Ste69 Posted June 12, 2007 Share Posted June 12, 2007 Would it be safe and possible to bridge a normal PA amp into a Stereo Guitar Cab? Link to comment Share on other sites More sharing options...
Ynot Posted June 12, 2007 Share Posted June 12, 2007 Would it be safe and possible to bridge a normal PA amp into a Stereo Guitar Cab?Not being an authority on guitar cabs, but my first instinct would be to say no. The high (speaker) output from a PA amp is not something I'd deem suitable to send into the relatively low level input to any other amp. is that what you're thinking of doing? If so, why would you want to?I'm assuming here that the guitar cab is a powered (ie internal amp) cab. And the term 'bridging' on an amp usually means combining the two output speaker lines into a single mono signal, yet you're talking of an input to a stereo cab..... Clarification is in order methinks. TD Link to comment Share on other sites More sharing options...
Ste69 Posted June 12, 2007 Author Share Posted June 12, 2007 I have a stereo signal going into the PA amp, I want a stereo signal going into the guitar cab (which doesn't contain an amp, just purely speakers) via the two input jacks on the back which are left and right. Link to comment Share on other sites More sharing options...
J Pearce Posted June 12, 2007 Share Posted June 12, 2007 Is it left/right or in/out? Link to comment Share on other sites More sharing options...
Ynot Posted June 12, 2007 Share Posted June 12, 2007 I have a stereo signal going into the PA amp, I want a stereo signal going into the guitar cab (which doesn't contain an amp, just purely speakers) via the two input jacks on the back which are left and right.In that case.... If the guitar cab IS unamplified, and the jacks ARE a stereo input pair, then you theoretically MIGHT be able to send the PA output into the cab. BUT Are you sure the cab is a STEREO cab? Are they marked as LEFT/RIGHT?What is the impedence of the amp and speakers? Do they match?What is the power rating of both the amp output and speaker inputs? Many free-standing passive speakers have a pair of jacks (or other connector) simply as an In/Out - as J Pearce suggests. So if you tried plugging the stereo speaker outputs into what essentially is an in/out arrangement you do seriously risk damage to either or both of the amp/speaker. I'd check exactly what you have before doing anything further Link to comment Share on other sites More sharing options...
dbuckley Posted June 12, 2007 Share Posted June 12, 2007 Sounds like my setup. Boss GX700 -> slave -> butchered old Marshall 4x12 cab to have two sets of inputs and a divider down the middle of the box. Only problem is that 4x12 has (for some unknown reason) still one original Celestion 30W speaker, and it's buggered (years ago, courtesy of a Marshall 100), and I continue to wonder during which decade I'll replace it. Doesn't look like this one :D Link to comment Share on other sites More sharing options...
Rob_Beech Posted June 12, 2007 Share Posted June 12, 2007 SO this is not bridged at all then. You would use a stereo power amplifier and output a left signal to the left speaker and a right signal to the right one. there would be no bridging involved here. this is perfectly acceptable providing the wiring of the cabinet it correct. You could sum the input to give a mono signal and bridge the ampand then run the 2 speakers in parallel (or series for that matter) but this would depend on the load, and whether this was right for you. Rob Link to comment Share on other sites More sharing options...
Ynot Posted June 13, 2007 Share Posted June 13, 2007 SO this is not bridged at all then. You would use a stereo power amplifier and output a left signal to the left speaker and a right signal to the right one. there would be no bridging involved here. this is perfectly acceptable providing the wiring of the cabinet it correct.Personally, I believe some more informed and accurate info from the OP is needed before we can make too many assumptions/recommendations..... Link to comment Share on other sites More sharing options...
Jivemaster Posted June 13, 2007 Share Posted June 13, 2007 In speaker enclosure theory it is bad practise to feed different signals to two speakers in the same enclosure. Does the cab have a divider between the drivers? Link to comment Share on other sites More sharing options...
JimWebber Posted June 13, 2007 Share Posted June 13, 2007 In speaker enclosure theory it is bad practise to feed different signals to two speakers in the same enclosure. Does the cab have a divider between the drivers? Not being a speaker expert, I am surmising here, but I cannot imagine it being a good idea! It must play havoc with air movements, if each driver is doing something different... I would also imagine that in a worse case scenario, the air movement from one driver will move the other, turning it into a microphone, and pushing electronic signals every which way? Just my thoughts Jim Link to comment Share on other sites More sharing options...
dbuckley Posted June 13, 2007 Share Posted June 13, 2007 All of which is true, which is why when we converted my old 4x12 it got a divider down the middle. The Marshall stereo cabs are divider equipped, so I was informed by a nice man at Sensible Music http://www.davidbuckley.name/pix/marshall_1960_panel.jpg Link to comment Share on other sites More sharing options...
Ste69 Posted June 13, 2007 Author Share Posted June 13, 2007 http://www.thomann.de/gb/harley_benton_g412a_gitarrenbox.htm that was the guitar cab I was going to get and my amp output is 8 ohms Link to comment Share on other sites More sharing options...
Rob_Beech Posted June 13, 2007 Share Posted June 13, 2007 Well it appears that you can run this as 2 sets, though as was mentioned earlier it would help if it there is some division between the 2. Your amplifier will see the load of the cabinet, so will be whatever the cabinet impedance is, in this case 2 lots of 16ohms. I will assume that this is 2 8ohm drivers in series in each section and a series parallel connection when using 4 together giving a total impedance of 8ohms. It is quite possible if this is the case that you'd be able to alter this to 2 lots of 4ohm but this would depend what your amp could drive. And you'd also have to be warned that if you did decide to use all 4 together the amp would then see a 2ohm load. Rob Link to comment Share on other sites More sharing options...
Ynot Posted June 13, 2007 Share Posted June 13, 2007 Well it appears that you can run this as 2 sets, though as was mentioned earlier it would help if it there is some division between the 2. Your amplifier will see the load of the cabinet, so will be whatever the cabinet impedance is, in this case 2 lots of 16ohms. I will assume that this is 2 8ohm drivers in series in each section and a series parallel connection when using 4 together giving a total impedance of 8ohms. It is quite possible if this is the case that you'd be able to alter this to 2 lots of 4ohm but this would depend what your amp could drive. And you'd also have to be warned that if you did decide to use all 4 together the amp would then see a 2ohm load.Hmmm....I'm not so sure the Thomann description is necessarily accurate...Here's a screen-cap from their 3D pic...http://i76.photobucket.com/albums/j40/Ynot_01/Harley_Benton_G412A.jpgIt does NOT say "STEREO" anywhere there, and the jacks are NOT labelled L/R....That looks far more likely to be a misprint on the website, and the jacks are simply mono-in mono-out.... Unless you have a manual to say otherwise...? Struggling to Google anything for the cabs on the web.... Link to comment Share on other sites More sharing options...
Rob_Beech Posted June 14, 2007 Share Posted June 14, 2007 But with a simple bit of wiring here and there it shouldn't be a problem. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.