XPAULUSX Posted February 17, 2011 Share Posted February 17, 2011 (edited) Hey, i'm looking at getting myself a power amp. The three i am trying to decide between are. Peavey cs 800 Peavey PV 8.5C QSC USA 850 I am looking at using my VT Bass Deluxe Pedal as a pre amp however, it says in the manual that it can drive a power amp with an input sensitivity between -10db and 0db. I've had a look around and i have found the following: Peavey PV 8.5C - 0db Peavey cs 800 - +3dbv QSC USA 850??? I have a link to the QSC manual here but the only thing i can find in it is input impedence, not sensitivity, if somebody could help me out that would be great. [url="http://media.qscaudio.com/pdfs/manuals/discontinued/USA_legacy_manual.pdf"] QSC Manual[/url] Does it matter about the input sensitivity at all, will the vt deluxe be okay as a pre when paired up with these power amps? Cheers Paul Edited February 17, 2011 by XPAULUSX Quote Link to comment Share on other sites More sharing options...
dincz Posted February 17, 2011 Share Posted February 17, 2011 [quote name='XPAULUSX' post='1131485' date='Feb 17 2011, 09:09 PM']I have a link to the QSC manual here but the only thing i can find in it is input impedence, not sensitivity, if somebody could help me out that would be great.[/quote] It's listed in the specifications as 1.16 volts, which is about +1.3dBv. So you won't be able to get full power out of the amp with that pedal. Quote Link to comment Share on other sites More sharing options...
XPAULUSX Posted February 17, 2011 Author Share Posted February 17, 2011 [quote name='dincz' post='1131496' date='Feb 17 2011, 08:21 PM']It's listed in the specifications as 1.16 volts, which is about +1.3dBv. So you won't be able to get full power out of the amp with that pedal.[/quote] How much power will I lose? Is that possible to work out? Will it be that noticeable or not? Thanks Quote Link to comment Share on other sites More sharing options...
slave Posted February 18, 2011 Share Posted February 18, 2011 [quote name='XPAULUSX' post='1131687' date='Feb 18 2011, 07:14 AM']How much power will I lose? Is that possible to work out? Will it be that noticeable or not? Thanks [/quote] I've used a regular VT for years with a tube slave. The VT has quite a LOT of volume on tap - especially if you have the gain up a bit. Just make sure the amp you buy has some extra headroom and you should be okay. If the VT is incapable of driving massive volumes, the poweramp will need to be set a little louder. If you have the extra headroom, you'll be fine.... but it may increase any noise (hiss etc.) just a little. If you're still not sure, just try it out? I find I have my VT significantly set lower than unity, so I can get just the right sound with my tube slave..... Quote Link to comment Share on other sites More sharing options...
dincz Posted February 18, 2011 Share Posted February 18, 2011 [quote name='XPAULUSX' post='1131687' date='Feb 18 2011, 12:14 AM']How much power will I lose? Is that possible to work out? Will it be that noticeable or not? Thanks [/quote] According to the figures, you'll be missing out on only about 1dB. That's barely noticable and it will help you keep clear of clipping the power amp. Quote Link to comment Share on other sites More sharing options...
eddiehoffmann Posted February 18, 2011 Share Posted February 18, 2011 Slightly off topic, but I use my VT Bass as preamp with a QSC PLX1602 power amp and it's great! Only think that can beat it is a real SVT but the difference is subtle. If that's what you're looking for, go for it. You won't regret. I really don't know much about the Peavey stuff but I can say I've been using my QSC live heavily for the last 8 years (previously with the MXR M-80 as a preamp) without any problems and with with no maintenance whatsoever. I cannot think of a more reliable piece of gear. QSC rocks, man. Quote Link to comment Share on other sites More sharing options...
XPAULUSX Posted February 18, 2011 Author Share Posted February 18, 2011 [quote name='dincz' post='1131496' date='Feb 17 2011, 08:21 PM']It's listed in the specifications as 1.16 volts, which is about +1.3dBv. So you won't be able to get full power out of the amp with that pedal.[/quote] That's at 8 ohms right? Surely it will be slightly less at 4 ohms? Quote Link to comment Share on other sites More sharing options...
markstuk Posted February 18, 2011 Share Posted February 18, 2011 Nope, Still 1db :-) Quote Link to comment Share on other sites More sharing options...
