Red Lego caps, replace them or leave them?
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Red Lego caps, replace them or leave them?
Would replacing the stock Lego caps with Sozo or other film caps like Xicon MPP, NTE or Panasonic be an improvement if you're looking for a smoother less fizzy tone?
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Reeltarded
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Re: Red Lego caps, replace them or leave them?
Probably not. What amp and what is done to it? Might be an easy thing like a plate bypass or a resistor across the treble pot.
Signatures have a 255 character limit that I could abuse, but I am not Cecil B. DeMille.
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Stevem
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Re: Red Lego caps, replace them or leave them?
Yeah, on what amp? And I am assuming you mean fizzy tone when the amp is pushed into clipping?
A easy thing to try is placing a .005 uf cap rated for 400 volts across the plate load resistor before of after the tone stack.
This can be a cheap disc type cap or whatever, in fact .01 disc caps are easy to find and two in series will do just fine if you do not have the .005 on hand!
You may also be getting bad crossover distortion from the output stage but you need a scope and a load resistor to pin that down.
A easy thing to try is placing a .005 uf cap rated for 400 volts across the plate load resistor before of after the tone stack.
This can be a cheap disc type cap or whatever, in fact .01 disc caps are easy to find and two in series will do just fine if you do not have the .005 on hand!
You may also be getting bad crossover distortion from the output stage but you need a scope and a load resistor to pin that down.
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
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Stevem
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Re: Red Lego caps, replace them or leave them?
Stevem wrote:Yeah, on what amp? And I am assuming you mean fizzy tone when the amp is pushed into clipping?
A easy thing to try is placing a .005 uf cap rated for 400 volts or better across the plate load resistor before of after the tone stack.
This can be a cheap disc type cap or whatever, in fact .01 disc caps are easy to find and two in series will do just fine if you do not have the .005 on hand!
You may also be getting bad crossover distortion from the output stage but you need a scope and a load resistor to pin that down.
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: Red Lego caps, replace them or leave them?
It's a JMP 2203 from the early to mid 70s I'd guess.
It's pretty much stock, the inputs have been changes so they're both high gain and mixed with a pair of 68k resistors. And all the power supply can caps have been replaced with Ruby caps.
There's nothing really wrong with it but I assumed that replacing the little red Lego caps with nos Philips/mullard mustard caps would be an improvement, and I'm wondering if there are any other caps that may be cheaper or easier to get that would be a similar upgrade.
The distortion is not overly fizzy or harsh, it's typical for this amp I think, I'm just wondering how to improve it, make it a little smoother without doing any major mods, killing the harmonics or making it more distorted. I want a fat meaty overdrive with lots of body and bite with as little fizz as possible. Eric Johnson and joe bonamassa seem to get nice fat smooth tone from a Marshall and I know it's fingers and there are a ton of variables but that's the direction I want to go.
I hear people talk about Sozo and Mustard caps and I wonder if I should replace them or if it's BS or sacrilege to shitcan the Legos?
Could use a little guidance, thanks!
It's pretty much stock, the inputs have been changes so they're both high gain and mixed with a pair of 68k resistors. And all the power supply can caps have been replaced with Ruby caps.
There's nothing really wrong with it but I assumed that replacing the little red Lego caps with nos Philips/mullard mustard caps would be an improvement, and I'm wondering if there are any other caps that may be cheaper or easier to get that would be a similar upgrade.
The distortion is not overly fizzy or harsh, it's typical for this amp I think, I'm just wondering how to improve it, make it a little smoother without doing any major mods, killing the harmonics or making it more distorted. I want a fat meaty overdrive with lots of body and bite with as little fizz as possible. Eric Johnson and joe bonamassa seem to get nice fat smooth tone from a Marshall and I know it's fingers and there are a ton of variables but that's the direction I want to go.
I hear people talk about Sozo and Mustard caps and I wonder if I should replace them or if it's BS or sacrilege to shitcan the Legos?
Could use a little guidance, thanks!
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Stevem
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Re: Red Lego caps, replace them or leave them?
Since the feedback signal tapped off the secondary of the output transformer extends the amps high frequency response ( and low end ) you might try placing a range of resistors in or a 50k pot in series with that, like 5k to 20k and see if that gets things more to your liking?
You will notice more overall gain and hence volume from the amp as you increase the value of this added resistor and you will notice a bit looser Bass response when the output stage is clipping.
With less and less feedback you will also notice that the output stage goes into clipping smoother and your playing thru that range of the amps output will have a greater dynamic range, in other words the with feedback there comes a point where the output stage jumps right into clipping due to the preamp stage kicking out a surge of signal.
Also note that if you find you like little to no feedback voltage getting back into the preamp section than at that point both plate load resistors on the PI need to be made the same value, the largest resistance is what they will both need to be!
You will notice more overall gain and hence volume from the amp as you increase the value of this added resistor and you will notice a bit looser Bass response when the output stage is clipping.
With less and less feedback you will also notice that the output stage goes into clipping smoother and your playing thru that range of the amps output will have a greater dynamic range, in other words the with feedback there comes a point where the output stage jumps right into clipping due to the preamp stage kicking out a surge of signal.
Also note that if you find you like little to no feedback voltage getting back into the preamp section than at that point both plate load resistors on the PI need to be made the same value, the largest resistance is what they will both need to be!
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
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martin manning
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Re: Red Lego caps, replace them or leave them?
Feedback or the lack thereof doesn't affect the PI balance! Leave the 82k/100k plate loads as they are!Stevem wrote:Also note that if you find you like little to no feedback voltage getting back into the preamp section than at that point both plate load resistors on the PI need to be made the same value, the largest resistance is what they will both need to be!
Some simple things to try: add a small cap from one PI plate to the other (the "fizz cap" seen on Fender and Marshall PI's), or put a cap across the PI's 82k plate load resistor.
Re: Red Lego caps, replace them or leave them?
martin beat me to the PI fizz cap. Current one should be about 47pf. Add another 100 to 120pf in parallel.
You could also try lowering the cold stage cathode resistor (second gain stage, 10k). Don't do anything drastic, just tack a 20K 1/4-watt in parallel to existing and see if that steers you in the right direction. IMHO it'd be better to make slight adjustments across the amp like this rather than one large adjustment in the circuit.
You could also try lowering the cold stage cathode resistor (second gain stage, 10k). Don't do anything drastic, just tack a 20K 1/4-watt in parallel to existing and see if that steers you in the right direction. IMHO it'd be better to make slight adjustments across the amp like this rather than one large adjustment in the circuit.
Re: Red Lego caps, replace them or leave them?
I have changed out all those caps with mustards, I wouldn't do it again not worth the work and time very little tonal difference- maybe a little less highs with the mustards