Old Marshall Repair

[jerrydyer]

Personally if you are in the LA location I would take it to another tech...
Dave Friedman, racksystems ltd.
Would be my first choice. Then Mark Cameron.

uuuhhh ?

someones not doing their reading.

 

[glpg80]

Personally if you are in the LA location I would take it to another tech...
Dave Friedman, racksystems ltd.
Would be my first choice. Then Mark Cameron.

uuuhhh ?

someones not doing their reading.

lol jerry

 

[glpg80]

The first flag for me, and maybe I'm wrong, is when he says "the amp is X years old and it's time to change..." It seems to me that they need to be changed or not based on failure, rather than time. I'm only just learning about vintage amps, just bought a 35 yr old fender and it sounds great on original parts.

electrolytic capacitors have a gell like substance between plates which is what holds the charge. over time this gell can solidify, the canisters can leak, and other small problems.

this is why caps have to be changed after so many years.

electrolytics also have to be formed if they have been on the shelf for many many years.

these circuits are not cut and dry "build them and never touch them again" - tube amplifiers have to be maintained.

 

[jasonP]

Personally if you are in the LA location I would take it to another tech...
Dave Friedman, racksystems ltd.
Would be my first choice. Then Mark Cameron.

uuuhhh ?

someones not doing their reading.

I don't get it.

 

[jasonP]

Personally if you are in the LA location I would take it to another tech...
Dave Friedman, racksystems ltd.
Would be my first choice. Then Mark Cameron.

uuuhhh ?

someones not doing their reading.

lol jerry

lol matt

 

[glpg80]

hows that slo build treating you

 

[jasonP]

hows that slo build treating you

Seems like the never ending project of tweeking, testing and lot's of money spent on different parts. Pretty cool sounding amp both before and after. Just finished it up last night and not going to touch it for a while. On to the Marshall's. I think honestly this has been fun and everything to build something yourself but I almost wish I would have bought a Marsha or CCV instead, the knowledge about circuits those two guys have and parts they use...
How about for you dude? I know you wanted to start making some amps. How are you coming along?

 

[glpg80]

hows that slo build treating you

Seems like the never ending project of tweeking, testing and lot's of money spent on different parts. Pretty cool sounding amp both before and after. Just finished it up last night and not going to touch it for a while. On to the Marshall's. I think honestly this has been fun and everything to build something yourself but I almost wish I would have bought a Marsha or CCV instead, the knowledge about circuits those two guys have and parts they use...
How about for you dude? I know you wanted to start making some amps. How are you coming along?

im at a standstill

i need $1,400 to purchase eagle to get the mm x mm x mm board size i need - to take my pen-drawn and multisim schematics into an actual circuit so i can produce the gerber files. i dont have the cash, and obama has caused some problems in office - so im going to wait to claim my business with a tax form first before i buy it, so that when tax time comes around i can use it as a tax writeoff.business loss. so that means im at a complete dead still stop

ive been emailing a few laser etching companies for their pricing on bulk services and also prototyping services for small businesses.

in the mean time ive been concentrating on the bias circuits, relay circuits, and toying what circuit i want to do for a crunch channel. i cannot decide if i want AC30 influences or something custom off the wall that will match the lead channel i have designed better.

its a hell of a task to do this from scratch. 2 years in the making, its getting down to the nitty gritty. im hoping to get my 5150 II back up and running first, then saving up for the design program

 

[Mudder]

The first flag for me, and maybe I'm wrong, is when he says "the amp is X years old and it's time to change..." It seems to me that they need to be changed or not based on failure, rather than time. I'm only just learning about vintage amps, just bought a 35 yr old fender and it sounds great on original parts.

electrolytic capacitors have a gell like substance between plates which is what holds the charge. over time this gell can solidify, the canisters can leak, and other small problems.

this is why caps have to be changed after so many years.

electrolytics also have to be formed if they have been on the shelf for many many years.

these circuits are not cut and dry "build them and never touch them again" - tube amplifiers have to be maintained.

I was aware that caps do leak and need replacement, but is it a set time? If the tech says, your caps are leaking, fine. I can get with that.

 

[glpg80]

The first flag for me, and maybe I'm wrong, is when he says "the amp is X years old and it's time to change..." It seems to me that they need to be changed or not based on failure, rather than time. I'm only just learning about vintage amps, just bought a 35 yr old fender and it sounds great on original parts.

electrolytic capacitors have a gell like substance between plates which is what holds the charge. over time this gell can solidify, the canisters can leak, and other small problems.

this is why caps have to be changed after so many years.

electrolytics also have to be formed if they have been on the shelf for many many years.

these circuits are not cut and dry "build them and never touch them again" - tube amplifiers have to be maintained.

I was aware that caps do leak and need replacement, but is it a set time? If the tech says, your caps are leaking, fine. I can get with that.

when the time is right. if you are a single owner of an old amplifier you will hear low end loss, sustain loss, sagging, and other tone changes over time. these usually are the deffects of running the electrolytic caps. if you are buying an old amplifier, its better to be safe than sorry. caps shorting in your filter supply can lead to nasty results. as they always say, transformers are the worlds best fuse savers.

now they have oil-filled capacitors which last 10x as long, but are 10x as pricey. not really sure if their tonal benefits either.