Can we have a POWER AMP thread?

[NancyJohnson]

I'm pretty happy with my front end choice of bass/processing (Thunderbirds/Sansamp RBI or Sansamp BDDI), but as the years roll on, the sheer weight of my backline is killing me...my cabinets are on castors and are manageable, but the weight of my 4U rack literally feels like it's going to yank my arm from it's socket. Recently, I've been looking at replacing my racked amplifier with a [b]Class-D [/b]power amp. The main draw is the neutrality of the output aligned with the increased power output and most importantly a drop in weight. (For the record, I run the Sansamp into the effects return of the head bypassing the pre-stage.)

I've done a bit of personal research and as of yesterday, I was leaning towards a [url="http://peavey.com/products/index.cfm/item/703/118436/IPR2%26trade%3B%26nbsp%3B2000"]Peavey IPR2/2000[/url] - not on sale here until next month. Looking at US prices and comparable amps (Crown/Yamaha/Crest etc.). I'm probably looking at a purchase price of c.£400.00, which is fine. Peavey gear seems to have a reputation for being pretty much bombproof and this amp will deliver 600w into 4ohms, weighs under 4kg and is 10" deep, so it'll fit in a shallow rack.

Yesterday, I demoed a £500 Carvin DCM2000L (550w into 4ohms) at Bassgear, Twyford and was mightily impressed. (I didn't even know Carvin outboard gear was available over here.)

So advice (and please don't muddy the water with regular amp postings...try an keep it to Class-D power amp content). What are you using as a pre-stage? How reliable is it? Problems? This isn't a vanity project; I'm certain that there's dozens (hundreds) of members here who are in the same boat as me and I'm sure we could all do with some clear advice and recommendations.

Thanks
Paul

Edited May 28, 2014 by NancyJohnson

[roonjuice]

For that kind of outlay you could go for a crown or other pro manufacturer. Onboard dsp (if u want) and more meat!

[Roland Rock]

You could have bought my Crown XTi2000 but as of yesterday, I've pulled it from the marketplace to use in my rig with a preamp (Avalon U5)
As soon as I have the rig up and running and gigged it a few times, I'll let you know my thoughts.

[Ed_S]

I used an RBI into a Crown XLS1500 for a while. Obligatory grainy phone-camera picture included..



They're great power amps, but sadly they need to be driven with more oomph than my RBI could ever put out, so whilst it was a loud rig, it was always running flat out to try and keep up. I ended up dismantling the rig, using the RBI for recording and the XLS to power the PA tops.

Guess what I'm saying is whatever you choose, run the numbers and make sure that the sensitivity of the power amp input is right to match up with the pre-amp output.

[LukeFRC]

[quote name='Ed_S' timestamp='1401089216' post='2459817']

Guess what I'm saying is whatever you choose, run the numbers and make sure that the sensitivity of the power amp input is right to match up with the pre-amp output.
[/quote]

what he said - I picked my Hellborg preamp up partly because 2x18's nice power amp needed more output than it could give

[Roland Rock]

[quote name='LukeFRC' timestamp='1401094265' post='2459858']


what he said - I picked my Hellborg preamp up partly because 2x18's nice power amp needed more output than it could give
[/quote]

You mean the Hellborg didn't have enough output for the power amp?

This compatibility is tricky to know in advance, as not many preamp manufacturers state the output levels. I had to contact Glockenklang (who were great) to ensure that my head's preamp had enough output for the Crown.
For the Avalon, I've just had to go on anecdotal web stuff where people have said that they've happily run their U5 with a Crown power amp.

Edited May 26, 2014 by Roland Rock

[LukeFRC]

[quote name='Roland Rock' timestamp='1401094940' post='2459865']
You mean the Hellborg didn't have enough output for the power amp?
[/quote] yeah.
As I'm trying to sell the hellborg I'll point out it was for a [i]specific[/i] power amp that Will had. I have no problems with it! Not sure what it was, when I was looking for an amp myself I remember reading how some of the newer class D amp need a higher input sensitivity..... actually rather than repeat half understood things I've read on forums this thread is interesting.... http://www.talkbass.com/threads/crown-xls-drivecore-amps-input-sensitivity.711228/page-2

[NancyJohnson]

[quote name='Ed_S' timestamp='1401089216' post='2459817']
I used an RBI into a Crown XLS1500 for a while.

They're great power amps, but sadly they need to be driven with more oomph than my RBI could ever put out, so whilst it was a loud rig, it was always running flat out to try and keep up.
[/quote]

Can you clarify from memory how you were using the RBI/amp together? I've heard/read so many conflicting methods of connections (jack to jack, XLR to XLR), going into the front panel RBI or the rear one. Power amp full up and control the overall output with the RBI level knob. And so on.

