Should I put an effects loop in a plexi build?

[shocki]

I am about to build something like this.
http://www.ceriatone.com/images/layo...exi50-Lead.jpg

As you can see from the layout it has a very simple Send/Return. I would like add a delay in this position. But the delay I have has just instrument level. So this will not really work I think.

Tube buffered loop is too much hassle for me. Something like this could be an option with a true bypass switch.
Zero-Loss FX Loop Kit - $95.00 : MetroAmp, Amplifier Kits and Parts Online Store

But I am asking myself does an effects loop really make sense in such an amp? If I want one it should really be transparent.

Thanks.

[pdf64]

My take is with that scheme, for any realistic control setting, power tube distortion will dominate; as signal level is increased from zero, the power tubes will be the first devices to distort, and as it is decreased they will be the last devices to stop distorting.
Therefore there's much less benefit to be gained from putting an fx loop before the power amp, compared to an amp intended for lots of pre-amp overdrive (ie with a master volume).
Pete

[shocki]

The Amp will get a MV which is out the circuit when fully turned up (La MAR PPIMV). Other than that I will use pedals to boost or overdrive the amp.
I know that the given effect loop design is not great. I am just wondering if I should use one at all.

[daz]

The Amp will get a MV which is out the circuit when fully turned up (La MAR PPIMV). Other than that I will use pedals to boost or overdrive the amp.
I know that the given effect loop design is not great. I am just wondering if I should use one at all.

I wouldn't on an amp that derives it's OD from the PA. Gotta be effects after distortion. Just do what I do.....use a small combo, even a SS combo, and use a line level taken from the speaker out into your effects run with 0% direct signal and output that to the combo. The combo only needs very little volume since it's fully wet signal. Plus it has the added effect of keeping your amp's signal pure right thru to the speaker.

[frus]

The Amp will get a MV which is out the circuit when fully turned up (La MAR PPIMV). Other than that I will use pedals to boost or overdrive the amp.

your effect loop should be after the master volume, and since it's after the PI, it's not really doable

[shocki]

your effect loop should be after the master volume, and since it's after the PI, it's not really doable

Sorry. I don't understand why exactly? I also noticed 65amps added an effects loop to their amp. And it is an passive one. I know they never wanted to do that but they did it cause many customers wanted it.
So if it's passive it also should be very simple.

[soundguruman]

I am about to build something like this.
http://www.ceriatone.com/images/layo...exi50-Lead.jpg

As you can see from the layout it has a very simple Send/Return. I would like add a delay in this position. But the delay I have has just instrument level. So this will not really work I think.

Tube buffered loop is too much hassle for me. Something like this could be an option with a true bypass switch.
Zero-Loss FX Loop Kit - $95.00 : MetroAmp, Amplifier Kits and Parts Online Store

But I am asking myself does an effects loop really make sense in such an amp? If I want one it should really be transparent.

Thanks.

Should I put an effects loop in a plexi build?

No.

[shocki]

Should I put an effects loop in a plexi build?

No.

Clear answer. He,he

[J M Fahey]

your effect loop should be after the master volume, and since it's after the PI, it's not really doable
Sorry. I don't understand why exactly?

Because you have between 40 and 90V RMS there, while an effect needs around 100 to 200 milli Volts.
And if you pad it down, process and reamplify .... it's not PPIMV any more !!!

As stated repeated times above, an amp which derives its (beautiful) distortion from overdriving power tubes, the *last* link in the chain, has no point where to add a loop.
That's what "last" means.
Accepted practice in studio (and live by some, I've seen EVH do it) is to mike tha cabinet and add effects "in the mix".

The fact that "65 amps" (and many others) do it comes from the fact that they don't want to lose a customer.

And in Preamp distorted amps, there's a "good" way to do it: Soldano SLO distorts the typical tone driver cathode follower duo , pads trhat to line levels, processes it and then re amplifies (and eventually distorts) it in an identical cathode follower duo.

