Running pedals straight into a power amp

[Bubby Brown]

You consider a bass block?

 

[220_Hz]

Hey gang,

I imagine this must be discussed somewhere else on the threads, but a search didn't reveal anything helpful. So forgive me if this has been discussed before, but . . .

Does anybody run pedals straight into a power amp? It has been said that a pedal that I have coming in the mail has enough headroom and output to push a power amp. That got me thinking. Why have I never tried that before? Well, I'll answer that. Because I didn't think it would work. I assumed a pedal wouldn't have the output, the power, or the output impedance, etc, to adequately push a power amp. I assumed the level would be too quiet, too noisy, or both. I assumed I needed to use my rackmount preamp to get the signal to line level to sound halfway decent through a power amp.

But I found the thought of not having to lug my huge rack around in my old age all too appealing. I couldn't leave well enough alone. Just carrying my pedalboard, which I would definitely bring anyway, and a Carvin DCM2000L power amp in a 2-space rack that weighs next to nothing would be amazing.

So I tried running my pedals straight to my power amp tonight just for poops and giggles . . . and you know what? . . . it kind of worked! It sounded good, but it didn't sound great. It certainly was plenty loud, but it didn't have the punch that my rack pre has (a Geddy 2112 run clean with subtle EQ). My pedalboard is pretty Broughton-heavy, ending in an SVPre and RFE. I find the SVPre to be pretty quiet compared to other preamps. It sounds good in headphones through a DI, but lacked the same punch coming through the power amp and cab.

What is the solution? Do you need to have something with a line level output to really get a great tone when running from a pedalboard straight to a power amp? Something like a Sansamp (that I don't really love the sound of) that has a +10db switch on the 1/4" out, maybe?

Does anybody even do that, or am I crazy . . . or both?

If so, what are you guys using?

Or could I get away with just a boost pedal of some kind at the end of my pedalboard to bring the output up to line level? Maybe? Or do you need something that actually physically converts the signal to line level to give it more strength and not just more volume? Something like what a rack pre is designed to do, I can only imagine. I'm not adequately educated in the physics/science/electronic engineering side of things to even know how to ask the question.

Thanks

My main rig since last November has been a Crown XLS 1002 with pedals pushing the front end. I usually run the input sensitivity at .775 but some pedals can get so loud I need to step back to 1.4v

I own plenty of broughtons as well, Silver Deluxe and SV-Pre easily makes enough level to drive it at .775, but I usually use a messenger V1. I recommend getting a BBA, I might do the same thing.

Hope any of this helped! I personally think my tone has never been better since deciding to use a stand-alone power amp and pedal preamps. I’m looking into a traynor flavored preamp and a Sunn Model T type preamp. Also consider using rackmount type preamps like a Warm Audio Neve EQ or 500 series type preamps!

 

[XLunacy]

Hey gang,

I imagine this must be discussed somewhere else on the threads, but a search didn't reveal anything helpful. So forgive me if this has been discussed before, but . . .

Does anybody run pedals straight into a power amp? It has been said that a pedal that I have coming in the mail has enough headroom and output to push a power amp. That got me thinking. Why have I never tried that before? Well, I'll answer that. Because I didn't think it would work. I assumed a pedal wouldn't have the output, the power, or the output impedance, etc, to adequately push a power amp. I assumed the level would be too quiet, too noisy, or both. I assumed I needed to use my rackmount preamp to get the signal to line level to sound halfway decent through a power amp.

But I found the thought of not having to lug my huge rack around in my old age all too appealing. I couldn't leave well enough alone. Just carrying my pedalboard, which I would definitely bring anyway, and a Carvin DCM2000L power amp in a 2-space rack that weighs next to nothing would be amazing.

