Guitar amp- don't hurt me..

fattmann · March 2010

I'm sure I'll get a lot of crap for this, but worth asking.

I have an old Fender rack mountable 2ch head that I used for my dual 15" Bass amp cabinet that is neglected (sadly I haven't picked up my bass in two years..). Could I use that for externally amplifying my HT speakers? (have the TSI-500s in the front for those that haven't seen my ramblings in the speaker section)

Not sure on the specs of the amp other than it was a 400w head. It was a thought. Figured that you generally want clean, uncolored sound from guitar amp heads before sending to a DSP (at least that was always my impression..), that it may be suitable for HT amping use. Just trying to utilize equipment I have laying about. Going to be getting the Yamaha 765 (more than likely) at some point here for the pre-outs.

Thoughts?

halo71 · March 2010

I am not so sure how good an idea it is. I have used one of my TubeWorks rackmount guitar amps before just to test out. And was not all that impressed with the sound through some home speakers. Driving my 2 4x12 cabs its awesome though.

F1nut · March 2010

There are no dumb questions, but there are dumb answers and since I don't have clue about your question, I'm not going to be a dummy.

halo71 · March 2010

and btw....what model is this old Fender?

fattmann · March 2010

May have to lug it up to my HT rack and give it a whirl and see... Thinking about it another issue is the fact that it only has 1/4" phono in, and I think 1/4" and XLR outs on it, not sure if any signal loss going from say 1/4" to bare speaker feed...

Will have to dust it off and take a look. Googleing real quick, I think it's a Fender BXR 400, its been soo long since I've messed with it I don't remember for sure...

Thanks for the input guys, anyone else have an opinion please let me know! Even if it's to tell me I'm silly.

F1nut · March 2010

Thinking about it another issue is the fact that it only has 1/4" phono in, and I think 1/4" and XLR outs on it, not sure if any signal loss going from say 1/4" to bare speaker feed...

There are adaptors available.

comfortablycurt · March 2010

Is this a an actual amp head(with separate preamp stages and power amp stages), or just a power amp?

When you say two channels...do you mean two actual channels of amplification, or 2 channels as in clean/distortion?

Better yet...what model is it?

fattmann · March 2010

Pretty sure it's a BXR™ 400, it's at my brother's place so I can't check it right now.

Not 100% on the channels. It is an external head, with a 15 (?) band EQ on board. I also remember it having two sets of phono outs to send the high pass, and low pass cutoffs to different cabs. Quick reading it sounds like it had two 200w amps in the chassis. Don't think it had a clean/distortion "feature," I usually achieved that by cranking the gain above the volume. Thinking about all this I bet it would be a nightmare getting it dialed in and EQed properly... but again I'll stop by and grab it tomorrow night and see whats up with it.

http://webzoom.freewebs.com/lowendr/fndrdb400.jpg
http://www.gbase.com/files/store_images/gear/2029922/p1_u3agj4woq_so.jpg
http://homepages.shu.ac.uk/~eitjmh/music/fen-bxr-dual400.jpg

Almost 100% thats it..

halo71 · March 2010

The BXR400 is an unbridgeable solid state stereo amp. A bass guitar amp.

fattmann · March 2010

Well after this I'm off for the night, one last thought: if it's not practical to use for the mains (doesn't sound like it would be), could it be adapted to run my sub? (separate 12" sub currently running off a crown pre-amp and sony 2ch)

Thought I had tried that way back when, and remember it being ridiculously loud, like I couldn't turn it down, but I may have known less of what I was doing back then (yes, I only act like I do currently.. lol)

TNRabbit · March 2010

Guitar amps are GENERALLY incredibly noisy & not suitable for H/T or anything of an audiophile nature. That said, it can't hurt to try it & see what you think~

billbillw · March 2010

Guitar amps were not designed to be hifi. They were designed to have a signature sound, add certain amounts of distortion, etc. I wouldn't recommend using a guitar amp anywhere in a HiFi setup, 2-ch or home theater.

halo71 · March 2010

Well this is a bass guitar amp so its voiced a lot different than a regular 6 string guitar amp. One of the bands I once played in, the bassist had a old Carvin tube head that he used to push some big ole' subwoofers with for his home stereo. Didn't sound all that good really, that was a 2 channel setup. I thought it sounded like ****$, but he liked it.

He could use it, but I wouldn't recommend it either. Thinking if I were done with playing bass. I would stick on fleabay/Craigslist to sell it. And pick up the proper equipment.

unc2701 · March 2010

Bass amps tend to be a lot cleaner in sound than guitar amps.

