The Amp Garage

I admit I am curious... Are you even going to try to resurrect this beast? How do you even begin to evaluate whether an amp like this is worth saving? And to what lengths you might go to preserve the legacy value of the original? Yes, I want to save the amp, I don’t know what it will take to get it...

I never seen a Fender with these lugs before either but it is what it is. The lugs are original as the resistor attached to the lugs is the very same type as is used on the other side of the P.I. grid. There are no signs of the resistor being removed and resoldered. The solder joints are untouched a...

Purely for interest sake here is a picture of tagstrip being used to eliminate problems with a conductive board at the Fender factory.

They knew about the problem in the silver face amp days.

I have a silver face Twin on the bench and I have never seen a board like it. The board is stuffed.

When I got the amp the power transformer was stuffed, I noticed that the tone control caps are soldered on one side

Oddly enough I had a friend get a Fender Blues Junior come in. It was built in 2019 and is a Mark 2 amp which uses cathode bias. The filter caps were the blues IC and they looked fine, no signs of spilling their guts.

In the diagram the switch is set to fast ( higher gain) mode.

https://ampgarage.com/forum/files/Expre ... iation.jpg

What makes you think the problem is exclusive to the Hot Rod series Fender amps? Something I recall reading about some time ago. May be just internet lore, but maybe Fender did end up with the bulk of the bad product from that era. Yeah, it’s hard know if they are still bad. I would rather have mor...

The output transformer is quite an old version. It has a 5.5K primary from memory and it is quite loud. I remember RJ’s was quite full on. I thought it was in the vein of Richie Hall’s amp. https://youtu.be/HHiJrufUbF0?feature=shared https://ampgarage.com/forum/viewtopic.php?t=30033 https://cdn.shop...

Stevem wrote: ↑Fri Apr 19, 2024 10:01 am Yes they are not at the bottom of the ladder any more.

What makes you believe they are a good brand to use again?

What is on the bottom of the ladder these days?

I think F&T is my cap of preference, though if Nichicon had a product I would use that.

This problem was specific to Fender amps manufactured over some range of dates, and limited to IC electrolytics sold to Fender, IIRC. Great to hear from you as always Martin. I appreciate your input. I must admit that I don’t know if the bad IC brand caps were limited to Fender. Perhaps if there wa...

I think that will be your biggest challenge finding the right parts. The parts of greatest concern are the transformers. I would build it on a Garolite board, phenolic boards can be conductive and you don’t need that. https://modulusamplification.com/wrocket-top-boost-30watt---4-x-el84-head-kit-3229...

In the past I’ve seen quite a few fender amps with IC branded capacitors which are leaking, I dare say quite a techs made a good living replacing capacitors from Fender amps.

Have IC caps turned a corner and become reliable or do they still leak?

I probably would look for something like this Hammond output transformer. https://www.hammfg.com/part/1628SEA If you disagree that’s fine, but I would like to know why. It is touted as a Hi Fi transformer, but I don’t like Class A amp with rubbish bass response generally. From my experience this tra...

Measure the leakage at rated DCV. Measure the ESR. Measure the capacitance. Look for deformities. Fairly simple, but it takes time. It can be done by lifting one leg with care, and can be done using the amp's power supply when you have a variac and use a series resistor for current sensing. Right, ...

]The Two Stroke seems a strange amp to me. The tone control on these amps is nice but it does mean the amp loses signal so it doesn’t have the same break up as a Champ. I don’t know why the second 1.5K cathode resistor wasn’t bypassed by a 5uF to 22uF cap for extra gain and a 47 ohm tail resistor pu...