Can I go directly into a Power Amp?

[32Hz]

I just got my [i]'forever bass'[/i] a '96 USA deluxe fender jazz 5 string with John East j-retro preamp (with passive option switch). This is my first [i]'grown ups'[/i] bass and I love it. I am finding the the j-retro pre-amp just amazing, no, hold on, it's better than that! it's phenominal. Anyway, I play through an Alesis compressor in Genz Benz 1200 head into Ampeg 4 x 10. I'm setting everything on the Genz flat, and use the j-retro to form my sound. So, everything flat on the Genz, why do I need it? So my question is, does anyone out there do away with the pre-amp and rely on the guitars internal pre-amp and go straight into a decent power amp? Or am I being stupid? What would be a good mono power amp (I want at least 500W into 4Ohms)?

[icastle]

Nice idea, but it won't work.
Even though the Genz is set to 'flat', it's still amplifying the signal from the bass so that the power amp section is able to get a signal large enough to work with.

[gjones]

This question has occurred to me too as I have a j-retro fitted to my Jazz. But I also have passive basses so I need the pre on my ABM. I'm assuming in theory if all you ever use is your jazz with a preamp you could use a power amp. Not sure what the benefit would be though if you already have a Genz Benz?

Edited April 1, 2012 by gjones

[xgsjx]

Yes, you could go directly into a power amp, but the point of having an EQ section is that each venue is different & may need a tweak here & there to suit the acoustics.

Most folk on here set their EQ flat.

Other thing is that your GB will have it's own EQ settings at "flat" & won't really be flat at all.
I see icastle has just said that! I can't type fast enough!

[gjones]

I did a quick google and I came up with the Crest CA9 which is a stereo power amp with 600w per channel which can be used for bass. Only one small down side though...................it weighs 52lbs.

I think I'll stick with my ABM.

Edit : And you do need a outboard preamp too

Edited April 1, 2012 by gjones

[hubrad]

Well worth a try IMHO.. a mate of mine gave up on 'normal' bass amps for quite a while since he was using only active basses at the time, Yamaha TRB5 IIRC.
His sound was most definitely not lacking in anything.. 'Rockin' Mal' is summat of a legend around Bradford!

[longtimefred]

just like everyone else has said really. you may be putting your eq on the amp flat but its still putting out the amps own tone as well as your bass. I thought the same with my Sandberg's pre amp but when i did a DI into my recording rig from the bass, it sounded very sterile and lifeless. Ran it through the pre amp of my V4 and it sprung to life. I wouldnt underestimate what your amp is actually doing.

[32Hz]

Thanks for all your input guys, I might just borrow something and give it blast. At the end of the day I guess I'm just trying to create a clean, un-coloured sound path so as to let the bass do the talking. I come from a regular guitar playing background and always love my US strat playing crystal clear through a good tube amp (with a touch of reverb), Generally I don't do FX. Keep your input coming guys. Cheers. Tony.

[xgsjx]

[quote name='32Hz' timestamp='1333310462' post='1599946']
At the end of the day I guess I'm just trying to create a clean, un-coloured sound path so as to let the bass do the talking. I come from a regular guitar playing background and always love my US strat playing crystal clear through a good tube amp (with a touch of reverb), Generally I don't do FX. Keep your input coming guys. Cheers. Tony.
[/quote]

But that "colour" is what gives you that tone. Like your Strat through the "Tube amp", with or without reverb, it's getting coloured to create the tone that you like.
Even through a power amp, it's gonna colour the tone to an extent or like longtimefred says, might sound a bit sterile.

[JTUK]

Not enough signal into the power amp to work

[Prime_BASS]

[quote name='JTUK' timestamp='1333349326' post='1600225']
Not enough signal into the power amp to work
[/quote]

You'll just find the master volume being closer to maximum to get a good SPL rather than for example half way round the knob to get a good SPL. You loose headroom, but thats why you get a power amp with lots of power on tap.

Personally my rig is there for on stage monitoring and changing the EQ to suit the room, the bass is EQ'd in a isolated situation and compared to the DI sound using the John East inside, as 90% of the time I'm going to the FOH desk anyway.

If you like the sound you are currently getting (weather it's set flat or not) then there is no point changing, unless you find it really isn't working for you.

[bertbass]

You'll still need a preamp to get the level up to a usable, well level. In an emergency, I once used a graphic eq pedal into a power amp and was surprised at how good the sound was and had plenty of volume.

[Mr. Foxen]

Totally depends on the input sensitivity of the power amp, and the output voltage your preamp puts out. It might even have an internal adjustment.. Some power amps can reach full power with really low signal. Check the power amp specs for a input sensitivity, which will be a voltage, much less that 1v and you have a change, but a preamp is going to be much easier.

[xgsjx]

Passive mode, I can see a problem. I've used my active bass direct to a power amp a few times in the past & it's had the volume I needed for gigging.
It is better with a pre in front though.

[markstuk]

As other folk say it's all about power amp input sensitivity.. My QSC has a input sensitivity 1.4 V and needs a preamp to get it to gigging levels even with an Active bass... Some power amps have adjustable input sensitivity, but they are usually designed to run at line levels..

[leftybassman392]

As others have said, aside from the risk of signal matching issues any half decent preamp is doing much more than amplifying the signal, and for most people is an essential element in the sound. I'm not sure there's any such thing as a clean, neutral amplification chain - especially not if you start talking about valve guitar amps. Phil Jones would probably disagree, but even HiFi amps aren't completely linear.

If your heart's set on it then by all means..... but I don't understand why you would have such a nice amp and not want to use it (even after reading your post - twice).

[fretmeister]

Depends on the bass. Some have monster output and have plenty of juice to run into a power amp, some don't.

The issue will be tone.

