Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: mresistor on April 19, 2015, 03:46:59 pm
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I got a Hammond S-6 chord organ for free and it has many 12au7s some oddballs and a couple of 6V6 and very large PT. I'm wondering if any of the components are worth salvaging. the resistors look like they may be Allen Bradley. Anyone know?
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There may be an "AO-" number on the chassis. What is it?
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There isn't a Major AO designation, the separate sub-assemblies have AO designations. The power pack is AO-27-1. The Generator Assy. is AO-30-1, and the Oscillator Assy. is AO-20-2. that's what I've located so far. The whole organ designation is S-C-6ELA. Some pics of internals. The first pic is inside the osc. assy., the next are of the generator internals. It's funny the organ is rated at 117V, but the power transformer has 115V stamped on it.
(http://i122.photobucket.com/albums/o250/privateacct/Hammond%20Chord%20Organ%20Pics/IMG_3617_zpsmuko83gm.jpg)
(http://i122.photobucket.com/albums/o250/privateacct/Hammond%20Chord%20Organ%20Pics/IMG_3613_zpsfjcwwavr.jpg)
(http://i122.photobucket.com/albums/o250/privateacct/Hammond%20Chord%20Organ%20Pics/IMG_3611_zpsazeufcol.jpg)
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What I like is that Hammond has left the lead length nice and long on the majority of the resistors, making them easy to reuse if in spec.
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I'm not fond of salvaging/reusing resistors and caps from old stuff. But I am very fond of reusing Hammond iron. My last three builds all used Hammond iron.
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My thought is if the resistors are AB's then they might be good for something. They sure are colorful. LOL The tube complement is:
1 5U4G/GB
18 12AU7
3 12BH7
2 6BA6
2 12AX7
1 6C4
1 6BJ7
2 6V6
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Is there an AO number on the chassis that has the 6V6s on it?
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AO-30-1
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Here's the power pack. It's pretty much just the PT and 5U4 rectifier. It appears that at some time in the past someone replaced the power cord.
(http://i122.photobucket.com/albums/o250/privateacct/Hammond%20Chord%20Organ%20Pics/IMG_3618_zpspxp4tlks.jpg)
(http://i122.photobucket.com/albums/o250/privateacct/Hammond%20Chord%20Organ%20Pics/IMG_3620_zpsbchnjqqt.jpg)
(http://i122.photobucket.com/albums/o250/privateacct/Hammond%20Chord%20Organ%20Pics/IMG_3619_zpsnygfpc4e.jpg)
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You'll most likely find that those caps are all rated 200 volts (I seem to see 150 volts on many of them) and thus should not be used in anything Fenderish. I see the 12AU7 organ curse is in effect.
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Yes it looks like they are still a dime-a-dozen. Must be totally useless for guitar amps.
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What kind of amp do you want?
2 6V6's and a matching PP OT, PT and 5U4 a lot of good things start there.
2 12ax7's I think you can figure something to do with those
18 12AU7's, I actually prefer 'AU7's to their high mu brethren, especially in high gain amps, but you need to adjust the circuit for them, and often use more.
6BJ7, If you like diode distortion, tubes give a softer more gradual kind, seems more useful in a pedal.
12BH7, a lot like a 12au7, but I prefer them when I really need current. better bass
6C4, Pretty much half a 6sn7, so like half a 12au7 or 12bh7, but more better.
6BA6 They are remote cut off pentodes, most useful if you wanted to make a amp with a compressor. Bet that is what they did in combination with the 6bj7. "
guess that sums it up for me...
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I popped a 12AU7 into the reverb driver spot in my HPR and I have to say....... I like it. :-)
I can turn the R dial up to 5 and it has really good sound.
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1 down, 17 to go. Next time get a CONN, then you'll have 36 of them, LOL.
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I think this is the last one I want to c-ball. It's a lot of work for little gain in this case. I'd never dismantle a B3 or later M series tone wheel Hammond.