When I was a sprogg at UCL doing Electrical Engineering practical exams and theory a tutor called Dr Watts(really) told all the students present(8) to please keep any designs and any work as simply laid out as possible" Keep it simple "! he would growl in that Scottish(really) accent and I never forgot it. Bring that 50watt head back to stock(as near as poss) and it will sell. They are simple designs and a Master vol just turns them on their heads. One tip for anyone who uses a master vol Modded amp"Turn the master up full and use the gain/pre-amp knob as your volume" , a it's warmth and clarity returns and if you want fuzz just get a Rat pedal and a spare lead"! BTW you have earned a commendation from me because of your enthusiasm and that is no2 after "keep it simple".
Dude, that transformer mounting plate scheme @16:40 fricken genius. I've been contemplating for years trying to come up with some kind of temporary transformer mount that would allow for a more convenient way to change out and try different examples in an amp. Particularly with output transformers it's always a bit of a crapshoot of what you're going to get when you first power it on because they're so difficult to remove, you're essentially wedded to it. I like the metal plate using an electrical outlet box cover, it's been in my face the whole time and I didn't put one and one together, pretty standard for me. The only thing that would need to be figured out is a wiring scheme from the connection points to the rest of the amp. I'd be tempted to try solderless connectors but with voltages this high it would be dangerous to use screw type terminals because the metal parts of a screwdriver would have the full B+ on it if adjusted while live. I think I'll try using old PTP terminal strips and try to put it somewhere near the power tube sockets that's easy to get to with a soldering iron without burning nearby wires, unlike having to remove and install a transformer the old fashioned way 😂 Off to Home Depot to grab some electrical box covers and see how it goes. I can't thank you enough👍
Thank you for your comment! If you are looking for a safer way to do quick connections, check out the European style terminal blocks as were used in vintage Vox/JMI amps. There have models rated up to 600 Volts. The wires are encased in plastic and not exposed like our American Terminal Blocks/Barrier Strips.
@@enginerdamps2562 Are they called euroblock connectors? I see a million different types but basically a terminal block with a plastic set screw, good call on that👍 I probably should have payed better attention to the video because I pulled out a Marshall 100 watt repro chassis and only then realized it's drilled for stand up transformers🤦♂️ After thinking about it some more though I might have come up with a solution that does away with another problem I have, I hate can-caps! They're big, expensive and all that just for just 2x 50uF electrolytics, you can buy 10+ modern electrolytics for the price of a one can-cap. What I'm thinking about doing is cutting a square hole along the outer dimensions of 4x can-cap bank between the power and output transformers and mount studs for the baseplate to slide on to. That's actually where Marshall originally mounted the output transformer until 1969 when the all can-cap P/S became standard. On the surface it would seem it wouldn't make a difference but it does in my view. The stray electromagnetic fields coming from each transformer will normally interact with the other in any amp unless the chassis is big and you mount them on the opposing corners. That works when you want to eliminate all possible noise sources like in a high gain amp where the preamp is doing all the work but in a non-master volume amp it's both the preamp and poweramp working together. Subtle things like power supply sag, filtering amount, transformer interaction, ect is much more apparent in this context. Ken Fischer of Trainwreck amps went one step further to get the maximum amount of interaction between the output and power transformers by mounting them together on one end of the chassis practically touching each other. I wouldn't go that far unless I was doing a Trainwreck clone but really it's maybe a couple inches difference between that and a true plexi era Marshall. With the removable plate it would be possible to experiment with the concept further to find that sweet spot.
Actually, it not a kit. I selected every component and I also staked the GP03 fiberboard myself. It's more of a reproduction. If you have a spare Marshall 50W that you would like to donate, I would be happy to accept it, go over it and put out a video on it.