So I tried running my pedals straight to my power amp tonight just for poops and giggles . . . and you know what? . . . it kind of worked! It sounded good, but it didn't sound great. It certainly was plenty loud, but it didn't have the punch that my rack pre has (a Geddy 2112 run clean with subtle EQ). My pedalboard is pretty Broughton-heavy, ending in an SVPre and RFE. I find the SVPre to be pretty quiet compared to other preamps. It sounds good in headphones through a DI, but lacked the same punch coming through the power amp and cab.

What is the solution? Do you need to have something with a line level output to really get a great tone when running from a pedalboard straight to a power amp? Something like a Sansamp (that I don't really love the sound of) that has a +10db switch on the 1/4" out, maybe?

Does anybody even do that, or am I crazy . . . or both?

If so, what are you guys using?

Or could I get away with just a boost pedal of some kind at the end of my pedalboard to bring the output up to line level? Maybe? Or do you need something that actually physically converts the signal to line level to give it more strength and not just more volume? Something like what a rack pre is designed to do, I can only imagine. I'm not adequately educated in the physics/science/electronic engineering side of things to even know how to ask the question.

Thanks

Yep I do exactly this : pedalboard with amp and cab sim at the end (Torpedo Cab M+), XLR goes to FOH, and 1/4" jack goes to a simple power amp (GSS Baby Sumo, input sensitivity is ~0.5V) paired with a FRFR cab, with a little para EQ in between that acts like a stage preamp, to tweak the stage sound (tame annoying frequencies) and boost the signal a bit more to allow the power amp to work at its full capacity
Very happy with this setup, FOH sound is consistent and decoupled from the stage sound, and I can make do with any backline and keep my FOH tone the same by bringing only my pedalboard.

 

[chriscarcinogen]

I used a Sans Amp Classic directly to a power amp with fine results.

 

[220_Hz]

Yep I do exactly this : pedalboard with amp and cab sim at the end (Torpedo Cab M+), XLR goes to FOH, and 1/4" jack goes to a simple power amp (GSS Baby Sumo, input sensitivity is ~0.5V) paired with a FRFR cab, with a little para EQ in between that acts like a stage preamp, to tweak the stage sound (tame annoying frequencies) and boost the signal a bit more to allow the power amp to work at its full capacity
Very happy with this setup, FOH sound is consistent and decoupled from the stage sound, and I can make do with any backline and keep my FOH tone the same by bringing only my pedalboard.

How do you like the baby sumo? I didn’t know the input sensitivity was so low, I might have to cop one

Do you ever think you’re running your input signal too hot for the amp? Does it have input monitoring? That’s my biggest problem with setting levels, and I find the monitoring on my Crown to be pretty essential.

 

[g-dude]

The Tech21 YYZ manual suggests running it into an effects loop return, which should be the same as straight into a power amp. I do this on my Rumble 200 and it sounds great!

I’ve done this on guitar using a Leeds pedal straight into the return of a solid state Fender amp.

Just be sure to turn the pedal’s volume all the way down first, and then slowly increase until you hit the right volume.

 

[Wasnex]

I guess that's partly my question. And perhaps a stupid one at that. But is instrument vs line level simply a matter of volume? And would that difference be something that can achieved with a boost pedal? Or is there some other inherent difference in the quality/attributes of a line level signal?

I didn't see anywhere that you identified your special pedal that can drive a power amp...course I have only skimmed the thread, so maybe I just missed it . Pedals in general are not designed to push a power amp, so knowing the specific pedal would be helfpul. A regular boost pedal is unlikely to get the job done.

For the most part yes. Instrument level runs around -30 to -20dB. Line level is generally considered +4dB nominal.

FYI the sensitivity rating is the spec that indicates how hot of a signal is required to push the amp to full power. Sensitivity for the DCM2000L is 1.4V, which is about +5dB. The Max output of the device driving the power amp must be at least +5dB if you want full power.

Something to keep in mind is power amps generally expect a balanced input. Pedals usually have unbalanced output. AFAIK, you generally lose 6dB when you plug an unbalanced output into a balanced input.