XPAULUSX Posted February 18, 2011 Author Share Posted February 18, 2011 (edited) [quote name='markstuk' post='1131945' date='Feb 18 2011, 10:40 AM']Nope, Still 1db :-)[/quote] Well if 1db is only going to make and inaudible difference I may as well go for it right? Is the qsc usa 850s a good match for my cab you reckon? Also, if I ran it bridged at 4 ohms would that be overkill, or would it give me decent headroom if I'm careful? Cheers Paul Edited February 18, 2011 by XPAULUSX Quote Link to comment Share on other sites More sharing options...
markstuk Posted February 18, 2011 Share Posted February 18, 2011 What Cab do you have? Quote Link to comment Share on other sites More sharing options...
XPAULUSX Posted February 18, 2011 Author Share Posted February 18, 2011 [quote name='markstuk' post='1131968' date='Feb 18 2011, 10:52 AM']What Cab do you have?[/quote] Ampeg svt 410hlf Quote Link to comment Share on other sites More sharing options...
markstuk Posted February 18, 2011 Share Posted February 18, 2011 Which is rated at 500 W RMS? 4 Ohms... The QSC will make 800W RMS or so into 4 ohms in bridge mode so you might want to be careful with the Master volume.. The good news is that you can't quite drive the QSC 100% on the input side so that helps.. Mark Quote Link to comment Share on other sites More sharing options...
XPAULUSX Posted February 18, 2011 Author Share Posted February 18, 2011 [quote name='markstuk' post='1132015' date='Feb 18 2011, 11:20 AM']Which is rated at 500 W RMS? 4 Ohms... The QSC will make 800W RMS or so into 4 ohms in bridge mode so you might want to be careful with the Master volume.. The good news is that you can't quite drive the QSC 100% on the input side so that helps.. Mark[/quote] Yeah that's the specs for my cab. According to the specs the qsc does 1100 watts bridged at 4 ohms, will this be too much power, even if I'm carefull, I was also thinking of running my cab just off one side at 425 watts, with a view to getting another hlf in the future and running that from the other side. 425 should be enough right? for medium sized gigs. Quote Link to comment Share on other sites More sharing options...
XPAULUSX Posted February 19, 2011 Author Share Posted February 19, 2011 I've also been looking at a QSC RMX 2450. This is 750 Watts per channel at 4 ohms, this should give me a decent amount of headroom, however the input sensitivity on this amp is 1.23v (+4.0 dBu) Would this be worth getting for the extra power? Cheers. Quote Link to comment Share on other sites More sharing options...
markstuk Posted February 19, 2011 Share Posted February 19, 2011 Might be worth looking at some of the lightweight QSC's - PLX's, PL's and GX's... In terms of SPL you could gain an extra 3-4 db just by changing to a more efficient cab - bergantino or Epifani both run 410's with 103/4 db/1w/1m compared with your 410 HLF's 99 db 1w/1m Cheers Mark Quote Link to comment Share on other sites More sharing options...
XPAULUSX Posted February 19, 2011 Author Share Posted February 19, 2011 [quote name='markstuk' post='1133216' date='Feb 19 2011, 11:36 AM']Might be worth looking at some of the lightweight QSC's - PLX's, PL's and GX's...[/quote] Why is that? How do you think the QSC RMX 2450 would pair with my amp? 750watts per channel @ 4 ohms. I'd run it in parellel mode if i ever got another svt410hlf. Would 750 watts be overkill or would it give me a decent amount of headroom if again i was careful? The input sensitivity of it is 1.23v (+4.0 dBu) Surely the extra headroom i would have in stereo mode could counter balance the input sensitivity issue? Also running only one channel in stereo mode with the other channels gain control rolled off would not damage the amp right? Sorry for all the questions Paul Quote Link to comment Share on other sites More sharing options...
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