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Ampeg SVT-II appreciation thread
- Thread starter i_got_a_mohawk
- Start date
Did you already try patching a guitar cord in-between the preamp out & poweramp in jacks?
OMG!! that worked!
anderbass you are awesome. I never would have thought that would work.
Is that supposed to be like that all the time, or is there something wrong still?
This is my very first all tube amp.
UPDATE - It worked for a lil bit then the volume dropped down again.
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So i replaced the 2 12ax7s closest to the volume knob ...they worked for a min and got quiet again, but after messing with the volume knob..it turned on really loud.
has not gone low again..
Anyone know what kind of tubes were the original ones? These are all Sovtek
I probably could have gotten away with replacing just one..
I'm very far from a tech, but... sounds like either a pre amp tube, as you've alluded to and addressed, or cracked/ dry solder joint/s.
Could even be a problem with the volume pot.
Could even be a problem with the volume pot.
It could be the lighting but those small signal tube pins look very oxidized. The can be scrubbed clean with some deoxit. Do not sand or wire brush the pins, they have a protective plating that you don’t want to remove. If the tube pins are that bad, the tube socket contacts can also be oxidized. They should be inspected. If they look black like the tube pins, the contacts need cleaning.
Even though you changed the tubes, the socket should still be inspected and cleaned. Oxidation is an insulator and acts like a resistor in the circuit. Not a good thing.
Deoxit can also be used on the jacks and more importantly the jack shunts on the pre-out and poweramp in jacks that were patched with the cable earlier. The signal flows through the shunt from the pre to the power amp when no plug is inserted. If the shunt is oxidized, the signal flow is impeded and decreases, the amp goes quiet.
Even though you changed the tubes, the socket should still be inspected and cleaned. Oxidation is an insulator and acts like a resistor in the circuit. Not a good thing.
Deoxit can also be used on the jacks and more importantly the jack shunts on the pre-out and poweramp in jacks that were patched with the cable earlier. The signal flows through the shunt from the pre to the power amp when no plug is inserted. If the shunt is oxidized, the signal flow is impeded and decreases, the amp goes quiet.
I always agree with beans on toast, he's a very knowledgeable amp tech & knows a lot more about these matters than me.
When I bought my very-lightly used 1993 SVT-ll back around 2006, all of its small-bottle tubes appeared to still be original, and all of them were labeled as being 'Hot Rods'.
I think I remember someone here on talkbass claiming that these 'Hot Rod' labeled tubes came in most all SVT-II amps, and I think someone else claimed these tubes were actually manufactured by Sylvania, and were simply custom-labeled as being 'Hot Rod's for factory-installation in some, or possibly all Ampeg amps made in that era by SLM.
When I bought my very-lightly used 1993 SVT-ll back around 2006, all of its small-bottle tubes appeared to still be original, and all of them were labeled as being 'Hot Rods'.
I think I remember someone here on talkbass claiming that these 'Hot Rod' labeled tubes came in most all SVT-II amps, and I think someone else claimed these tubes were actually manufactured by Sylvania, and were simply custom-labeled as being 'Hot Rod's for factory-installation in some, or possibly all Ampeg amps made in that era by SLM.
Hi Eric
The SVT-II's that I had originally came with Phillips labeled 6550's. I've owned some later '90's/2000's Ampeg products that had the Hot Rods - like B15R, SVP-Pro, SVT-2 Pro. Maybe the last of the SVT-II's had the Hot Rods.
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From the very early days, Ampeg branded tubes came from Sylvania. Maybe that’s how that comment came about.
I can’t comment on the Hot Rod tube brand other than they are good sounding tubes. I believe that they were made by EI in Yugoslavia with the Philips factory tooling. If that were the case, they wouldn’d be from Sylvania.
I can’t comment on the Hot Rod tube brand other than they are good sounding tubes. I believe that they were made by EI in Yugoslavia with the Philips factory tooling. If that were the case, they wouldn’d be from Sylvania.
oops - I meant Phillips - not GE. I will edit my post.
