The Amp Garage

seveneves wrote: ↑Mon Feb 12, 2024 8:48 pm

Mark wrote: ↑Mon Feb 12, 2024 3:15 pm Jupiter caps won’t like this. They have a good product.

Well, sure. How could they? How many "Jupiter" branded caps do you see in vintage Fenders?

I know of a Bandmaster 6G7a that has some of them in it.

I replaced them with Vishay caps. Vishay bought up a lot of companies and makes components for many brands. I would have preferred Nichicon, but Vishay was all that I could get locally.
https://au.rs-online.com/web/p/aluminiu ... 45379?gb=s

Jupiter caps won’t like this. They have a good product.

A funny thing happened, I’m in the midst of repairing a Mesa Boogie 295 dual power amp. In another thread I talk about my findings and update the circuit diagram. https://ampgarage.com/forum/viewtopic.php?f=6&t=36878 I didn’t replace the filter caps as there is so many of them and I’m not experienci...

Here is a bit more information on the circuit diagram of the 295. It includes the presence control which is omitted.
Measurements will be forthcoming.

I fixed the blowing fuses, but I was getting bugger all out the amp. I checked the voltages on the plate and the first plate was 7vdc. I checked the plate resistors one was 22K and the other was 42K. I didn’t think that was the source of the fault. I lifted the coupling caps and the voltage returned...

I measured the resistance of the primary windings of the output transformer. The channel A transformer measured from blue/white to brown/white 87.2 ohm (EL-34’s class A). 108.6 ohms was measured from blue to brown. The channel B transformer measured from blue/white to brown/white 89.2 ohms. 111.1 oh...

What I was looking for was the blue to brown resistance, and the blue/white to brown/white resistance. Are you able to check the primary to secondary voltage ratios? eg if a measured low V AC is applied to the 4ohm secondary, what V AC is produced across blue to brown, and blue/white to brown/white...

bepone wrote: ↑Thu Feb 01, 2024 1:11 pm to throw all in scrap and reuse hardware? rebuilt some normal power amp..caps are too old now also

I measured the filter caps with my Peak ESR meter and they measured fine. As there are so many caps, I didn’t want to replace them unless I had to.

Hi PDF64 Good question, that’s the sort of thing I would be curious about. Given my curiosity I had to find out. I measured the transformers from the 6L6 tapping to the EL-34 tapping. On the first output transformer both side were 12 ohms. On the other transformer the measurements were 9.8 and 10.6 ...

Whilst looking up info on how this output stage works I came across this. https://www.ampbooks.com/mobile/classic-circuits/extended-a/ It harkens back to Randall’s days of patenting other people’s ideas. I don’t know why he thought that was a good idea. The real name is extended class A. I have come...

I have a Mesa Boogie 295 dual power amp to repair. IMG_1096.jpeg IMG_9252.jpeg It has an unusual story as the owner was going to throw it away and my brother took it. Oddly enough I never have this sort of luck. The EL-34’s are shot as you’d imagine, and a couple of the 12AX7’s are no good. I have n...

Did you carry out any mods to the guitar? Brass block etc. Only added a kill switch. After I received my Kiesel Delos with Floyd Rose, I realized the FR that came with the EVH is lower quality--the tuning machines are not as nice and smooth as Kiesel's German FR. I’m ignorant of Floyd Rose bridges,...

I bought this guitar (EVH Striped) last year, and have since put hundreds of hours in, practicing and playing more than a dozen gigs with my EVH tribute band, VanHagar. I have been very pleased. I changed the stock pickup to a Seymour Duncan, then back again to the original. The shielding has been ...

My son wanted his own guitar about a year ago and I got him one. He wanted a EVH guitar, he’s not a big fan of EVH, he liked the colour of the guitar, the fact it only has a bridge pickup and it can go into dropped D with the flick of a switch. He was a fan of Black Sabbath and I got him a Catanlynb...