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Ampeg SVT-II appreciation thread

#761
I'd like to know what your source is for these 210w SVT's. SVT's in proper working condition hit their marks no problem. Tubes might get weakened a little over the years, but failing that, they should hit their marks.
 
#762
JimmyM said:
I'd like to know what your source is for these 210w SVT's. SVT's in proper working condition hit their marks no problem. Tubes might get weakened a little over the years, but failing that, they should hit their marks.
Click to expand...

Just stacking the numbers together as I go from tube spec sheets. The tube store, tube depot, euro tubes, wiki etc. I just dont see how 6-6550s in an SVT can put out the same 300 watts as 6-kt88s in a SVT when they are different watt tubes? Am I missing something here? Does the output tranny have something to do with it? Will a higher watt tube just open up more clean headroom vs. early breakup?
 
#765
Johnathan Herrera of BP magazine says the output transformer is the main interface between your amp & speakers & has a large influence on sound because of different winding arrangements, amount. & quality of copper & iron etc. This is one of the main reason I may. Hange to a new tranny. They degrade over time & start to muck up your amps performance
 
#766
tbird36go said:
Johnathan Herrera of BP magazine says the output transformer is the main interface between your amp & speakers & has a large influence on sound because of different winding arrangements, amount. & quality of copper & iron etc. This is one of the main reason I may. Hange to a new tranny. They degrade over time & start to muck up your amps performance
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The one in my 69 SVT isn't degraded whatsoever, and considering how it was treated before I got it, if any trannies should degrade, it's that one.
 
#768
tbird36go said:
Average plate dissipation rating of 6550s is 35W, KT88s is 42W, KT90s are 50W & KT120s are 60W. I'm no math magician but it seems to me if you run 6 6550s in a SVT you would push about 210+ Watts or you could drop in KT88s for 252+ watts so on & so on. I wana run KT120s at 360+ watts & this is where the new tranny comes in. I sent an email to Mercury so i'll se what they have to say about it. I know tubes give a little more power in the push/pull they do but not a ton more. I could be totaly wrong about all this but I spend alot of time reading specs with my OCDisum. A guy at Watford Valves in Hertfordshire, England swears by the KT120s & runs them in his SVT. I don't know if hes done any mods to it but Im gona find out.
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You are quoting specifications. Many times with tubes they operate outside of their design parameters. Many times successfully, sometimes not ;).


tbird36go said:
Just stacking the numbers together as I go from tube spec sheets. The tube store, tube depot, euro tubes, wiki etc. I just dont see how 6-6550s in an SVT can put out the same 300 watts as 6-kt88s in a SVT when they are different watt tubes? Am I missing something here? Does the output tranny have something to do with it? Will a higher watt tube just open up more clean headroom vs. early breakup?
Click to expand...

Tube vendor data, which *hopefully* is reliable.
The SVT runs a relatively high plate voltage which is necessary to get the 6550s to produce their max. It also supplies a good amount of current at those voltage to keep up with the electrical demand even WHEN THE AMP IS RUNNING FLAT OUT. As I said earlier, the power supply must be able to properly deliver voltage and current to produce the power.

(There are 4xEL34 amps that can produce clean 120w RMS, too. But that tube is *rated* for only 25w max.)

Does the SVT-II even have the capability to:
1) Safely operate the KT-120?
2) Produce the claimed (thank you, NS) output of the KT-120?


tbird36go said:
Johnathan Herrera of BP magazine says the output transformer is the main interface between your amp & speakers & has a large influence on sound because of different winding arrangements, amount. & quality of copper & iron etc. This is one of the main reason I may. Hange to a new tranny. They degrade over time & start to muck up your amps performance
Click to expand...

Yes, the OT has a significant influence on the sound, feel, frequency bandwidth.

The OT degrades over time? Who said this, and why?
If a mishap occurred in the amp, it could damage the OT. But, under normal operation this sounds like pure BS.

tbird36go said:
Thats cool I hope mine checks out OK. If its good to go I might just pop in some JJ KT88s & call it a day.
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That may be all that you need, or you may need nothing at all. For example: 320w vs 270W in your amp. Will you hear or feel the difference, all else being equal?
BTW, how much power is it actually producing right now?
 
#769
I just purchased an Ampeg SVT II (nonpro) from a guy in the midwest, and it is currently on the UPS truck on its way to me.

It's in fantastic condition and I got it for a smokin price. The only thing the amp is missing are the little white plastic covers that go on the ends of the EQ sliders (his 3-year old nephew took them off a while back, never to be found again).

Would any of you happen to know where I could buy a set of those thingies?

Thanks.
 
#770
SactoBass said:
I just purchased an Ampeg SVT II (nonpro) from a guy in the midwest, and it is currently on the UPS truck on its way to me.

It's in fantastic condition and I got it for a smokin price. The only thing the amp is missing are the little white plastic covers that go on the ends of the EQ sliders (his 3-year old nephew took them off a while back, never to be found again).

Would any of you happen to know where I could buy a set of those thingies?

Thanks.
Click to expand...
Holy cow, good luck with that one! EQ slider thingies are some of the hardest replacement parts to get for any amp.
 
#775
Thanks for all the info & calming of my nerves but the head hasn't even reached me yet its on its way FedEx. That's the kind of guy I am I need to know damn near everything before I touch something. I've been working on & building basses for years but never did any major amp tweaking other than rolling tubes & speaker wiring. This may just be the OCD project I've been looking for. I might overdose on this head just to see what happens. Nobody else on this forum is doing it so why not be the first. Im also in the process of preping my 810E to get a coat of LineX. Lots of projects ill keep everyone posted.
 

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