 3000mA}.


And the P7D is rated for about just that....3A draw from the 6.3Vac winding.

Now...what are you doing?

4 x 5881 @ 900mA / ea.

you don't tell me the "little tube compliment", but a DR has 6 little tubes @ 300mA / ea. so i'll go with that....

draw = (6 * .3) + ( 4 * .9)
draw = 1.8 + 3.6
draw = 5.4A

did you say it runs hot? i bet it does! you're 80% over the rating.

so my immediate thought is "put in a bigger PT {like a twin reverb}.

but here's the deal: for a couple of years, i ran a tricked-out b'master with EL34's, and a 5th "little tube. EL34's draw 1.5A each...my total was still under yours, so your numbers still concern me, but read on.

i gigged my amp regularly....3, 4 nights a week, 4+ hours per. on some nights, the on-off switch was too hot to touch at the end of the night! although the PT never fried it ran hotter than you can imagine. eventually, it would have failed...of this there is no doubt.

now, think this through...

a transformer isn't really rated for current, per se. it's rated to handle the heat associated with the rated current. if you draw too much current, it's not the current, per se, that will kill the PT, it's the associated heat.

the answer: get rid of the heat! my b'master was pretty well cut up, so i went a step further & cut a hole in the front grille / baffle and mounted a back-blowing pancake fan. this drew cool air from in front of the amp and blew it out the rear, taking the PT's heat with it. the amp ran cool-to-the touch therafter.

for you, however, there is a better solution. ted weber makes a PT that will drop right into the mounting hole, offers the same B+ winding as the P7D {as well as a tap that's the same as a P5D...don't use those wires}, but best of all, the filament winding is rated for 6A...more than you need! cool, huh?

i'm not suggesting that you change the PT yourself...that's a job best left for someone with a knowledge of electricity, as you can seriously hurt yourself if you don't know what you're doing. but this is a swap that i'd do if i were you.

anyway, those are my thoughts du jour. hope they are of value to you...

mn

[Sir Ricardo]

Mark:

Thanks for your advice and scare-tactics (! :) ) .

When you said that in your modded Bandmaster "my total (current consumption) was still under yours, Richard, so your numbers still concern me" I was worried, but when you then said "eventually, it would have failed...of this there is no doubt" I said, "OK, Richard, you have been warned!"

Your solution, getting the Weber PT, is an excellent one, and may be my longer-term goal. Shorter term, I took 2 of the 5881s out, and now the PT is noticably cooler (though it is still very warm/hot). But not as boiling as before.

Your assumption was correct, 6 12s and 4 5881s, for a draw of 5.4. Now, with 2 5881s, the draw is 3.6, so only 20% above the rated 3.0. I say "only" like I know that 20% isn't bad....now that's overconfidence for you!

I must admit, it sounds just about the same as before. Could the extra 2 5881s' contribution simply have been to produce more volume, with little/no tonal impact? If so, I am happy, because even with just 2 5881s it is very loud, and the 2 10" speakers provide a ton of sound. A very very nice clean-sounding amp!

Now it's on to the next task; fixing the tremolo. There are 2 problems. 1) as you increase the speed control past 4, the tremolo effect starts to diminish to virtually nothing. 2) there is audible ticking.

I've looked at the "roach," and you can clearly see its light pulsing. So I guess the roach is OK, and the problem must lie elsewhere.

Thanks much for your help - -

Richard