What was done to this amp?

[Shiny_Surface]

It's a '78 JMP, sounds great but some of the components look different than what I'm used to seeing.

Can anyone tell? Just curious....

 

[jerrydyer]

looks like a couple tantalum caps where the .68 would be or a couple pico farad caps.I know someone who was playing around with that idea there.

 

[King Crimson]

Don't know but ...

may know.

 

[rockstah]

sounds great is to ones liking. what are the value of the two caps across the input stages cathode resistor? otherwise its a stock circuit value wise... other than the .1u in the PI if they are in fact .1u's.

Mark

 

[tjon]

Extra crystal lattice.

 

[Ventura]

Don't know but ...

may know.

Who's the betty?

 

[IndyWS6]

Amanda Righetti - actress on "The Mentalist". Tight, athletic (volleball) body

 

[Shiny_Surface]

sounds great is to ones liking. what are the value of the two caps across the input stages cathode resistor? otherwise its a stock circuit value wise... other than the .1u in the PI if they are in fact .1u's.

Mark

I'm not sure to be honest I'd have to look at it again.

I definitely don't want it to sound like Van Halen though, no offense.

 

[Shiny_Surface]

looks like a couple tantalum caps where the .68 would be or a couple pico farad caps.I know someone who was playing around with that idea there.

Thanks Jerry, a few things did look different than what I expected to see.

I just wanted to make sure whatever was changed wouldn't effect the overall reliability of the amp or anything like that.

 

[FortinAmps]

I just wanted to make sure whatever was changed wouldn't effect the overall reliability of the amp or anything like that.

As for reliability, in the future those supply and bias caps will need some attention. The only other thing is to make sure is that impedance selector plug socket is nice and tight.

Cheers,
Mike

 

[briango2000]

Happiness is a tight impedance selector

 

[rockstah]

sounds great is to ones liking. what are the value of the two caps across the input stages cathode resistor? otherwise its a stock circuit value wise... other than the .1u in the PI if they are in fact .1u's.

Mark

I'm not sure to be honest I'd have to look at it again.

I definitely don't want it to sound like Van Halen though, no offense.

none taken.
Mark

 

[jerrydyer]

looks like a couple tantalum caps where the .68 would be or a couple pico farad caps.I know someone who was playing around with that idea there.

Thanks Jerry, a few things did look different than what I expected to see.

I just wanted to make sure whatever was changed wouldn't effect the overall reliability of the amp or anything like that.

looks like a clean solid amp to me.

 

[Gainzilla]

Amanda Righetti - actress on "The Mentalist". Tight, athletic (volleball) body

I love that chick!!! Wow, she looks totally different above!!!

 

[IndyWS6]

Right thee with you, brother.