I think I'm getting the hots for a Cameron

[mentoneman]

i’ve played several mods, the ccv and had Zach’s atomica at my house for a while and in my friend’s studio to makes some Kemper profiles:



hung out with mark a few times and he was always really cool to chat and jam with. i wish he hadn’t done what he did to so many people here.

that being said, his amps/mods are pinnacle rock tones in my experiences. optimized marshall top end explosive tight attack mixed with boogie mark grind/grease and slippery legato touch dynamics. playing Zach’s Atomica dialed in and cranked through his wdw rig at his shop was a benchmark rock tone moment in my mind. used his VH bumblebee (duncan 78 pu i think) and my Tyler and both sounded incredible.

this is Zach playing the Atomica rig lower volume with his valley arts lukather clone through my iphone 6 so not great audio- just a look at the rig



he had some cameron modded marshalls in that wall too.
dave’s Jose is great but i was hoping for more of the greasier thing i heard and felt in the atomica.

 

[FourT6and2]

Never played one. But from all the clips I have heard online, I totally get what is so appealing about them. I do hear that same slippery, greasy, fun/easy to play quality in all of the Gower clips I have heard as well. And there is a Gower Kali on the 'verb right now unless someone has snapped it up.

I played that amp. It didn't seem "slippery" or "greasy". It's quite tight and aggressive due to the plate-fed tone stack. Kicking in the extra gain stage does add a bit more saturation. But the overall vibe is on the tighter, more aggressive side. Same circuit as the Fortin Cali. Very different sound/feel compared to the Atomica/Molecular and Meshuggah/Gargoyle and Chupa, Yeti, Cameron Jose, CCV, etc. The former is plate-fed stack + tube gain stage. The latter are all 3 gain stage amps + diode clipping.

Seriously - I'd hit up one of the excellent amp techs on this forum who are familiar with the circuit and send them an clean, unmolested, 1959 reissue as a donor to mod to your specs. That sound and feel is out there in a much more reliable and cost effective format than sourcing an OG.

For the diode clipping Jose thing, a 2203/2204/800 works great too because the gain stages are already cascaded and there's already a master volume. But a Super Lead works fine as well. Just slightly more work.

 

[PDC]

^^^ I do wish I was in the market for a new amp. Id be PM'ing you and shipping out a donor!!

 

[romanianreaper]

View attachment 441687

Is that a 6L6?

 

[Toneboner]

I don’t know if you cant see them but the pics are in the post

Is potato resolution

 

[S̷͖͑m̵͎͂á̵̺s̸͚̈́h̴̬̑]

MGL

Have you pulled the trigger yet?

 

[RaceU4her]

Is potato resolution

oh shit, i didnt realize it was so blurry. well if anyone else has them, post them up please

 

[fusedbrain]

Lets see if these are any better:
Also, I can confirm from pics that the resonance or depth caps are mis-labeled in the schematic.
the .001uf is the mallory, and the .0033uf is a ceramic disc.

Please see this note from PsycoDave re these schemes:

So here are the mods I did to my JCA20. Have fun modding and don’t be a bozo by saying the mods are your own or selling them. Tone stack is 560pf, V1 snubbers are 47pf. Diodes are 5 volt and MPSA20. Caps on the gain pot are 2000pf and 4700 pf. Depth caps are .0433 (two caps .0033 and .001. I mixed caps on purpose since they have a very audible effect here). Choke is a Mojo 778. Presence is .1uf. Everything you need to know is in the pictures.

 

[paulyc]

Yeah, Crazynutz, thats the guy. I wonder whatever happened to him? He used to post some cool shit.
I believe Psycodave liked to use a cab with G12H30 anniversary speakers, which sound really good with diode clipping circuits.
Could explain the diff in the sound of your amp.
If Crazynutz built it, it should be pretty close. That guy knew what he was doing.

Funny story: I was intending to build one of these back in the day. I saved the schematics, and referencing Psycodave's pics, I collected up all the correct value and brand caps and parts to do the mod, right down to the funky Erie ceramic disc cap for the nfb circuit.
I also have a donor amp, and its all in a big box in storage somewhere.
Life turned into a giant Covid shitstorm, and I never built the amp.
I should probably go and look for that shit.
All the vids sound great for sure.

Mine is overly dirty. You can’t dial it out with the gain pot. It’s line blocking distortion of something. It’s real easy to lift a trace on those amps of burn up a component soldering so.., idk. That’s my experience.

