Univox U-1011 Lead - tube chart?

[DonMoose]

On my U1511(more or less the 150W 6550 tube version) there is no tube chart either, however the chassis is labeled near each tube. Sometimes it takes a bit of cleaning to see them.
The 6AN8 is indeed the reverb tube in this model as well.

Good Luck

A little cleaning was all it took! Thanks!

This thing does sound pretty nice, once cranked way the heck up - typical for a '73 vintage monster. The pull 'HB' (high-bright?) makes a huge boost in volume and overall richness, so I'm thinking there may have been a mod or two in the amp's past.

So, that was step 1.

Step 2 - decide exactly what variant I want to build. Thinking non-HRM 100W BluesMaster ODS (huge cleans, rich OD, suitable for a relatively soft picking style)

Step 3 - save up for a Ceriatone or BrownNote board set and hack to get where I'm going (not a lot of available money, but even less available time)

Thanks everyone, this community is a very rich and confusing place to lurk!

[Bob-I]

...I found that there's a distinct difference in the way old iron sounds....

I don't think that is because it is "broken in." I think that is because of the quality and quantity of materials used, as well as the actual construction of the transformer (winding pattern, etc). I use recycled iron quite often and have had very good results. I just don't believe there is any "break in" factor. Well, at least we agree on reusing the good stuff.

We can agree to disagree on the reasons but we agree that salvaging old iron is worth the effort.

There are still companies out there making decent iron with quality materials and I still think old iron changes magnetic characteristics with use. Speakers do, why wouldn't xformers?

[Structo]

Old transformers are better because the electrons in the copper wiring are aligned with the stars.
It is no wonder they sound better!

[selloutrr]

not sure this helps much but...

[DonMoose]

Odd power amp topology - insights?

The pairs of output tubes are set up oddly - the pair 'closer' to the OT is separated from the pair closer to the PI by a 100R0 in the plate path and by 1k5 between the grids.

Would anyone care to speculate on this design choice?

Also - the reverb is capacitor coupled to the plate of the 6AN8 triode - no transformer. That's not the usual, but I like not having that extra part.

[Structo]

Leaning transformers tell me the amp has had a drop or two in it's life.
If you don't like it now, then by all means gut it and build something you want.

[DonMoose]

Leaning transformers tell me the amp has had a drop or two in it's life.
If you don't like it now, then by all means gut it and build something you want.

(um, that's selloutrr's Univox - photos of mine are in https://tubeamparchive.com/viewtopic.php?t=12195 )

[Structo]

Yeah sorry, I should have noticed that.

[selloutrr]

instead of hacking up a perfectly good amp why not sell it and buy a blank chassis and some iron with the profits and make a frankenamp?
It's sad to see good amps get violated.

[DonMoose]

instead of hacking up a perfectly good amp why not sell it and buy a blank chassis and some iron with the profits and make a frankenamp?
It's sad to see good amps get violated.

This word, profit, is the issue - I paid $300 for the Uni and it seems a fair price. It has a chassis, iron, cab and tubes. If I resold it for the same dough, that would about pay for the iron and the filter caps. I'd still need chassis tubes, cab, and all that other stuff.

Did I mention the tubes are nice old Mullards and GEs?

If we were talking about a popular amp - an SF Twin or something - I'd be disinclined to start hacking. I'd also have paid quite a bit more. If it were a Sound City or KMD or any of a long list of B- and C-list donors, I wouldn't hesitate.

[Trout]

instead of hacking up a perfectly good amp why not sell it and buy a blank chassis and some iron with the profits and make a frankenamp?
It's sad to see good amps get violated.

This word, profit, is the issue - I paid $300 for the Uni and it seems a fair price. It has a chassis, iron, cab and tubes. If I resold it for the same dough, that would about pay for the iron and the filter caps. I'd still need chassis tubes, cab, and all that other stuff.

Did I mention the tubes are nice old Mullards and GEs?

If we were talking about a popular amp - an SF Twin or something - I'd be disinclined to start hacking. I'd also have paid quite a bit more. If it were a Sound City or KMD or any of a long list of B- and C-list donors, I wouldn't hesitate.

If you rip it apart, what do you want for the PCB board? Just thinking.

[DonMoose]

If you rip it apart, what do you want for the PCB board? Just thinking.

Had been thinking of just filing it in case I decide to restore. It will likely be months before I actually heat up the iron and start moving things around - would you mind sending me an email (subject U-1011 boards) so I can ping you when it's time?

don dot moose at bentwave dot net

Would include both boards, 'verb tank and most of the wires that leave the board. May include pots and pot-mounted components if I don't need them.

Hope this helps!

[Trout]

Isnt that a single board amp>?

I have a U1511 and internally it is basically the same. The board in the U1511 is actually labeled U1011.

[DonMoose]

Isnt that a single board amp>?

I have a U1511 and internally it is basically the same. The board in the U1511 is actually labeled U1011.

(see photos here: https://tubeamparchive.com/viewtopic.php?t=12195) There's a tiny board near the PT with these odd little button-shaped rectifiers. Seems to work OK, so potentially useful in a clone or restoration.

Hope this helps!

[DonMoose]

Stalling again - this amp does sound nice if you get it up to bleeding ears volumes (where it starts breaking up).

Looking at doing the Dumble FET preamp as an input overdrive on a bit of perfboard. May try moving the trem's 'AX7 to the PI, first.