#1
Hey everyone,
This is my first post on UG though I've used this forum for gear answers for years!

I've been a guitarist for 20 years. Always used a traditional combo amp+pedals setup. However I'm exploring building a rack in order to increase my tone options more easily. I have a couple of differing styles I dabble in with different groups and my current rig is a little too one-dimensional. Ideally, the rack rig I want to build will be for playing electric blues (Clapton/Cream), 70's rock (Rush, T. Rex), 90s alternative (Smashing Pumpkins), and modern electric blues (SRV, Black Crowes).

I realize multiple preamps will be required to cover all this ground, but I'll cross that bridge when I come to it...

Now my initial struggle is understanding how much output I need in a power amp. All of the amps I've owned before have been in the 30W range and that has always been great for the venues I play and allow me to get a good "sweet spot" tone without blowing the audience away. But the overwhelming majority of rack-mounted power amps I find are 50W per side, minimum. Some rate as high as 300W!

Why are there no smaller wattage power amps for rack applications? Is there something I'm missing. Is there a reason higher wattage is required in a rack system? Enlighten me.
#2
Quote by joshhorne

Now my initial struggle is understanding how much output I need in a power amp. All of the amps I've owned before have been in the 30W range and that has always been great for the venues I play and allow me to get a good "sweet spot" tone without blowing the audience away. But the overwhelming majority of rack-mounted power amps I find are 50W per side, minimum. Some rate as high as 300W!

Why are there no smaller wattage power amps for rack applications? Is there something I'm missing. Is there a reason higher wattage is required in a rack system? Enlighten me.


Well firstly, most* modern power amps are solid state, so there isn't as much of a sweet spot in the power section - it's fairly linearly good sounding,
This means that you could have a 50 or 500 watt power amp and at the same kinda output, it should sound more or less the same.
You can always turn it down!

Second, generally - and this is a big generalisation - most people who use large racks play at big gigs. Power amp makers cater to the audience that needs them most. There's a reason why bass practice amps are normally <100w and why professional grade stuff can be 1000w+.

Basically, find a power amp which has the cab outs, inputs and other features you need first, then if it has more power than you need, just keep the volume low.

That's what I'd do anyway

*there's obviously a large amount of valve rack amps out there, but SS seems more common due to higher power, more efficiency, price and of course reliability.
#3
Thanks, CorrosionMedia, for your response. I'd have to do more research then bc so far I've always been an all-tube kinda guy.

And I understand that racks are geared toward larger venues, etc. However I need one, not for crazy volume per se, but for versatility. Having a rack with a couple different preamps will be better for me than having to buy two or three different combo amps or heads.
#4
Quote by joshhorne
Now my initial struggle is understanding how much output I need in a power amp.


you have quite a number of options when using a rack setup, you could use a tube power amp (usually 50 too 100 watts), you could use a solid state power amp (usually 100+ watts), you could just run your setup into a cabinet emulator and then run it to the PA (you can do this with or without a power amp).

you could use a guitar cabinet for monitoring (which would usually require less than 200 watts). you could use a more flat response 2-way or 3 way speaker system for monitoring, these could be either self powered and require no power amp or they could be passive and require a power amp (usually they require less than 500 watts depending on you cabinet choice). then again you can bypass a speaker cab and just run it into an emulator (emulators, like a two notes torpedo, usually don't handle much more than about 100 watts if you are running a power amp into it), you could use on stage monitors for your monitoring at that point.

but this question of 'how many watts do i need' will pretty much be answered by: "What type of cabinet setup will you be playing out of".

Quote by joshhorne
All of the amps I've owned before have been in the 30W range and that has always been great for the venues I play and allow me to get a good "sweet spot" tone without blowing the audience away. But the overwhelming majority of rack-mounted power amps I find are 50W per side, minimum. Some rate as high as 300W!


this was pretty much already answered above. most power amps are solid state, so they have such high ratings so that you don't need to crank them out and they can operate in their linear range. plus many power amps are used with speaker systems that have a much lower sensitivity (they aren't as loud as guitar speakers), so more power is needed.

besides, people generally buy power amps to handle whatever amplification they need, there is just not much market for underpowered power amps. if you don't need all of that 300 watts, then just run the amp on 2.
punk isn't dead, it's always smelled that way.

"A perfection of means, and confusion of aims, seems to be our main problem."
-ae
#5
A good tube guitar amp only needs around 30w to get the job done. Rack amps are mostly designed for PA, keys, and bass which need a lot more power. No one buys 30w rack amps so no one makes them. Supply and demand.

The volume control works so just use as much as you need. I am a reformed rack amp guitarist. I missed the warmth and connectedness with a tube amp and also got tired of dragging all that stuff around when my roadies went on to grad school.

