Insane Gain Pre amp advice wanted

[chromaticdeth87]

The sloclone isn't a ghost town, i'm one of the ones working to get an uberschall layout done and up. The delieverance 60 is a good project too. The other guys are right about the number of gain stages, building volatge gains across multiple stages. The ecstasy actually needs a good power amp to rid the preamp of it's harshness, just like an jcm800 it won't sound the same without the kickass poweramp and PI configuration. the schematic heaven schematic is only for the lead channel and has wrong values, go over to SLO clone to see what is going on in the corrected schematic. The express can be used for metal and hardcore if you changed around some of the filtering and adding a clean boost in front, almost any amp can with modifications and a few pedals really. I'm currently assembling the pieces for a K60 and hope to use it for post hardcore and stoner rock stuff.

[Travis]

Does anyone reccomend and certian pre-amp design books and guides. I want to expand my library on this. Anything from Clean, Dirty, to Metal pre amp explaination theory ideas concepts. thanks.

[jaysg]

'rockstah' built up one or more high gain Marshall circuits and posted clips on some sort of board...I'm trying to find it...soundclick.com

There is a schematic floating about the internet for a Roccaforte HG-100 which is very similar to a London Power design found in TUT. (I lost my copy in a hard drive crash.) Both work with the existing 3 preamp tubes in your basic Marshall. You get an extra triode by eliminating the cathode follower.

[Darkbluemurder]

this looks like it would be worth trying:

http://schematicheaven.com/newamps/bogner_ecstacy.pdf

and, yes, I'm thinking about building one, too

on the bogner ecstacy: could you use this pre amp circuit for a lower power amp, something like 30 watts?

Why not? Of course a high gain preamp benefits from a strong power amp but if the gain is taken a bit down it should work fine.

Even though the schem might not be correct it is a good place to start. With a smaller output stage you can implement the "blue channel" (that would be only 3 gain stages). If you want to implement the "red channel" with all 4 gain stages you may want to use 4,7k at the second cathode (= structure switch set to "low" permanently).

One thing which I believe to be a mistake is the 500k/470pf network before the 3rd stage's grid. This should come BEFORE the 500k to ground. The reason I believe this is that the circuit is reported not to be too gainy. This is not exactly my experience but I built it as it is in the schem. Moving the network before the ground connection should drop the signal a bit and thus lower the overall gain.

Have fun
Stephan

[fishy]

Travis,
The only books I know of that discuss guitar amp theory in depth are
the books by Richard Kuehnel. There must be others though.
He has one on preamps, another discusses the Fender bassman in depth and one on power amp design.
I have the preamp one and its definitely interesting but a bit over my head in places. From memory, the verdict was open, some like the book, others not so much. Maybe someone else can comment.

http://www.pentodepress.com/ for a description of his books.

[Travis]

Thanks, I'll check the books out.

[John_P_WI]

Travis,

The grand daddy of book series is from Kevin O'Connor. Check out

http://londonpower.com/

for more info.

I have all of them since I have been doing this since the mid-90's. The latest book, TUT 6 has many examples of high gain amps and their history. A good read, but fairly technical. Another book TUT 5? discusses setting up high gain stages with a scope and signal generator.

You can also buy pre-amp kits from him, check out the Zen.

Good luck,

John

[Cameron]

One thing which I believe to be a mistake is the 500k/470pf network before the 3rd stage's grid. This should come BEFORE the 500k to ground.
Have fun
Stephan

No, after the 500k is right.

[Darkbluemurder]

One thing which I believe to be a mistake is the 500k/470pf network before the 3rd stage's grid. This should come BEFORE the 500k to ground.
Have fun
Stephan

No, after the 500k is right.

Hi,

Is that based on the Blue Guitar preamp schematic or first hand experience from an actual amp? The handdrawn schematic does show the 500k series, then the 500k/470pf and then the 500k to ground. I tried both ways and the variation of the preamp schem offers more gain than that on the handwritten one. The difference is not too big though IMHO.

C8 on the preamp schem (which parallels the 500k series resistor going to the 4th gain stage) is missing on the handwritten schem. This is a very important cap which drastically changes the sound. I tried both ways and I am not sure which I like better.

Kind regards,
Stephan

[Abstract]

Why doesn't anyone build Bogner Fish preamp clones?

Are there schematics drawn?

[chromaticdeth87]

here you go some errors on this I believe