Cameron mod

[nico21]

So to be clear, from what i understood :

4 gain stages + CF + JCM 800 TS + 0,1µ Output couplers

1st stage : 100k plate, 10k cathode, 22n CC, 470K//470p, 470k to ground (or 470k, 470K//470p to ground ?)
2stage : 100k plate, 2,3k cathode with 1,5µ cap, 2,2n CC, 500k gain pot
3rd stage : 100k plate, 10k cathode, 2,2n CC, 500k gain pot
4th stage : 100k plate, 820 cathode with 0,68n cap

All plates bypass with 470p
Filtering 50/16/16/33/33

am I right?

[Triodinator]

Brotha? You Rock! If someone would make a layout?! Maybe we could put your name on it! Not really fair to M.C. to associate your design with his is it? It does sound bad assed on my PC spoeakers!

Thanks for the insight to your genius!

[peterc52]

It sounds awesome!

[MarkCameron]

I was thinking about the plate driven tone stack and I think if you have the tonestack and then the 4th stage behind it, it helps to smooth some of that harshness and allows some more shaping to be done before it hits the PI. I believe Lee Jackson was one who started doing this with his mods. I also think it depends where or what type of MV you use in this circuit to push things.

No, it's been Laney, who came up first w/ four gain stages & CF before the tone stack and an additional gain stage after the tone stack already in mid 80's - at a time, as Lee Jackson (and me too) still were learning electronics and studying schems of others

They've also introduced some kind of solid state clipper after the 5-th gain stage, still before the Master.

Check the attached schem!

Larry

Lee was working at Fender in the late 70s with Paul Rivera. Paul Rivera started to do this mod.. around the mid 70s I think.
There is no clipper circuit...I think you are looking at the switching for the bass boost circuit...Its kind of like a loudness control on hi-fi stuff

[novosibir]

There is no clipper circuit...I think you are looking at the switching for the bass boost circuit...Its kind of like a loudness control on hi-fi stuff

Yep, you're correct!

Actually I was mislead by the here attached schem of the AOR100 Series 2, what I've overlooked too quick.
On this schem the FET's are for Master switching purpose, not for signal clipping - what I saw after 5 seconds longer than before looking at it.

Larry

[briango]

There is no clipper circuit...I think you are looking at the switching for the bass boost circuit...Its kind of like a loudness control on hi-fi stuff

Yep, you're correct!

Actually I was mislead by the here attached schem of the AOR100 Series 2, what I've overlooked too quick.
On this schem the FET's are for Master switching purpose, not for signal clipping - what I saw after 5 seconds longer than before looking at it.

Larry

Thanks Mark and Larry. I always am interested in the history of when/how these things developed...very cool. And thanks univalve1234 for sharing...sorry if I came off as a dick, but I was hoping we could learn some cool stuff together. I have been working on a 50 watter I have and it sounds really close to what you have done. Mine has lower filtering and is real similar stage wise in components, but I just have 3 stages in this one and a diode clipper. The reason I didn't goto 4 on this particular amp is I have it able to easily switch from plexi to a JCM 800 type of cascade. From there I have a switch on the front that changes the cascade mode from #34(AFD) to 800 to SLO. I also have a resonance on the back and have another switch where some dumbass before drilled a weird hole, so I have a cathode bypass switch for the last stage with some different caps. I have a footswitchable boost with a relay that adds some more gain and boosts the mids/highs by about 9db. Pretty versatile and it sounds good.

Brian

[univalve1234]

So to be clear, from what i understood :

4 gain stages + CF + JCM 800 TS + 0,1µ Output couplers

1st stage : 100k plate, 10k cathode, 22n CC, 470K//470p, 470k to ground (or 470k, 470K//470p to ground ?)
2stage : 100k plate, 2,3k cathode with 1,5µ cap, 2,2n CC, 500k gain pot
3rd stage : 100k plate, 10k cathode, 2,2n CC, 500k gain pot
4th stage : 100k plate, 820 cathode with 0,68n cap

All plates bypass with 470p
Filtering 50/16/16/33/33

am I right?

looks good, try 1000pf on the first stage plates too , see if you like it better. Its 470k to ground btw.
you really need greenbacks for this tone too, its 50% of the tone and and guitar that sings too

[univalve1234]

Brotha? You Rock! If someone would make a layout?! Maybe we could put your name on it! Not really fair to M.C. to associate your design with his is it? It does sound bad assed on my PC spoeakers!

Thanks for the insight to your genius!

Thanks alot man , i cant get enough of this amp . I have 2 friends of mine that really want me to build them one now lol.
Lets call it the chameleon mod , still though inspired by marks awesome soundings mods i have to give him credit . Im sure the gurus here are laughing at such an easy mod but what can you do , sometimes simple sounds good !!!!!

[novosibir]

Im sure the gurus here are laughing at such an easy mod but what can you do , sometimes simple sounds good !!!!!

Less not seldom is more and sometimes it are the simple things, what are reaping admiration.
And I'm shure, that the gurus don't laugh about it! If they do, then they cannot be gurus!

Larry

[univalve1234]

Im sure the gurus here are laughing at such an easy mod but what can you do , sometimes simple sounds good !!!!!

Less not seldom is more and sometimes it are the simple things, what are reaping admiration.
And I'm shure, that the gurus don't laugh about it! If they do, then they cannot be gurus!

Larry

Spot on larry, id really like to play through one of your amps one day

[novosibir]

So to be clear, from what i understood :

4 gain stages + CF + JCM 800 TS + 0,1µ Output couplers

1st stage : 100k plate, 10k cathode, 22n CC, 470K//470p, 470k to ground (or 470k, 470K//470p to ground ?)
2stage : 100k plate, 2,3k cathode with 1,5µ cap, 2,2n CC, 500k gain pot
3rd stage : 100k plate, 10k cathode, 2,2n CC, 500k gain pot
4th stage : 100k plate, 820 cathode with 0,68n cap

All plates bypass with 470p
Filtering 50/16/16/33/33

am I right?

Together with the confusing postings of univalve1234 on the previous page I've understood it quite different.

Either this way:

[novosibir]

... but rather this way:

[novosibir]

And yes, I forgot to change the Presence circuit in both schems to JCM800 specs, but everyone knows the difference

Larry

[nico21]

too nice Larry ! great clear schem !!!

I would go with the first version of the schem with a secong gain pot between 3rd and 4th stage

Maybe univalve1234 could confirm between the two schems ?

BTW univalve1234, what NFB resistor are you using? which tap?
what would you change to make it sounds with V30 speaker? removes one of the treble peaker?

Anyway, univalve1234, and

Thanks

[robert]

Hi Larry,

welcome "back" on the forum and thank's for that nice schematic!

BTW: a clear scheme (like yours) has so many advantages in opposite to the mostly very "flowery" word descriptions of a mod.

IMHO every amp DIYer should be able to read and draw schematics, it wouls make things much easier

Regards & einen "guten Rutsch ins neue Jahr"

Robert