However, if the rig is getting loud enough for your needs, the signal level is probably not the problem.

Yes, I need to look into the input impedance of the power amp vs the output impedance of whatever I'm running into it, maybe. But I don't understand what that means well enough to know what I'm looking for. I'll look into that.

Most modern audio gear uses impedance bridging rather than impedance matching. Impedance matching means the output impedance of the driving devices is the same as the input impedance of the driven device. For example in the old days 600 ohms was common.

Impedance bridging means the input impedance of the driven device is at least 10X higher than the output impedance of the driving device. Essentially the input impedance is so high that that the driving devices thinks there is an open circuit.

My guess is you are missing the mojo/baked-in tone of your normal rig. Dialing in the EQ and compression is where I would start.

 

[N. Kentucky Bass]

Hey gang,

I imagine this must be discussed somewhere else on the threads, but a search didn't reveal anything helpful. So forgive me if this has been discussed before, but . . .

Does anybody run pedals straight into a power amp? It has been said that a pedal that I have coming in the mail has enough headroom and output to push a power amp. That got me thinking. Why have I never tried that before? Well, I'll answer that. Because I didn't think it would work. I assumed a pedal wouldn't have the output, the power, or the output impedance, etc, to adequately push a power amp. I assumed the level would be too quiet, too noisy, or both. I assumed I needed to use my rackmount preamp to get the signal to line level to sound halfway decent through a power amp.

But I found the thought of not having to lug my huge rack around in my old age all too appealing. I couldn't leave well enough alone. Just carrying my pedalboard, which I would definitely bring anyway, and a Carvin DCM2000L power amp in a 2-space rack that weighs next to nothing would be amazing.

So I tried running my pedals straight to my power amp tonight just for poops and giggles . . . and you know what? . . . it kind of worked! It sounded good, but it didn't sound great. It certainly was plenty loud, but it didn't have the punch that my rack pre has (a Geddy 2112 run clean with subtle EQ). My pedalboard is pretty Broughton-heavy, ending in an SVPre and RFE. I find the SVPre to be pretty quiet compared to other preamps. It sounds good in headphones through a DI, but lacked the same punch coming through the power amp and cab.

What is the solution? Do you need to have something with a line level output to really get a great tone when running from a pedalboard straight to a power amp? Something like a Sansamp (that I don't really love the sound of) that has a +10db switch on the 1/4" out, maybe?

Does anybody even do that, or am I crazy . . . or both?

If so, what are you guys using?

Or could I get away with just a boost pedal of some kind at the end of my pedalboard to bring the output up to line level? Maybe? Or do you need something that actually physically converts the signal to line level to give it more strength and not just more volume? Something like what a rack pre is designed to do, I can only imagine. I'm not adequately educated in the physics/science/electronic engineering side of things to even know how to ask the question.

Thanks

Your query is exactly what I do: passive P-bass --> Noble tube preamp --> powered speaker. Simple, elegant, sounds lusciously thick like a p-bass should!

 

[moon-bass]

and I’ve run my trace Elliot 12 band pedal

Not to hijack the thread, but what's the 12 band trace pedal? I have a 7 band, would love to track the 12 down. TIA!

 

[PeaveyPlayer]

Not to hijack the thread, but what's the 12 band trace pedal? I have a 7 band, would love to track the 12 down. TIA!

this thing!

 

[moon-bass]

View attachment 4724578

this thing!

Okay cool that's the one I have. I love it!!

 

[XLunacy]

How do you like the baby sumo? I didn’t know the input sensitivity was so low, I might have to cop one

Do you ever think you’re running your input signal too hot for the amp? Does it have input monitoring? That’s my biggest problem with setting levels, and I find the monitoring on my Crown to be pretty essential.

