Making pedals for use in between amp and speaker cabinet

[22uf]

Hi,
I like amps that have power amp clipping, which ultimately makes any form of an FX loop useless. How could a pedal be designed so that it can be used in between a 50w amplifiers output and the speaker, without any form of attenuation and reamplification.
Any ideas?

[swever]

Welcome to the forum. I think that is a very interesting concept. Reverbs, delays, and possibly modulation effects of all sort all do belong there after all "color", in theory. I'd be interested to see what others have to say about this idea.

[printer2]

Hi,
I like amps that have power amp clipping, which ultimately makes any form of an FX loop useless. How could a pedal be designed so that it can be used in between a 50w amplifiers output and the speaker, without any form of attenuation and reamplification.
Any ideas?

Hi again. It can't.

[22uf]

Hi,
I like amps that have power amp clipping, which ultimately makes any form of an FX loop useless. How could a pedal be designed so that it can be used in between a 50w amplifiers output and the speaker, without any form of attenuation and reamplification.
Any ideas?

Hi again. It can't.

Haha on here too I see!

Well, I'm thinking that if I build a pedal with parts of higher watts and volts it should be able to handle it. I mean, I just can't under why, with different pedal design of course, a pedal can't deal with an amp output. I'm sure the pedal would be larger due to the need of way bigger resistors etc but it would be the best way to use modulation effects for absolute clarity, unless your also clipping the speaker!

FX loops are a total failure in my opinion, unless you're either a totally clean player, or a metal head.

[Danich_ivanov]

I'm not an expert, but here are some thoughts. First of all, you would have to feed output from the power amplifier into the pedal which will likely result in burning the pedal, since poweramp's output is incredibly powerfull, so you would have to come up with some sort of circuit that makes this output suitable for a pedal (and i'm not entirely sure that this is possible at all), and then you would have to add another power amp after the pedal, because you would not be able to drive a speaker with just a pedal. So it is a quite a task, i would think of other ways to achive the result you're looking for.

[printer2]

It is viable to make a low powered amp, 1-4W where you get power amp clipping and then reduce the voltage to be used in a pedal. It is virtually impossible to take 1W never mind 30W and send it through, say a delay circuit and send it to speakers. You have no idea on what is possible. It is more practical to take your AC-30 and reduce the output voltage, send it through a pedal, then back into another AC-30 going to speakers than design pedals to accept and pass through 30W.

[stallik]

Impedance matching transformer with a line out between main amp and speaker, attenuate that signal before hitting the pedals then out to a second amp?
Just thinking out loud

[22uf]

It is viable to make a low powered amp, 1-4W where you get power amp clipping and then reduce the voltage to be used in a pedal. It is virtually impossible to take 1W never mind 30W and send it through, say a delay circuit and send it to speakers. You have no idea on what is possible. It is more practical to take your AC-30 and reduce the output voltage, send it through a pedal, then back into another AC-30 going to speakers than design pedals to accept and pass through 30W.

I know what you mean, but there are two problems with your method.
1. AC4 doesn't sound exactly the same as an AC30.
2. It would be be nice to use post-amplification pedals on other amps too.

I know putting a standard pedal there would blow up, but I'm talking about rebuilding pedal design/components from the ground up.

Or maybe instead of a new pedal design, there could be a box where the output of the amp is split into two, one goes direct into the speaker, and the other goes through normal pedals via attenuation, and then reamplifies the 100% wet signal in parallel with the direct signal. Only problem with this is that the box may end up impractically big, I mean it must take like 1000W of SS power to compete with 50W valve power.

[Danich_ivanov]

It is viable to make a low powered amp, 1-4W where you get power amp clipping and then reduce the voltage to be used in a pedal. It is virtually impossible to take 1W never mind 30W and send it through, say a delay circuit and send it to speakers. You have no idea on what is possible. It is more practical to take your AC-30 and reduce the output voltage, send it through a pedal, then back into another AC-30 going to speakers than design pedals to accept and pass through 30W.

I know what you mean, but there are two problems with your method.
1. AC4 doesn't sound exactly the same as an AC30.
2. It would be be nice to use post-amplification pedals on other amps too.

I know putting a standard pedal there would blow up, but I'm talking about rebuilding pedal design/components from the ground up.

Or maybe instead of a new pedal design, there could be a box where the output of the amp is split into two, one goes direct into the speaker, and the other goes through normal pedals via attenuation, and then reamplifies the 100% wet signal in parallel with the direct signal. Only problem with this is that the box may end up impractically big, I mean it must take like 1000W of SS power to compete with 50W valve power.

I think what i would do if i liked the sound of a hot power amplifier, i would make a pedal that mimics that sound. Or, the other thing you can do is have a dry/wet rig with tosty amp on one side and clean on the other, which seems to be a quite common thing.

