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Ampeg SVT-7 PRO, cutting out, brand new...

Oystercopy

Oystercopy

Guest
Dec 6, 2017
7
8
#1
Hey guys... I just brought home a (loaner) SVT-7 pro with a 410 stack. Evidently, Ampeg has just been sold (again) to Yamaha this time and the amp I ordered is on hold from the mfr. The power of this thing is UNBELIEVABLE, and goes well with my Rick. However, during play, it would cut out and cut the signal to the speakers... what the heck? When researching this, it seems it is (was?) a common problem on the older 7-pros, but this one is a Revision C...

So.. removed the head from the top of the cab and insulated it with (the only thing I had at the moment) an empty box... VOILA.. amp begins punching at past the Master midway mark with NO CUTOUTS..

So, obviously, there is something in the vibration of the cab that's causing the amp to cut out, but WHY? I've never owned an amp of this power capability (let alone tubes), but I used to own a Yamaha 100 watt 1x15 reflex cab that had to be disassembled every couple of months and have some of the pots resoldered to the board.. I can't BELIEVE I would buy another amp (only the second in my over 40 years of playing) that has THE SAME problem as my first one! How unbelievable is that?

So, I know that I've seen these 7-pros in rack mounting environments; I wonder if that's why they're that way? All I know is that I'm having second thoughts about this amp when this (new) one is already having issues cutting out..

Thoughts?
 
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#2
That doesn't sound like the typical problem most people had with the 7 Pro, which was a chip frying. They have since replaced that chip with a newer model that seems to have fixed it. What you have going on sounds more like a loose connection inside of it. When you say "loaner," that makes me think "used and abused." One thing you might try is to stick an instrument cable between the effect return and send and see if that clears it up. If so, then your effect loop jacks need cleaning, which you can do by either spraying a little Deoxit in them or by running a plug in and out of them several times fast. If it doesn't, take it back and see if they can fix it or wait for Yamaha to gear up production again. Or get a PF800. Sounds almost as good as the 7 Pro. I give a slight tonal edge to the 7 Pro but the 800 is no slouch.
 
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#5
BogeyBass said:
Hate to be that guy....but

I've had zero problems with 7 pros

That is because I have never owned or will never own one including revision A , B , C ,D or F lol. I gave up after revision B
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I owned my 1st 7 pro years ago until it started cutting out. Got a 2nd one and the same thing started happening so I sold it. A bit over a year ago I bought an Ampeg PF 500 until it cut out on me at a show. We we’re 3 songs into the set . So all these years my trusty SVT 4 Pro has worked like a charm the whole time I was trying to replace it with something lighter. I also never had an issue with the three SVT 3 pros I’ve had over the years. I’ll also add I had a Fender Rumble V3 500 head that would cut in and out every now and then if I had it on too long. I think there is something inherently wrong with these class D amps. I honestly think they will run perfectly if run through a proper power conditioner. Something about odd power fluctuations mess them up. The only ones that aren’t affected by dirty power are “Quilters” they have a built in power conditioner. Anyway the 4 pro is pumping along sounding like a champ as usual lol
 
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#6
I was looking into a 7Pro or 3Pro.

In my research, the cutting-out issue comes from how the power amp section is dictated by the preamp section.
Basically, having the preamp gain too high will overclock the power amp.

Ampeg’s advice is to keep the master volume as max as possible and keep the pream as low as possible.

It makes me wonder how the power amp handles overdrive signal from the FX loop, but oerhaps that is different than driving the preamp section.

In my observation, the higher the series number (II, 3pro, 4pro,6,7,8) the more problems.

Being that this cutting out issue is still prevelant with the new owners, it seems to be a flaw in the design of the amp.
 
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#9
JimmyM said:
I have never once heard anyone from Ampeg say to keep the preamp as low as possible in their micros. As a matter of fact, Dino has a video up on Youtube saying just the opposite...



But I must admit that I got a good laugh out of your "higher number" theory :D
Click to expand...


Funny, because when I watched the video, he said what I said.

Also, you could do more research here on TB and see te posts confriming what I say.

Peace
 
#10
Bliff Curton said:
Funny, because when I watched the video, he said what I said.

Also, you could do more research here on TB and see te posts confriming what I say.

Peace
Click to expand...
No, it wasn't what you said. He turns gain up till he sees the light start blinking, then he backs off it till it stops. That is how you get a clean sound with some balls in those amps, and you said to turn the master up and keep the gain as low as possible, which is not the same thing. And if you want a dirty sound, let it blink. I've done it many times in Ampeg micros without mishap. And I've seen pretty much all the posts relating to these amps, and one person claimed someone at LOUD told them that. But that is how some people like to run them, especially if they have a pro audio background and not a bass amp background, as many of the CS folks at LOUD had/have. It has nothing to do with keeping them from faulting, and I think Dino's vid as well as my experiences with the Micro VR, PF350, PF800 and 7 Pro and many other people's experiences with their micros can attest. The problems with the PF500 and 7 Pro were unrelated to gain structure. Anyway, LOUD no longer owns Ampeg so it's all a moot point now anyway. And if in fact someone at LOUD told them to keep the gain as low as possible to keep them from faulting, then that is an unacceptable answer and they should have asked to speak to a manager.
 