I love it It's clean and only makes whatever is at the input louder, which is what I want it to do. The power/weight ratio is crazy (600W@4ohm for 1.5kg / 3.3lbs), and it's smaller (volume wise) than a milk carton
You're right that it does not have input monitoring (even though it seems you can contact the company making them and they'll add it for you, quite sure I've read that somewhere) but I judge with my ears and once my gain is properly set I won't change it much; I'd be more concerned with underpowering it rather than overpowering it

 

[PeaveyPlayer]

View attachment 4724578

this thing!

Did I say 12? I meant 7! Lol

I did try the ashdown but it was noisy.

I changed out the eletrolyryc caps
And op amps to newer ones
And got a shielded 2MM to 2.5MM cable for my pedal board for 18V

 

[dbsfgyd1]

Hey gang,

I imagine this must be discussed somewhere else on the threads, but a search didn't reveal anything helpful. So forgive me if this has been discussed before, but . . .

Does anybody run pedals straight into a power amp? It has been said that a pedal that I have coming in the mail has enough headroom and output to push a power amp. That got me thinking. Why have I never tried that before? Well, I'll answer that. Because I didn't think it would work. I assumed a pedal wouldn't have the output, the power, or the output impedance, etc, to adequately push a power amp. I assumed the level would be too quiet, too noisy, or both. I assumed I needed to use my rackmount preamp to get the signal to line level to sound halfway decent through a power amp.

But I found the thought of not having to lug my huge rack around in my old age all too appealing. I couldn't leave well enough alone. Just carrying my pedalboard, which I would definitely bring anyway, and a Carvin DCM2000L power amp in a 2-space rack that weighs next to nothing would be amazing.

So I tried running my pedals straight to my power amp tonight just for poops and giggles . . . and you know what? . . . it kind of worked! It sounded good, but it didn't sound great. It certainly was plenty loud, but it didn't have the punch that my rack pre has (a Geddy 2112 run clean with subtle EQ). My pedalboard is pretty Broughton-heavy, ending in an SVPre and RFE. I find the SVPre to be pretty quiet compared to other preamps. It sounds good in headphones through a DI, but lacked the same punch coming through the power amp and cab.

What is the solution? Do you need to have something with a line level output to really get a great tone when running from a pedalboard straight to a power amp? Something like a Sansamp (that I don't really love the sound of) that has a +10db switch on the 1/4" out, maybe?

Does anybody even do that, or am I crazy . . . or both?

If so, what are you guys using?

Or could I get away with just a boost pedal of some kind at the end of my pedalboard to bring the output up to line level? Maybe? Or do you need something that actually physically converts the signal to line level to give it more strength and not just more volume? Something like what a rack pre is designed to do, I can only imagine. I'm not adequately educated in the physics/science/electronic engineering side of things to even know how to ask the question.

Thanks

I haven’t done this is long time, but I have used my Eden WTDI as a preamp for my Eden WT-1250 power amp.

That said, I sure there are minimum pre amp output requirement power amps, but not sure if there is a unified standard sensitivity rating. My thinking that migt vary from amp to amp.

 

[jacoby75]

I’m not getting it. Your one rack space Geddy can’t weigh that much. The Carvin amp doesn’t weigh anything. So you need a what? A two or three space light weight rack? Like a SK roto molded kind of thing?
Or maybe integrate the Geddy into your board, or replace it with the stomp box form?
What’s the goal here? Reducing the schlep? Downsizing?

Excellent question. What is ever the goal? Lol. Just me looking for an excuse to spend more money I don't have on more things I don't need, I suppose. The ever-revolving, ever-evolving tone quest.

Pull up a chair next to the fire. Grab a stick and a marshmallow, and let me tell you a little story . . .

