Members B.Daws Posted September 20, 2010 Members Share Posted September 20, 2010 Not to confuse SSH so just ignore this...Will there be any difference in running it in 16-ohm vs. 4-ohm? I was thinking 4 ohm would draw more power output from the amp than 16 ohm but then again I'm thinking in terms of car stereo where the ohm's can directly affect the output wattage except for JL amps which are uniform. Are guitar amps typically uniform across the different ohms is probably a better question?Tube amps don't like low-impedance loads, so running 16ohm is ideal...I did not know this. Why do they not like them? Link to comment Share on other sites More sharing options...
Members soul-x Posted September 20, 2010 Members Share Posted September 20, 2010 Not to confuse SSH so just ignore this... I was thinking 4 ohm would draw more power output from the amp than 16 ohm Not on a tube amp. The output stage isn't directly attached to the load like on solid-state amps. There's an output transformer sitting in-between to match the output to the load impedance. Link to comment Share on other sites More sharing options...
Members ac30guy Posted September 20, 2010 Members Share Posted September 20, 2010 Not to confuse SSH so just ignore this...Will there be any difference in running it in 16-ohm vs. 4-ohm? I was thinking 4 ohm would draw more power output from the amp than 16 ohm but then again I'm thinking in terms of car stereo where the ohm's can directly affect the output wattage except for JL amps which are uniform. Are guitar amps typically uniform across the different ohms is probably a better question?I did not know this. Why do they not like them? 4Ohms probably would draw a little more output, but realistically, who needs to up output, seems more people need to work on lowering output so I would say that 16 would be the best choice. 1 cable. simple is good. Link to comment Share on other sites More sharing options...
Members B.Daws Posted September 20, 2010 Members Share Posted September 20, 2010 Thanks for clearing that up for me Soul-X.4Ohms probably would draw a little more output, but realistically, who needs to up output, seems more people need to work on lowering output so I would say that 16 would be the best choice. 1 cable. simple is good.Could he not just run it from one of the parallel jacks to the 4 ohm connection on the cabinet and flip the switch to 4-ohm still using one cable? Link to comment Share on other sites More sharing options...
Members GCDEF Posted September 20, 2010 Members Share Posted September 20, 2010 4Ohms probably would draw a little more output, No it wouldn't. Link to comment Share on other sites More sharing options...
Members GCDEF Posted September 20, 2010 Members Share Posted September 20, 2010 Tube amps don't like low-impedance loads, so running 16ohm is ideal... in the red configuration you're running a 4ohm load which can stress the amp, but shouldn't hurt anything. No wonder the poor guy is confused. This isn't correct either. As long as the output transformer has a setting that matches your cabinet, the amp will be happy and you won't be stressing anything. 4 or 16 ohms are equally fine for that amp. 16 is just simpler since the OP won't have the confusion of the parallel outputs or the impedance selector to worry about. Link to comment Share on other sites More sharing options...
Members GCDEF Posted September 20, 2010 Members Share Posted September 20, 2010 Thanks for clearing that up for me Soul-X.Could he not just run it from one of the parallel jacks to the 4 ohm connection on the cabinet and flip the switch to 4-ohm still using one cable? That was answered back on page 1. Yes he could. Link to comment Share on other sites More sharing options...
Members Racehead Posted September 20, 2010 Members Share Posted September 20, 2010 "Dear lord thank you so much for this thread .... and may I please have another ? " Amen .......... Link to comment Share on other sites More sharing options...
Members Ryan. Posted September 20, 2010 Author Members Share Posted September 20, 2010 Link to comment Share on other sites More sharing options...
Members SteinbergerHack Posted September 20, 2010 Members Share Posted September 20, 2010 Correct, except -- look again -- his cab isn't wired for 16 ohm. It is 8 ohm/side stereo, or 4 ohm mono. No, it's a standard Marshall wiring. Left jack by itself in Mono is 4 Ohms, Right jack by itself in Mono is 16 Ohms, in stereo it's two 8 Ohm cabinets in one box. Link to comment Share on other sites More sharing options...