Of course you could always run a pre-amp pedal like a Tech 21 VT Bass pedal into a power amp. But most poweramps weigh more than your Genz anyway.

[icastle]

[quote name='32Hz' timestamp='1333310462' post='1599946']
I come from a regular guitar playing background and always love my US strat playing crystal clear through a good tube amp (with a touch of reverb)[/quote]

...and that 'good tube amp' has a pre-amp in the same way that your Genz Benz has.

I suppose the really obvious question has to be... what don't you like about the sound you've already got?

[Dood]

For info, i used to plug my Tobias 6er directly in to an Alesis 3630 then directly in to a 450w power amp and then out to a Hartke 4.5xl many years ago. I used the gain control on the Alesis to boost the bass signal up to line level so the power amp received a strong enough signal. Bass and Treble control came from the bass alone. Worked a treat for me.

[paul_5]

[quote name='fretmeister' timestamp='1333483354' post='1602460']
Of course you could always run a pre-amp pedal like a Tech 21 VT Bass pedal into a power amp. But most poweramps weigh more than your Genz anyway.
[/quote]

+1, I've got East pre's on both of my Jazzes and use a Sansamp BDDI between the basses and a hulking big Ampeg SVP1500 to drive a Hydrive 4x10. Great sound. Heavy though...

[The Dark Lord]

You CAN go straight into a power amp - even with a passive bass like a Precision. I've done it a couple of times. You'll get surprisingly low volume though, even if you a big powerful amp. Active basses are a bit different. They interact with power amp somehow .... and hey presto, you get power somewhere akin to what you'd expect from the amp.

I stopped doing it, as although my P bass is the ultimate in tone heaven, you do need to be able to tweak an EQ. Best to get a bass amp for that.

[leftybassman392]

Thinking about it, why not bypass the Genz' preamp and plug straight into the effects return? You'll still need to think about boosting the signal to somewhere near line level though...

[32Hz]

Glad I started some this thread, some really interesting in-put coming from you all. At the end of the day, I'm a bit of a novice at this. I'm 54 yo, always a regular guitar player, latterly a bassist. I have two claims to fame. [b]1) [/b]I had lunch with HM The Queen in 1992. [b]2)[/b] I once jammed with Mark Knopfler when he was still an English teacher at Loughton College[i] (yes, I'm that old)[/i]. Played since age of 8, first stage performance at 11 yo [i](strumming Edelweiss to 200 kids and parents)[/i]. Always admired Mark King with his percussive style and punchy, trebley sound. So I guess roll that all up and I have trouble with a boomy, shapeless and characterless sound. I think I've found the answer in my new (1996) Fender Jazz with j-retro preamp. My though process is/was 'why do I need this GB monster with 18 knobs and 9 switches[i] (not counting the back or foot switch)[/i] when I'm never likely to use any of them'. Also, my 1982 Pioneer Hi-Fi amp [i](yes I bought it new and still going strong)[/i] has a 'By-pass' selector, to by-pass all the knobs, bells and whistles. But I'm probably missing the point somewhere. Oh, and (BTW) just got in from rehearsal with my 80's covers band. Been using studio bass combo.. an Ashdown something or other, and it too had an EQ bypass. I discovered it when, thinking the sound was a bit boomey, I tried winding down the lows and low mids to no avail. Thought the thing was busted. Then I found this little EQ push button depressed. And this was after I had wound the j-retro bass EQ all the way down to naught. So, perhaps I am barking up the wrong tree here. It's probably true.. I need the amp EQ to set me up for the venue, and my j-retro to set 'my' sound. Keep it coming chaps.

[32Hz]

Thanks Paul_5, I just viewed [url="http://www.youtube.com/watch?v=D_56iFr402U"]http://www.youtube.com/watch?v=D_56iFr402U[/url] this does everything the j-retro does (except the overdrive and I don't want that anyway), so this is whole point. Are you using the BDDI, just to up the output voltage? or are you using it to shape your sound. If so why is the j-retro so valuable. T.

[Mr. Foxen]

[quote name='32Hz' timestamp='1333494632' post='1602645']
Glad I started some this thread, some really interesting in-put coming from you all. At the end of the day, I'm a bit of a novice at this. I'm 54 yo, always a regular guitar player, latterly a bassist. I have two claims to fame. [b]1) [/b]I had lunch with HM The Queen in 1992. [b]2)[/b] I once jammed with Mark Knopfler when he was still an English teacher at Loughton College[i] (yes, I'm that old)[/i]. Played since age of 8, first stage performance at 11 yo [i](strumming Edelweiss to 200 kids and parents)[/i]. Always admired Mark King with his percussive style and punchy, trebley sound. So I guess roll that all up and I have trouble with a boomy, shapeless and characterless sound. I think I've found the answer in my new (1996) Fender Jazz with j-retro preamp. My though process is/was 'why do I need this GB monster with 18 knobs and 9 switches[i] (not counting the back or foot switch)[/i] when I'm never likely to use any of them'. Also, my 1982 Pioneer Hi-Fi amp [i](yes I bought it new and still going strong)[/i] has a 'By-pass' selector, to by-pass all the knobs, bells and whistles. But I'm probably missing the point somewhere. Oh, and (BTW) just got in from rehearsal with my 80's covers band. Been using studio bass combo.. an Ashdown something or other, and it too had an EQ bypass. I discovered it when, thinking the sound was a bit boomey, I tried winding down the lows and low mids to no avail. Thought the thing was busted. Then I found this little EQ push button depressed. And this was after I had wound the j-retro bass EQ all the way down to naught. So, perhaps I am barking up the wrong tree here. It's probably true.. I need the amp EQ to set me up for the venue, and my j-retro to set 'my' sound. Keep it coming chaps.
[/quote]

Sounds a bunch like you need a more transparent cab. That is totally going to be the weak point.