4 stager

[Smokebreak]

I want to share this amp that I've been working on this week, as I've drawn much inspiration from the higher gain switching posts lately. These are the things that interest me most these days.
I built this 100W into the chassis of a Weber Orange kit. That sounded good, despite a lousy layout, but I had no need for it.
While carefully taking out the board and throwing it into the corner, I figured I'd build a proper 1959, as I can never just build 1 amp in an amp, but I ended up with a bunch more holes.
I'm thrilled with this amp. The most difficult thing for me is finding a balance, and compromising when so many different elements are in play, without having too many switches. I'd love to hear how you guys would tweak it just by looking at it. I'd change the couplers, myself, but they seem to work.

2>4 1959
1>2>4 Cali modded thing without being so damn bright and thin
2>3>4 Dark , ballsy JCM800, no peakers yikes
1>2>3>4 Bright Cali thing but more complex with gain backed off
1>2>3>4>RIB switch> Slayer

Cheers,
Jeremy

[Reeltarded]

I love the notes!

Not sure what I could add. Pretty interesting stuff going on in there. The only thing left is twaeking each switch mode.. what's it sound like?

I am terrible at high gain. The last 30% of gain is always a dog whistle.

[martin manning]

Jeremy how did you drive at the filter sizes going down the rail? typically they would be descending from the reservoir to the preamp.

[Colossal]

Jeremy how did you drive at the filter sizes going down the rail? typically they would be descending from the reservoir to the preamp.

Martin,

I'll certainly let Jeremy provide his own answer but for myself, these values are typical for lower plate voltage high gain Marshall builds. A lot of guys on Metro for instance have experimented with the feel of different cap values to get the chewy, elastic Van Halen quality without being too stiff and clanky. I have nearly the same values in a '68 SuperLead on the bench right now.

[Reeltarded]

Lower on the big end feels really good. It's easier just to go all 50u though.

[martin manning]

I see... standard 1959 already has the large PI node filter:

Rectifier - 50u(plate) - choke/50u(screen) - 20k/100u(PI) - 10k/50u(V2) - 10k/50u(V1).

Jeremy's 32u and 22u are probably plenty for V1 and V2; it's the small 16u screen filter that looks odd to me.

[Smokebreak]

Yea, exactly, it's basically the '68 spec filtering. I've never really experimented with the lower filtering, so I thought I'd give this's arrangement a shot. I would guess the reasoning behind the 100uf on the PI is that it's gotta be tight somewhere, and bumping it there provides that without the whole amp feeling stiff.

Amps sounds real good! The challenge of course is getting all 4 possible modes to sound good. I never thought I'd say it but I really like the 2>3>4 mode, which is kinda an dark 800, no peakers anywhere. At the least, it offers a dark option .

I'm still messing with that first stage, but right now 1>2>4 sounds really good without the peaker, like a jacked up plexi but smoother than the Jose thing. Running all stages with the peaker(reign in blood switch) sounds pretty good for the non-modern chunkage. I was actually going for seasons in the abyss , but whatever...those boys just used stock JCM800s right?

Something I'd been wondering about for a while is the whole "reversed divider" thing before the last stage. I see it in various designs. It's still a divider, right? I figured that the 220k would act more like a stopper in this arrangement as opposed to the trad way, and have a different effect, on maybe the treble response. I put it on a switch for a minute, and couldn't hear much difference, if at all. One was a hair less hissy. What's going on here?

Edit: Martin, that screen filtering definitely had me second guessing as well. I'm not sure why that's the spot that's the lowest. I'm gonna bump it up today and see

[martin manning]

Not a divider... you have 4n7/330k high-pass with ~100 Hz knee, then the 220k is a large grid stopper that will roll-off some highs; -3dB is at ~7.2 kHz.

[Smokebreak]

Aha, thanks Martin.

[Firestorm]

Yea, exactly, it's basically the '68 spec filtering. I've never really experimented with the lower filtering, so I thought I'd give this's arrangement a shot. I would guess the reasoning behind the 100uf on the PI is that it's gotta be tight somewhere, and bumping it there provides that without the whole amp feeling stiff.

Late 1967-mid 1968 Marshalls were all over the place with PI filtering. They were using 32uF cans in series and there's just a physical limit on how many will fit. So they wound up with 32uF on the main filter (series/parallel) 16uF on the screens and sometimes as little as 16uF on the PI. I don't think it was all that deliberate early on, just space management. I wonder what the difference in sound is between the early light filtering on the PI versus the later heavy filtering.

[Reeltarded]

The higher filtered amps are the ones that go usably louder and don't squash out like VAN EFFING HALEN!!! Wooooo! VH!!!

Did anyone see the South Park where Cartman dressed up the ginger cow?

VAN HALEN!! WOOOO!! (raises shirt)

[roberto]

Looking at the schematic seems you have mixed some parts of the SLO100 with others of the classical marshall derived hotrodded amps.

Well, the first part is that with such a schematic is absolutely normal that the larmar sounds bad: you have too much signal at the end of the preamp way before you enter in the right point to overdrive it.

I personally do not like that kind of preamp, but I'd suggest you to be able to swap 2nd and 3rd stage (can be done by switches). At the time I worked with this kind of preamps I liked the hot cold hot hot stages solution.

[Smokebreak]

Looking at the schematic seems you have mixed some parts of the SLO100 with others of the classical marshall derived hotrodded amps.

Exactly. More specifically, the Marsholdano.

I'll switch around the 2nd and 3rd cathodes and see how I like that. Thanks for the suggestion!

What kind of preamps do you like?

[Meat&Beer]

"Flower Child Smasher 100" Hahahahahhahaaaaa!!!!! I love it, would love even more to hear it! Looks really neat, kudos.

[roberto]

Nice. So probably you have seen the thread where both me and Joey give some suggestion on how we'd upgrade our Marsholdano after five years.