Members SteinbergerHack Posted September 20, 2010 Members Share Posted September 20, 2010 FWIW, there is a slight difference in output between the various impedance taps on an output transformer, based on the change in internal losses. Some guys say they can hear it........ Link to comment Share on other sites More sharing options...
Members monthlymixcd Posted September 20, 2010 Members Share Posted September 20, 2010 Well, technically the 16ohm tap on his amp's OT would be using more of the windings of that transformer and many prefer this (if the tranny is of good quality) as it makes the output tubes work just a little harder and shape the tone a little more. We're talking shades of grey here... no profound "Holy Grail" tone secrets or anything. Honestly, I think that cab switch design is one of the few bits of GENIUS that poured out of Jim Marshall's head over the years. Very flexible use of cabs with one of those on board. Subs... try it both ways as 16 or 4 ohm and see which you like best. Incidentally, what 16ohm drivers are in the cab? Link to comment Share on other sites More sharing options...
Members Ryan. Posted September 20, 2010 Author Members Share Posted September 20, 2010 Four 75 watt Celestion G12T-75 Speakers Link to comment Share on other sites More sharing options...
Members monthlymixcd Posted September 20, 2010 Members Share Posted September 20, 2010 Not to complicate things, but in that case... an additional safe setting would be to run the amp into just half of the cab to get a little more speaker cone breakup going on... another tone flavor that some people like, some don't. So, to summarize... safe settings with that amp and that cab would include; 16ohm tap amp jack into 16ohm jack on cab with cab switch set to mono, amp set on 4ohm using the jack next to that switch into the 4ohm jack on cab with cab switch set to mono, using that same output jack on the amp with the amp set on 8ohm into either of the jacks on the cab with the cab switch set to stereo. Got it? Good news - You're not going to blow speakers no matter how you connect it to that amp. (EDIT: Assuming the cab is wired stock.) Bad news - You WILL eventually fry your OT in the amp if you mismatch the impedences too often. Link to comment Share on other sites More sharing options...
Members Ryan. Posted September 20, 2010 Author Members Share Posted September 20, 2010 Not to complicate things, but in that case... an additional safe setting would be to run the amp into just half of the cab to get a little more speaker cone breakup going on... another tone flavor that some people like, some don't.So, to summarize... safe settings with that amp and that cab would include;16ohm tap amp jack into 16ohm jack on cab with cab switch set to mono,amp set on 4ohm using the jack next to that switch into the 4ohm jack on cab with cab switch set to mono,using that same output jack on the amp with the amp set on 8ohm into either of the jacks on the cab with the cab switch set to stereo.Got it?Good news - You're not going to blow speakers no matter how you connect things.Bad news - You WILL eventually fry your OT in the amp if you mismatch the impedences too often. I see. My plan is to go to the studio ASAP and switch everything to the 16ohm settings. Link to comment Share on other sites More sharing options...
Members monthlymixcd Posted September 20, 2010 Members Share Posted September 20, 2010 Sounds like a good plan. BTW - I'd recommend getting a THD Hotplate or Weber MASS attenuator to use with your amp when you need it. The 16 ohm model would work, but I find the 4 ohm model is more versatile for what I need it for... A unit like this would let you push the amp a little more but keep the room volume down. As with anything, there are trade offs. Pushing the amp a little harder (properly impedance matched to a cab, of course) gets you a little more of the sweet output tube grind, but shortens the life of those tubes. Using an attenuator keeps the total room volume of the rig down, but robs the tone of the speaker cone breakup that some like. Horses for courses... Link to comment Share on other sites More sharing options...
Members Ryan. Posted September 20, 2010 Author Members Share Posted September 20, 2010 Maybe this goes too far off topic... but... Why do they match up a 100W head with a 300W cab? Is that efficient? Link to comment Share on other sites More sharing options...
