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Discussion Starter #1 (Edited)
I have wanted a Herzog forever. I started researching Champ kits thinking it would be the easiest/cheapest way to get there (with a few extra components on top), but it turns out I can do a lot better buying the parts myself..... so scope drift and now I have come up with a Champ/Herzog hybrid (tube rectified like a Champ; actually dual tube/ss with a switch) with a stinger circuit added for good measure (I play bass, and the Stinger was originally designed as a bass fuzz - looking at Pro/BTO schems it sits right between V1a and V1b and the front end, minus the tone stack, is pretty much the same).

This looks good to me and I am excited to build it. However it is my first foray into building a tube curcuit from scratch and I tend to be the cautious type, so just wanted to post the schem here in case I missed something or did something stupid. Extra eyes and all that.

[outdated schem removed; updated one down below]

Changes from the aboved schem that I think I will implement:

1) Relay bypass with manual switch on the chassis. Not worried about that; it's pretty simple as I got some cool octal plug in 120VCA DPDT relays with indicator light (no no worries about loading down the filament supply; I also figure that adding the 6AN8 for the stinger is no big deal as I am eliminating the pilot light and the 5Y3 shouldn't have an issue with the extra load).

2) I will use On-off-on switches for the bright and deep controls (2 options + defeat). 1n seems high for the bright cap vs what I have seen in other amps so I will try 1n, 560p, and 220p and go with the 2 I like best. For deep I will try the 220n and take it from there (see what other caps I have laying about - any suggestions?)

3) since I've got the relay on the global bypass, I was thinking that I should put the stinger bypass on a relay too (which mean the footswitch cable can be a standard mic cable with shared ground, or in this case since AC, neutral, vs 4 conductor cable because can't share the 2nd conductor).... now if I do that, should I bypass it, as in the original Garnet schem (and as drawn in mine) by lifting the cathode ground, or (since the relay is DPDT) should I lift the connections both in front of the 4.7n after the grid stopper and after the 470p cap behind the intensity pot?

4) I'm gonna use 4007s instead of 4005s as drawn
 

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Sounds like a cool project. In terms of bright cap values 1n is on the higher end of the spectrum but it's not unheard of. Marshall superleads often had a 5n bright cap if i'm not mistaken. In terms of the relay stuff I'll leave that to the smarter fellas.
 

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I was trying to build a reverb unit a while ago and stumbled into something I'm going to try to build this year, a Herzog-type unit using a Fender 22921 Reverb transformer, 1 x 12AX7, 1 x 12AT7, lots of voltage.

I have a Herzog I bought last year, built by Pete Thiessen at Garnet. I highly encourage you in your build!

Is that your drawing? What great drafting skills you have.

Relay bypass with a switch on the chassis: I've got lots of lights in my house with two switches. If two switches were wired in parallel, the light would be on if either was closed.

Stinger Bypass: No one asked for true-bypass when the original was made, and no one was looking over Gar's shoulder. It may solve a problem for you, and I don't see it creating a problem.

Here's an FYI. The Herzog I have was built so that you can plug it into a speaker. When you engage the bypass, it shuts off the sound to the output jack, but the sound still comes out of the speaker. So it's not true-bypass. I'm not using it as an amp very often, and when you bypass it and the gain is up high, you get the buzz of the distorted sound, probably coming through the ground somehow.
 

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Discussion Starter #4
Is that your drawing? What great drafting skills you have.
Yes, but I cheated. 80% traced from existing schems (Fender 5F1, Garnet Herzog v1 and Garnet Pro Preamp section which was the trickey but - upside down and mirror imaged). Had to manually stretch a few things out to fit the Stinger and some manual additions in.

Stinger Bypass: No one asked for true-bypass when the original was made, and no one was looking over Gar's shoulder. It may solve a problem for you, and I don't see it creating a problem.
The only problem is the footswitch cable issue I mentioned. Not a problem but I'd also have to add an indicator light (the relay has one built in). Also consistency; It just feels weird to use a relay true bypass in one place and a ground lift in another, but maybe I'll get over it.