[duck_arse]

I just want to be an arse and ask - if your effectors after the power amp include some form of tone shaping circuit, you will lose signal level. how are you going to get it back to the original output power level without further "gain" stage?

[22uf]

It is viable to make a low powered amp, 1-4W where you get power amp clipping and then reduce the voltage to be used in a pedal. It is virtually impossible to take 1W never mind 30W and send it through, say a delay circuit and send it to speakers. You have no idea on what is possible. It is more practical to take your AC-30 and reduce the output voltage, send it through a pedal, then back into another AC-30 going to speakers than design pedals to accept and pass through 30W.

I know what you mean, but there are two problems with your method.
1. AC4 doesn't sound exactly the same as an AC30.
2. It would be be nice to use post-amplification pedals on other amps too.

I know putting a standard pedal there would blow up, but I'm talking about rebuilding pedal design/components from the ground up.

Or maybe instead of a new pedal design, there could be a box where the output of the amp is split into two, one goes direct into the speaker, and the other goes through normal pedals via attenuation, and then reamplifies the 100% wet signal in parallel with the direct signal. Only problem with this is that the box may end up impractically big, I mean it must take like 1000W of SS power to compete with 50W valve power.

I think what i would do if i liked the sound of a hot power amplifier, i would make a pedal that mimics that sound. Or, the other thing you can do is have a dry/wet rig with tosty amp on one side and clean on the other, which seems to be a quite common thing.

Yeah, a pedal to sound like that would be great, but that would even be more impossible. I mean in all reality, OD pedals sound abosolutely terrible compared to power amp clipping.

[printer2]

It is viable to make a low powered amp, 1-4W where you get power amp clipping and then reduce the voltage to be used in a pedal. It is virtually impossible to take 1W never mind 30W and send it through, say a delay circuit and send it to speakers. You have no idea on what is possible. It is more practical to take your AC-30 and reduce the output voltage, send it through a pedal, then back into another AC-30 going to speakers than design pedals to accept and pass through 30W.

I know what you mean, but there are two problems with your method.
1. AC4 doesn't sound exactly the same as an AC30.
2. It would be be nice to use post-amplification pedals on other amps too.

I know putting a standard pedal there would blow up, but I'm talking about rebuilding pedal design/components from the ground up.

Or maybe instead of a new pedal design, there could be a box where the output of the amp is split into two, one goes direct into the speaker, and the other goes through normal pedals via attenuation, and then reamplifies the 100% wet signal in parallel with the direct signal. Only problem with this is that the box may end up impractically big, I mean it must take like 1000W of SS power to compete with 50W valve power.

You can attenuate any amp and put it through a pedal. You can not send all the power through it, you will need to reamplify it at that point as I said. If you want to take the 30W output, attenuate it, send it through a pedal and then out to another amp, that has been done also. As you realize, that means you pretty much have to have another parallel rig. I have made a 3W 5E3 Deluxe. Sounds great while I had it. About the power of the AC-4 and much lighter. There is no reason you can not build a small scale P-P amplifier and then send it through your pedals and to your main amp. Whether it sounds exactly how you want it to depends on luck as you have little knowledge of electronics and would not know how to go about it. But it is more doable than building a pedal that will modulate your 30W amp output which then goes to your speaker.

[22uf]

It is viable to make a low powered amp, 1-4W where you get power amp clipping and then reduce the voltage to be used in a pedal. It is virtually impossible to take 1W never mind 30W and send it through, say a delay circuit and send it to speakers. You have no idea on what is possible. It is more practical to take your AC-30 and reduce the output voltage, send it through a pedal, then back into another AC-30 going to speakers than design pedals to accept and pass through 30W.

But the problems with your method are 1, attenuation degrades sound quality, and 2, the ac4 doesn't sound as good as the AC30.

I understand that it would be complicated, but the best way as far as sound quality is concerned is to 'simply' make pedals that are capable of handling the output of the amp. All this re-amping is a compromise.

I know what you mean, but there are two problems with your method.
1. AC4 doesn't sound exactly the same as an AC30.
2. It would be be nice to use post-amplification pedals on other amps too.

I know putting a standard pedal there would blow up, but I'm talking about rebuilding pedal design/components from the ground up.

Or maybe instead of a new pedal design, there could be a box where the output of the amp is split into two, one goes direct into the speaker, and the other goes through normal pedals via attenuation, and then reamplifies the 100% wet signal in parallel with the direct signal. Only problem with this is that the box may end up impractically big, I mean it must take like 1000W of SS power to compete with 50W valve power.

