New (old) Amp Day - '71 Sunn Coliseum

[P-oddz]

So...
This one came through this weekend and I made the purchase:

1971 Sunn Coliseum with the two matching 1x18 cabs. Only one (original) owner before me. Excellent condition with everything original including the original slip covers.

It probably wasn't the most practical purchase I've ever made, but the price was really good due to a trade in on a Precision I wanted off my hands. I'm a little familiar with Sunn's history (also with this amp a little bit), but I'd like to hear if anyone can offer any more insight on this amp, including personal playing experience or any opinions.

Right now, I'm kind of discovering a few things:

1. The amp sounds great and has really versatile EQ section with a lot of heft.
2. The cabs are ridiculously large (it took two cars to bring the whole rig home, I brought one cab home and the other is at the practice space)
3. For the size and immensity of the cabs, I'm discovering that they (at least the one I took home) can start to fall apart a lot more easily than I would expect.

I'm getting some nasty buzz/vibrations out of the cab I took home that lead me to believe it either could benefit from some sort of extra vibration dampening internally, or that something (perhaps voice coil? I'm not that familiar with speaker technology) is fried. I'm finding that past about a 3.5 on the volume knob, certain notes are just making it fart out. Not every note mind you, but some notes are just a plain out splat.

I'm pretty stoked about the purchase, but if it turns out the 18's really can't handle what I need out of them, I might have to weigh my options and take it back. I can sacrifice using another cab with the amp, (though the idea of just stashing two unusable giant cabinets so that the set stays together doesn't tickle my fancy that much), but the other problem is that the head is sized to the cabs... very large. On top of any other cab it just kind of pairs awkwardly.

But it sure is a neat looking rig...

Anyone have any input or advice on the amp or cabs?

 

[Interceptor]

I used a Sunn Coliseum regularly when they were new. It wasn't mine, it was a fellow bassist's rig, and we routinely used each others stash. My stuff was better suited to smaller halls, his was, um, not. The Sunn cabinets did not buzz. I suspect time has gotten its nasty hooks into the plywood and it is delaminating.

I really enjoyed playing through that beast. No trouble with a guitarist in a full Marshall stack at stage volume that was beyond stupid. His didn't have the 18" drivers, he had a pair of 2 x 15 cabs. Loud as I ever got before the days of big PA.

 

[99Z3]

So...
This one came through this weekend and I made the purchase:

1971 Sunn Coliseum with the two matching 1x18 cabs. Only one (original) owner before me. Excellent condition with everything original including the original slip covers.

It probably wasn't the most practical purchase I've ever made, but the price was really good due to a trade in on a Precision I wanted off my hands. I'm a little familiar with Sunn's history (also with this amp a little bit), but I'd like to hear if anyone can offer any more insight on this amp, including personal playing experience or any opinions.

Right now, I'm kind of discovering a few things:

1. The amp sounds great and has really versatile EQ section with a lot of heft.
2. The cabs are ridiculously large (it took two cars to bring the whole rig home, I brought one cab home and the other is at the practice space)
3. For the size and immensity of the cabs, I'm discovering that they (at least the one I took home) can start to fall apart a lot more easily than I would expect.

I'm getting some nasty buzz/vibrations out of the cab I took home that lead me to believe it either could benefit from some sort of extra vibration dampening internally, or that something (perhaps voice coil? I'm not that familiar with speaker technology) is fried. I'm finding that past about a 3.5 on the volume knob, certain notes are just making it fart out. Not every note mind you, but some notes are just a plain out splat.

I'm pretty stoked about the purchase, but if it turns out the 18's really can't handle what I need out of them, I might have to weigh my options and take it back. I can sacrifice using another cab with the amp, (though the idea of just stashing two unusable giant cabinets so that the set stays together doesn't tickle my fancy that much), but the other problem is that the head is sized to the cabs... very large. On top of any other cab it just kind of pairs awkwardly.

But it sure is a neat looking rig...

Anyone have any input or advice on the amp or cabs?

Consider the age.. that there might be some shrinkage to the wood because of that and the cab may just need to be tightened back up some. Also, the screws to the speaker could be loose.. check those..

 

[Interceptor]

I see the OP is in Milwaukee.

The Sunn I ran got hammered HARD in the venues just north of Milwaukee, Zivko's, Weiler's and the Port Washington Band Shell. The '70's were fun.

