New Tubes for my Ampeg SVT 2Pro

Alexander · #1 03-21-2010, 02:52 PM

So, I bought (used) an Ampeg SVT 2Pro a few weeks ago and it obviously had a problem with it - a bit more hum than normal and some overtones that shouldn't be there. The guy I got it from said he would cover the repair which is nice. My tech said 3 of the output tubes were bad and need replacing, so I am getting a full set of new power tubes installed this week.

My question is this - should I expect better tone and\or more volume with the new tubes installed or will the tone\volume remain the same with just the noise gone? Since I'm new to the SVT world, I'm not sure what to expect.

Thanks for the help!

username1 · #2 03-21-2010, 03:52 PM

If the other 3 tubes are ok i wouldnt waste the money on changing them all. They need to be matched in sets of 3 so all you would really need is to replace the bad ones with a matched set of 3. Can't comment on if it will sound better or louder, depends on how bad the other tubes were.

Alexander · #3 03-21-2010, 05:21 PM

Well, I paid a premium for this amp because the guy selling it said it was 100% with new tubes. So, I just want what I paid for - this is a lot of money for me and I want it to be right.

Just wondering if having all new tubes in the output section would give more volume\tone. Also wonder if KT88s would be better than the stock 6550s? Any thoughts?

Krügmeister · #4 03-21-2010, 05:45 PM

I put JJ's KT88's in mine and it opened it up.. more grunt but less growly!

username1 · #5 03-22-2010, 07:41 AM

I would make shure your tech gives you the 3 good tubes to keep as spares if you want to change them all. And yes you would notice a difference in volume and tone if the original tubes were weak.

Alexander · #6 03-22-2010, 08:53 AM

Cool - thanks - I will be sure to ask for them. Looking forward to trying out my (now healthy) SVT...

KramerBassFan · #7 03-22-2010, 12:58 PM

Well if the amp calls for 6550's... but 6550's in it!

Now, if its modern tubes, then Most Chinese and Sovtek 6550's and KT88's are more or less the same thing. But if its NOS tubes, then 6550's and KT88's are NOT the same thing. One draws more current than the other, and needs a higher heater current.
But if your just getting new stuff, then they are more or less the same thing.. and hope your tech knows what he's doing.

Alexander · #8 03-22-2010, 01:02 PM

I went with EH 6550s - they should be in by Wednesday, just in time for rehearsal this week. Looking forward to hearing what a healthy SVT sounds like...

username1 · #9 03-23-2010, 07:14 AM

Quote:

Originally Posted by Alexander

I went with EH 6550s - they should be in by Wednesday, just in time for rehearsal this week. Looking forward to hearing what a healthy SVT sounds like...

I think you will be pleased with the EH6550 tubes. I have used them in an svt before and loved the tone. Good choice.

Alexander · #10 03-23-2010, 08:40 AM

Good to know - I chose them based solely on the tech's suggestion. He also mentioned I should get considerably more power once installed. When I got the amp, I really had to crank the master to between 1 and 3 o'clock to get any reasonable volume and tone out of it. I knew something was wrong...