Kurt Stewart Effects Loop for Marshall Amps

[youaerone]

Has anyone tried this circuit on a 2204? Is there something better? Thanks.

[pdf64]

It's likely to drag down all the 'post screen node' voltages some, especially with a 12AU7.
It will also flip the polarity of the signal (due to the additional inverting stage) when it's switched in, which some may regard as a bad thing. Whatever, it's not ideal for the polarity to be one way with the loop switched out, the other way with it switched in.
Pete

[ampdoc1]

The basic Dumbleator circuit seems to work for most anything. Without the EQ switches and parallel/series switching, nit's about as simple to build as the one you show. I used this in an amp with a Express front end, and it's great! I built it inline on my amp so it's always in use, but I think it adds to the tone and it works well with most effects.

[Markusv]

Folks

Hope someone who has experience with this will help a bit
If one wanted to use the circuit shown above in an amp with a PPIMV- Where is the best point to insert it?

Thanks!
Markus V

[Structo]

Between the preamp and phase inverter.

[Markusv]

Thanks Tom

Thought so but just to be sure..

Markus

[Markusv]

Probably a dumb question - sorry
Has anyone used this in a deluxe type amp?
I'm thinking of using it in a Bovine Pusher.
If so please explain if the loop runs in parallel or series. i.e. Do I use mixer resistors after stage 3 and before the PI or how? (Given the lack of a Master Volume)
Thanks in advance

Markus

[10thTx]

I'll offer a thought to consider. IF I were building that FX loop, I would not use the 1M pots or 1M resistors to ground. I think 250k pots would be more reasonable and maybe 220k or 470k resistors to ground.

IF you note, the D'Mars ODS preamp has some similarities to a Marshall topology. And I love this FX in the amp. Sounds excellent to me.

The FX I am using leaves the amp quite loud. I essentially have a 250k send, 82k resistor to ground for return and 250k level pot. I used the 82k resistor based on the return pot setting on several D'Lator external FX units that I built.

I typically have the 250k send pot set at "5" & the 250k level pot is typically set between "4-7".

So in light of that, 1M pots and 1M resistors to ground would NOT sound very good in my amp.

Just an FYI With respect, 10thtx

[JazzGuitarGimp]

I'll offer a thought to consider. IF I were building that FX loop, I would not use the 1M pots or 1M resistors to ground. I think 250k pots would be more reasonable and maybe 220k or 470k resistors to ground.

IF you note, the D'Mars ODS preamp has some similarities to a Marshall topology. And I love this FX in the amp. Sounds excellent to me.

The FX I am using leaves the amp quite loud. I essentially have a 250k send, 82k resistor to ground for return and 250k level pot. I used the 82k resistor based on the return pot setting on several D'Lator external FX units that I built.

I typically have the 250k send pot set at "5" & the 250k level pot is typically set between "4-7".

So in light of that, 1M pots and 1M resistors to ground would NOT sound very good in my amp.

Just an FYI With respect, 10thtx

You are also using a 12AY7, rather than a 12AX7?

[Markusv]

Thanks for that 10THX!

I will adjust accordingly
I used one in another different amp and found the settings of send and return to be too aggressive
So you pot value advice is great as well as the AY7

Markus

[martin manning]

I'll offer a thought to consider. IF I were building that FX loop, I would not use the 1M pots or 1M resistors to ground. I think 250k pots would be more reasonable and maybe 220k or 470k resistors to ground.

IF you note, the D'Mars ODS preamp has some similarities to a Marshall topology. And I love this FX in the amp. Sounds excellent to me.

The FX I am using leaves the amp quite loud. I essentially have a 250k send, 82k resistor to ground for return and 250k level pot. I used the 82k resistor based on the return pot setting on several D'Lator external FX units that I built.

I typically have the 250k send pot set at "5" & the 250k level pot is typically set between "4-7".

So in light of that, 1M pots and 1M resistors to ground would NOT sound very good in my amp.

Just an FYI With respect, 10thtx

So you want to present a lower impedance to the amp at the send, and a lower impedance to the return from the FX. Why do you think that the 1M input impedances will sound bad? Are you concerned about loading or HF roll-off?

[10thTx]

I use a 12AY7 and sometimes a 12AV7. And I have tried a old 5751. I like the 12AY7 best, but thought they all sounded decent.

When I turn the 250k pots both up past "7", I think it loses some musical sweetness. The 82k resistor emulating the "send pot" was because I found on the D'Lators I built, that I never changed the send pot setting and it was around 82k.

With respect, 10thtx