Preamp (pedal) into a power amp

[groooooove]

the topic of pre / power combos is always tempting. but, i've found there is a reason this is less common..

let the amp makers pair power and pre, and just plug in and move on.

i do use a VT bass pedal into the effects return of an old hartke LH1000 sometimes. it produces "good results," but for all i know it's a less-than-optimal setup for tech reasons. but it definitely.... sounds like my vt bass...

other than that, i find there to be very few real reasons to go for separate pre/power rigs aside from being someone who likes to tinker around with gear. which is cool, and can certainly work very well, but buying a quality bass amp is almost always a better idea i'd say?

 

[smo]

I am wondering if buying a preamp pedal such as a Sans amp and running that directly into a power amp would be a good idea or not? Has anyone done this?

It's common enough to be normal.
Many players like having a preamp on their board straight to FOH, so they get "their tone" regardless of the backline (like me!)
Providing you're only feeding FOH a DI signal, you then have the freedom to tweak your stage amp volume, gain and/or EQ without dramatically effecting the PA and pissing off the sound guy or gal.

I've used a VT Bass or some sort of preamp on my pedalboard for exactly this purpose for 20 years, so I can quickly get my sound without knowing the amp on stage. I've had many a sound guy tell me how easy it was to make my tone work with FOH, especially with quick change overs.

FWIW - don't get too caught up on which amp if you're talking only SS power section. I could go into using Tube Slave's, which is where the topic gets much more fun....
Personally, I'd look at 2nd hand options, like the Aguilar Tone Hammer (great amps) as they're easy to sell if you decide to change later.
With an amp like this, the send/return feature means you can choose to use it like an amp, or bypass the Tone stack and only use the power amp.

 

[N. Kentucky Bass]

I'm in the market for an amplifier. I am thinking a more cost effective (more watts for the power) and (more flexibility on the pre.) solution might be this. Power amplifiers are cheap such as those used in audio. QSC etc. I am wondering if buying a preamp pedal such as a Sans amp and running that directly into a power amp would be a good idea or not? Has anyone done this?

This idea definitely works for me and my dog. Noble preamp into QSC PLX 3602 power amp. Boom.

 

[burgerdj]

I ran a PV6 Mixer into a Peavey power amp for many years. On smaller gigs, I would run the kick into my amp, for "fullness", when without sub support.View attachment 5460388

Love that TE Bright Box!

 

[agedhorse]

Which make & model bass preamps can appropriately drive a power amp that has 1.4 volts sensitivity?
I'd buy it.

Both Subway Pre-DI’s and the Magellan Pre-Di for sure have both adequate gain AND maximum output level to drive well beyond +6dBu (~1.5Vrms) on the balanced outputs.

The Magellan operating with an 18V power supply can deliver +22dBu (~9.5Vrms) balanced output signal.

The challenge is that most pedal specs are dreadfully incomplete which makes determining the amount of available gain and maximum output level impossible.

 

[OnlyFlats]

I do this using a Yamaha px 8. I chose that power amp because it has inbuilt fully adjustable cross over and filters, as I like to get nerdy with that and my varied cabs.

I prefer the control and versatility of a modular setup. I've changed preamps and cabinets along the way but stuck with separate power amps for 20yrs.

I agonised over preamp pedals for a while. They're fun to explore and trial. Currently I just use a boost pedal on my pedal board and a TS lead connection to get enough juice to the power amp. No preamp pedal.

Be mindful that flipping a power amp (if you change your mind and want a traditional bass amp instead) might be hard.

 

[el murdoque]

I have no clue about the specifics, but I've driven several poweramps with a Sansamp PBDDI and it worked well for me. Entirely possible that the pedal's output was not strong enough to drive a power amp to its full potential, but it drove it hard enough for my requirements.

 

[pbassnut]

I'm in the market for an amplifier. I am thinking a more cost effective (more watts for the power) and (more flexibility on the pre.) solution might be this. Power amplifiers are cheap such as those used in audio. QSC etc. I am wondering if buying a preamp pedal such as a Sans amp and running that directly into a power amp would be a good idea or not? Has anyone done this?

I own a rackmount Tech21 RPM as well as Paradriver I and Bass Driver II pedals. My RPM has plenty of gain to drive most poweramps. However, my Paradriver I (which is more or less the same thing as the RPM) has quite a bit less gain than my RPM yet it has more than enough juice to drive my Ampeg B2-RE * head via the POWERAMP IN or EFFECTS RETURN patch points). On the other hand, my Bass Driver II pedal has considerably more output potential than my Paradriver I ... quite possibly approaching the output level of my RPM.

