SVT2-PRO problem: no sound

[WhiteNinja]

Hey all!

So, today I received my first all-tube amp, a new SVT2-PRO. I got a very good deal on it (more or less half price), so I'm quite chuffed.

I checked the impendence if it was set to 4ohm (it was), plugged it via speakon cable into my SVT810E, hit the power switch, waited a few minutes, hit the standby switch, and then.... Nothing. Gain was at 9-10 o'clock, then I turned the master, but nothing happened. No Sound. The standby light remains green. The tube-bias lights at the back also stay green. My bass was turned up, the -15db pad was out, as was the mute pad. I switched to a different bass, still the same. I switched cables, nothing.

The cab and bass were both used the day before at a gig, and performed well.

I asked a mate qho also uses the SVT2-PRO and he's also clueless. Could it be that the master pot isn't working properly?

It's quite frustrating (it still cost quite a lot of money) and I have no clue what it could be.

Thanks in advance for you help!

[eastcoasteddie]

Adjust the gain to about noon and hit some notes rather aggressively. Is the red peak/mute light flashing? If so, then it is getting a signal, and perhaps something is off in the power amp section. If not, then perhaps a problem with the input...?

[Tim1]

Were the tone controls up? IIRC tone controls at zero = no volume with this tone stack.

[BassmanPaul]

Is the speakon wired correctly? If you use a "bridge" cable it simply won't work. It should be wired +1 >>> +1 and -1 >>> -1.

[WhiteNinja]

@eastcoasteddie:

I tried that, and the peak light didn't light up, even with the gain at max. Seems to be preamp/input issue.

@Tim1:

Tone controls are at noon, not zero.

@BassmanPaul:

Speakon is connected correctly, as I did get a sound when bypassing the preamp stage.


I tried running my bass through the VTBass as preamp an go straight to the poweramp via Effects Return, thus bypassing the preamp. It worked perfectly well, so there is no issue with the poweramp. The preamp is the problem, somehow it doesn't reveive a signal at all.

So, what does it mean? Input jack broken?

[BassmanPaul]

Try jumpering the effects send and return with an instrument cable and see what you get. Could be as simple as a dirty contact.

[WhiteNinja]

Tried that, but nothing happened. Still the same issue as before.

Anyway, I'm able to send it back to the store I bought it from. I'd still like to know what the problem is. It's my first all tube amp, and I'm still kind of afraid that it was me wgo messed something up when first trying it out.

[WhiteNinja]

So I read in another thread here on TB that someone else was having the same problem, and managed to get it worked pluging in cables into each jack on the backpanel. Before I do that (is it even safe to do?), I noticed when I plug in a cable into the footswitch that the front panel peak/mute light is on. I assume that is normal though, if it's not an actual stereo/dual footswitch?

I also used some contact cleaner on the input jack, but nothing changed, it's still the same as before.

[runmikeyrun]

didnt you try this amp in the store before you bought it? If you bought it with a credit card check with the cc company you may be able to have the cc company take the money back from the store. If the cc company will do this, then you've got some ammo when you go back to the store- you demand they either fix it or give you your money back. If they balk at you, tell them you're going to have the cc company take the money back. see how fast they fix it then.

[WhiteNinja]

I bought it online, not with a cc though. The store said they would take it back and check it. It shouldn't be a problem. I just wanted to find out if this was a familiar problem and if there is a simple fix to it that I could do myself, and also the nature of the problem. My guess is that it's a broken input jack, but I'm no expert, especially not with tube amps.

[BassmanPaul]

May I suggest you take the amp to a tech before you ship it back. He might well find something simple and save you the cost of shipping it back.

[Alex1984]

Shipping an SVT is not cheap. An hour of tech time would be a quicker turn-around and cheaper too.

[jmpiwonka]

i have a non pro svt-II
was having problems with it cutting out and losing ~90% of the signal so volume dropped way way down
tried replacing preamp tubes and thought it was fixed only to have it do it again at our next practice

did the usual swapping cables and tried it through a different cabinet as well, tried a short cable across the preamp out/amp in jacks
still did it
not sure if my cable was bad but i took the thing to a tech i know and he said as soon as he started messing with it it sputtered kinda loud and wouldn't pass a signal, he cleaned the jacks and then didn't have a problem with at all after that

went ahead and replaced the power tubes, one was microphonic and had him check everything else out...

he said the tung-sol sound a little puffier than the ruby's it had and a little less headroom, just got it today so here's to hoping the thing works trouble free now...

[WhiteNinja]

Update: I found out that it ISN'T the input jack that is broken. I checked the schematics and saw that the tuner out comes right after the input and before the preamp/mute. So I plugged my tuner into the tuner out jack, and it does receive a signal; I'm able to tune my bass via tuner out. So the problem IS in the preamp section. Could it be a broken preamp tube?

[jastacey]

I'd get a couple of 12ax7's and swap them out to see ....sometimes it could be a bad tube

[BassmanPaul]

Look to see if any of the pre-amp tubes appear white inside instead of silver. If one is so replace it.

[Jerrold Tiers]

if the tuner out works but regular amp does not, you could have a case of "no high voltage".

THAT can be due to loose connector, bad standby switch, etc.

The power for the tuner out does not come from teh high voltage, so there very likely isn't any high voltage on......

Are you certain the standby switch is set right?

[WhiteNinja]

Well, the standby/power LED works just fine. It's red in standby, and green when I hit the standby switch. Also, the power section works just fine when using a different preamp (VTbass in this case) and going into the effects return jack. What else could I do to find out if there is no high voltage?

[jmpiwonka]

if yr getting sound through the amp in jack then you have high voltage power i believe...

[B-string]

Use a guitar cable to "loop" the effects send to effects return and see if your in business then.