I think I can speak for a lot us fans in saying PLEASE make that video on shielding and the different kinds of grounds in amps! Would love more insight on that very subject!
really good video, thankyou for making it. the relocation of critical grounding points explained in this video is really good info for people ...the use of brass screws and nuts to bolt down an eyelet has to be considered an inferior design for grounding due to the issues you've pointed out and clearly explained, the old fashioned solder pool on the chassis as a grounding point is superior ( but no good for aluminium ). After all, they were cheap(ishly) made things, but the sound....
yes can you take the time out and make a different about the differences between AC ground, Signal ground, DC ground, circuit ground, chassis ground, the difference between ground VS shielding, etc. that would help out a lot. Would using Brass Nuts, Brass Washers, Brass lock washer be better to use compared to Zinc silver nuts, washers, lock washers for a better metal to metal connection to improve the grounds?
I had a 100w jcm lead series, traded it for a1961 bassman. Years later got a 1981 jmp 2204 50w. The jmp is the one made for sale in Canada or so I told. Tube amplifiers rock.
had to stop playing guitar to watch this video! Very nice grounding scheme, i'm guilty...i soldered the bus wire on the back of pots in my marshall clone , same bus i ground cathodes and pot , so maybe i'm just isolating the pots...don't know , wish i could show you😂 anyway great job again 🤟🏻
In the past I have seen JCM800's with the filament wires parallel to each other, ie: noit twisted at all. Have you run across this before? I always twist them as part of the work.
Yep, they do exist. I’ve seen that mainly in 800s with horizontal inputs (Pots mounted on PCB), maybe somebody had the idea to safe a few minutes during manufacturing….I usually mod them to twisted wire Version if Owner agrees…
@@Burgschall I always thought it was very bad design on Marshall's part to attach a PCB to the chassis using just the pots for support with nothing to hold the board in place. You know those solder joints will break after a while with the board moving around.
I've seen this before. they don't have to be twisted as long as they are parallel and can't be separated, basically like a "lamp cord". The idea is that the inductive effects of each wire get cancelled out by each other.
I remember this era ground messes in Marshalls particularly the combo amps. I would only disagree about your sheilding not not needing to be perfect if there are any op amps in the entire design like some amps that had op amp effect loops. Of course it doesn't make a lot of difference on all tube designs
Oh no fixing a design error using science . Heretic Blasphemer how dare you use science and truth about a subject such as this. Really a full fact based explanation of why thing need fixed.
