is it possible my sunn is too much amp for my cabs?

[foxfire]

i got my first tube (350L) sunn last week. it must have taken a hit somewhere on it's way across America cause a bolt had sheered off which happen to be grounding a filter cap and i believe the OT. i didn't realize this until i replaced my second screen (47Ω 2W) resistor i found the broken bolt/bad ground. i fixed the ground and got new JJ kt88's and biased it up to 70%. then i made the mistake of checking the bias one last time , and while checking the plate voltage i shorted pin 3 and pin 2 of one of the power tubes to which blew the plate (47Ω 5W) resistor. i replaced all the plate resistors and the 3) 50µF and 1) 1000µF caps. long story short today was my first chance to get to hear it through my 4x12's and when run it clean i am hearing a fair amount of crackle when i dig into the guitar. it's somewhat distorted with the volume at 4-5. i have the treble at 0, the bass maxed, mid at 3, and the mid boost on. i can reduce the crackle by rolling the guitars tone down a bit or picking softer.

i tried it through 3 different cabs and every combo of the 3, and the crackle was always there. now all 3 cabs are old and 2 of them have speakers that either have a hole or 2 punched in them of have had ripped repaired by me. they are all at least 100 watt boxes. i hooked up my main head (a V4) and i can hear a bit of crackle but not nearly as bad as it is with the sunn.

ok so if you're still with me. my question is, is it possible that my cabs just aren't up to the super clean punchyness of the sunn or that i screwed up more than i thought with the bad ground and shorting the pin 3? i know there are a lot of variables so hopefully it's not a stupid question...   

[doomedfuzz]

Maybe so (sorry not a solid answer) but I'm learning some about Sunn heads and cabs myself the last few days. I have an Orange PPC412 and my Sunn Enforcer sounds great through it, but the volume blows -- especially for a vintage, powerful 100 watt tube head. I tried it tonight through a Marshall 1960A and holy smokes, just insane - loud, powerful and killer tone (it was load with V30s just like my Orange). My Orange head is heaven through the Orange cab and really, really loud. So moral of story, amps and cabs really need to be matched up for optimal performance.

[xsolarusx]

I would dare say there's an issue within the head, if any combination you try gives the same results.  I've played my Model T through low-powered cabinets, and at worst the speakers get driven pretty hard, but never to the extent you're writing of.

Have you taken the head in for a second opinion? It might be worth a shot.

[foxfire]

i'm gonna take the head to practice today and try some other cabs. i agree it does sound like an issue with the head. the main reason i'm not giving up on it being the cabs is that the amount of crackle varied from cab to cab. well that and the fact that all my cabs are old and kind of beat. it really doesn't like my ampeg cabs, but sounds pretty good with my sound city cab with a collection of old low to mid grade speakers.

this amp i just so clean and crisp that i can't tell it what's going on. with the volume at 4 it's clean, but if you get heavy on the pick it starts to breakup. with the volume at 5 it's breaking up smoothly in a nice way. nowhere near realm of metal or anything though. it sounds incredible with a muff or rat in front of it which is how i'm gonna use it...i'll see what happens at practice today and some point i'll get it looked at by someone who knows what they're doing.  

i should add that it's pretty damn loud at 4-5...

[foxfire]

well i've got some sort of good news, the speakers have the same distortion/crackle with my V4 as they do with the Sunn. i know i tried it before, but this time i listened without any mental assumptions that i must have blown something in the Sunn, and it really seems like it could be the speakers not the head.   

[foxfire]

well i tried it through a 5th cab and the distortion/breakup was still there, and it's totally bumming me out. it helps if i disengage the mid boost. my fear is that one of the transformers took a hit either from the bad ground or when i shorted the plate. the thing of it is it doesn't sound all that bad, and with a dirt box in front of it kills. it just worries me that it breaks up so early. i guess i'm gonna have to get it looked at...

[doomedfuzz]

The one factor you haven't mentioned -- the guitar. Are you using the same one on all of your tests and getting the crackling noise? My Les Paul has a bad toggle and sometimes I get strange noises or reduced tone (and crackling at times) on the bridge pup if I don't jiggle it a bit.

[pickinatit]

How about cables and/or jacks?  Are you using the same cable from amp head to cab each time you change cabs?  Using the same cable from guitar to amp head each time?  (using the same guitar, like doomedfuzz asked ?).

[foxfire]

3 different guitars, 2 or 3 instrument cables, and 3 different speaker cables...i spent some time searching and reading this weekend and i'm thinking that there is a good chance that my amp is working as it should. with the mid boost off i can crank the volume a good bit higher before it starts to breakup. i read more than a few posts confirming that the mid boost can cause some slightly unpleasant distortion or early breakup. i read a few posts describing the distortion on these amps as sometimes being harsh or brittle and not exactly smooth. i think i may have been wrong in describing what i was hearing as a crackle. it's probably more of a ripping than a crackle.

i chopsticked just about everything in the amp and didn't hear anything. i also checked a bunch voltage points and they're all high but only by around 30 volts. i got in touch with my amp guy and made plans to take it in this week. i figure it's worth it to have it checked by a pro otherwise i'll never trust it...though i'll still listen to any suggestions you've got.       

[foxfire]

i'm feeling more and more that the mid boost playing big part in whatever is going on. with the boost on i get the unpleasant breakup and i loose a lot of my low end. i'm not totally sure how the mid boost circuit works cause it's different then the circuit in the schematic i have for the 1200. i'm gonna trace it out tonight and try to figure out what it's going. i've also got 2 "NOS" 6an8  coming to me so i can rule out it being a bad PI tube.

[foxfire]

a little mini follow up, i hooked up my V4 again and rolled the mids up, and got the same sort of sounds as i get with the sunn when the mid boost is on. i did trace the mid boost circuit, and i was wrong about it not matching the circuit in the schematic i have. i'm still taking it in to have it looked at so that if i end selling it i can sell it in good conscious...

[foxfire]

well it got a clean bill of health from my amp guy. we looked at what the mid boost is actually doing, and now what i'm hearing makes sense. i can stop worrying about it and just play the damn thing now...i'm also working on getting some new speakers.