Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: okguitarman on May 20, 2016, 06:59:03 pm
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20 and 30 watt output on plate. Baldwin organ amps
going to look at them on Monday.
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Second one.
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mod#
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Good looking tubes and output transformers. I have the 50 watt (2 qty 6L6) version of the upper one.
The PT on that one puts out huge volts, like 425-0-425 which will result in very high B+, almost 600 volts. The PT ran probably 30+ tubes elsewhere in the organ so its heater winding will be 10 amps+ which is not a bad thing but you'll see, the PT is a monster. 3" tall chassis (steel, heavy) is a bit awkward and will require a fair amount of rearrarranging, it is kind of narrow, so while you may picture a row of preamp tubes parallel to the line of 6L6 and they could indeed go there, there is probably NOT enough room for a parts board, those tubes AND access to a line of pots. You *could* of course go point-to-point but then much of the preamp section will be kind of right next to the 6L6 row and that is generally a recipe for some problems. Not trying to discourage you from buying it, just passing along what my experience was. [eg; don't overpay] I ultimately decided the form-factor of that chassis was not a good candidate for a guitar (or other) audio amp. You *could* make a functioning amp out if but I would suggest leaving it pretty much alone and building a completely separate preamp chassis instead of trying to hack away metal and throwing some 12AX7's and tone controls in there. That way, you would have a much easier time carving up aluminum vs steel and the preamp would be well shielded. And, such a preamp could be moved to another power amp or duplicated if you got it to where you liked it. The OT is probably the most valuable part outside of the 6L6 tubes.
Just trying to pass on my experience. I stared at it a long time before deciding it was problematical.
The second one looks more promising but I've never dealt with that particular flavor of Baldwin amp.
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thanks I was adding and felt like price was high.
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When valuing this type of non-functional equipment,
I try to identify all the parts, and figure their new costs.
Then I pay 50% or less of new parts costs, including shipping. :icon_biggrin:
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I wasn't quite clear.
I take new parts costs, not including shipping.
And pay less than 50% of that including shipping to me.
If you are willing to search Ebay a lot, and are patient you can get some good deals on these vintage parts. :icon_biggrin:
I seem to have more than I know what to do with at this time. :l2:
I paid less than $65 each including shipping for these. :dontknow:
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I measured my Baldwin chassis...it's all of 6" wide.
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Yes, the top one has lots of nice parts but absolutely no room for a guitar preamp circuit to be added.
That means you are going to need to strip the parts out of this and reassemble them into a chassis designed for your desired guitar amp.
Or make a separate chassis for the preamp, and then try to figure out how all this is going to be made to fit in an amp cabinet.
The 2nd one appears to be a PP 6V6 radio amplifier missing a few parts to me.
Maybe it is an organ amp, but you will only want the PT, OT, output tubes, and any 12AX7s or other preamp tubes it might have.
Some of these PP radio amps can be modified to sound pretty good as a guitar amp.
But they don't look like one, fit in an amp cabinet, or sound quite as good as if those same parts are re-purposed into a real guitar amp circuit and chassis.
Took me a while to figure that out myself. :sad2:
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Thanks for the info
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From a search, the upper photo looks like it could be a Baldwin 45HP2 (http://s2.photobucket.com/user/nytrus1/media/Baldwin%2045HP2%20standalone%20sch_zpsaq555tiu.jpg.html). The 2 lumps of iron on top of the chassis are possibly the PT and the "Pedal OT", as someone stated (http://audiokarma.org/forums/index.php?threads/baldwin-amp-quesrtions.687141/#post-9181019) their were 2 "transformers" under the chassis on theirs, which are possibly the choke and the "Manual output transformer." (http://s2.photobucket.com/user/nytrus1/media/Baldwin%2045hp2%20stereo%20vs%20stock3_zpsnsrcutit.jpg.html) If my guess is right, the two plugs beside the pair of rectifier tubes should say, "Manual Speaker" and "Pedal Speaker."
The tag appears to refer to the amp above.
Don't know about the other chassis.
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On closer inspection, the 2nd one doesn't have 6V6s after all.
It does have an output transformer that looks like a Hammond organ one for 6V6s or EL84s.
It doesn't look big enough for a high powered 6L6 OT.
What is the guy asking for these, if you don't mind me asking?
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This is the one I have. The one HBP linked shows that it has 1 pair of 7027 and 1 pair of 6L6"GB". My chassis is marked for 6L6"G", thus I suspect it is older. The transformer right next to the lay-down PT is a choke (!) See also the 5th pst down in the link HBP posted for the older style.
But the point is, you can see the chassis is not really any wider than the long dimension of the PT, and even if the PT is huge (it is) it will cause you problems building anything in there.
(http://i172.photobucket.com/albums/w32/ttm4/baldwin_1_zpsltt9rchv.png) (http://s172.photobucket.com/user/ttm4/media/baldwin_1_zpsltt9rchv.png.html)
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Just use it the way it was designed: build a separate preamp, connected via an umbilical. You may wish to update the connector type for that umbilical, if only to have a wider selection of vendors available.
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Thanks for the info!