Another option today is to use a Digital Multi Effects pedal for versatility and a powered wedge for sound. I have used one of these to good effect driven by a Vox Tonelab LE.

http://www.electrovoice.com/product.php?id=2583

It might give you the versatility you need in a very portable setup.
"Your sound is in your hands as much as anything. It's the way you pick, and the way you hold the guitar, more than it is the amp or the guitar you use." -- Stevie Ray Vaughan

"Anybody can play. The note is only 20 percent. The attitude of the motherfucker who plays it is 80 percent." -- Miles Davis

Guthrie on tone: https://www.youtube.com/watch?v=zmohdG9lLqY
Last edited by Cajundaddy at Jun 14, 2015,
#6
Thanks for your responses. Finding the right preamp will probably be just as challenging!
#7
maybe i'm confused but it sounds like you just need a good amp with a few pedals to get what you need. i mean much of what you mentioned isn't that different tone wise. a good clean channel and a good dirt channel plus an overdrive, a muff for pumkins and perhaps a delay and a wha and seems ike you'd be good to go. what do you really need a rack system for?
#10
Sounds to me like you need a tube power amp and preamp combo.
I think tube power is the way to go and for one would head in that direction. I've been there myself and I just couldn't bear using PA amps, at the time I tried about 10 brands and they were all pretty much lifeless and the sound lacked something which I found with the Peavey Classic 50/50 since I couldn't afford the Mesa 2:90 that I borrowed from a friend.


As far as power amps currently made I know of these two:
http://carvinamplifiers.com/products/ts100-100w-tube-power-amp
http://mesaboogie.com/amplifiers/electric/all-tube-stereo-power-amps/index.html

Out of these two the Mesa sounds better IMO. The Mesa is livelier as the Carvin is more traditional clean. They both sound good.

As far as rack mount preamps you have these that I know sound good:
http://www.tech21nyc.com/products/sansamp/psa1_1.html

The PSA-1 is all analog signal path, digital switching, very versatile and covers pretty much any sound you can think of.
I use that (PSA-1 earlier version) through a Peavey Classic 50/50 power amp, which is pretty much a knockoff of the Mesa power amps. Sounds fantastic and you can use digital switching with a midi pedal, in my case I do 4 cable method through Boss GT-10, which I use for all other effects but preamp dirt. You can look into the GT-100 as it does the same thing and essentially the Boss unit becomes the switcher for the preamp patches (you can have 100 different patches) and the effects settings. What is cool about this is that you can move your preamp anywhere you want in the signal chain and it has two built in noise gates that you can engage for silent operation.

Some other preamps I like:
Mesa Triaxis - beyond fantastic as well, think of all Mesa sounds in one.
http://mesaboogie.com/amplifiers/electric/tube-pre-amplifiers/index.html

Now they also have a recording preamp which is 2 Mesa channels if I am not mistaken, that should probably be good as well but haven't tried it.

There are other preamp options, Rocktron VooduValve and Widowmaker, I've tried the Vooduvalve and it is a nice clean to AC/DC crunch type of preamp, I need more distortion on tap but I liked it:
http://www.rocktron.com/preamps.html


Marshall JMP-1 (now sadly only found used)- basically the "Triaxis" of Marshall preamps, covered every Marshall sound there was up to that point, so pretty much any earlier Marshall up to JCM2000. Don't know why they stopped them from production as there were quite a few pro bands touring with them, Def Leppard, Judas Priest, etc. This one sounds fantastic as well:
http://www.music123.com/amplifiers-effects/marshall-jmp-1-tube-midi-guitar-preamp

Some other good sounding preamp options:
http://www.voodoolab.com/preamp.htm


As far as switching there are a few digital options from Voodoolabs, Rocktron and analog switching options by the same two above plus Octaswitch from Carl Martin...not sure what else but you can basically run your rig and pedals all with one floor switch, with something like Ground Control Pro and GCX, I actually bought that but ended up ditching my pedals...well, leaving them at home, for the Boss GT-10.

Back to your original question - 100 watt power amp (tube) will be more than enough. I still can't be convinced that it doesn't sound better than the solid state power amps, especially if you're running pedals and analog preamps. On digital multifx...I don't know, still hear a bit of an extra something that the tube provides but I guess is not as much as with the other setup.
Last edited by diabolical at Jun 16, 2015,
#11
Quote by joshhorne
Man, yeah! That could be the ticket!


No.

Money down the drain.

Don't determine your power amp needs based on what you've purchased for guitar before.

This was a fun read, because I've been there before, done that, but a while back.

I (as an all-tube guy) picked up a Carvin Quad-X, a Mesa Triaxis and a Carvin TS-100 power amp. The latter is a 50W/50W 2-unit rack amp that will run EL34 or 6L6 power tubes. The Quad-X has nine 12 AX-7 tubes, the Triaxis about five, and the TS-100 another three or so. Still have these. If I were seriously hunting a tube preamp these days it would be an Egnater M4 (four "personality" modules - interchangeable - give you your choice of amp sounds). Lots more 12AX7 tubes (sorry, ECC83s these days). Ran it all into 4x12s.