There should be an effects loop return- this will bypass most the tone processing and the impedance on it will be appropriate for a home pre-amp (the instrument inputs will have an impedance appropriate for a pickup).

The effects return usually doesn't bypass any compression or reverb/chorus, so make sure you disable all those, then you should be left with a plain old SS power amp. It won't be great, and don't be surprised if it's a little noisy, but you could definitely use it as a Sub amp.

comfortablycurt · March 2010

I wouldn't use it.

Guitar/bass amps and home audio amps are entirely different animals.

The purpose of a home audio amp is to reproduce sound without coloring the signal, adding distortion...etc.

Guitar amps are designed to be able to get any kind of tone you want out of them. They're very colored sounding. Think of it this way...

The guitar amp is the device that you use, to create the tone you're trying to preserve through your home audio amp. Obviously there are several other steps in the chain there...but that's the gist of it.

Knowing that, a guitar amp is anything but "uncolored". They aren't meant to send a completely blank signal through. Even when an amp is in clean mode, the signal is still being manipulated to a great extent. Tone controls, reverb, gain, presence...it all adds it's own bit to the tonal flavor.

halo71 · March 2010

comfortablycurt wrote: »

Knowing that, a guitar amp is anything but "uncolored". They aren't meant to send a completely blank signal through. Even when an amp is in clean mode, the signal is still being manipulated to a great extent. Tone controls, reverb, gain, presence...it all adds it's own bit to the tonal flavor.

Not so true in some cases. Maybe in the case of this amp. But there are amps out there that run totally silent and do not color the signal at all. Usually running through the effects loop, as said, will bypass the preamp and gain stages all together. Leaving basically just a power amp. In my experience this has been true mostly with high end, and very expensive, boutique tube amps.

reeltrouble1 · March 2010

well, it will work and I suppose if you have nothing else its beats nothing until you can locate a proper home amplifier, there certainly are folks here who use or have used pro amps in there rigs, particularily for subwoofers.

RT1

unc2701 · March 2010

comfortablycurt wrote: »

Knowing that, a guitar amp is anything but "uncolored". They aren't meant to send a completely blank signal through. Even when an amp is in clean mode, the signal is still being manipulated to a great extent. Tone controls, reverb, gain, presence...it all adds it's own bit to the tonal flavor.

Actually if you bypass to the power section and defeat the reverb (which goes in parallel and gets mixed back in) bass amps and keyboard amps run the signal completely clean. Go check out the block diagram on a few- they add things, but not at the power stage. Now, the quality of that SS amp is questionable, but you can get a clean signal there. Oh, and you'll have to down-rate the power spec some. They'll spec the max power at no more than 1khz, so if you want a clean 20khz signal, you'll have to crank it back a bit.

Guitar amps are a slightly different creature- depends on the design. Some are just like bass amps where all the color is before the power stage, but some rely on getting their funky sound out of the power stage.

unc2701 · March 2010

OK, here you go, block diagram on page 6 (BXR200, couldn't find the BXR400):
http://www.fender.com/support/manuals/pdfs/manuals_elec/basspdf/BXR200.pdf

So take the effects loop in, bypass chorus and deltacomp (whateverthehellthatis) and you're tapped right into the poweramp.

In the manual for the BXR300:
http://www.fender.com/support/manuals/pdfs/manuals_elec/basspdf/BXR_300C.pdf
It's got the bandwidth as 20hz-20khz (sometimes the bandwidth is limited on bass amps)

Hard to say about the power spec- the one manual is definitely at 1khz, whereas the other seems to imply it's full range...

Don't get me wrong, I'm not saying that this is going to sound as good as most home amps, but you can absolutely get clean-signal power amplification out of it.

comfortablycurt · March 2010

I stand corrected.

I know much more about playing guitar than I do about effects loops/preamp stages and all that razmatazz though. Anymore I'm on a back to basics kinda theory with my guitar playing...and I play almost exclusively acoustic guitar.

So...Should I hook up my SDA's to my Mesa/Boogie Dual Rectifier!?:p:eek:

halo71 · March 2010

comfortablycurt wrote: »

So...Should I hook up my SDA's to my Mesa/Boogie Dual Rectifier!?:p:eek:

lol, No that will sound very bad. The Dual REc is a NICE amp! I used to have a Single Rec and wish I had kept it.

I have played through a Triple Rec before and didn't like it all that much.

EDIT: And I will take trades on that Kramer I got.

Whatcha got laying round?

comfortablycurt · March 2010

halo71 wrote: »

lol, No that will sound very bad. The Dual REc is a NICE amp! I used to have a Single Rec and wish I had kept it. I have played through a Triple Rec before and didn't like it all that much.

