Ampeg SVT-VR

[Joe123]

I have an Ampeg SVT-VR that won't come out of standby unless I have at least 118 volts at the wall. I am in a bar band and voltage varies. This is becoming a problem for me. Does anyone have this problem, or can someone give me some feedback?
Thanks, Joe

 

[Passinwind]

Joe,

This belongs in the Amps Forum, this forum is for bass guitar mechanical setup, not amps or pickup related issues. I know you're new here... so welcome to Talkbass.

You might want to PM Jerrold Tiers, who was an engineer at Ampeg until recently. There's a cast of good techs who are regulars on the Amps Forum as well. I don't have any direct experience with the VR, or too many other modern Ampegs for that matter. There are at least a few other guys who are aces with 'em though. Best of luck!


--Charlie E

 

[HeavyDuty]

This belongs in the Amps Forum, this forum is for bass guitar mechanical setup, not amps or pickup related issues. I know you're new here... so welcome to Talkbass.

Moved...

 

[alfredpunkjazz]

I think is the same for any Tube ampeg... Same happens to mine, which is actually very often, Voltage in México it's a bad joke...

 

[Psycho Bass Guy]

Use Invalid Link Removed.

 

[Psycho Bass Guy]

I think is the same for any Tube ampeg...

...only the post-SLM made ones that use relay protection for powering up. In the SVT3Pro, which has a s/s output section, the relays can get out of whack and cause the amp to fry just by turning it on.

 

[One Drop]

I use mine often in a bar that has very dodgy power, but i go through a step-down transformer and never have any problems. I wonder if this regulates power fluctuations better.

 

[Psycho Bass Guy]

A transformer will absorb some smaller line transients and also acts a filter for line noise. The Tripp Lite model I mentioned uses transformers for this very reason.

 

[Jerrold Tiers]

If it cuts out at low voltage, there may be something goofy about the voltage detection circuit.

If the circuit has a problem, OR if there is an abnormally low voltage, it may cut out early. But it SHOULD allow operation way below that.

...only the post-SLM made ones that use relay protection for powering up. In the SVT3Pro, which has a s/s output section, the relays can get out of whack and cause the amp to fry just by turning it on.

Nost so sure about that..... with the 3PRO, the relay just connects the speaker to the amp. There isn't much it can do to cause a problem, particularly one that could cause damage. I can't think of a reasonable way it could cause damage, in fact.

If it DOES NOT connect, no problem except that there is no sound. If it DOES, no problem unless the output is shorted.

 

[Psycho Bass Guy]

Nost so sure about that..... with the 3PRO, the relay just connects the speaker to the amp. There isn't much it can do to cause a problem, particularly one that could cause damage. I can't think of a reasonable way it could cause damage, in fact.

If it DOES NOT connect, no problem except that there is no sound. If it DOES, no problem unless the output is shorted.

I had to rebuild mine three times (new drive and output transistors) because of the relay fault. IIRC, the relay controlled B+, and there was a problem with it being applied before output bias. I don't remember specifics because it was several years ago, but I've still got my skits, tech notes, and parts lists from the work. It was the most aggravating repair I ever had to do because the failures cascaded across so many seemingly otherwise unrelated systems.

 

[Jerrold Tiers]

I had to rebuild mine three times (new drive and output transistors) because of the relay fault. IIRC, the relay controlled B+, and there was a problem with it being applied before output bias. I don't remember specifics because it was several years ago, but I've still got my skits, tech notes, and parts lists from the work. It was the most aggravating repair I ever had to do because the failures cascaded across so many seemingly otherwise unrelated systems.

Not in the 3PRO....... the only relay in there is one that is on the output, as with a number of other amps. Mostly to prevent thumps on turn on/off.

The output bias has no relation to the tube B+, but the bias does come from the +- V to the SS part of the poweramp.

 

[Psycho Bass Guy]

Not in the 3PRO....... the only relay in there is one that is on the output, as with a number of other amps. Mostly to prevent thumps on turn on/off.

The output bias has no relation to the tube B+, but the bias does come from the +- V to the SS part of the poweramp.

I wasn't talking about the tube voltage; I was talking the main supply line to the output transistors and THEIR bias voltage. Maybe I should have said 'primary bus line.' I DO remember it wasn't active until the relay hit.

I'll dig out my notes just to be sure. What you're saying isn't adding up to what I remember having to fix.

 

[VicDamone]

I have an Ampeg SVT-VR that won't come out of standby unless I have at least 118 volts at the wall. I am in a bar band and voltage varies. This is becoming a problem for me. Does anyone have this problem, or can someone give me some feedback?
Thanks, Joe

Joe, What kind of support did you receive from either the manufacturer or local dealer?

Vic