I don’t know about the 6550’s. A lot of SVT’s wound up with GE6550A’s in them. They are very nice tubes, I have a set in my ‘71 SVT. Kind of expensive to buy today, even if you can find them. Tctubes.com sometimes has some on offer. I see that they currently have an octet of Sylvania 6550’s for $875.
At those prices I'll just stick with JJ's, thank you.
They don’t have a sextet but if you offered to purchase six, they might be willing to split the octet. In general, tubes like these Sylvanias or GE6550A sell for around $100 and up per tube.
A couple of years ago these tubes were more readily available at affordable prices.
The advantage of places like tc is that they are burnt in and well matched. If you aren’t dealing with a trusted reseller, you’ll never have confidence in getting what you think you are paying for.
www.tctubes.com
Dang, those are pricey.
My amp tech/buddy has a stash of GE-6550's, and I have a large recording/rehearsal studio full of guitar & bass amps, plus other gear that occasionally needs service. ~ He digs Ampeg & Mesa amps, so Instead of paying him cash for my repairs; I've been swapping him my older Mesa Boogie gear that I hardly ever seem to use anymore. ~ So far, I've swapped him my Mesa Studio Preamp & Buster 15" combo, and I still have my 400+ and D-180 heads standing by for future swaps.
So I've got a feeling my SVT-II & 72 Blueline SVT will remain equipped with GE-6550's for quite awhile...
My amp tech/buddy has a stash of GE-6550's, and I have a large recording/rehearsal studio full of guitar & bass amps, plus other gear that occasionally needs service. ~ He digs Ampeg & Mesa amps, so Instead of paying him cash for my repairs; I've been swapping him my older Mesa Boogie gear that I hardly ever seem to use anymore. ~ So far, I've swapped him my Mesa Studio Preamp & Buster 15" combo, and I still have my 400+ and D-180 heads standing by for future swaps.
So I've got a feeling my SVT-II & 72 Blueline SVT will remain equipped with GE-6550's for quite awhile...
Can you describe the tonal differences in the 400+ and SVT II, or at least why you like the SVT II more?
Yep, all of my Ampegs (including SVT's, 72-V4, 66 B-18n & a pair of B-100r combos) have a lot more of the low-mids I dig, with a better balance of nice warm sounding mids & highs.
I still break out my Mesa amps from time to time and give them yet another try, but I constantly get the urge to be tweaking all their knobs, push/pulls & eq's in a futile search of more prominent low-mids & less harsh/brittle sounding mids & highs; all while still cutting-through my bands; without playing too loud. It's like I cant ever get that balance just right, and then when I get close; I'll have to start all over again when playing in a different room or stage, and/or using a different cab...
I kinda dug my Mesa's for awhile, but all of my Ampeg's have always been way more of a 'just plug in & play' type amp for me, from room to room & stage to stage. My Ampeg's always just seem to let me concentrate on my playing & groove, instead of being distracted & constantly thinking about what new combination of knob settings I could try out next...
I even tried modding my 400+, you could check out my old thread at this link for more info about that: SWITCHABLE MAX OUTPUT MOD, FOR a 300/w TUBE AMP.
I still break out my Mesa amps from time to time and give them yet another try, but I constantly get the urge to be tweaking all their knobs, push/pulls & eq's in a futile search of more prominent low-mids & less harsh/brittle sounding mids & highs; all while still cutting-through my bands; without playing too loud. It's like I cant ever get that balance just right, and then when I get close; I'll have to start all over again when playing in a different room or stage, and/or using a different cab...
I kinda dug my Mesa's for awhile, but all of my Ampeg's have always been way more of a 'just plug in & play' type amp for me, from room to room & stage to stage. My Ampeg's always just seem to let me concentrate on my playing & groove, instead of being distracted & constantly thinking about what new combination of knob settings I could try out next...
I even tried modding my 400+, you could check out my old thread at this link for more info about that: SWITCHABLE MAX OUTPUT MOD, FOR a 300/w TUBE AMP.
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