Mystifying Herzog Schematic

[The New Steve H]

Someone clue me in. Again.

I decided to build a Herzog. The schematic is attached.

As you can see, there are two different drawings with different values. The lower drawing has a lot more detail, so I figured I'd start there.

There is a capacitor at the bottom-left corner. I can't read the value. Anyone know what it says?

I don't see any values on the filter caps, but the Champ 5F1 has 8uF/450V in these spots, so I assume that's what I should use.

The "Relay Coil" component at bottom left is a mystery to me (no value), and I don't understand how the rotary switch connects to the .02uF capacitor in the center of the schematic.

As for the diodes: it calls for 1n4005s. I have 1n4007s on hand, and they are rated for higher voltage. Any reason why I can't use them instead?

I found some Champ schematics and layouts. I'm hoping they'll give me direction.

Interesting note: Doug Hammond, the Firefly guy, has posted a mod for the Firefly amp, allowing it to be used as a Herzog. It's called the Firezog.

[martin manning]

The relay coil is just that, the coil of a relay controled by the footswith to mute the effect and bypass it (jumper the input to the output). Looks like it would be getting about 10VDC from the half-wave rectified filament supply, and it's normally-closed, so the effect is off unless the relay is energized. The high negative voltage mute (cuts off the output tube) seems kind of overkill, but I guess it would shut off the high idle current of the SE output. Notice the Bachman version dispenses with that. The cap at the lower left looks like 2200 mfd, old notation for microfarad. Big filter for the DC relay supply. 1N4007 sub is fine. The rotary switch must close the bass and bright switches in a one or the other fashion, but it is not too clear. Again, omitted from the Bachman version, with just the bass switch moved to the first stage.

[The New Steve H]

Thanks. Extremely helpful. I still don't understand why the transformers have different numbers, but I guess a Champ transformer is a Champ transformer, so I suppose it's safe to order a pair that are known tweed Champ replacements.

Or not.

[diagrammatiks]

well you don't need to worry about what the transformer is named..

a single ended 6v6 output tranny is usually 8k

the voltages on the schematic show 320 after rectification

you'll want a 228-230vac non centertapped secondary on your power transformer

or a 460vct(230-0-230) centertapped secondary.

[The New Steve H]

Great. Thanks.

I think this is a good next project. The 5f6a was a big job. I should be able to knock this out in a hurry, and it will be a pretty unusual item.

[gar13]

I built a PTP Herzog (the first version, not the one with the relay) last year. A friend of Gar Gillies gave me an NOS Herzog chassis.

I added the switched speaker jack from the second version and switchable NFB. Allows me to use it as a slightly higher gain Champ.

[The New Steve H]

How do you like the sound? I mean when you use it as an effect.

[The New Steve H]

Can anyone tell me why this thing has two fuses on it, in series? It has a 1A external fuse and a 1.5A internal fuse. I would rather just omit the internal fuse and use a 1A external, unless it's a problem. Also, can I assume this is a slow-blow?

[The New Steve H]

Also, if somebody could tell me what part to order for the footswitch relay coil, I would be grateful. I can't find it online anywhere.

[Andy Le Blanc]

champ with a line out... bet you could lift some cabinet voicing ideas from
mesa schematic.

Garnet had that "stinger" fuzz with a 6au8 I've always want to tryout

there was also some garnet rigs like selmer with a transformer inverter.

I bet the extra fuse was in there just in case some knuckle head blew the
external fuse and then tried to wrap it in aluminum foil as a quick fix.
or put in the wrong fuse rating..

[M Fowler]

How different is this Herzog from the project shown in TUT 3?

Mark

[Andy Le Blanc]

the herzog came first...

[The New Steve H]

I'll tell you what. This schematic is a puzzle. When I took my two semesters of electronics in college, we always knew what the symbols meant. Now I see an arrow going to nowhere, an object labeled "relay coil" with no more information, two fuses in series, transformer names I can't find on the Internet...I guess I'm going to have to study the 5F1 schematic and try to use it to fill in the gaps.

[The New Steve H]

Another thing. The 10 ohm 5w resistor. Will I need a special resistor with a heat sink?

Edit: I found this job on Mouser's site. Looks like you screw it to the chassis, and the whole box would sink heat.

http://www.mouser.com/ProductDetail/Vis ... Y0ASJK0%3d

[Andy Le Blanc]

the relay in scheme 2 replaces the dpdt switch in scheme 1

its run off the fil. or heater winding through a half wave rectifier with cap input load
should get you around 1.4 x the ac v peak or .9 x ac v avg.

look for a general purpose relay with a 6v dc coil

it looks like bypass/mute switch

theres differences with the load resistor between scheme 1 and 2
which gives you wiggle room to select, probably use a 10 to 20w cerment
should be ok to dissipate 5w from the 6v6, just a dummy load
make it bullet proof if you feel the need...

A lot of old hand drawn schematic follow older conventions
some have penciled in changes, some have things missing from being scanned
I bet the arrow to nowhere was intended to indicate switch type
but the annotation isnt there... don't panic