Here's an FYI. The Herzog I have was built so that you can plug it into a speaker. When you engage the bypass, it shuts off the sound to the output jack, but the sound still comes out of the speaker. So it's not true-bypass. I'm not using it as an amp very often, and when you bypass it and the gain is up high, you get the buzz of the distorted sound, probably coming through the ground somehow.
Mine will bypass all, and that's fine for my purposes - I won't be using it as an amp and preamp at the same time. Since the bypass switch shorts the input jack directly to the output I hope to not have that signal leak problem you describe; in fact the thing should be dead quiet (especially if I use sheilded wire in critical areas and get the star grounding right; working on my layout I think it'll be good due to the ground bus bar I am putting along the rear of the chassis; I should post that too I guess; but it's a hack job in excel).
 

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Discussion Starter #5
Frick; found some typos in the schem.
 

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Discussion Starter #7
I mean, do the true-bypass on the stinger, use a relay, it's the best way to do things.
Oh, that's what you meant. I just wonder if there's a good reason not to do that. I suppose Garnet did that only to keep things simple and cut costs, but maybe there's more to it than that.

There are times when true bypass isn't the best thing
 

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If you look at the later H-Zog schematic you can find, they grounded the input of the power tube when the bypass was active.

With true-bypass, I think sometimes you get a pop because the dangling input is at an unknown or possibly increasing value.

But I just think true-bypass just wasn't a feature back then, it was a solution when you had trouble.
 

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Discussion Starter #9 (Edited)
See yes, that's the sort of thing I was getting at (and not that I looked at the H-Zog schem a lot, but I totally missed that - but sure enuf; there it is at point "D"). I was wondering why I saw nothing like that.... not even a pull down resistor. Thanks!

I have some revisions to do.
 

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Discussion Starter #11
Personally I'd Zog the Pepco. Then u have verb, trem and OD in front of any other amp. Also the Valve Jr is worth more unmodified/ has a better power section I'd think.
 

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I don't think you need to mute it if you have it true-bypassed, but it does suggest the problem I have with mine was there as long as they were running that power tube.

I asked someone who had an earlier one and he didn't have the sound bleeding through.

I was using the Herzog as an amp a few weeks ago, into a very heavy duty speaker in a tiny cabinet, and I was surprised at how much less growl there was than I expected. I had planned to record from the output jack but I didn't get around to it.
 

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wow this sounds like a great project

I was using the stinger on my rebel deluxe the other day, it is only the single knob version and it is totally out of control

it was like this guy drove a car thru the wall & blasted into my living room

"I'm a fuel injected suicide machine. I am the rocker, I am the roller, I am the out-of-controller!"



interested to see how you make out!!
 

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Discussion Starter #14 (Edited)
Updated schem:


Got the relays (P+B KRPA-11AN-120 - octal base like a power tube, 120V AC with indicator light built in; think it'll look real cool, but a little concerned about coil noise; I'll live considering how easy they are to implement). They're used but I tested them and they work fine.

[image removed; updated schem below]

Got the chassis (and tube sockets) from A-1 the other day (good price!) - going with a Hammond 1444-18 enclosure which is the same size as a Champ but longer so it'll fit the extra bits in without getting too tight; I want a nice clean layout here. Gonna get everything other than the iron from Mouser (enuf for free shipping if I include a few other items I need for unrelated things) and the iron probably from Classic Tone, unless the shipping is crazy, in which case I'll get the standard Hammonds from NextGen (enuf for free shipping).

Ordered some screw-in split shaft turrets to use with the 1/4" masonite board I already have to build the circuit on. Decided against using the perf board I already have because it'll be easier to work on (won't have to remove the board from the chassis to get at the bottom).

Working on a layout diagram (in MS Excel; not too pretty but easy to follow/move around bits). Pretty much done just gotta double-check it.
 

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You've got your negative feedback loop shorted to ground by that 25uF capacitor. You might want to borrow from the AA764 Champ and put in an additional 47 ohm resistor after the 1.5k/25uF combo with a 2700 feedback resistor instead of the 22k.
 

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Discussion Starter #17
I see Garnet also did that ( RE the NFB loop) in the Gnome and Banshee. Gonna mess up me neat diagram [grumble, grumble....]
 
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