Gotta a power transformer, can't seem to decided what to do with it - any thoughts ???

[kevtronic]

So, I've got a power transformer I picked up a while ago that has been sitting and collecting dust. Figured I'd build something around it, but I can't really seem to decide just what I want to to build around it. So, I figured for the hey/fun of it I'd post the specs here and see if someone may have some idea's or suggestions.

About the only thing I know for sure is I want reverb and tremolo. The reverb will most likely be tube driven (not tranny driven) and the tremolo will most likely be one half a dual triode tube. So, essentially a 12ax7 and a 12au7 for those. With this tranny it's almost certain to be push/pull and I was thinking of using the long tail phase inverter. So, three dual triode preamp tubes at this point.

I've got 5y3, 5U4GB, and GZ34 tubes on hand and plenty of diodes for rectification.

I've got plenty of el84 tubes and a couple 6l6wxt output tubes on hand, but I can buy power tubes If need be - don't necessarily have to use what I have on hand.

I've also got a fair selection of dual triode preamp type tubes on hand.
I actually got some 7-pin power tubes and preamp tubes, but not thinking the power tubes will come in play with this tranny.

This is just all for fun, and low key, to build an amp for the hey of it, to use up a nice power transformer that needs a tube amp to call home.
Generally I just decide what I'm building and do it, but I'm curious what someone else might do with this tranny if they had it.

Here are the specs for the power transformer:
550 VCT @ 173 mA: 275-0-275 , 173mA , 5v @ 3A , 6.3v @ 5A
The 6.3v is center tapped.
It's a newer production tranny design for USA mains, so specs should be real close (it's a hammond tranny).

Thanks either way ahead of time...

[nosaj]

So, I've got a power transformer I picked up a while ago that has been sitting and collecting dust. Figured I'd build something around it, but I can't really seem to decide just what I want to to build around it. So, I figured for the hey/fun of it I'd post the specs here and see if someone may have some idea's or suggestions.

About the only thing I know for sure is I want reverb and tremolo. The reverb will most likely be tube driven (not tranny driven) and the tremolo will most likely be one half a dual triode tube. So, essentially a 12ax7 and a 12au7 for those. With this tranny it's almost certain to be push/pull and I was thinking of using the long tail phase inverter. So, three dual triode preamp tubes at this point.

I've got 5y3, 5U4GB, and GZ34 tubes on hand and plenty of diodes for rectification.

I've got plenty of el84 tubes and a couple 6l6wxt output tubes on hand, but I can buy power tubes If need be - don't necessarily have to use what I have on hand.

I've also got a fair selection of dual triode preamp type tubes on hand.
I actually got some 7-pin power tubes and preamp tubes, but not thinking the power tubes will come in play with this tranny.

This is just all for fun, and low key, to build an amp for the hey of it, to use up a nice power transformer that needs a tube amp to call home.
Generally I just decide what I'm building and do it, but I'm curious what someone else might do with this tranny if they had it.

Here are the specs for the power transformer:
550 VCT @ 173 mA: 275-0-275 , 173mA , 5v @ 3A , 6.3v @ 5A
The 6.3v is center tapped.
It's a newer production tranny design for USA mains, so specs should be real close (it's a hammond tranny).

Thanks either way ahead of time...

So what your asking for is a deluxe reverb is what comes to my mind. I'd want to build a 6g6 and add the trem and reverb.

nosaj

[Chuck H]

I might use it for those 6l6's with a hot bias and and a bias wiggle trem (and I'd dedicate two triodes for that). Use the GZ34 and probably get a B+ around 350V and 30W clean. Magic trem and just about the perfect wattage for gigs.

[g1]

The spec's look like Hammond 270FX. Some of the amps that come up for that are 4 x 6BQ5.

[kevtronic]

The spec's look like Hammond 270FX. Some of the amps that come up for that are 4 x 6BQ5.

Actually that is what the tranny is and I was actually thinking about going with 4 el84's to eat up some of the filament current available.