They really are nice amps. I'm thinking about picking up a Fender Twin Reverb combo though too...eventually.:D

The big problem with the Triple Rec is that it's almost overpowered for most situations. 150 tube watts in a guitar head is a lot of power...and for most situations it's really overkill. You can mod them to remove two of the 6L6's though, and tame the wattage down to 100, making it sound virtually identical to a Dual Rec.

I've got the Dual Rectifier Solo head, with a full size Rectifier 4x12 cab. Makes for an excellent sounding rig.

edit-And I'm thinking about that Kramer!!

fattmann · March 2010

Double post

fattmann · March 2010

I know its got the diagram on the top, will try to post It when I get home (still in class ugh). So If I can bypass the preamp and eq portions it would render it nearly a SS power amp that I can then either run w my 765 (when I get It..) or my crown power line two preamp?

I know several of you are shaking your heads, but if I can get it to run my sub w decent accuracy, I can then free up my 2ch Sony ta-n511 for my 500 mains... which I think would be beneficial.

unc2701 · March 2010

Yeah, get a pic of the block diagram and the i/o's. Should be able to tell from that.

unc2701 · March 2010

comfortablycurt wrote: »

I stand corrected.

I know much more about playing guitar than I do about effects loops/preamp stages and all that razmatazz though. Anymore I'm on a back to basics kinda theory with my guitar playing...and I play almost exclusively acoustic guitar.

So...Should I hook up my SDA's to my Mesa/Boogie Dual Rectifier!?:p:eek:

That would be a perfect example of a guitar amp that has a lot of flavor on the power amp side

fattmann · March 2010

Damn flash was giving me hell.

Diagram: pretty self explanatory.

Front panel: Just to the left of EQ it reads;
Crossover stereo/biamp (button)
Line Out pre/post (button)
Pot is Vol 1-10
Deltacomp B (Light)
Power (Light)
Deltacomp A (Light)
Deltacomp on/off (button)

Brother broke some knobs off, wasn't too thrilled...

Back Panel: Where the flash is: Patching In Out High/B

unc2701 · March 2010

Got it. Turn off the deltacomp, get a couple 1/4 to RCA mono adaptors and use the patch inputs. For the speaker outputs you'll have to rig some speakerwire to 1/4 plugs- don't think I've seen an adaptor for that.

fattmann · March 2010

So sub out into the Patch Low input, then Low A out to the sub with, bi-amping on? Hmm definitely a hassle.. if I ever get done with this electrical engineering (ironic...) hw I'll poke at it tonight..

fattmann · March 2010

So just hooked it up. Not too bad, not really that impressed. Went Sub out from my receiver, to Patch A in, then 1/4" to bare leads to the sub with some Liberty wire I had laying around. No discernible distortion as far as I can tell- but then again my old KLH receiver is beat, and it's a car sub...

One odd note though, it isn't very loud... I have a "SPL meter" on my HTC Hero (no I don't take it seriously, just good for comparing output levels), and the Fender read a full 7-8dbs under the Sony at the same receiver vol, and preamp level. Had to tick the preamp up about two (four digits 40 to 44, goes from infinity (60) to 0) clicks to get it at about the same level. Fender is rated at 200w RMS @ 4ohms (from what I can tell), where as the Sony is rated at 135w 8ohms. Speaker being driven is a 2ohm DVC wired in series for 4ohms. Is the fender just old and worn out?

Segway to the other note- I tried the High B input, but the front panel threw the Deltacomp light at me, which I'm assuming is clip-protection? Got no sound out of High B at all.. Assuming that channel is dead? I did get it second hand, and never used it on more than one cab. So could indicate it's on the way out.

Have a similar sound level issue with a Crown Power Line Four amp I have that matches the Crown preamp. It is ALOT quieter than my Sony. Someone mentioned that the mosfets were wearing out, but don't know much about the actual circuitry.

I don't know, sounds alright to me, but again I stress my lame receiver and sub, lol. Using the patch input seems to bypass all other controls like was theorized. Oddly the Deltacomp on/off switch does nothing, even though it throws that light at me. Will have to see what it does when I get that 765 (damn tax return..). Will run it for a few days and see what it does, definitely won't be using it for my mains, but like I said that frees up my Sony for that detail later on.

Looks like it runs for about $200-350 on a few craigslist postings. Missing a few knobs, and possibly missing a channel, figure I could only get about $80-150. Think it'd be worth hawking and buying a plate amp for my sub box?

Guitar amp- don't hurt me..

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