Couple questions about Ampeg SVT-2 Pro's and tubes

marantz10 · #1 10-16-2010, 06:27 AM

Hey everyone, 3 weeks or so ago I purchased an Ampeg SVT-2 Pro from Guitar Center (used for $750). Their warranty only covered 7 days but their 1 year extended warranty would not cover tubes so I thought that was pointless.

Last night at band rehearsal the amp quit playing on me. Bummer, but you get what you pay for--and I'm not entirely too upset about it. The front indicator light blinks red/green. One of my power tubes is not lit up and the manual supposidly says that a power tube died. I have 9 days until my next band rehearsal.

1.) How much are we looking at costwise to replace the power tubes for "stock" standard tubes including labor?

2.) How often do you guys find yourselves replacing your power tubes?

3.) Would I save a lot by replacing the tubes myself? I'm pretty good with my hands and usually a DIY kind of person, I've just have never done tubes before.

4.) Anything I should besides the obvious?--i.e. use standby switch before/after playing, don't move amp immediately after playing, don't drop it, etc.....

Thanks!

jastacey · #2 10-16-2010, 07:01 AM

Here's what I would do, I also recently aquired a used SVT II Pro, First determine how much money you want to spend, then here are the choices: One is to just replace the bad tube ( I'd try to borrow a tube to see if that will solve the problem of the amp going into protection mode, if it does do that, then that is the issue and you can do the rest your self, if it still is in the protection mode, get the amp serviced by a person who understands tube amps ), Two: Replace all the power tubes and keep the remaining tubes as a back-up set, some people have some very opinionated views on the brand of power tubes, but do some research on that subject, I believe the current production SVT's are using Sovtek 6550WE, it's not a bad tube, some people like using Tung-Sol 6550's, and some people like Winged "C" 6550's, remember the Ampegs use the power tubes in 2 sets of three, in a push pull fashion, the cost can be anywhere from $150.00 for the Sovtek to $220 for the Tug-Sol/Winged "C", these are priced from the Tube Depot price list, I'd also check pricing with Antique Electronic Supply, most of these places will ship for free if you spend $100.00 +. The third option: New power tubes, and replace the phase inverter and the driver tubes, get a balanced 12AX7, and get 2 NOS JAN 6189W (these are the heavy duty version of the 12AU7, these are not that expensive $12.00-$19.00 ea.). the inverter driver tubes are key in getting good service life out of a tube power section ... IMHO ..... I wouldn't fool with the rest of the preamp tubes, unless they are noisy or you just want to do some tube rolling .... this is some thing you can do your self, but buy the tubes from a repubale tube seller, and set the bias, once the amp issue is resolved ( the red/green lite blinking ) let the amp warm up on stand-by for 30 minutes, make sure the amp is plugged in to a cabinet, then turn the stand-by switch off, and turn the bias controls till the each light is green. and your good to go .... I'm still using a set of GT 6550-R's in my amp and they are pretty old, so you should get at least 10 years out of a set of power tubes

RickenBoogie · #3 10-16-2010, 07:19 AM

When buying a used tube amp, the smart thing to do is have it checked by a tech before you even use it. You have no idea the condition of anything inside the amp, and there's plenty that can cause you grief. A good thourough check up doesn't usually cost very much, (consider it part of the cost of buying a used amp), but NOT doing it can cause even more problems.. I'd just suck up and put it in the shop now, rent or borrow for the upcoming gig, and be sure you have a great working 2Pro for the next one.

DanRJBrasil · #4 10-16-2010, 08:16 AM

Take to a good repairman and get the repair costs, is also a very a good idea to get the amp checked.
The svt power section are in sets of 3 tubes so you may only need to replace 3, but you can replace only one if you get that one tube matching with the other 2( you have to test the tubes and order a match)

marantz10 · #5 10-16-2010, 08:28 AM

Thanks for the responses!

jastacey--you have been especially very helpful. Thank you!

RickenBoogie & DanRJBrasil--I definitely figured that new tubes would be something in the immediate future with a used tube amp. Wasn't much of a shock to me that one went out already but with a quality amp such as this, I definitely have decided I will take it in and give it a good "checkup" along with fixing the current issue(s). The next 'gig' is just a practice where they have loaner amps at the studio, so I'm not completely SOL. Hoping repair time won't take more than 9 days because I love this amp so much.

This SVT-2 Pro is the best sounding amp I have ever heard (when it was working). I'd do anything to make it last forever, and despite normally being a buyer/seller of goods, I really can't picture myself ever selling this one or upgrading to something else.

Thanks for all the advice! (and jastacey, I'll be taking down a list of the manufactures and models of the tubes for discussion with the tech guy).

JimmyM · #6 10-16-2010, 10:40 AM

you kinda sorta have to think about buying new tubes when you get a used amp, but not always. i've got a couple tubes that have 40 years worth of use on them, and many that have over 10 years. changing tubes needlessly is the biggest waste of money ever. that's why i agree with Dan about only replacing 3 power tubes at the most. and since you have those bias lights, maybe you could even bias it yourself. there's a standard bias control in them for a tech to use (or for you to use if you know how to bias with a voltmeter), but me being cheap, i'd probably just do it with the lights.

marantz10 · #7 10-29-2010, 05:09 PM

Update:

I got my amp back from the shop today. I opted for the repair guy to not only repair it but check over the amp. He checked out the soldier joints and such he said. He replaced the power tube (which had a crack in it and caused it to short I guess) and interestingly, it took down a pre tube with it. The old pre tube was Chinese and he replaced it with a JJ (12AU7). Total cost was 150 including labor. I don't mind so much mainly that it is A) working and B) checked out and everything looks good inside.

flyingfinbar · #8 10-29-2010, 05:28 PM

Quote:

Originally Posted by marantz10

Update:

I got my amp back from the shop today. I opted for the repair guy to not only repair it but check over the amp. He checked out the soldier joints and such he said. He replaced the power tube (which had a crack in it and caused it to short I guess) and interestingly, it took down a pre tube with it. The old pre tube was Chinese and he replaced it with a JJ (12AU7). Total cost was 150 including labor. I don't mind so much mainly that it is A) working and B) checked out and everything looks good inside.

Are you happy with the amp now? I got my IIpro used last month, and the thing kills it!

marantz10 · #9 10-29-2010, 05:33 PM

Quote:

Originally Posted by flyingfinbar

Are you happy with the amp now? I got my IIpro used last month, and the thing kills it!

This is an amazing amp for the price (I paid 750 for mine). Sure, I mean a VR or CL are similar amps but they cost a bunch more and frankly, I feel like the SVT-2 Pro's are more flexible tone wise. I haven't plugged in the amp yet until I go to band rehearsal tonight--it's a pain to setup at home just to test it out for an hour.

JimmyM · #10 10-29-2010, 05:53 PM

have fun, bro...nothing like an ampeg tuber!