Category Archives: Amps

Capacitors revamping

I had to replace capacitors in my ’68 Fender Bandmaster : I replace with very good F&T, but I want to keep this very cool vintage look, so … let’s revamp ! F&T with a Mallory look ! New caps … Continue reading

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Fender Bandmaster AB763 circa 67 or 68

Got this amp to fix : Despite it has not the typical “Alu frame drip edge”(removed by a previous owner ?), I think it’s a “blackline” from end 67 or beginning 68 : transformer code, AB763 schematic, blackline, chassis stamp … Continue reading

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IT11 Supercharger ’70s amp

Here is an amp I designed and build on request. Based on ’70s great amp such as Marshall, Orange … Good clean with extra boost triodes. 1 x 12AU7, 2 x 12AX7, 1 x EF86 and 2 x KT66 for … Continue reading

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KT66 Model for PSPICE

I was looking for a KT66 model for PSPICE. The one found on Norman Koren seemed to be cool, but unfortunately, I did not succeed to use it “as is” (syntax errors during simulation). So I have modified a little … Continue reading

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Marshall stack …

Just for fun, my “marshall stack”, picture taken in my … kitchen From top to bottom : Marshall 1917 “PA 20″ circa 1970 Marshall 2203 late ’70s “Master model lead mkII” Marshall 1987 “JMP 50″ (1974) Marshall 2045 2×12 circa … Continue reading

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Generating a bias voltage with PT without Bias Tap

Assume we have a power transformer without bias tap and we want to generate a bias supply. This example is based on a 4 diodes supply, PSPICE simulation. As always, we must prototype to validate the model … Schematic : … Continue reading

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Gimp and Inkscape under Mac OS X Mountain Lion

Gimp and Inkscape are free open-source pieces of software I use during the design process of my amps. They both need X11 window management system, but Apple does not support X11 under OS X 10.8 Mountain Lion any longer. You … Continue reading

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Marshall JMP 50 Lead (1987 model)

I got this JMP 50 lead (1987) circa 1974. Reforming caps test, it seems to work (a few mA through the resistor 100k/2W, for several hours, until the voltage across the 100k resistor is less than 10% of the maximum … Continue reading

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Bulgin Plug Wiring

A female bulgin plug. E is for Earth, L for Lead, N for Neutral. Used for old Marshall, Hiwatt, Carslbro … amps.

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