An "All American" tube Project

alexmoose · 14th July 2006, 04:28 AM

hey I have a surplus of the All amercian five tubes, and I was wondering if anyone had bulit a guitar project using the raw, un-clean sound that these tubes produce, does anyone have any project ideas?

I'm refering to the 50lgt, and the 12sq7 specificly, however if anyone has any idea with the other tubes, i'm all ears

DigitalJunkie · 14th July 2006, 09:13 AM

I think there used to be a few guitar amps that used the 50L6 and similar tubes,I recall seeing a few,maybe at Triode Electronics,or something. Not alot of power,but maybe you could parallel a couple tubes or something,if you want more power.

One warning,I think most of the amps (and radios) that used these tubes were Line-Op.

DO NOT build your amp that way,Use a transformer. You don't want your guitar strings to be electrified.

tubelab.com · 14th July 2006, 01:08 PM

I bought an "Electrolab" guitar amp at a flea market in West Virginia for $5. It uses the 7 pin AA5 tube set. 35W4 rect, 50C5 output, 12AV6 driver, and 12AU6 preamp. I put in some new caps, installed an isolation transformer (don't skip this step they are $11 from Mouser) and cranked it up. It sounds like it is trying hard to be a Champ, but doesn't quite make it. It is a good amp for practice, but it doesn't scream when pushed. I set it asside for future modifications.

alexmoose · 14th July 2006, 01:27 PM

I know to use a transformer, haha they are the Diy-ers friend. If I just take the schematic of an All Americian 5, and take out the amplifier part, and re-create a similar circuit will it work?

tubelab.com · 14th July 2006, 01:43 PM

You will need more gain than the single 12SQ7 can supply. If you have a 12SJ7 (common in this tube set) it can provide all of the gain that you need. The 12SK7 can be used although you will get some distortion. Use the Fender 5C1 schematic and adjust the resistor values to get the tube currents right for the B+ that you are using. (make the 25K in the power supply much smaller, same with the 2 meg on the 6SJ7 screen). The 50L6 will need a smaller cathode resistor, maybe 180 ohms.

http://www.schematicheaven.com/fende..._5c1_schem.pdf

14th July 2006, 04:28 AM	#1
alexmoose diyAudio Member Join Date: Mar 2006 Location: Michigan	An "All American" tube Project hey I have a surplus of the All amercian five tubes, and I was wondering if anyone had bulit a guitar project using the raw, un-clean sound that these tubes produce, does anyone have any project ideas? I'm refering to the 50lgt, and the 12sq7 specificly, however if anyone has any idea with the other tubes, i'm all ears

14th July 2006, 01:08 PM	#3
tubelab.com diyAudio Member Join Date: Jul 2005 Location: South Florida	I bought an "Electrolab" guitar amp at a flea market in West Virginia for $5. It uses the 7 pin AA5 tube set. 35W4 rect, 50C5 output, 12AV6 driver, and 12AU6 preamp. I put in some new caps, installed an isolation transformer (don't skip this step they are $11 from Mouser) and cranked it up. It sounds like it is trying hard to be a Champ, but doesn't quite make it. It is a good amp for practice, but it doesn't scream when pushed. I set it asside for future modifications. __________________ Too much power is almost enough! Turn it up till it explodes - then back up just a little.

14th July 2006, 01:43 PM	#5
tubelab.com diyAudio Member Join Date: Jul 2005 Location: South Florida	You will need more gain than the single 12SQ7 can supply. If you have a 12SJ7 (common in this tube set) it can provide all of the gain that you need. The 12SK7 can be used although you will get some distortion. Use the Fender 5C1 schematic and adjust the resistor values to get the tube currents right for the B+ that you are using. (make the 25K in the power supply much smaller, same with the 2 meg on the 6SJ7 screen). The 50L6 will need a smaller cathode resistor, maybe 180 ohms. http://www.schematicheaven.com/fende..._5c1_schem.pdf __________________ Too much power is almost enough! Turn it up till it explodes - then back up just a little.

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14th July 2006, 09:13 AM	#2
DigitalJunkie diyAudio Member Join Date: Apr 2003 Location: Portland,Oregon Blog Entries: 4	I think there used to be a few guitar amps that used the 50L6 and similar tubes,I recall seeing a few,maybe at Triode Electronics,or something. Not alot of power,but maybe you could parallel a couple tubes or something,if you want more power. One warning,I think most of the amps (and radios) that used these tubes were Line-Op. DO NOT build your amp that way,Use a transformer. You don't want your guitar strings to be electrified.

14th July 2006, 01:27 PM	#4
alexmoose diyAudio Member Join Date: Mar 2006 Location: Michigan	I know to use a transformer, haha they are the Diy-ers friend. If I just take the schematic of an All Americian 5, and take out the amplifier part, and re-create a similar circuit will it work?

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