You can attenuate any amp and put it through a pedal. You can not send all the power through it, you will need to reamplify it at that point as I said. If you want to take the 30W output, attenuate it, send it through a pedal and then out to another amp, that has been done also. As you realize, that means you pretty much have to have another parallel rig. I have made a 3W 5E3 Deluxe. Sounds great while I had it. About the power of the AC-4 and much lighter. There is no reason you can not build a small scale P-P amplifier and then send it through your pedals and to your main amp. Whether it sounds exactly how you want it to depends on luck as you have little knowledge of electronics and would not know how to go about it. But it is more doable than building a pedal that will modulate your 30W amp output which then goes to your speaker.

[GGBB]

Why leave the speaker out? In the studio (at least in the old days), an amp would be miced and recorded and studio effects would be added. You can easily do the same for "live" sound with ordinary pedals. Guitar->amp->mic->mic-pre/mixer->effects->power amp->monitor. The post-effects feed could also be sent to PA.

[22uf]

Why leave the speaker out? In the studio (at least in the old days), an amp would be miced and recorded and studio effects would be added. You can easily do the same for "live" sound with ordinary pedals. Guitar->amp->mic->mic-pre/mixer->effects->power amp->monitor. The post-effects feed could also be sent to PA.

Well, in some situations that isn't practicacle. I mean, a lot of the times live sound engineers can be down right antisocial! Also, you would lose control.

But adding the pedals after the mic would be the best solution so far. I feel that attenuating and then re amping would dull the sound out, create noise, and take away the rawness of the sound. I think that keeping the interaction of the hot power tubes > speaker is the only way to keep things sounding pure. Maybe having the effects post power amp would sound even more organic than having the effects post mic as the effects would be more 'connected' if you know what I mean.

[Mark Hammer]

Not a pedal, but certainly an effect between amp and speaker: rotating speaker.

Just about any day of the week, you'll be able to find an ad in your local Craigslist equivalent that offers a 2-keyboard organ "free to a good home" if you pick it up.  Not always, but usually, there will be an internal Vibratone-type single-rotor dual-speed speaker.  Build it into a cab, and feed it with the output of an amp.

[R.G.]

I like amps that have power amp clipping, which ultimately makes any form of an FX loop useless. How could a pedal be designed so that it can be used in between a 50w amplifiers output and the speaker, without any form of attenuation and reamplification.
Any ideas?

Yep, got some ideas.

The term "power amp clipping" is a little too broad. A Fender Princeton will clip different from a Fender Bassman, and that will be different again from any solid state amp. In fact, most tube power amps and most solid state amps will clip differently, depending on what exactly is clipping inside the amp. It's not always the same thing distorting when a power amp clips.

So "power amp clipping" is by itself too broad to be useful. It's a little like saying "how fast can a horse run?" without specifying which horse.

Then there's the whole question of whether the sound you like can ever be reproduced by something other than the basic power amp itself. If you recorded the sound with a GREAT mike and recording gear and played it back through GREAT amps and speakers, would it sound the same? If not, how is it different? If it would sound the same, there is a way to do it not involving the path from amp to speakers.

Then there's the question of how much the speakers contribute to the clipping. Speakers are even more wildly different in sound from one another than amps are. They interact with the amp itself to change the nature of the audio in the air, including changing the loading on the amp (and therefore the onset of clipping) and the tonal quality of the clipping, as well as themselves clipping.

It's not hard designing a pedal to work between a power amp and speaker. You just have to (1) think of what you want the pedal to do and (2) design the components to handle the signal levels that involves. It will be VERY difficult to replicate many of the effects that happen at signal level if you mean you want this speaker-level pedal to do the same effects - distortion, phase shifting, delay, chorus, etc. While it's not hard to think of what the pedal would need to do and how to make it withstand the power and voltage levels, it may well be that components do not exist that handle those power levels. For instance, it will be VERY hard to find any kind of sampled-data delay chip to do chorus, flanging, echo, or reverb. You CAN do reverb well enough - just play the amp in a highly resonant room. I suspect that isn't what you had in mind, though.

[GGBB]

Also, you would lose control.

I think you missed my point. No control lost at all - the mic->mixer->fx-pedals->pwr-amp->monitor is part of your setup, not the sound engineer's - maybe I didn't make that clear. Although a lot less practical than just pedals and a guitar amp, this is billions of times more practical than designing and building power amp signal level effects that don't alter the sound (other than fx) of the original amp+speaker combination. I'm not even convinced it is actually both possible and somehow better than just using the effects loop with ordinary pedals. Also, the attenuation of the power amp signal idea for using with ordinary pedals and then re-amping it is not likely to accomplish anything beneficial unless the sound of a guitar power amplifier being run through another guitar power amp is desirable. It sure would be fun to watch someone try any of these approaches though.