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#11
Rodslinger said:
I owned my 1st 7 pro years ago until it started cutting out. Got a 2nd one and the same thing started happening so I sold it. A bit over a year ago I bought an Ampeg PF 500 until it cut out on me at a show. We we’re 3 songs into the set . So all these years my trusty SVT 4 Pro has worked like a charm the whole time I was trying to replace it with something lighter. I also never had an issue with the three SVT 3 pros I’ve had over the years. I’ll also add I had a Fender Rumble V3 500 head that would cut in and out every now and then if I had it on too long. I think there is something inherently wrong with these class D amps. I honestly think they will run perfectly if run through a proper power conditioner. Something about odd power fluctuations mess them up. The only ones that aren’t affected by dirty power are “Quilters” they have a built in power conditioner. Anyway the 4 pro is pumping along sounding like a champ as usual lol
Click to expand...

According to talk bass, these class D problems don't exist. But if they do, the old led Sleds " do the same thing"

Maybe the internet lol

In Real life, it's a much different story ;)
 
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#12
BogeyBass said:
According to talk bass, these class D problems don't exist. But if they do, the old led Sleds " do the same thing"

Maybe the internet lol

In Real life, it's a much different story ;)
Click to expand...

If you were to think about it for a minute, you might remember that there have been plenty of problems with the lead sled products too, it's not exclusive to class D amps.
 
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#15
So, just to follow up on this, I went ahead and bought a brand new SVT-7Pro and an 8/10 Classic cabinet... monstrous sound! I am unable to duplicate the head cutting out on this new one, but will try to keep everyone updated here at TB if I have any issues. I really don't play out live with this thing, so not sure how to "field test" it, but suffice it to say, it seems good so far. Brought home a couple of MXR effects pedals as well, which adds some nice dynamic to the sound. Got a Bass Chorus and a Carbon Copy.. pretty cool...

Happy Holidays to all!
 
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#16
Oystercopy said:
So, just to follow up on this, I went ahead and bought a brand new SVT-7Pro and an 8/10 Classic cabinet... monstrous sound! I am unable to duplicate the head cutting out on this new one, but will try to keep everyone updated here at TB if I have any issues. I really don't play out live with this thing, so not sure how to "field test" it, but suffice it to say, it seems good so far. Brought home a couple of MXR effects pedals as well, which adds some nice dynamic to the sound. Got a Bass Chorus and a Carbon Copy.. pretty cool...

Happy Holidays to all!
Click to expand...
Got both those pedals and they rule! I only wish I could find use for the Carbon Copy on bass. Hats off to those who use delay on bass who can.
 
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#18
Not sure if anybody made a similar comment yet but here it goes anyways.

Anytime you have drop off of sound from your power head check the pots first. The heads are shaken to thier limits if used regularly and if you have a loose pot it will cuase cutout issue's. I learned this with my Hartke HA3500. $12 later and a quick soldering job and all fixed.

With that said, before I fixed my Hartke I went on quest for an upgrade and came across a free svt-7 with a overheated main board. I purchased a new one (about $250) from Full Compass and put her back together. So far I havent found any issues but I have yet to run it at a gig. (Ive been using my good old relaible pre fender workingman 4004 for that) I have only ran the svt on a Gallien Krueger 410 glx and its sounds pretty good considering the cab. I plan on hooking it up to my swr Giii and big ben to put it to its limits through a set before hauling it out to the band room or a gig. With all I've heard about the svt 7 cutting out I wont take any chances.
 
#19
JimmyM said:
That doesn't sound like the typical problem most people had with the 7 Pro, which was a chip frying. They have since replaced that chip with a newer model that seems to have fixed it.
Click to expand...
I've got a 7 Pro sitting with exactly that problem. I don't think you can just replace the chip with a newer/higher spec chip...the entire motherboard needs a newer engineering change level...which includes that newer chip.

You can just replace the chip on the original, but sooner or later it'll probably blow again unless you happen to get a chip that happens to be a little more robust than average.

I keep meaning to order the new board and swap it out, but I don't NEED the amp since I got my D-800+ so I just keep stubbing my toe on it periodically when I walk through that part the room o' gear.
 
#20
Lol rad

I used my broken Svt classic to keep the drummers bass drum from sliding.

Guy attending show got all butt hurt
I told him if it bothers you then buy it from me.

Lol dude actually bought it....bye bye
 
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