Members tlbonehead Posted September 20, 2010 Members Share Posted September 20, 2010 My old Marshall 2X12 cab had stereo inputs. yes, and your point is? Link to comment Share on other sites More sharing options...
Members tlbonehead Posted September 20, 2010 Members Share Posted September 20, 2010 I dunno why guitar amp manufacturers make their speaker connections so damn confusing. 16 OHM ONLY and 8 OHM PARALLEL ONLY and {censored}. With 4ohm, 16ohm, and stereo 8ohm connections on the cabs... just wire the damn cabs for 16ohm and put a couple speaker connections on it in parallel.what's confusing about it? Link to comment Share on other sites More sharing options...
Members tlbonehead Posted September 20, 2010 Members Share Posted September 20, 2010 Maybe this goes too far off topic... but... Why do they match up a 100W head with a 300W cab? Is that efficient?what's wrong with that? 100 watts is less than 300, so you are safe. Link to comment Share on other sites More sharing options...
Members monthlymixcd Posted September 20, 2010 Members Share Posted September 20, 2010 Maybe this goes too far off topic... but... Why do they match up a 100W head with a 300W cab? Is that efficient? Because a 100W tube amp with 4xEL34s DIMED can put out considerably more that 100W into certain frequencies once it distorts and starts pushing square waves at the speaker cab. Link to comment Share on other sites More sharing options...
Members Ryan. Posted September 20, 2010 Author Members Share Posted September 20, 2010 Sounds like a good plan.BTW - I'd recommend getting a THD Hotplate or Weber MASS attenuator to use with your amp when you need it. The 16 ohm model would work, but I find the 4 ohm model is more versatile for what I need it for...A unit like this would let you push the amp a little more but keep the room volume down. As with anything, there are trade offs. Pushing the amp a little harder (properly impedance matched to a cab, of course) gets you a little more of the sweet output tube grind, but shortens the life of those tubes. Using an attenuator keeps the total room volume of the rig down, but robs the tone of the speaker cone breakup that some like. Horses for courses... I've always been interested in modding my amp, BUT, since I have no real direction its hard to make any decisions. I've been told that some people will put different speakers in the same cab to get a different tone. I guess I'm really happy with how my tone is right now, but I'm also thinking about buying a smaller amp just to have options. Egnater Tweaker possibly. Who knows... its so hard to pinpoint anything I actually like. Link to comment Share on other sites More sharing options...
Members Ryan. Posted September 20, 2010 Author Members Share Posted September 20, 2010 what's wrong with that? 100 watts is less than 300, so you are safe. Lol, tlbone, I'm just curious about the science behind it. I didn't say there was anything wrong with it! Link to comment Share on other sites More sharing options...
Members tlbonehead Posted September 20, 2010 Members Share Posted September 20, 2010 Lol, tlbone, I'm just curious about the science behind it. I didn't say there was anything wrong with it!not really that much science behind it. Link to comment Share on other sites More sharing options...
Members monthlymixcd Posted September 20, 2010 Members Share Posted September 20, 2010 I guess I'm really happy with how my tone is right now... then by all means STOP!!! Seriously, it's human to want to tinker... but if the above statement is true, you'll only blow a LOT of money trying to improve something that doesn't need to be improved. Do what I didn't do for a long time and just work on your playing. Once your playing improves enough... you'll know when you need to tweak your rig. EDIT: For lower volume gigs with the same head you could go the attenuator and 1x12 cab route or if you think you'd really like to have more amp flavors at hand... build a little Marshall 18Watt clone. I recommend Ceriatone kits. I was in the same boat and built Nik's 36W TMB EF86 and it covers a LOT of territory. Total build cost (with nice head cab from Reason) set me back about $800 though. Be prepared to cough up the cash if that's where you want to go. That Tweaker amp looks like fun. I've had a THD Univalve for years and it's a blast. Link to comment Share on other sites More sharing options...
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