You could do this in a Plexi by driving an attenuator, padding output to line level, processing, and reamping (Tube or SS, your choice).
The Yngwie/EVH and others solution.
In fact, they use SS PA amps afterwards (with HH MosFet amps being a classic) , driving tons of 4x12" cabinets.

[shocki]

Thanks alot for the long answer. Now everything is crystal clear and when I think about it this really does not make any sense at all. Probaly Ceriatone is offering this due to customers demand for an effects loop.

[exclamationmark]

I never really understood the dual DCCF's in the SLO... I've always stuck the effects loop directly after the tone stack and MV combo (if the amp has a MV in that position). I make sure the gain stage after the effects loop matches the voltage divider before the effects loop in (inverse) voltage gain. Hard to do with tubes, but easy with transistors . That way, the only difference the PI sees is the source impedance driving it - the voltage is otherwise identical to an effects loop-less version (without the PI attached yet). The source impedance probably DOES make some difference though (particularly when the PI is overdriven), so it's not perfect by any means. I guess that's an advantage of pre tone stack effects loops. The intermodulation distortion on chorus/delay/etc would suck though. A PPIMV effects would be almost impossible to implement in that location! (though you could do it before the PI).

[dai h.]

IMO the metroamp loop may be worthwhile despite it being before some of the distortion generation in a typical Marshall. I would suggest to check out youtube for (at least one I vaguely recall) a video of the metro efx loop in action (the one I saw/heard was used with an analog delay in the loop and it sounded quite nice--not the weirdness you get when you try to stick a delay in the front end). The guy who designed the loop (Steve something) also seems to know what he is doing tech-wise. While it is general good practice to place some time based efx like delays after all the distortion (so the effect works better) there are Marshall amps (like the recent 1987/59, 2203, etc. with their stock solid state loops) and a mod (Custom Audio Electronics/Bradshaw added tube driven/buffered loop) that place a loop in the plexi/Bassman type circuit, so it might be worth trying at least.

[soundguruman]

Clear answer. He,he

Why are you taking something so beautifully designed, and thoroughly proven, and screwing it up with some hokey modification?

The way to play it is wide open, to overdrive the power tubes. THAT IS the Marshall sound. You mic the cabinet, and feed effects through the PA mixer. That is the way it's always been done.
But no, you have to goof it up....ignore tradition and insist on modifying it. There's no way to make it better. People made it better and finished the design decades ago. AND you think you know more better than the people who designed it?

YOU do not want a Marshall.
YOU want a mesa boogie, with effects loops. OR a Fender with effects loops, etc...etc...
YOU don't want the real Marshall sound. You want distortion pedals, and digital effects.
That's NOT what a Marshall is about. YOU are off track, bud.

[shocki]

Why are you taking something so beautifully designed, and thoroughly proven, and screwing it up with some hokey modification?
The way to play it is wide open, to overdrive the power tubes. THAT IS the Marshall sound. You mic the cabinet, and feed effects through the PA mixer. That is the way it's always been done.
But no, you have to goof it up....ignore tradition and insist on modifying it. There's no way to make it better. People made it better and finished the design decades ago. AND you think you know more better than the people who designed it?

I really took your advice seriously. No offense from my side.
I do absolutley not insist on modifying it. I just wanted to know about other people opinions. It is totally clear to me that the best option is to mike it and add effects later is the way to go. Also probably putting a delay pedal before the amp might work. This is how many people do it. As stated above I will not included the effects loop.

[soundguruman]

I really took your advice seriously. No offense from my side.
I do absolutley not insist on modifying it. I just wanted to know about other people opinions. It is totally clear to me that the best option is to mike it and add effects later is the way to go. Also probably putting a delay pedal before the amp might work. This is how many people do it. As stated above I will not included the effects loop.

The thing is a Marshall is just what it is, and you don't need to try to change it into something it isn't.
If you want effects loops, build an amp that was designed for it in the first place.

I have seen all kinds of mods done to Marshalls. The only one I liked was (don't call me Howard) Dumble's !!!
But that was not an effects loop.