I toured full time for several years with various amp heads before finally settling on a rack-based setup. I almost never used a pedal other than in the studio. Didn't have a need for it, or so I thought. But things change. Then our daughter was born and I had to get a "real job" again, and music has taken a back seat for a while now. Since pre-Covid, I have had basically zero gigs apart from an occasional church function and one community theater HS production of "Beauty and the Beast" right before Covid hit. Yet those modest opportunities to play inspired me to embark on a journey to find that ever-elusive perfect ampless pedalboard tone, especially since many churches were running ampless these days. Let's not discuss how many dollars worth of pedals, preamps, etc. I have blown through over the past few years in that quest. It would make a grown man cry. And a grown man's wife. But I think I finally have my pedalboard dialed in as well as I'm going to. I love the tone. However, up until recently the whole quest has been to develop a fantastic tone in my headphones for my own enjoyment, which had yet to manifest itself in the real world through any sort of amplification for others to enjoy, save for the select few present at the handful of functions I was fortunate enough to play at.

Then, a couple of months ago, the opportunity for a cover band gig finally materialized after a few years of trying to put the pieces together by draining and dragging the bottom of the incredibly shallow talent pool in my small, rural Michigan town, looking for signs of life. But the effort paid off. I've got a great group together. So now the quest for tone has gone from far more theoretical to an actual, tangible and physical reality.

We have a long way to go before we will be gig ready, but I decided to pull out all my old gear and dust it off, just to make sure everything still worked. I don’t think I have opened my rack in maybe 9 years, apart from the occasional headphone jam just to see how it compared to various pedals I was trying. It is a six space SKB rack consisting of the Carvin power amp, a Demeter VTBP-201s, Rane DC-24 compressor (a recent addition), tuner, and Monster power conditioner. I used to lug it around without giving it much thought, but it seems a bit heavier these days, or maybe I'm just getting significantly weaker in my old age. But either way, I'd like to lighten the load. But that's a side note. I fired everything up, and much to my dismay, the XLR out of the Demeter has crapped out. It was getting a bit crackly a couple of years ago when I was headphone jamming. It would cut out unless I jiggled the XLR cable just right, then it would be good for a while. But I wasn't really worried about it, because at the time I didn't need an amp, and had no prospects for the need of one in the foreseeable future. I figured I would suss it out later. Well, now I need an amp, and now the Demmie's XLR out is not working at all, no matter how vigorously I shake the XLR cable. There will be intermittent crackling and tone, just enough to let me know it's still alive in there somewhere, only to be followed by deafening silence. And there are other issues as well. I know it can be fixed, but I didn't want to wait to sort that out, so I dusted off an old Tech 21 GED 2112 that I recently acquired, and stuck that in its place, and now the rack setup works just fine, but it's much more weight than I'd like to schlep, if I can avoid it. Especially since I now also have the ginormous pedalboard that I didn't used to have.

The only real purpose for having the rack mounted preamp at this point is to amplify the great tone I have coming from my pedalboard through the power amp and cab, and to give me an effects loop within which to use the Rane DC24. And the GED 2112 does both swimmingly. But neither the Demeter nor the 2112 sound as good on their own as they do with my pedalboard feeding it/them. And I'm not really utilizing the 2112 to its full potential. I don't use it to sound anything like Geddy. It's set to be basically just clean, with a mostly flat eq, to make my pedalboard louder and make use of the Rane compressor. It's a lot of weight to carry around for what might be minimal gain that might otherwise be achieved through my pedalboard, which I'm also going to schlep regardless. And I do have a really good compressor pedal on my board which does most of the heavy lifting anyway.

Well, then I got to thinking. I said, "Hey self, if you're going to chose to lug around this huge pedalboard anyway, I wonder if there's a way you can use JUST the pedalboard, power amp and cab, and still send great tone to FOH and to the input of my power amp, so I don't also have to lug around a huge rack." To which I responded to myself, "I dunno."

And here we are.

 

[jacoby75]

I am here to report that after a brief, lower-than-bedroom-volume-level attempt at running my pedalboard to the Radial JDI and taking the 1/4" thru and running that into my Sansamp Bassdriver DI, and taking the 1/4" out of that, with the +10dBu engaged and running that into my Carvin power amp, the resulting tone was absolutely thunderous. I couldn't turn it up much at all because the kid was in bed right next door. But I have no reason to doubt this will work just fine. Plus, there is the added bonus of the controls available on the Bassdriver, to further shape my amp's tone and customize what is coming out of the pedalboard to the amp, without changing my FOH signal at all.

