Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Misc Schematics and Layouts => Topic started by: savanasdad on August 02, 2007, 12:28:21 pm
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I just picked up a Gretsch 6159 amp, and am having trouble locating an accurate schematic. I have a schematic that has a solid state rectifier, but my amp has a tube. All the markings are gone, but I suspect it is a 5U4.
Also can't find any info on the transformer codes. They are:
PT:
E3738A
5246245
OT:
570-1
166237
The speakers are grey frame Jensen Concert Vibranto, with these codes:
220 7240
LMI 122-C8503
The pot codes are:
1376216 and 1376222
The filter caps (3 of them) are multisection 10/10/20 @450v. Can I safely use 20/20/40 @500v?
What do I have here and when was it built?
Any help is appreciated.
Thanks
Tony
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The pots are CTS and were made during the 16th and 22th weeks of 1962.
The Jensen speaker (220 7240) was made during the 40th week of 1972.
The 20/20/40 cap can is fine for a 5U4. (Max input cap is 40uF)
The amp is a bass amp. Good luck finding a schematic. Look for Valco as well. I'll bet you could draw a schematic faster than you could locate one on the web.
...Steve
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6169 a bass amp? The one I worked on was most certainly a guitar amp.
Here is the schematic I drew up, do not take this as gospel but it is most likely correct, at least good enough to get you were you need to go. Drew this one up in a rush, it had to go back to its owner.
http://www.sdiy.org/oid/schematic/Gretsch6169.gif
They are great sounding amps. Good chance the coupling caps are very leaky, and a dusty waxy mess.
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6169 a bass amp? The one I worked on was most certainly a guitar amp.
Thanks for posting that schematic :). However, it is for a 6169, and my amp is a 6159. I have gotten a 6158/6159 schematic from 2 different sources, and the are identical, both with a SS rectifier. Seems to be all that's out there
The transformer codes have escaped me. I can't find specs on the OT, and can't tell what the output impedence is. And the speakers in it don't help, the may not be the originals, and read 11.4 and 7.9 ohms respectively. If they are original, I'm perplexed by pots that date to 1962 and speakers that date to 1972.
Still searching.
Tony
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Whoops, misread that.
5U4 is likely for a 6L6 amp. Check the wiring on the socket to the 5U4s data sheet make sure it makes sense, Cathode, plates, and heaters all go to the right spots. If it does plug one in and see what happens to the 5 Volt heater supply, if it sags much the amp was probably ment to use a rectifier with a 2Amp heater. Most likely it is one of the bigger 3Amp bottles though like the 5U4.
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A Jazz guitarist by the name of Joyce Cooling has an album called "Playing it Cool" One of the tracks is called "Savanah" and is a vocal. It's about Savanah, Georgia though and not a person. An interesting number.
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If its any help, I had a similar Gretsch ( same schem I think, but 1x10 cab) through the workshop last year,and drew the schem and a full-size drawing of chassis and component layout. Too big to swcan but I could photocopy it and mail it to someone, if useful....