[kevtronic]

I might use it for those 6l6's with a hot bias and and a bias wiggle trem (and I'd dedicate two triodes for that). Use the GZ34 and probably get a B+ around 350V and 30W clean. Magic trem and just about the perfect wattage for gigs.

I was wanting to use up the 6L6's. I'll have to check into again. I could always tweak the filament voltage down some if it was a bit high when all was said and done.

[kevtronic]

So what your asking for is a deluxe reverb is what comes to my mind. I'd want to build a 6g6 and add the trem and reverb.

nosaj

A Fender Bassmen with tremolo and reverb - I would like to use up my 6L6wxt+ tubes - sounds like cool project - The Bass-O-Trem-O-Verb

So, everyone is pretty much on the same pages I am on.
So, probably best match - 4 el84's, with most interesting 6L6 tweaky bend and twist project based on the two 6L6 amp suggestions.
Thanks for all the input guys - appreciate it.
I think I'll call it one or the other - it's now narrowed down to two
Thanks again.

[Leo_Gnardo]

A Fender Bassmen with tremolo and reverb - I would like to use up my 6L6wxt+ tubes - sounds like cool project - The Bass-O-Trem-O-Verb

NOW you're talkin'! Can't say I've ever seen such a thing, but that sounds like a sweet combination.

[Gingertube]

HV current is a bit light on for 4 x EL84/6BQ5, also light on for 2 x EL34
The 2 x 6L6WXT seems a better fit
OR
4 x 6V6GT into a 4K3 to 5K Raa output Tranny would also work.

Weirder:
2 x KT66 into about 5K Raa
2 x KT88 in Ultralinear about 5K Raa


Cheers,
Ian

[kevtronic]

Well, every one who has posted is pretty much on the same page I am. Great input and appreciated. However, I still can't get myself to sacrifice a chassis for this transformer. With that I like to say thanks for the input, but I guess for now I am going to put it back on the shelf to collect dust for a while. Bass-o-trem-verb, gotta love it. If nothing else I think this short thread produced a cool name and idea

[jmaf]

Well, every one who has posted is pretty much on the same page I am. Great input and appreciated. However, I still can't get myself to sacrifice a chassis for this transformer. With that I like to say thanks for the input, but I guess for now I am going to put it back on the shelf to collect dust for a while. Bass-o-trem-verb, gotta love it. If nothing else I think this short thread produced a cool name and idea

Gotta be an amp?

Perhaps try a different kind of project like a tube tester or a tube matcher?

[kevtronic]

Gotta say those are two things I didn't think of. Got a tube test. Don't have a dedicated tube matcher, however I'm clueless on how one would make a diy tube matcher.

[jmaf]

Gotta say those are two things I didn't think of. Got a tube test. Don't have a dedicated tube matcher, however I'm clueless on how one would make a diy tube matcher.

I'm planning on starting a open-source tube matcher project which I'd share here, but I don't have the time right now. I do have it on my to-do list though.

[kevtronic]

Well, like I said, I have no clue on what it'd take, as I've never thought about it, and I'm not sure how much I could contribute to such a project/thread, but it sure seems like a great idea for a project/thread. Tube test wise I just use an old tester I purchased that was had already been gone thru and calibrated - it actually works quit well and it's like in a military grade metal case. So, sounds like a cool thread. If you start it and can remember message/email me about it - I'd like to tag along with it if nothing.

[eschertron]

Perhaps try a tube matcher?

You mentioned that, and now I can't put the idea out of my head, so...


HV for B+, probably doesn't need too much filtering?
bias supply, variable over a wide range?
I have a couple 0..100mA meters for real-time comparison testing of plate or cathode current. Or maybe both plate and cathode, and have a single socket.
I'm still trying to imagine a jig to compare the current differential between two tubes. Two 1R resistors on the cathodes and measure mV difference at the cathode pins? I guess that could be done on any amp with bias test points.

Who's done this before?

edit: of course I should be looking at bias current too, but my assumption is that plate dissipation is what tells how closely the tubes match at any given bias voltage.