what is the herzog circuit output impedence?

[jackplug1]

What is the Herzog circuit output impedence?
If a isolation transformer were added to the output for connecting to an audio interface to avoid hum loops, what would the turns ratio be?

https://el34world.com/Forum/index.php?topic=16934.0

[shooter]

forgot the Reply #, seems HBP had it at 150k?
I'm guessing 1:1 would be fine

[PRR]

Just don't ground the secondary anywhere (this does not need NFB). Use a 1k to 10k pot and call it "600 ohms, sure!" (Zero to 2.5k, who can tell the difference?)

[jackplug1]

Just don't ground the secondary anywhere (this does not need NFB). Use a 1k to 10k pot and call it "600 ohms, sure!" (Zero to 2.5k, who can tell the difference?)

I intend to use the herzog output circuit in a separate direct injection box so it would be in between a studio amplifier and audio interface.
The original circuit incoporates a 1meg pot and 150k in series with it so would it be between 1.15M and 150k so maybe around 500k?

[sluckey]

I intend to use the herzog output circuit in a separate direct injection box so it would be in between a studio amplifier and audio interface.
The original circuit incoporates a 1meg pot and 150k in series with it so would it be between 1.15M and 150k so maybe around 500k?

There is a 6Ω resistor parallel to the 1M pot so the impedance would be between 150,000Ω and 150,006Ω.

[jackplug1]

I intend to use the herzog output circuit in a separate direct injection box so it would be in between a studio amplifier and audio interface.
The original circuit incoporates a 1meg pot and 150k in series with it so would it be between 1.15M and 150k so maybe around 500k?

There is a 6Ω resistor parallel to the 1M pot so the impedance would be between 150,000Ω and 150,006Ω.

Oh yes  -I forgot about that!

[HotBluePlates]

I intend to use the herzog output circuit in a separate direct injection box so it would be in between a studio amplifier and audio interface.

How is that supposed to work?  A Herzog is an amplifier itself, it's not supposed to receive the output of an amplifier.

The "Herzog output circuit" is nothing but the speaker output of that amplifier.  Sure, Garnet tacked a 1MΩ pot across a "dummy load resistor" and then added a series resistor.  But in the Herzog there is no negative feedback, so the OT secondary could be floated to avoid hum.  If you're messing with some other amplifier, maybe you cannot do that.  You'll have to identify what this other amplifier is.


If you're looking to make a home-brew load box for recording, well...  There's a reason why the good ones are expensive.

[jackplug1]

I intend to use the herzog output circuit in a separate direct injection box so it would be in between a studio amplifier and audio interface.

How is that supposed to work?  A Herzog is an amplifier itself, it's not supposed to receive the output of an amplifier.

The "Herzog output circuit" is nothing but the speaker output of that amplifier.  Sure, Garnet tacked a 1MΩ pot across a "dummy load resistor" and then added a series resistor.  But in the Herzog there is no negative feedback, so the OT secondary could be floated to avoid hum.  If you're messing with some other amplifier, maybe you cannot do that.  You'll have to identify what this other amplifier is.


If you're looking to make a home-brew load box for recording, well...  There's a reason why the good ones are expensive.

I'm well aware of all that you are saying, but all I need to build is a simple load box with DI out for a 5watt champ style amplifier which I have built similar to the seplex design
 

[sluckey]

I'm well aware of all that you are saying, but all I need to build is a simple load box with DI out for a 5watt champ style amplifier which I have built similar to the seplex design

So what's that got to do with herzog? The herzog is simply a tube type fuzz box or overdrive pedal. I don't see the connection.

[jackplug1]

I'm well aware of all that you are saying, but all I need to build is a simple load box with DI out for a 5watt champ style amplifier which I have built similar to the seplex design

So what's that got to do with herzog? The herzog is simply a tube type fuzz box or overdrive pedal. I don't see the connection.

They only difference between the herzog and the fender champ more or less is the load resistor, pot plus 150k resistor at the output transformer

[dwinstonwood]

jackplug1, so you have an existing amp with a line out that you would plug into the Herzog? In other words, it's the reverse of how the Herzog is typically used: instead of plugging your guitar into the Herzog, and feeding its signal into your amp, you want to feed your amp's signal into the Herzog, and then feed the Herzog into an audio interface?
Thanks.

[jackplug1]

jackplug1, so you have an existing amp with a line out that you would plug into the Herzog? In other words, it's the reverse of how the Herzog is typically used: instead of plugging your guitar into the Herzog, and feeding its signal into your amp, you want to feed your amp's signal into the Herzog, and then feed the Herzog into an audio interface?
Thanks.

No that is not what I intend to do, I would utilise the circuit after output transformer which consists only of a 8R resistor to act as a load instead of a speaker and a 1M pot with a 150k resistor in series with the wiper and nothing else, in other words not the amplifier circuit - sorry for the confusion I thought "Herzog" referred to this modification to an ordinary SE amplifier.
This is clarified in the link in my original post

https://el34world.com/Forum/index.php?action=dlattach;topic=16934.0;attach=42552;image

I now intend to use an L pad attenuator* in conjunction with a small speaker in a sealed box or maybe an inductor with a DI out via an isolation transformer

*Monacor L-Pad Attenuator 100W 8 Ohm Wirewound Volume Control AT-62H

[dwinstonwood]

Thanks jackplug1. A while back I bought the Weber MiniMass. It has a speaker motor inside, a 3-way impedance selector, treble boosts, a line out, and can be used as a dummy load when testing amps. It serves my needs fine. But, it looks like you can build something very similar yourself from parts.

https://www.tedweber.com/minimass/