[Ed_S]

[quote name='NancyJohnson' timestamp='1401096132' post='2459891']
Can you clarify from memory how you were using the RBI/amp together? I've heard/read so many conflicting methods of connections (jack to jack, XLR to XLR), going into the front panel RBI or the rear one. Power amp full up and control the overall output with the RBI level knob. And so on.
[/quote]

I'm pretty sure I tried the lot, but the setup as pictured was going into the front of the RBI with the DBX in the loop and out to the XLS over XLR-XLR. Wow.. that was a lot of TLAs! The other problem I found with the RBI was that it's not the quietest (or least noise susceptible, maybe) pre-amp out there, so when I tried going jack-jack instead of XLR-XLR and putting a clean boost (MXR MicroAmp) in the middle, the electrical hum was just too prevalent.

Edit: forgot to answer the last bit - I ended up with the power amp full-up and using the level on the RBI as the master volume, even though that doesn't appear to be the case on the picture.

Edited May 26, 2014 by Ed_S

[NancyJohnson]

[quote name='Ed_S' timestamp='1401098573' post='2459930']
I'm pretty sure I tried the lot, but the setup as pictured was going into the front of the RBI with the DBX in the loop and out to the XLS over XLR-XLR. Wow.. that was a lot of TLAs! The other problem I found with the RBI was that it's not the quietest (or least noise susceptible, maybe) pre-amp out there, so when I tried going jack-jack instead of XLR-XLR and putting a clean boost (MXR MicroAmp) in the middle, the electrical hum was just too prevalent.

Edit: forgot to answer the last bit - I ended up with the power amp full-up and using the level on the RBI as the master volume, even though that doesn't appear to be the case on the picture.
[/quote]

It's been trial and error here too. I've been looking on Talkbass - consensus seems to be that the RBI doesn't seem to have any issues driving a poweramp - someone from Tech 21 posted on one thread that they recommended running the poweramp on full and using the RBI level knob to control the master volume. Interestingly, going back to my set up, I'm presently running the RBI through the effects return on an Ashdown ABM EVOIII racked head, effectively bypassing the Ashdown pre-stage and utilising just the poweramp side of the amp. I've never run the Ashdown with the master volume (or in the power amp sense, accentuator) maxxed out, so this might be worth trying too. That said, good or not, it's still going to weigh a ton and that's part of the issue for me to look for something lighter.

Personal choice of (Class-D) power amps seem to increased somewhat over the last 48 hours...Peavey IPR2/2000 (£400-ish), Carvin DCM2000L (£499) and the Crest Pro-Lite 2.0 (£549).
P

Edited May 26, 2014 by NancyJohnson

[krysh]

I use this as my ultra light and portable rig:


-handmade in germany GP Lightstone Twister (2-Channel TubeBassPreAmp)
-acoustic image focus sa 300w@8Ohm/600W@4Ohm class D poweramp

usually with my custom SAD 1/12H cab.

sounds fantastic, I never needed more volume and it is very reliable.

[JPJ]

I'm four gigs in to my pre/power amp setup and so far, all is fine! I've gone with the SWR Marcus Miller pre into a QSC PLX1602 to drive (in bridge mode) my 6x10 mini-fridge.

Because the mini-fridge is 'only' 1,000w 4 ohms nominal, and the QSC puts out 1,600w @ 4 ohms, I run it with the QSC on about half with the SWR master acting as er the master!

So far, this rig has done two pub gigs, one outside gig (pub beer garden, no PA support) and a large bike rally (with PA support) and has handled them with ease.

Weight-wise, racked up together they are a one-handed carry (as against the SM1500 that was a two man carry). Also, the amp appears to handle transients and low B stuff better than the SM, it's more immediate and less of a delay waiting for the note to develop.

[Owen]

One of the great pleasures in life is a proper power stage. Endless headroom and instant transient delivery is totally where it is at. I used to run 3Kw bridged into an Eden 410XLT. Every note was a joy.

[Roland Rock]

[quote name='owen' timestamp='1401140841' post='2460584']
One of the great pleasures in life is a proper power stage. Endless headroom and instant transient delivery is totally where it is at. I used to run 3Kw bridged into an Eden 410XLT. Every note was a joy.
[/quote]

Do you still have your Avalon U5 Owen? I don't suppose you know the output voltage?

[Owen]

[quote name='Roland Rock' timestamp='1401142123' post='2460601']
Do you still have your Avalon U5 Owen? I don't suppose you know the output voltage?
[/quote]

I'm afraid that the U5 went in the great preamp cull of 2013 It was a lovely piece of kit, but I have no idea what it put out. Sorry.

