Differences between MTI era SVT's and Linden/Magnavox era SVT's

snowblinder · #1 02-17-2011, 12:36 PM

As stated in other posts on here, I am the owner of an Ampeg MTI era SVT. I just got it repaired after a long stint on the sidelines. It sounds great, just as it did before it broke down.

My question is: in relation to the SVT's of the late 60's through 70's, how do the MTI SVT's differ (other than cosmetics of course) from their predecessors? Tonally, is one or the other typically more sought after or preferable?

From personal experience, I've played through two different 70's Magnavox SVT's when mine stopped working at a couple of shows, and....maybe I'm dreaming, but I feel like mine just sounded better with the same settings. Maybe a little "meaner," if that makes any sense. I typically run the volume at about 4 and the MTI one really cut through whereas the others seemed a little more buried.

Side note: I've entertained the notion in the past of buying a 70's SVT replacement head cabinet and faceplate from Fliptops and mounting my MTI chassis in it, solely because I prefer the cosmetics of the older heads (definitely don't plan on ever selling this amp, so I would never consider scamming anyone into believing it was a USA 70's SVT). Does anyone know if this would work without any modifications?

coreyfyfe · #2 02-17-2011, 01:38 PM

The MTI era SVTs switched over to using 12AX7s instead of 12DW7s in the preamp, and they also sent out a service update for older ampegs - not sure if there was a supply problem for 12DW7s then or what, but there seem to be a lot of them available as NOS now. When I got my '74 SVT it had at one point undergone the 12AX7 conversion and I had it brought back to 12DW7 specs. It's only a change of a few resistors, and because this was done at the same time as a cap job and retube I can't really tell you what the difference in tone would be between the two.

JimmyM · #3 02-17-2011, 01:42 PM

all well tuned svt's sound identical to me, except for the ones with separate gain and volume, and that difference is only slight. for all the changes it's gone through over the years, it's stayed remarkably consistent.

there are two types of mti's, one that just took the original design with the 12dw7 tubes, one where 12ax7's and 12au7's were subbed out when 12dw7's suddenly became unavailable. but since the 12dw7 is half 12ax7/half 12au7, it sounds the same.

zachoff · #4 02-17-2011, 02:44 PM

Didn't the early early ones have EL34s in the power section or am I mistaking this for the V4?

snowblinder · #5 02-17-2011, 02:46 PM

Quote:

Originally Posted by zachoff

Didn't the early early ones have EL34s in the power section or am I mistaking this for the V4?

All SVT's had 6550's except the earliest ones which had 6146's.

I don't think any V-4's ever came stock with EL-34's, though some have undoubtedly been modded to take them.

coreyfyfe · #6 02-17-2011, 03:55 PM

Quote:

Originally Posted by snowblinder

I don't think any V-4's ever came stock with EL-34's, though some have undoubtedly been modded to take them.

Less common than the 6550 mod AFAIK but I have heard of V4s modded to use EL34s. The stock tubes were 7027s.

snowblinder · #7 02-20-2011, 07:01 PM

I've gotten to play around with this amp some more in the last few days. I've completely fallen back in love with it. P-Bass, Channel 1, Normal input. Volume: 11:00. Treble: 12:00. Midrange: 2:00. Bass: 1:00. Ultra Hi: off. Mid selector: center position. Ultra Lo: off. Before, when playing through it, I would always have the Ultra Lo switch engaged, and found myself getting lost in the mix often. With this switch off, the amp seems noticeably louder and more present, which is nice.

Now...the previous owner of this amp had removed the grill on the front and replaced it with black wire mesh. I find myself going back and forth on this, but it is kind of cool to glance back at the amp while playing and see all of those tubes glowing orange in a dark room. With that being said, I am still interested in possibly picking up one of the 70's replacement head boxes and control faceplates from Fliptops and installing my MTI chassis in that. I would imagine that the chassis would mount into the headbox with no issues, but...does anybody know if the faceplate would line up properly with the controls, switches and inputs on my amp? As stated in my first post I don't intend to try to sell this amp to anyone under the pretense that it is a 70's SVT. In fact I don't think I'll ever sell it, period. I just personally prefer the cosmetics of that era and wouldn't mind having it that way if at all possible.