Heavy (weight) and delicate setup. The power amp weighs about 25 lbs by itself, but it's outstanding. $550 or thereabouts.

I eventually changed out the speaker cabinets, moving to two stereo 2x12s that used 400W 12" speakers and a pair of 1165N-series tweeters in a ported 3.5 cubic foot cabinet. I swapped out the Carvin TS-100 tube power amp for a 1500W Carvin solid state unit that only weighs 9 lbs. The setup gave me bottom end that I couldn't come CLOSE to reaching with the 4x12s, and the solid state power amp is a LOT less delicate. And it fit in a Honda Civic. Now we're getting somewhere.

It wasn't long before I was swapping out the tube preamps (do you realize what it costs to retube those suckers?) for a Line6 Pod. At some point there's been an Axe-FX Ultra in that spot as well, but honestly that was too expensive a rig to take out. The Pod was enormously versatile, lighter (lots) than the tube preamps, less delicate, and I could run just an ethernet cable out to a relatively inexpensive line 6 pedalboard.

So now the brain unit was lighter, far more powerful and far more versatile. I was running NO AC power to the front of the stage and no expensive guitar cables (this was about where I switched to a wireless, too).

The cabinets were still seriously heavy (overbuilt and hosed down with LineX pickup truck bedliner), with huge magnets on the Eminence Delta ProA speakers. Something on the order of 75-80 lbs each.

About this time I was being coerced into playing bass (who, ME? I don't know nuttin' about no steeenkeeng *bass*!) for a project, and I was getting back into keyboards (Korg Kronos, etc.). I wanted ONE set of speakers that could handle anything, and I decided I wanted them light.

At this point I have a pair of fEARful 15/6/1's. Neo-based speakers, specially braced cabinets designed specifically for these speakers, and extremely wide range and bottom end power handling. No farting out. Each cabinet will handle 800-900W. Pretty much perfect for the Carvin DCM1540L power amp's specs. And each cabinet is just under 50 lbs.
Shortly after, I bought a pair of fEARless F115s (slightly smaller, slightly lighter, with the same basic design and a cabinet that will allow me to use it as a floor wedge in addition to normal stacking, etc. Same basic speaker setup, same essential design, same power handling. I added a Carvin HD1500 to the mix, and a BX1500 bass amp and a Bass Pod XT and a Two Notes Torpedo C.A.B. (this, combined with the Pod HD, works at a whole 'nother level by providing IR-based cabinet sims and *power amp sims*).

Not all that stuff goes out on a standard gig, obviously.

In fact, a standard gig might include just the Pod+C.A.B., power amp, FBV Shortboard and one F115 cabinet. The HD1500 puts out 900W, bridged, mono, into an 8 ohm load (one cabinet). Perfect. If I'm switching between keys and guitar, a mixer goes along.

If I need more output (small outdoor gig), I just add another cabinet. The HD1500 puts out 1500W, bridged, mono, into a 4 ohm load (two cabinets). And if I need LOTS more, the second power amp and pair of speakers joins the party. Beyond that, I'm into the PA and just using one f115 cabinet for a personal or band monitor.
Last edited by dspellman at Jun 16, 2015,
#12
In my case power amp retube (about $150) was every 3 years and that is after heavy gigging. I opted for solid state analog preamp (PSA-1) after testing it out vs my and other rigs at the time and that has held solid for 10+ years. The cabs are the cabs. There was a bit of loss of signal when I went to the Boss GT-10 from analog pedals, but I managed to dial it back in and the switching was definitely worth it, which also shortened the setup time and no pedal power to go awry in the badly electrified pubs in Houston.

@dspellman - you're probably talking class D power amp? I don't know, not quite convinced on that, but that's why we have different types of gear
#13
Quote by dspellman
No.

Money down the drain.

Don't determine your power amp needs based on what you've purchased for guitar before.

This was a fun read, because I've been there before, done that, but a while back.

I (as an all-tube guy) picked up a Carvin Quad-X, a Mesa Triaxis and a Carvin TS-100 power amp. The latter is a 50W/50W 2-unit rack amp that will run EL34 or 6L6 power tubes. The Quad-X has nine 12 AX-7 tubes, the Triaxis about five, and the TS-100 another three or so. Still have these. If I were seriously hunting a tube preamp these days it would be an Egnater M4 (four "personality" modules - interchangeable - give you your choice of amp sounds). Lots more 12AX7 tubes (sorry, ECC83s these days). Ran it all into 4x12s.

Heavy (weight) and delicate setup. The power amp weighs about 25 lbs by itself, but it's outstanding. $550 or thereabouts.