 

[old spice]

I own one of those. The cabinets don't rattle at all and are the best built boxes I've ever owned. The design is acoustically correct in terms of horn loading and tuning and displacement.
A power drill is essential to opening the cabinets up. There is foam damping in there originally. Lotta screws to tighten up.
I have replaced one of the 18's twice, the other not at all. You want 4 ohm speakers if you need replacements. (I used first a Gauss that I could NOT get reconed correctly and then a JBL, which FWIW has to be wired in reverse to work. TMI, I suspect.)
The EQ is designed so that each band is OFF when the knob is at zero, thus very precise tone control is possible.
I think it has a great sound, especially for loud gigs: clean and clear. I run a scooped or "smile" kind of sound. The cabinets can be put on each side of the stage. 320 watts RMS with both cabinets. 2 ohms.
I had my amp checked out by an excellent tech when it developed a hiss and he was able to improve its performance a bit: he found a kind of solid state bias issue, a tired transistor and capacitor or two.
I hope you enjoy your amp; I've had mine since about 1980 and I love it.

 

[Basshappi]

That is sexxaaayyy!
Congrats!

 

[Michedelic]

Old Spice has it right; get out the power drill and a good Phillips bit, take those backs off, and see what you have inside. The 18's in those cabs were usually Cerwin-Vega's; see what you got. Carefully check them out for any cone rub, surround fatigue/problems, and so on. Use a small vacuum to blow out the 40+ years of dust that might have accumulated in there besides the rat turds and half-used bags of pot. If the speaker wire is soldered, redo the solder joints, or if they're push in/thread through, spray a little D4 or some other contact cleaner(it's best to do ALL of this outside for ventilation). If you're adventurous, you may want to upgrade the cab wiring to a heavier guage. Check the input jack from the inside, it will probably need a shot of contact cleaner, in tandem with a little in-out in-out from a quarter inch jack, OR it may need total replacement. Check the wheels, they will probably need replacing, but just go with a 'best match' from the hardware store, don't be tempted to install the 'pop-in' type, as you will need to drill into the wood to fit the socket part, and that is, of course, a non-reversable mod. It might not please the next owner. Plus, if the two cabs are stacked properly they will be hanging on one side or the other. The grill cloth frame can be popped out with a screwdriver and rotated so that the logo can be in the upper left, if that's important to you, but do it carefully. The frame is held in place by several white plastic proto-velcro thingies; I sparingly spray a little WD-40 on all of them to make the next removal easier. Tighten all the screws and nuts you can find, and then DO replace the plastic feet(If they are still there). If they are, they're probably destroyed or very worn down, plus that hard plastic material was worthless. If you have a store near you that carries PA speaker replacement parts, get the rubber feet that are at least 1.5 inches in diameter, and at least a half inch high. You can find these on Ebay as well; look for seller aaronsher, he's in the St. Louis area, a solid guy and has available all sorts of Sunn cab trim, like the clips for the handles(that always go missing), complete handle kits, switches, corners(they are a very specific design)and so on. As far as the amp goes, get some disposable rubber gloves, a small paintbrush with very fine bristles, and then unscrew and remove the tolexed top/case. Get the vacuum again, and then with gloves on, blow off all the dust, using the brush gently, and I DO mean gently, to help dislodge the fine coating of crud. Don't be hasty, be methodical; use the contact cleaner and 1/4" plug again on all of the input, output, and FX send/receive jacks, as well as all the pots and switches, dust off the blades on the internal fan(a tiny drop of 3 in 1 oil on the fan axis wouldn't hurt), give everything a few minutes to air out, make a note of the 'born' date(it will be written plainly on the inner chassis)and put it all back together again. Fire it up, and piss off the neighbors. If you feel uncomfortable with doing ANY of the above, take the amp to a trusted tech. I've got two of the heads, two of the 1x18's, and two of the 4x12's, so yeah, I've been through the ringer with these guys. For your enjoyment, here's some old school workouts...



(hang in there 'til 2:16)


uh, yeah...

enjoy

 

[P-oddz]

Wow! Thanks for all the info, guys - and hats off to you Michedelic for the very detailed break down.
I was having some trouble finding any specific help like that, so the time you took is very much appreciated!

 

[iualum]

Consider the age.. that there might be some shrinkage to the wood because of that and the cab may just need to be tightened back up some. Also, the screws to the speaker could be loose.. check those..

Shrinkage .

 

[iualum]

Is that the same as the 880 (although without the 880 printing on the face)? If so who knows the output @ 2, 4, & 8-ohms?