Their website says

[b]Maximum Output Level (Class A):[/b] +30dBu DC coupled, balanced 600 ohms (mic and line out)

but I am blissfully unaware of what that means

[dincz]

[quote name='owen' timestamp='1401176708' post='2460724']Their website says

[b]Maximum Output Level (Class A):[/b] +30dBu DC coupled, balanced 600 ohms (mic and line out)

but I am blissfully unaware of what that means
[/quote]

That means it will drive any power amp with absolute ease

[Roland Rock]

That's good to know! Thanks chaps :-)

[Ghost_Bass]

I've already posted this somewere around here but here ti goes again.
I recently turned to a pre+power config for the bigger gigs and got myself a Alembic F1-X and a KMT DC-5 power amp. The amp is feeding the S12 with 1kW, bridged at 4 ohms. In total my rack weights a bit less than 15kg.

The amp is class-H so i have all the bottom end but without the size and weight of a class-AB amp. Sounds lovely to my ears, it's a shame that i can't use it more often but this is completely overkill for the majority of pub gigs i'm doing at the moment. Here's a pic (again):

[krysh]

[quote name='Ghost_Bass' timestamp='1401189723' post='2460904']
I've already posted this somewere around here but here ti goes again.
I recently turned to a pre+power config for the bigger gigs and got myself a Alembic F1-X and a KMT DC-5 power amp. The amp is feeding the S12 with 1kW, bridged at 4 ohms. In total my rack weights a bit less than 15kg.

The amp is class-H so i have all the bottom end but without the size and weight of a class-AB amp. Sounds lovely to my ears, it's a shame that i can't use it more often but this is completely overkill for the majority of pub gigs i'm doing at the moment. Here's a pic (again):


[/quote]

really nice!

[peted]

I run my Line6 POD X3 Live into a W-Audio Horizon 600 (http://www.decks.co.uk/products/amps/W_Audio/Horizon_600#.U4gzBb1wbqA). I only use the left channel, I don't like being very loud on stage, and I run it at about 4/10 at most. I think these amps are a bit difficult to track down now as my guitarist had to wait for his to come into stock and be delivered.

[Roland Rock]

Looking forward to getting to grips with this rig. If this doesn't satisfy my 'ultra clean' quest, nothing will

[dincz]

[quote name='LukeFRC' timestamp='1401095527' post='2459875']some of the newer class D amp need a higher input sensitivity[/quote]

Maybe pedantic, but some power amps need a high input [i][b]level [/b][/i]because they have low input [i][b]sensitivity. [/b][/i]Not trying to be snarky but this can lead to confusion.

[NancyJohnson]

[quote name='Ed_S' timestamp='1401089216' post='2459817']
I used an RBI into a Crown XLS1500 for a while. Obligatory grainy phone-camera picture included..



They're great power amps, but sadly they need to be driven with more oomph than my RBI could ever put out, so whilst it was a loud rig, it was always running flat out to try and keep up. I ended up dismantling the rig, using the RBI for recording and the XLS to power the PA tops.

Guess what I'm saying is whatever you choose, run the numbers and make sure that the sensitivity of the power amp input is right to match up with the pre-amp output.
[/quote]

One of the options I'm looking at is/was a Crown Drivecore XLS1500, with the Sansamp as the front end. I got an email from Harman who say my cabinets daisy-chained will be 1500w/4ohms and the XLS1500 (running in bridged mono) is the minimum I should be using to drive the speakers to their best capacity. Apparently (this was inferred by Harman), it's OK to run a higher output amp (XLS2000/2500) for more headroom...official specs say these two amps will deliver 2.1KW and 2.4KW respectively in bridged-mono, which frankly is overkill.

The more I read, the more confused I'm getting. I just want a lightweight amp, that delivers a decent amount of volume when required. Our (new) drummer is a very hard hitter and while my guitarist is (only) using a 120w Bugera 333XL head into one of their 4x12s and it's painful loud. I guess I just want to buy something that is fit for purpose. I mean what's the point of upgrading if things aren't right when you do?

P

Edited May 30, 2014 by NancyJohnson

[Guest bassman7755]

[quote name='JPJ' timestamp='1401105611' post='2460044']
Because the mini-fridge is 'only' 1,000w 4 ohms nominal, and the QSC puts out 1,600w @ 4 ohms, I run it with the QSC on about half with the SWR master acting as er the master!
[/quote]

Worth remembering that the master volume setting doesn't intrinsically limit the power of the amp, the amp can still deliver its full power if it gets a hot enough signal from the preamp.

[Monckyman]

I have a Peavey IPR1600 and it's bloody light.
Sound pretty good too. I used to use it with an Ampeg pre.