MGL RED Gutshot

  • Thread starter Thread starter Smash
  • Start date Start date
Smash
Smash
Hack
I finally took a little time to take this beast out of the headshell and have a peak at her nether regions. I don't know what I am looking at, but I sure know what I am hearing. And I fucking love it.
mgl gutshots.jpg
 
It’s got quality components including a couple of NOS Mustards early in the preamp, one of which is an unusual value (4n7 instead of 22n). It’s very Marshall with tweaks. Metro loop obv. Clean work. Hard to tell what’s going on with that small board near the input, something to do with the Master Volume. It also has the Friedman fixed Depth control in the NFB.
 
SpiderWars said:
It’s got quality components including a couple of NOS Mustards early in the preamp, one of which is an unusual value (4n7 instead of 22n). It’s very Marshall with tweaks. Metro loop obv. Clean work. Hard to tell what’s going on with that small board near the input, something to do with the Master Volume. It also has the Friedman fixed Depth control in the NFB.
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I know absoultely nothing, but the small board at front could be for "channel" changing. I have two masters that are footsiwtchable. I guess it could be for the footswitch also..
 
Smash said:
I know absoultely nothing, but the small board at front could be for "channel" changing. I have two masters that are footsiwtchable. I guess it could be for the footswitch also..
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Looks like all of the above. Is it a cascaded 2203 plus plexi type amp? That is, one channel JCM800 MV and one channel plexi?
 
SpiderWars said:
Looks like all of the above. Is it a cascaded 2203 plus plexi type amp? That is, one channel JCM800 MV and one channel plexi?
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No. This is the single channel versiion. The "channels" are just different volumes. So i have one set at not piss off wife, and the other at Holy shit the Toan
 
glpg80 said:
Take it to a tech immediately. Dude forgot to solder a few locations and on top of it there are a lot of cold solder joints. I’m not joking.

Otherwise looks clean.
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Yeah those 10k power resistor turrets are not filled. They could still be soldered but on my computer screen it doesn't look like it. They're probably bent/clipped underneath. Good catch. I didn't even look at the solder joints just the components.
 
glpg80 said:
Otherwise looks clean.
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Thoughts on the board near the input? On second look it seems a little 'shade tree' but maybe not. Whenever I used those boards I still used wires to connect and not the 'connect the dots with solder' method.

EDIT: and the wire to the PI input looks like a hot shield but that doesn't seem to be a big deal.
 
SpiderWars said:
Thoughts on the board near the input? On second look it seems a little 'shade tree' but maybe not. Whenever I used those boards I still used wires to connect and not the 'connect the dots with solder' method.
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I like to design cable tension loops that wires feed through so that movement and gigging don’t micro stress the solder joints hooked up flying style. That’s the only comment I have about the quality I’d improve on the board. It takes more work, planning, and cable, but it’s the proper way. I guess he connected the coax together thinking that’s good enough for vibration but I prefer hard mechanical vibration prevention near the joints. I don’t have a problem with the soldering on the board - I’m guilty of way more dense boards in amps that are double sided and vertical component placement as was done in the 50’s.
 
glpg80 said:
I like to design cable tension loops that wires feed through so that movement and gigging don’t micro stress the solder joints hooked up flying style. That’s the only comment I have about the quality I’d improve on the board. It takes more work, planning, and cable, but it’s the proper way. I guess he connected the coax together thinking that’s good enough for vibration but I prefer hard mechanical vibration prevention near the joints. I don’t have a problem with the soldering on the board - I’m guilty of way more dense boards in amps that are double sided and vertical component placement as was done in the 50’s.
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Yeah that spot in the conductor(s) that goes from soldered to not soldered is the weak link, the solder doesn't give at all and the unsoldered wire has no choice but to conform/bend/rattle along with the soldered part. I try to make things rigid but also make connections with the wires laying naturally, not stressed, such that they just lay there without solder. Then solder, then strain relief.
 
SpiderWars said:
Yeah that spot in the conductor(s) that goes from soldered to not soldered is the weak link, the solder doesn't give at all and the unsoldered wire has no choice but to conform/bend/rattle along with the soldered part. I try to make things rigid but also make connections with the wires laying naturally, not stressed, such that they just lay there without solder. Then solder, then strain relief.
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Also what’s up with the lack of zip ties? Amp seems oddly unfinished without them to me. They just keep wire management so much cleaner.
 
glpg80 said:
Take it to a tech immediately. Dude forgot to solder a few locations and on top of it there are a lot of cold solder joints. I’m not joking.

Otherwise looks clean.
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Yeah those unsoldered turrets dead center of the board jumped out at me right away.

@Smash if you're handy with a soldering iron it should be easy enough to touch up. Otherwise get it to a tech right away.
 
glpg80 said:
Take it to a tech immediately. Dude forgot to solder a few locations and on top of it there are a lot of cold solder joints. I’m not joking.

Otherwise looks clean.
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WOW , holy shit, they forgot to solder the 10K B+ rail dropping resistors, how the hell does that get missed..............and one of the left upper diodes looks like a cold solder joint and a few other possible ones. It think the MGL guy comes here and he can't be proud of that kind of work, he needs to take that thing back on his dime and make it right.

The build quality looks rushed to my eyes. Other than that... the layout looks good and all the clips of them have been a good solid slightly modded 2203 tones to my ears I hope that isn't a harbinger to come for MGL.

Good EYE there GLPG80!:2thumbsup:
 
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harddriver said:
WOW , holy shit, they forgot to solder the 10K B+ rail dropping resistors, how the hell does that get missed..............and one of the left upper diodes looks like a cold solder joint and a few other possible ones. It think the MGL guy comes here and her can't be proud of that kind of work, he needs to take that thing back on hid dime and make it right.

The build quality looks rushed to my eyes. Other than that... the layout looks good and all the clips of them have been a good solid slightly modded 2203 tones to my ears I hope that isn't a harbinger to come for MGL.

Good EYE there GLPG80!:2thumbsup:
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I think one of my favorite things about this amp is the two preamp tubes. Modern amps have added so many gain stages that you end up adding microphonics. So the bleed through in chords is ridiculous. With this amp, the gain stages give a very good base tone that is clear as fuck. I honestly couldn't be happier. I was on the fence because I didn't have a ton to go off of, but I am so happy I went this route. Luckily I did it before the circuit change, too, cuz I am a single channel guy.

The "slightly modded" is what i think about that makes me happy too. It is easy to do a ground up build and try to do too much. A lot of the actual modded marshalls I think sound better than the ground ups that come later. Such as Fortin. I would never buy one of his amps, but the amps he modded were badass.
 
Just know @Smash that those resistors are connected directly to the filter caps so there might be stored charge...ready to bite.
 
Smash said:
Modern amps have added so many gain stages that you end up adding microphonics. So the bleed through in chords is ridiculous.
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In many cases yes but I’d never assume all amps with 4 or more gain stages have those problems.
 
thegame said:
In many cases yes but I’d never assume all amps with 4 or more gain stages have those problems.
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Sure. For me, i am just speaking from my experience. I played and owned a good amount of amps. MGL nailed it with this circuit. It was something i was looking for before i totally understood what i was looking for.

A lot of times you have more of the microphonics, so you gate, but the gate doesnt take away when playing. I may just be picky. And i am not shitting on anyone's amps. Just happy with the circuit of this one
 
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