 

[P-oddz]

Is that the same as the 880 (although without the 880 printing on the face)? If so who knows the output @ 2, 4, & 8-ohms?

I don't think they are the same (though I don't know for sure). The 880 appears to have a different EQ section, which would lead me to believe it might have different power ratings (though again I'm just speculating).
Finding any specs on this amp is proving to be some work...

 

[iualum]

I don't think they are the same (though I don't know for sure). The 880 appears to have a different EQ section, which would lead me to believe it might have different power ratings (though again I'm just speculating).
Finding any specs on this amp is proving to be some work...

Wow. Just wow . Some Sunn product was the cat's meow, like the Coliseum. But the naming of the product? Yeah, well, not so much.

 

[P-oddz]

I was able to give the amp a run in full band context last night. It held up really well and the rest of the guys complimented me on the tone.
The only other amp to get the full "that amp sounded awesome" accolade from the band, has been my all tube Orange AD200.
The only issue I was having was that my normal "synthy fuzz" tone (which I use for a couple of songs in our set) seemed to be a little more "gacky" that I would like. Not really a deal breaker, and probably not even noticeable to anyone else but me, but at least noteworthy. Other than that, I was really enjoying playing on it.

The 18s (obviously because of their size) are proving to be a little tubbier in response than I care for, but they also offer a definite "thing". I need a little faster response for the majority of our songs than the 18 seemed to offer, so I opted to just plug into my Orange OBC410 (at 8 ohms) and the amp was running great. The natural "throat" of the Sunn compounded with the mid-range tendencies of the Orange 410, and I was definitely pleased. The amp felt natural in its response, and honestly had some qualities similar to what I like about the Orange - very organic, warm, but with an inherent little bit of bite. All things I have been missing with solid state heads I've played up to this point.

The problem with this setup however is due to the amp's fan being on the underside. I'm going to need to figure out a better solution to just placing it on top of my cab as the rubber feet hang off, leaving the amp sitting directly on the fan with no room for heat dissipation. They look pretty mismatched together, but they sounded quite well as a pair.

 

[iualum]

Nice report. There's no doubt whatsoever that the Coliseum is dripping with serious Mo-Jo . But fan on the bottom? How the heck did that ever get past anyone ?

 

[yakmastermax]

Bad ass vintage rig. Hopefully you can figure out the cab vibration/ speaker fart.

 

[Michedelic]

Nice report. There's no doubt whatsoever that the Coliseum is dripping with serious Mo-Jo . But fan on the bottom? How the heck did that ever get past anyone ?

Oh you youngsters don't realize that so many amp features that we take for granted today were unthought of earlier on, or have evolved over time. The fact that a hard working bass amp HAD a fan in those days was pretty forward thinking, trickling down from power amp technology. In fact, in '71/'72 PA systems themselves were just coming out of the dark ages, not that many straight ahead power amps had fans. The Coliseum heads were designed to be wide(to match the 30" wide cab)and a bit deep, not tall so much, for a sleeker look. So the fan(your standard little electronics box fan, still used today)fitted internally to the bottom of the chassis was the most ergonomic place(there are small intake vents all along the back). The only other instrument amps that had a fan in those days were the Traynor 'bumper sided' tube heads like the YBA's. The 'pre-amp out, power amp in' jacks(an early version of FX send/receive)were a bit ahead of the time as well. Now, looking at my 1972 Sunn catalog, the 880 essentially is the same as the Bass head, same EQ points, but with the addition of 'distort'(which trickled down to the Concert Bass head), and 'sustain', which I would assume is some sort of simple compressor circuit). I only own the Coli Bass and Lead heads(the Lead has two channels, both with the 'Bass' EQ points, one with tremolo labeled as 'vibrato' and reverb, the other without, but no 'distortion' or 'sustain' on either). In theory, then, the Coli Lead amp could be used for bass. Sunn always did have this weird redundancy among their various models(the classic 60 watt tube bass head, the 200s, was also labeled the Sorado, the Sonaro, or the Sonic II, depending on the configuration of speaker cab it was matched with). As far as power is concerned, all three models were listed as "320 watts RMS, 880 watts peak" typical amp company mumbo jumbo of the time(Kustom, Vox, and plenty of other companies were guilty of this, too). That's 320 watts at 2 ohms, by the way(the 18" OEM driver in the matching cab, if it is original, is a 4 ohm Cerwin Vega, so a pair would get you down to 2 ohms). Forget that 'peak power' hoodoo, you have a 175 watt amp(more or less)at 4, a 100 watter(probably)at 8. To the OP---if you're going to place that head on top of a narrower cab, get some dense foam strips that are at least as long as the head depth for it to rest on and elevate it, making sure the foam clears the opening for the fan. This will also cut down on speaker cab vibrations for the head(never a good thing for the electronics). Also, here is the vintage Sunn fan site:
Link Removed Unfortunately, it's kinda died down in the last few years, and a lot of good info from posts made in the 90's and early 2000's got lost when the server was changed, but there's still plenty of good reading.

