ivan H
Ambassador of Tubes & Grooves
Well, new amp build actually.
So I had built a little Fender Champ-ish type amp in a head format about a year & half ago, but used larger transformers that allow other tubes (EL84, 6L6, EL34 etc) to be used. While a decent amp, the bigger output transformer didn't sound quite the same as a champs & more importantly, didn't react like the smaller champ OT. So, I decided it would be better to rebuild that amp into something like a Marshall (Slash model) SL5 (only using the EL34's full potential) & build up a "proper" Champ. This is the result.
For this one I used a reproduction of the tiny, high load impedance output transformer as used in the very early 50's model tweed champs, seen here
(the chassis is chromed & there is a reflection showing on it). I have a couple of pics taken during the build;
Board drilled & turreted. I used my own layout rather than follow Leo's.
& a shot showing the guts. I also used a different grounding scheme than the originals. The only other deviations from the original tweed circuit is the addition of a 470 ohm screen grid resistor & a 1k5 metal film (beyschlag) grid stopper resistor on the output tube. Tubes used are NOS, NIB items. An early 60's GE 5Y3WGTB rectifier, a Philips ECG JAN 6V6GT & a Sino 6N4 12AX7. All voltages are within the correct range though the 6V6 is biased a little hot (about 120% max dissipation). Being a very rugged tube it can handle this no problem & shows no sign of red plating at idle or anywhere through to full clip, & does sound great, though I might bias it back down go 100% max dissipation in the interest of tube life. The speaker is an alnico Weber 8A125.
Volume goes to 12. Get a bit of that into you Mr Tufnel. One more pic
Cheers
So I had built a little Fender Champ-ish type amp in a head format about a year & half ago, but used larger transformers that allow other tubes (EL84, 6L6, EL34 etc) to be used. While a decent amp, the bigger output transformer didn't sound quite the same as a champs & more importantly, didn't react like the smaller champ OT. So, I decided it would be better to rebuild that amp into something like a Marshall (Slash model) SL5 (only using the EL34's full potential) & build up a "proper" Champ. This is the result.
For this one I used a reproduction of the tiny, high load impedance output transformer as used in the very early 50's model tweed champs, seen here
(the chassis is chromed & there is a reflection showing on it). I have a couple of pics taken during the build; Board drilled & turreted. I used my own layout rather than follow Leo's.
& a shot showing the guts. I also used a different grounding scheme than the originals. The only other deviations from the original tweed circuit is the addition of a 470 ohm screen grid resistor & a 1k5 metal film (beyschlag) grid stopper resistor on the output tube. Tubes used are NOS, NIB items. An early 60's GE 5Y3WGTB rectifier, a Philips ECG JAN 6V6GT & a Sino 6N4 12AX7. All voltages are within the correct range though the 6V6 is biased a little hot (about 120% max dissipation). Being a very rugged tube it can handle this no problem & shows no sign of red plating at idle or anywhere through to full clip, & does sound great, though I might bias it back down go 100% max dissipation in the interest of tube life. The speaker is an alnico Weber 8A125.
Volume goes to 12. Get a bit of that into you Mr Tufnel. One more pic
Cheers
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