JimmyM · #8 02-20-2011, 08:16 PM

you would have to ask bruce for sure but i'm pretty sure the controls don't line up for the faceplate. however, this pic shows they're not really too far off:

i'd still check with bruce before you buy.

snowblinder · #9 02-21-2011, 09:02 AM

Quote:

Originally Posted by JimmyM

you would have to ask bruce for sure but i'm pretty sure the controls don't line up for the faceplate. however, this pic shows they're not really too far off:

i'd still check with bruce before you buy.

Thanks Jimmy! I will contact Bruce and see what he says. Looking at the photo you posted, it looks like all of the controls and switches line up perfectly on the Skunkworks head and the later 70's head. I would imagine the MTI's controls are the same, but...for the money it would cost to have this done, I guess it's always good to be absolutely sure.

coreyfyfe · #10 02-21-2011, 09:15 AM

That is an MTI head on the bottom, you can tell by the cut of the head case on the top (straight with a cutout vs angled).

snowblinder · #11 02-21-2011, 01:28 PM

Quote:

Originally Posted by coreyfyfe

That is an MTI head on the bottom, you can tell by the cut of the head case on the top (straight with a cutout vs angled).

You are correct, thanks for pointing that out. When I first glanced at it, it looked like the headbox was angled, so I assumed it was a Skunkworks.

anderbass · #12 02-21-2011, 02:53 PM

Yep, I can confirm it's an MTI too, Jimmy lifted that pic from my thread here: 1800 watts of all tube SVT pics.

Calaverasgrande · #13 02-21-2011, 03:19 PM

are all the one with the cutout like that MTI? I totally passed one of those up last year.

coreyfyfe · #14 02-21-2011, 06:00 PM

Quote:

Originally Posted by Calaverasgrande

are all the one with the cutout like that MTI? I totally passed one of those up last year.

Yup. With the SVT-HD they went back to the slant case design and have stuck with that since.

Surly · #15 02-21-2011, 07:06 PM

I own an early 80's MTI SVT which has 12dw7's. It sounds like any SVT I've heard. The inner construction and soldering are perfect. I've seen some of these on ebay for less than the 70's SVT's and I believe they are a great value (especially compared to the VR). All the tone but not as pretty I suppose

snowblinder · #16 02-21-2011, 07:57 PM

Quote:

Originally Posted by Surly

I own an early 80's MTI SVT which has 12dw7's. It sounds like any SVT I've heard. The inner construction and soldering are perfect. I've seen some of these on ebay for less than the 70's SVT's and I believe they are a great value (especially compared to the VR). All the tone but not as pretty I suppose

Oh, tonally they are absolutely as good as any 70's SVT I've played through. As I said in my first post, I think I actually slightly prefer the sound from my MTI than any of the older ones I've played. Granted, my experience is limited to one early 70's "blackline" model and a later 70's model, each owned by a friend. I've never played through a "blueline" head, which seem to be held in a higher regard by some.

And speaking of price, I paid less than a grand for mine (with a super heavy duty roadcase with casters......thank god) on eBay a couple of years ago. No way a Linden or Magnavox one would ever show up nowadays for that price. The MTI's are an absolute bargain.

So glad I got this one repaired and didn't sell it.

JimmyM · #17 02-21-2011, 10:57 PM

i have one of the very first blue lines ever made. it is a finely tuned killing machine, and it sounds awesome. if i didn't have it, i would be perfectly happy with an mti.

johnk_10 · #18 02-21-2011, 11:03 PM

i've owned alot of SVT's since 1973, two of them were MTI's (bought them in the mid 80's), and they sounded exactly like my early 70's and late 70's ones.

One Drop · #19 02-22-2011, 02:23 AM

BTW, I have a blueline with original 6550s and it sounds the same as any from the '70s. The earliest bluelines like Jimmie's had the different 614B power tubes which would make for the only tonal difference.

JimmyM · #20 02-22-2011, 02:53 AM

Quote:

Originally Posted by One Drop

BTW, I have a blueline with original 6550s and it sounds the same as any from the '70s. The earliest bluelines like Jimmie's had the different 614B power tubes which would make for the only tonal difference.

honestly, i don't hear much of a tonal difference with the 6146b's vs the 6550's. now i haven't been able to directly ab a 6550 svt with mine, but to my ears it's the same basic tone. i've heard the 6146b's give it about a 30-40w boost over the 6550's but i doubt it makes a difference on a gig.