 

[Michedelic]

I do have to admit to my overlooking of the SVT as an amp with the early-on addition of a coolng fan. Sorry, but when and where I was growing up and all these amps were coming along, Ampeg was not a large presence in my local music stores. Since I was playing in teenage garage bands(ie nobody had any money), the only Ampegs I encountered were the old accordion amps, and smaller guitar combos like the G12 and VT40, bass wise, the B25. I didn't even play thru an SVT until 1980 at a club.

 

[P-oddz]

Michedelic - once again you have proven yourself to be an invaluable resource! Thank you for taking the time out again to set the record straight and impart your knowledge. I'm also really glad you sent the link for the Sunn forum. I assumed there had to be one that existed, I just hadn't discovered it yet. Time to do some reading!

 

[Fluid Power]

Wow that's nice! Time machine time
I bought a new Fender Bassman 100 new when I was 15-ish and my guitar player bought a Sunn Tube head with about 60 watts. It had a tall what I swear was a 3-12 in line up and down cab. Damn that was loud and my new Bassman was distortion city trying to keep up. Well a road trip to Ye Old Music shop in Marissa, Ill and Ed set me up with a Concert Bass with a 2-15 cab, brand new! The Who was just their getting Sunn and Heil PA gear! I swear ask Ed! Well wouldn't you know the guitar player trades his tube head in for a Concert Lead!! This was war and I traded in (to Ed) my Concert Bass for a new Coliseum head still using the 2-15 cabs. No one could touch me! I really liked that head. The tone was great (into the single or dual JBL 15's!). Oh, the thump was great as well. I now have a PF-800 Ampeg with a PF350 and PF500 going to the 800 is like going from the Concert to the Coliseum head room to spare and the both handle loads with ease. I hope someday to get a SVT-7 but am fine for now. Your score is a real beautiful setup. I've been to many concerts (old days) where the bass was using the full Coliseum stack with 2 18's and it really sounds great. As I was playing bars and not stadiums or coliseums the full sound of the head with he 2 15's was fine for me. In fact I recall the cops coming in to tell us to turn it down! That's when we pulled a little Porter Wagoner out of our list to thrill the cops, they always loved that!
Those were the days. Early 70's

 

[Fluid Power]

I was able to give the amp a run in full band context last night. It held up really well and the rest of the guys complimented me on the tone.
The only other amp to get the full "that amp sounded awesome" accolade from the band, has been my all tube Orange AD200.
The only issue I was having was that my normal "synthy fuzz" tone (which I use for a couple of songs in our set) seemed to be a little more "gacky" that I would like. Not really a deal breaker, and probably not even noticeable to anyone else but me, but at least noteworthy. Other than that, I was really enjoying playing on it.

The 18s (obviously because of their size) are proving to be a little tubbier in response than I care for, but they also offer a definite "thing". I need a little faster response for the majority of our songs than the 18 seemed to offer, so I opted to just plug into my Orange OBC410 (at 8 ohms) and the amp was running great. The natural "throat" of the Sunn compounded with the mid-range tendencies of the Orange 410, and I was definitely pleased. The amp felt natural in its response, and honestly had some qualities similar to what I like about the Orange - very organic, warm, but with an inherent little bit of bite. All things I have been missing with solid state heads I've played up to this point.

The problem with this setup however is due to the amp's fan being on the underside. I'm going to need to figure out a better solution to just placing it on top of my cab as the rubber feet hang off, leaving the amp sitting directly on the fan with no room for heat dissipation. They look pretty mismatched together, but they sounded quite well as a pair.

Hey, I cut a piece of plywood the size of the head so I could place it on top of the 2-15 Sunn Cabs (they are narrower like a 2 15 Peavey cab)
Worked just fine and I don't remember it ever moving. I know the Coliseum Head had nice rubber feet and I believe the aggressive Tolex used by Sunn kept the plywood from moving around. Good thing as we played loud!