# 5E3 - 6G2 - BF Amp



## Printer2 (Apr 8, 2012)

If I knew how good modeling amps were before I jumped into tube amps I probably would not be here right now. That being said I think I figured out how to have a 5E3 Deluxe in a box and with the flip of a switch go to a Brown Princeton one one channel and a BF Princeton on the other. OK I am cheating a little, I have the NFB on another switch along with the cathode bypass. Also the output tubes are cathode biased rather than fixed and are 6K6's rather than 6V6', the power transformer is a little small. I put a switch in to change the cathode resistor just in case the transformer can handle the 6V6's, might do an add on fixed bias later.


Schematic.











Amp










Layout


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## WCGill (Mar 27, 2009)

Very clever indeed. Have you bread-boarded it and does it work? I'm just wondering why you chose the 220k grid-leak value and the 470K grid-stopper, both on V2B. What purpose do the the diodes on the output tube plates serve? I'm expecting channel 1 A and B to be quite similar although there might be some subtle differences. Good luck.


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## vadsy (Dec 2, 2010)

Great looking cab woodwork!


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## Printer2 (Apr 8, 2012)

Nothing working yet, just did the Photoshop thing to help figure out the board. If Would not do it that way again as it was too much work. The grid leak and stopper is to do with grid blocking distortion. Suppose to tame down the circuit, I have used the 470k and some people have found changing the 1M resistor helps also. Since the stage has no gain and a lot of NFB it boosts the 220k value up to the Meg ohm range. The diodes are to catch the voltage kicked back from the speakers. Newer designed amps have them to reduce the potential voltage (feel funny putting those two words together) that can develop across the primary.

The values are just rough ones for now and I probably will adjust the power supply resistors. With the switches in the up position you get a 57 Deluxe 5E3 circuit where Ch 1 has a Tweed tone control where you get treble boost or cut and on Ch 2 you get cut from the interaction between the two. It is not so much that they will sound similar but rather the interaction between the two that gives the circuit its sound. Thanks.



Thanks also. Not quite perfect but pretty good for being new at building them. The cabinet is a bit smaller than a 5E3 cabinet due to the size of the grill cloth I am using, also I just wanted this as a practice amp. I had a circuit I thought up that I wanted to use in this amp which included reverb but with the added bass and treble I am running short on room. It will have a 10" speaker, I have not decided how I want to finish it yet, not covering it though.


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## WCGill (Mar 27, 2009)

I'd definitely breadboard it to see how it sounds. You might get some surprises and it's much easier to change something before it goes into that incredibly tight tweed chassis. I never liked the sound of those diodes on the output plates either. YMMV.


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## Printer2 (Apr 8, 2012)

Doing it on an eyelet board so not too hard to change parts. Actually this is a fairly roomy build as compared to my last one. Diodes are just a clip away to get rid of. The board without parts yet.


http://i406.photobucket.com/albums/pp142/printer2_photo/guitar amp/5E3BFEyeletBoard.jpg


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