Thank you to everyone who has taken the time to offer such wonderful, thoughtful, detailed feedback. It is much appreciated. I look forward to experimenting with this further by the light of day.

 

[singlemalt]

I’ve done a bit of “catch and release” myself. But sell my Smoothie comp? Inconceivable!

You, my friend, have waded into deep waters!

Good luck with the quest!

I see a Quad Cortex and super nice in ear monitors in your future.

 

[jacoby75]

You consider a bass block?

My main rig since last November has been a Crown XLS 1002 with pedals pushing the front end. I usually run the input sensitivity at .775 but some pedals can get so loud I need to step back to 1.4v

I own plenty of broughtons as well, Silver Deluxe and SV-Pre easily makes enough level to drive it at .775, but I usually use a messenger V1. I recommend getting a BBA, I might do the same thing.

Hope any of this helped! I personally think my tone has never been better since deciding to use a stand-alone power amp and pedal preamps. I’m looking into a traynor flavored preamp and a Sunn Model T type preamp. Also consider using rackmount type preamps like a Warm Audio Neve EQ or 500 series type preamps!

Thank you. I do have a BBA at the front of my pedalboard chain. I swapped it out for the end last night and ran that to my power amp from the end of my pedalboard, and it was definitely louder . . . like . . . . waaaay louder. I probably could have melted my power amp, or at the very least stripped the paint off the walls. But something still didn't sound right. Of course, part of the problem could have been that I had taken the BBA off of the front of my chain, where I felt it sounded best initially. I'd need two of them to test that theory, lol. But good idea.

 

[jacoby75]

You consider a bass block?

I have not. I have the power side of things down with 1000 watts of American Carvin lead. And a great preamp pedal. Just trying to figure out the best . . . and most affordable . . . way to bridge the two. But I have also considered scrapping the whole thing and just getting a lighter bass head. Even like a 2 space all-in-one head. But I would still need to lug my pedalboard anyway, so it seems it would be a waste, since I ultimately want the core of my tone to come from my pedals.

 

[jacoby75]

I didn't see anywhere that you identified your special pedal that can drive a power amp...course I have only skimmed the thread, so maybe I just missed it . Pedals in general are not designed to push a power amp, so knowing the specific pedal would be helfpul. A regular boost pedal is unlikely to get the job done.

A Broughton Locus Star. Probably just going to use it for dirt, but it has been known to be an effective clean preamp as well.

For the most part yes. Instrument level runs around -30 to -20dB. Line level is generally considered +4dB nominal.

FYI the sensitivity rating is the spec that indicates how hot of a signal is required to push the amp to full power. Sensitivity for the DCM2000L is 1.4V, which is about +5dB. The Max output of the device driving the power amp must be at least +5dB if you want full power.

Good to know. I think I'm there with the Sansamp.

Something to keep in mind is power amps generally expect a balanced input. Pedals usually have unbalanced output. AFAIK, you generally lose 6dB when you plug an unbalanced output into a balanced input.

Also good to know. I'll try the XLR output of the Sansamp tomorrow.

However, if the rig is getting loud enough for your needs, the signal level is probably not the problem.
Most modern audio gear uses impedance bridging rather than impedance matching. Impedance matching means the output impedance of the driving devices is the same as the input impedance of the driven device. For example in the old days 600 ohms was common.

Impedance bridging means the input impedance of the driven device is at least 10X higher than the output impedance of the driving device. Essentially the input impedance is so high that that the driving devices thinks there is an open circuit.

My guess is you are missing the mojo/baked-in tone of your normal rig. Dialing in the EQ and compression is where I would start.