I will try to include a poorly drawn schematic for your suggestions.
This is a 6l6GC PP amplifier with a 6SN7 for input and driver tube.
This is a 1940's vintage animal and is missing the field coil so I don't really know what voltage to run it at.
The output transformer measures 375 ohms across the plate winding out of circuit.
Any suggestions?
This is a 6l6GC PP amplifier with a 6SN7 for input and driver tube.
This is a 1940's vintage animal and is missing the field coil so I don't really know what voltage to run it at.
The output transformer measures 375 ohms across the plate winding out of circuit.
Any suggestions?
Please excuse me for not being clear. Its a organ amplifier and I believe the model number is 6420.
I am needing the correct B+ voltages to run the 6sn7 on and the correct 6l6gc plate and screen voltages in order to obtain maximum output. Right now the maximum I can get from it is about 22 watts into a 8 ohm load.
With a spare transformer sitting on the bench un terminated from the chassis I tried to figure the turns ratio and input impedance of the output transformer. I input a 400HZ signal at 10 volts into the transformer and loaded the output with a 150 ohm resistor.
(all I had handy)
The black lead from the transformer is terminated to the 2.2K feedback resistor so I'm going to guess its 16 ohm?
The yellow lead goes to ground from the transformer. There is a green lead I'm guessing is 8 ohm?
Voltage readings were .339 across the 150 ohm resistor (yellow to black. Yellow to green across the 150 ohm resistor was .471
Still haven't figured out what I have.
Any help would be appreciated.
The schematic is as wired so any suggestions for modifications would be appreeciated.
Thanks
I am needing the correct B+ voltages to run the 6sn7 on and the correct 6l6gc plate and screen voltages in order to obtain maximum output. Right now the maximum I can get from it is about 22 watts into a 8 ohm load.
With a spare transformer sitting on the bench un terminated from the chassis I tried to figure the turns ratio and input impedance of the output transformer. I input a 400HZ signal at 10 volts into the transformer and loaded the output with a 150 ohm resistor.
(all I had handy)
The black lead from the transformer is terminated to the 2.2K feedback resistor so I'm going to guess its 16 ohm?
The yellow lead goes to ground from the transformer. There is a green lead I'm guessing is 8 ohm?
Voltage readings were .339 across the 150 ohm resistor (yellow to black. Yellow to green across the 150 ohm resistor was .471
Still haven't figured out what I have.
Any help would be appreciated.
The schematic is as wired so any suggestions for modifications would be appreeciated.
Thanks
burnedfingers,
There is an older gentleman in Indiana who, along with his daughter, run a small business supplying old Wurlitzer organ parts and service manuals. He worked for Wurlitzer for 30-odd years and now tries to support all of these old organs. I found him with Google when I was looking for a manual for my mother-in-law's 1960 organ. Unfortunalely, the manual is in the bench for the organ but we will be there on Saturday and I'll see if your amp happens to be in it. I remember there were some diagrams for external amp-speaker units in the manual and they used 6L6s. If you can wait 'till then, I'll be happy to scan anything which looks realtive and email it to you.
Ken
There is an older gentleman in Indiana who, along with his daughter, run a small business supplying old Wurlitzer organ parts and service manuals. He worked for Wurlitzer for 30-odd years and now tries to support all of these old organs. I found him with Google when I was looking for a manual for my mother-in-law's 1960 organ. Unfortunalely, the manual is in the bench for the organ but we will be there on Saturday and I'll see if your amp happens to be in it. I remember there were some diagrams for external amp-speaker units in the manual and they used 6L6s. If you can wait 'till then, I'll be happy to scan anything which looks realtive and email it to you.
Ken
Really bad memory!
When I memtioned the fellow who has Wurlitzer parts and manuals, I was going from memory (always a risky thing). He is, in fact, in Mississippi. The correct name and address is:
Morelock's Organ Parts
37A Main Street
Rienzi, MS
662-462-7611
I hope this info will help others looking for schematics or other service doc. for Wurlitzer organs. I have no affiliation with Mr. Morelock other than a satisfied customer who thought he'd never find a manual for an organ purchased in 1960.
Ken
When I memtioned the fellow who has Wurlitzer parts and manuals, I was going from memory (always a risky thing). He is, in fact, in Mississippi. The correct name and address is:
Morelock's Organ Parts
37A Main Street
Rienzi, MS
662-462-7611
I hope this info will help others looking for schematics or other service doc. for Wurlitzer organs. I have no affiliation with Mr. Morelock other than a satisfied customer who thought he'd never find a manual for an organ purchased in 1960.
Ken
Need Wurlitzer 6420 advise!!!!
I recently bought a 6420 power amp with speakers and use it as a guitar amp. I was wondering if anyone could supply me with a copy of some sort of schematic. Pretty please!?
Also, my 6420 came with a crossover that sends the high end through a couple 8 inch speakers and the low end through a single fifteen. Any tips on how to bypass the crossover?
Jeez, while I'm at it, anyone ever successfully tacked a basic volume/ tone preamp onto one of these? I currently run my guitar into a Behringer tube pre and then into the amp in order to get sound. It sounds pretty amazing, but I'd like to hear it without the crossover involved.
Anyways, any help greatly appreciated!!!!
I recently bought a 6420 power amp with speakers and use it as a guitar amp. I was wondering if anyone could supply me with a copy of some sort of schematic. Pretty please!?
Also, my 6420 came with a crossover that sends the high end through a couple 8 inch speakers and the low end through a single fifteen. Any tips on how to bypass the crossover?
Jeez, while I'm at it, anyone ever successfully tacked a basic volume/ tone preamp onto one of these? I currently run my guitar into a Behringer tube pre and then into the amp in order to get sound. It sounds pretty amazing, but I'd like to hear it without the crossover involved.
Anyways, any help greatly appreciated!!!!
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