Marshall Black Panel JTM45 vintage reproduction Monkeymatic project

[xtian]

I've never seen any white paper science regarding this, only hear of ppl who swear it's The Way.

Do you LIKE hum in your build? I don't. Try it and trust your ears. Want to be shocked and amazed? Instead of headphones, use a guitar speaker connected to the OT secondary. Any hum you hear thru the speaker you'll hear when the amp is finished.

[bepone]

Oh, I also see that the Plexi faceplates are discussed on the Marshall forum. I would love to get me a JTM Black Flag for some reason (?), but I also learned on the Marshall forum that all of the Plexi plates are being sold for $95. Hm.

plexi back engraved faceplates in original green-gold color are the best from Modulus amps, for Marshall projects im taking from there.. Also is possible to order custom, all the others have some strange colours, not so close

[WhopperPlate]

I've never seen any white paper science regarding this, only hear of ppl who swear it's The Way.

Do you LIKE hum in your build? I don't. Try it and trust your ears. Want to be shocked and amazed? Instead of headphones, use a guitar speaker connected to the OT secondary. Any hum you hear thru the speaker you'll hear when the amp is finished.

Just because the factory did it doesn’t make it ideal…but if you need that vintage noise floor and subsequent intermodulation , then there’s no better substitute …

I have mentioned before how I am in the process of building an Ampeg SVT inspired amplifier for a client, and if you work on the old ones you will hear A LOT OF HUM if they aren’t biased and balanced on the money …

No wonder why ; the OT and PT are aligned .

Granted the stock dual bias setup makes this less of a problem and you can dial it out very well , and AFAIK and have come to understand , can caps and tubes in between help mitigate this hum theoretically to a degree, but I wonder why not go a step further?

With a simple headphone test and a new set of transformers I can null the hum entirely with a 90 degree rotation, even with the filament transformer installed.

If you aren’t cloning for exactness , then why not improve upon the design ? Seems like you are though…

[xtian]

Granted the stock dual bias setup makes this less of a problem and you can dial it out very well , and AFAIK and have come to understand , can caps and tubes in between help mitigate this hum theoretically to a degree, but I wonder why not go a step further?

Point being, even with NO TUBES INSTALLED, you'll hear the hum induced into the OT from the PT if they're sympathetically oriented as soon as the PT is energized.

[GAStan]

I just tested a new set of transformers I received but didn't have any headphones so used my o'scope instead. Very easy to do if one is available.

Very enlightening!

Found it impossible to remove ALL 60hz but did get it down to a few mV. Peak was a few volts on the 16 ohm taps.

I'm sure a multimeter would work too.

[rooster]

bepone, thanks for the direction to Modulus Amp. You are right, they have a lot of nice things there.

[bepone]

bepone, thanks for the direction to Modulus Amp. You are right, they have a lot of nice things there.

no problem, 15 yrs i'm taking faceplates from there and custom is possible.. plexi color is just perfect.. all the others have cheap gold/something/ nothing versions