 

[Toneboner]

Lets see if these are any better:

Thx!

 

[FourT6and2]

I removed those dreaded sounding MPSA transistors and use gold pin Motorola transistors. Brands make a difference in sound.

The reason is because transistors were never designed to be hooked together and run as if they were zeners. So their reverse breakdown voltage isn't something the manufacturers ever listed on the data sheets with regard to how they'd clamp a circuit as if they were diodes. So when run as zeners, one brand/model might clamp at 5v and another might clamp at 15v, regardless of what the data sheet says. It's completely random and luck of the draw. I personally like MPSA06 and 2N5401 but I forgot which brand I have. Probably Motorola.

 

[eero]

First post in four months.
Those schematics are correct. However, they do make the amp dark and bognerish...but I wanted a bedroom amp, so at those bedroom volumes the amp never sounded thin or like an AM radio. I had a CCV I was using as a base tone, so to me, it’s still Cameron sounding. I have since changed all of those Wima caps to EVOX. Same values, but they just sound better. I removed those dreaded sounding MPSA transistors and use gold pin Motorola transistors. Brands make a difference in sound. The PI caps are pretty big and jamming a lot of bass into those EL84’s. I’ve since changed to 0.47uf Mallory type (.82uf and .68uf work too) I’ve tried every cap around and the Mallory’s just sound right. Cap brands make a difference, so using “annything available” won’t cut it. I added a few switches to the depth circuit. One for the depth caps. I made it so I can have .0033uf and / or .0043uf. It’s an audible difference when using the .047uf PI caps. The .122uf is less noticeable. I also added a mid switch. The typical 39k resistor to focus in a bit more on the mids. I absolutely love vintage Erie ceramic caps for the depth in Jose type amps. Just adds some magic to my ears.

Simple modders will copy the schematic without understanding what I was doing. Look at the power section. The screens and grids are choked out together to balance out sound, but make the EL84’s last 10x as long. I literally just replaced the same Russian 6P14P tubes I’ve used for more than 10 years and 1000’s of hours on them. They were at 65% of new… remember I write down ALL tube info so I can measure and recreate sound as close as possible. I recently changed out the screens and grids to give a little more pop. I went 2.2k / 22k. Still choking the EL84’s out a bit for longevity, but certainly adding back some pop and push.

Important to note, in my experience EL84’s bias as typical, but a few mA difference can make a pretty big audible sound. Can make an amp that sounds mushy, to sound compressed by adjusting 2mA. I use pretty robust Russian tubes. When using the military 6P14P EV military version, those suckers need to be biased hotter to sound good. Just showing that you need to use your ears and not some magical 70% dissipation rule.

Last thing is I have a classic tone output transformer. Company went out of business and I’m too lazy to measure the specs on it.

Do you think it's possible to apply these modifications to single-ended class A amplifiers as well? I'm only referring to the power amp part of a Lexicon Signature 284, I would like to use it just as a low power stereo power amp for home playing and recording, It's currently almost unusable, completely lacking bass

 

[eero]

more details in this thread:
https://www.rig-talk.com/forum/threads/calling-resident-modders-lexicon-signature-284.338215/

 

[eero]

I know nothing about that power amp.

My suggestion is to ask AI. Upload the schematic and then prompt AI to provide you solutions for the flubby bass. Here is ChatGPT’s response. Good luck, since you don’t have a lot of space to tinker in that power amp.

View attachment 442128
View attachment 442127

Hi Dave, thank you for your kind reply


Although, from what little I understand about electronics, these changes concern the preamp section (which would need to be completely redone for my tastes)...
What I'd like to achieve is a better response from the power amp alone.
I'd use the head by connecting external preamps to its returns, bypassing the entire preamp section.Like a sort of fixed resonance or deep mod.
But I understand that this is a unique situation with the single EL84 in Class A...
but thanks anyway

 

[eero]

to the OP:
sorry if I derailed this thread in some way

 

[eero]

I guess you didn’t refer to AI since it provided power section modifications as well.

sorry, I didn't notice it, I only noticed the early stage cathode and coupling caps...
as I wrote, I'm not very expert in electronics, just an amps enthusiast

 

[eero]

Did you try consulting an amp tech to see what they might be able to do?

yes, but there aren't experienced local techs near me, only general technicians, certainly capable of following diagrams but without experience in amplifier modifications.
this is why i asked here

 

[311boogieman]

First post in four months.

Good to see you again.

Was actually wondering

 

[shredi knight]