I eventually changed out the speaker cabinets, moving to two stereo 2x12s that used 400W 12" speakers and a pair of 1165N-series tweeters in a ported 3.5 cubic foot cabinet. I swapped out the Carvin TS-100 tube power amp for a 1500W Carvin solid state unit that only weighs 9 lbs. The setup gave me bottom end that I couldn't come CLOSE to reaching with the 4x12s, and the solid state power amp is a LOT less delicate. And it fit in a Honda Civic. Now we're getting somewhere.

It wasn't long before I was swapping out the tube preamps (do you realize what it costs to retube those suckers?) for a Line6 Pod. At some point there's been an Axe-FX Ultra in that spot as well, but honestly that was too expensive a rig to take out. The Pod was enormously versatile, lighter (lots) than the tube preamps, less delicate, and I could run just an ethernet cable out to a relatively inexpensive line 6 pedalboard.

So now the brain unit was lighter, far more powerful and far more versatile. I was running NO AC power to the front of the stage and no expensive guitar cables (this was about where I switched to a wireless, too).

The cabinets were still seriously heavy (overbuilt and hosed down with LineX pickup truck bedliner), with huge magnets on the Eminence Delta ProA speakers. Something on the order of 75-80 lbs each.

About this time I was being coerced into playing bass (who, ME? I don't know nuttin' about no steeenkeeng *bass*!) for a project, and I was getting back into keyboards (Korg Kronos, etc.). I wanted ONE set of speakers that could handle anything, and I decided I wanted them light.

At this point I have a pair of fEARful 15/6/1's. Neo-based speakers, specially braced cabinets designed specifically for these speakers, and extremely wide range and bottom end power handling. No farting out. Each cabinet will handle 800-900W. Pretty much perfect for the Carvin DCM1540L power amp's specs. And each cabinet is just under 50 lbs.
Shortly after, I bought a pair of fEARless F115s (slightly smaller, slightly lighter, with the same basic design and a cabinet that will allow me to use it as a floor wedge in addition to normal stacking, etc. Same basic speaker setup, same essential design, same power handling. I added a Carvin HD1500 to the mix, and a BX1500 bass amp and a Bass Pod XT and a Two Notes Torpedo C.A.B. (this, combined with the Pod HD, works at a whole 'nother level by providing IR-based cabinet sims and *power amp sims*).

Not all that stuff goes out on a standard gig, obviously.

In fact, a standard gig might include just the Pod+C.A.B., power amp, FBV Shortboard and one F115 cabinet. The HD1500 puts out 900W, bridged, mono, into an 8 ohm load (one cabinet). Perfect. If I'm switching between keys and guitar, a mixer goes along.

If I need more output (small outdoor gig), I just add another cabinet. The HD1500 puts out 1500W, bridged, mono, into a 4 ohm load (two cabinets). And if I need LOTS more, the second power amp and pair of speakers joins the party. Beyond that, I'm into the PA and just using one f115 cabinet for a personal or band monitor.


So much good info to consider. I know tube amps are heavier but I have never found them to be more "delicate." I have owned numerous tube amps over the past 20 years. And I have never had a tube go out on me. Are the rack ones more delicate somehow?

I recognize the benefits of solid-state. However any solid-state amp I have ever played just felt lifeless.
#14
Quote by joshhorne
I know tube amps are heavier but I have never found them to be more "delicate." I have owned numerous tube amps over the past 20 years. And I have never had a tube go out on me. Are the rack ones more delicate somehow?

I recognize the benefits of solid-state. However any solid-state amp I have ever played just felt lifeless.


Totally

I've actually had more solid state fail on me and get repairs than tube amps. I gigged about 8 years with a Peavey 50/50 Classic power amp and had to retube after 8 years.
3 years I gigged with Marshall Valvestate - it was in the shop twice. Same thing with my Peavey bass amp, about 3 years of constant gigging and has been in the shop twice.
About 3 years of gigging and recording on Marshall JCM900 bought used, never retubed as it was done when I purchased, no issues. The rest of my tube amps: Ashdown FA-60, Laney LC15, Laney AOR50, Orange TT, Marshall Class 5 - no issues whatsoever. Had the Laney for a very long time. The Peavey Windsor head I had as backup popped up internal breaker during warranty, but I got that amp for $200, so it kinda comes with the territory. So, if you look at my track record, I've had to repair more solid state amps than tube amps.
#15
Thank you everyone! Please continue with the great feedback!

Let me also pose this question: pretty much all power amps can run stereo or mono. And, as an example, the Mesa 50/50 runs 50W per side in stereo or 100W mono. But it possible to run just one side? In other words, if I don't care about running stereo, do I have to run at te full 100W? Or can I run off one side at 50W?
Hopefully that question doesn't sound too ignorant. I really am still learning this stuff. Thanks!