Gear Discussion Forums > Bass Amps & Effects
Monster Fender rig - 400 PS
Happy Face:
https://reverb.com/news/the-most-powerful-tube-amp-of-all-time-behind-the-fender-400-ps?utm_campaign=e01aae5a23-rn170502_deals&utm_medium=email&utm_source=newsletter&utm_term=0_5889ed6702-e01aae5a23-57277785
Of course, there are some obligatory "oh my back!" kinda of posts in the comments section.
Psycho Bass Guy:
The comments about tube history in regards to the 6550A are bullshit, as are the comments about the SVT preamp rolling off bass naturally, and though it's an opinion, I would NOT describe the amp's tone on any channel are particularly "clear." Also, not using an output on the 400PS does NOT put its respective output tube pair into standby, but shorts it to ground.
Regarding the tubes, I knew the former head of QC for GE's Owensboro, KY factory; the 6550A was a US replacement for the KT88, a copy of Sylvania's 6550A, who produced ALL the tube glass envelopes for both companies. GE only made it because the envelopes already existed and they could use-off spec 6550A's, bottle and all, rebased as 6CA7's. The 6550A had more stable screen grids than both the original small bottle RCA 6550 and coke bottle Tungsol 6550, which allowed the tube to be driven much harder for more output power. It was made to accommodate both the burgeoning hi-power hi-fi designs of the day and output power hungry manufacturers like Fender AND Ampeg. RCA, Ampeg's former favored tube maker and neighbor in New Jersey (See the 7027), had already ceased most domestic tube production by the early 70's, though it sold other makes rebranded as its own until the mid 80's. When Magnavox bought Ampeg in 1971 and moved production to East Tennessee, it leveraged its relationship with Sylvania, similarly to Fender's famous "STR" Sylvania 6L6GC's made for the also-mentioned silverface Bassman amps, to help design a higher powered 6550, though SVT's shipped with Magnavox-branded Tungsol 6550's as late as the mid 70's.
In regards to the SVT preamp, a simple perusal of Bass Gear Magazine's curve trace of the SVT preamp set flat shows a distinctive bass BOOST, not cut, or more accurately, an inherent midrange cut that could be mitigated with the active midrange control; the rest of the tone stack is passive.
It's cool to see the 400PS get some press, but though the issues I take may be details, they are important ones.
Happy Face:
Thanks for the clarifications.
It's still interesting to many of us.
(I deleted the rest of my comment about the people on that thread whining about the weight of the amp.)
Psycho Bass Guy:
I don't deny the article is a long overdue tribute to an often unknown amp, but it doesn't do anyone any favors to spread falsehoods, intentionally or not. Maybe it's the leftover bad taste of my time in TV news and seeing corners cut at the expense of the truth one time too many.
gearHed289:
--- Quote from: Psycho Bass Guy on May 04, 2017, 03:07:55 PM ---In regards to the SVT preamp, a simple perusal of Bass Gear Magazine's curve trace of the SVT preamp set flat shows a distinctive bass BOOST, not cut, or more accurately, an inherent midrange cut that could be mitigated with the active midrange control; the rest of the tone stack is passive.
--- End quote ---
So the bass and treble are passive in an SVT? And as I'm sure you know, the "ultra lo" switch is much more of a mid cut than it is a bass boost.
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version