Was there a part two? Frankly mate, looking at the build, you're going to get noise. Your ground scheme is loopy, the resistors mounted directly next to capacitors and the generaly lack of common mode cancelation, unshelided signal runs, rf antenae's doesn't suprise me in the lesast. Pretty shitty for a grad tbh. 1.bp.blogspot.com/_16lay_eKXbA/ShhluXL9qrI/AAAAAAAAACQ/5YkMzknqc9I/s1600/plexifrontguts.jpg
When I was a sprogg at UCL doing Electrical Engineering practical exams and theory a tutor called Dr Watts(really) told all the students present(8) to please keep any designs and any work as simply laid out as possible" Keep it simple "! he would growl in that Scottish(really) accent and I never forgot it. Bring that 50watt head back to stock(as near as poss) and it will sell. They are simple designs and a Master vol just turns them on their heads. One tip for anyone who uses a master vol Modded amp"Turn the master up full and use the gain/pre-amp knob as your volume" , a it's warmth and clarity returns and if you want fuzz just get a Rat pedal and a spare lead"! BTW you have earned a commendation from me because of your enthusiasm and that is no2 after "keep it simple".
I recently remembered a RAT pedal I built and I'll give it a try next time I fire up the amp.
Dude, that transformer mounting plate scheme @16:40 fricken genius. I've been contemplating for years trying to come up with some kind of temporary transformer mount that would allow for a more convenient way to change out and try different examples in an amp. Particularly with output transformers it's always a bit of a crapshoot of what you're going to get when you first power it on because they're so difficult to remove, you're essentially wedded to it.
I like the metal plate using an electrical outlet box cover, it's been in my face the whole time and I didn't put one and one together, pretty standard for me. The only thing that would need to be figured out is a wiring scheme from the connection points to the rest of the amp. I'd be tempted to try solderless connectors but with voltages this high it would be dangerous to use screw type terminals because the metal parts of a screwdriver would have the full B+ on it if adjusted while live. I think I'll try using old PTP terminal strips and try to put it somewhere near the power tube sockets that's easy to get to with a soldering iron without burning nearby wires, unlike having to remove and install a transformer the old fashioned way 😂
Off to Home Depot to grab some electrical box covers and see how it goes. I can't thank you enough👍
Thank you for your comment! If you are looking for a safer way to do quick connections, check out the European style terminal blocks as were used in vintage Vox/JMI amps. There have models rated up to 600 Volts. The wires are encased in plastic and not exposed like our American Terminal Blocks/Barrier Strips.
@@enginerdamps2562 Are they called euroblock connectors? I see a million different types but basically a terminal block with a plastic set screw, good call on that👍
I probably should have payed better attention to the video because I pulled out a Marshall 100 watt repro chassis and only then realized it's drilled for stand up transformers🤦♂️
After thinking about it some more though I might have come up with a solution that does away with another problem I have, I hate can-caps! They're big, expensive and all that just for just 2x 50uF electrolytics, you can buy 10+ modern electrolytics for the price of a one can-cap. What I'm thinking about doing is cutting a square hole along the outer dimensions of 4x can-cap bank between the power and output transformers and mount studs for the baseplate to slide on to. That's actually where Marshall originally mounted the output transformer until 1969 when the all can-cap P/S became standard. On the surface it would seem it wouldn't make a difference but it does in my view. The stray electromagnetic fields coming from each transformer will normally interact with the other in any amp unless the chassis is big and you mount them on the opposing corners. That works when you want to eliminate all possible noise sources like in a high gain amp where the preamp is doing all the work but in a non-master volume amp it's both the preamp and poweramp working together. Subtle things like power supply sag, filtering amount, transformer interaction, ect is much more apparent in this context.
Ken Fischer of Trainwreck amps went one step further to get the maximum amount of interaction between the output and power transformers by mounting them together on one end of the chassis practically touching each other. I wouldn't go that far unless I was doing a Trainwreck clone but really it's maybe a couple inches difference between that and a true plexi era Marshall. With the removable plate it would be possible to experiment with the concept further to find that sweet spot.
This is a kit! Refurb a real one!
Actually, it not a kit. I selected every component and I also staked the GP03 fiberboard myself. It's more of a reproduction. If you have a spare Marshall 50W that you would like to donate, I would be happy to accept it, go over it and put out a video on it.
Was there a part two? Frankly mate, looking at the build, you're going to get noise. Your ground scheme is loopy, the resistors mounted directly next to capacitors and the generaly lack of common mode cancelation, unshelided signal runs, rf antenae's doesn't suprise me in the lesast. Pretty shitty for a grad tbh. 1.bp.blogspot.com/_16lay_eKXbA/ShhluXL9qrI/AAAAAAAAACQ/5YkMzknqc9I/s1600/plexifrontguts.jpg
Hence the "Repair and Rebuild" video!