The Amp Garage

Anyone can buy (or steal) the rights to a brand name, and start producing product with the branding and look of the original (in this case being produced by "Shin-ei, LLC" perhaps another purchased brand name, lol.) Call me cynical, but I propose that if they look really good it'd be hard to object...

Did you happen to compare your pre- and post-replacement bias voltages/cathode currents? I'd bet you altered the bias setting when you changed the caps. I checked out the bias today and it was much as muchness. I found the EL-34’s were conducting less and the 6L6’s were conducting more. So it’s a b...

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...

Those Vishay are noticeably upper midrange forward sounding , good for Marshall crunch , lots of harmonics . I really like that brand for the bias specifically. How did you determine that Charlie? I had issues with the highs in my Mesa Boogie SOB which I converted to a Mark 1. The fix was to get ri...

WhopperPlate wrote: ↑Mon Feb 12, 2024 6:08 pm

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

I like their electrolytic caps . Time will tell how they survive .

I haven’t used the electro caps. I tried to get them from CE Distribution and they had run out of stock.
What do Jupiter electro’s bring to the circuit?

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 ...