* You might want to consider an Ampeg B2-RE head as your poweramp solution. They are one of Ampeg's lower priced budget bass heads, but are real sleepers, IMHO and can often be found for a song on the used market. Its preamp section is kind of dry and colorless sounding, but its power section sounds really good with my gaggle of bass preamp pedals. I mostly use my pedals through the POWERAMP IN or EFFECTS RETURN patch points which utilizes just the power section of the B2-RE. However, my Ampeg Classic Analog Bass Preamp and my OneControl Blue 360 pedals sound good patched into the front-end of my B2-RE utilizing its native preamp/EQ section as well.

 

[Ian774]

It's common enough to be normal.
Many players like having a preamp on their board straight to FOH, so they get "their tone" regardless of the backline (like me!)
Providing you're only feeding FOH a DI signal, you then have the freedom to tweak your stage amp volume, gain and/or EQ without dramatically effecting the PA and pissing off the sound guy or gal.

I've used a VT Bass or some sort of preamp on my pedalboard for exactly this purpose for 20 years, so I can quickly get my sound without knowing the amp on stage. I've had many a sound guy tell me how easy it was to make my tone work with FOH, especially with quick change overs.

FWIW - don't get too caught up on which amp if you're talking only SS power section. I could go into using Tube Slave's, which is where the topic gets much more fun....
Personally, I'd look at 2nd hand options, like the Aguilar Tone Hammer (great amps) as they're easy to sell if you decide to change later.
With an amp like this, the send/return feature means you can choose to use it like an amp, or bypass the Tone stack and only use the power amp.

FOH engineers usually love a SansAmp. Last gig I played was at an alternative/hardcore festival in Newcastle, UK. The FOH guy has been taking DI from the back line bass amp all day, but when we saw my pedalboard with a SansAmp BDDI V2 on it, he immediately said “I’ll DI straight from your SansAmp”. Easy peasy. Sounded great!

 

[Passinwind]

The challenge is that most pedal specs are dreadfully incomplete which makes determining the amount of available gain and maximum output level impossible.

Not to mention the complicating factor of whether it actually still sounds good at the specified maximum level.

 

[LiptonJigglers]

Interesting thread.
I've often wondered about this kind of set up.
Just going by the responses on the first page, I think I'll stick to my amps and cabs.
Good luck with it all.

 

[Jeff Scott]

This idea definitely works for me and my dog. Noble preamp into QSC PLX 3602 power amp. Boom.

View attachment 5460433

Shepherd approved!

 

[paskisti]

RBI and BDDI output depends on the blend and drive settings too. Output is strong when blend is fully dry, but when you go more into wet side, you need to add drive to get similar output. I never had problems of driving power amps with 1,28V and 1,4V input sensitivity.

 

[YourGuitarist]

Also consider input sensitivity might be stated for a higher THD rated power. It may list sensitivity of 1V rms for max power, but max power might be distorting unpleasantly.

 

[YourGuitarist]

How?
Even if you know the frequencies an amp cuts and boosts, and even know the amp may cut by 15 db and boosts by only 12 db. Do you know the starting point of the boost or cut already baked in before you start at “flat or noon” ? That is where some of the “secret sauce” lies. The amp companies don’t tell us that.

If it was that simple these kids wouldn't need to develop that amp modeling thing, you would just need frequency plots from all the amps on the market.

View attachment 5460311

Not to mention how wide or narrow those boosts are and their placement before or after gain stages.

 

[MCS4]

I'm using this type of setup currently. I've spent most of my playing career using a pre/power setup, although it's only more recently that I've switched from a rackmount pre to a pedal pre. I'm definitely a fan of this approach overall, although as others have made clear at this point you need to do some research to ensure the preamp is going to be able to drive the power amp. At the moment I'm using a Mesa Subway DI into a Crown XLS pre and it works very well for me.

 

[agedhorse]

Also consider input sensitivity might be stated for a higher THD rated power. It may list sensitivity of 1V rms for max power, but max power might be distorting unpleasantly.

Any difference is going to be a fraction of a dB.

 

[tech21nyc]

Our rack units will easily work with most power amps. If using one of our pedal DI's you are best off with a power amp that has a .775 volt input sensitivity. The type of power amps being discussed here (Crown, QSC etc) are designed for sound reinforcement applications. They are not musical instrument amplifiers.

 

[Jim C]

Our rack units will easily work with most power amps. If using one of our pedal DI's you are best off with a power amp that has a .775 volt input sensitivity. The type of power amps being discussed here (Crown, QSC etc) are designed for sound reinforcement applications. They are not musical instrument amplifiers.

Since both brands mentioned have models with .775 inut sensitivity, why would they not work as good or better than a dedicated MI amplifier? I've found more problems using the effects return with an outboard pre with a MI amp.

 

[agedhorse]

Since both brands mentioned have models with .775 inut sensitivity, why would they not work as good or better than a dedicated MI amplifier? I've found more problems using the effects return with an outboard pre with a MI amp.

This has not been my experience, the effects returns usually have higher sensitivity which works better with many pedals.