Ampeg performance package upgrade

[jpatt2]

I saw in the Ampeg Book: the Story Behind the Sound that a performance package was an option for v4's in the 70's. It used 6550 tubes to up the wattage to 130 due to the ability or the transformers. Did anybody order this upgrade, or can at least give me some more info on it?

[mikeddd]

Calling Jimmy! Paging BassManPaul!

I'm just going by what little I know about tube amps. The more power the tubes put out, the greater the supply voltage must be. I.E. bigger transformer and other associated "supply grid" parts. I would assume that getting your standard V4 up to 130 watts is not as simple as just swapping out tubes, else everyone would've done it already.

I'm curious to hear the technical explanation though.

[JMac4strngr]

From what I was told by the amp tech that did the work on My V4.
1) It involves changing the tube sockets/retainer clips for ones that fit the 6550/KT88. (In which acording to him is a pain in the arse.)
2) Bias accordingly, which with the V4 is done by the use of a resistor versus an adjustment potentiometer.
3) More expensive tubes (6550 vs 6L6GC/7227)
4) The tranny will take the load but it's a bit much for what it was designed run with.
5) You wont really gain much other than a very small amount of extra headroom.

[BassmanPaul]

You Called???

Dropping 6550s into a V4 will gain you nothing that's worth the effort and expense. Even if you could boost the output by 30W over the 100W the difference would be almost inaudible.

[BassmanPaul]

Add to that the increased heater load of 1.5/1.6A over the 0.9A of the 6L6 family will make the power transformer run hotter. If the 6550 was an option then hopefully the PT was sized for the difference.

[nashvillebill]

Also, that performance mod was only shown on the schematic for the later V4's (the ones with master volume).