john mayer's two rock??

[jelle]

jelle wrote:
I'd like a copy too.

Jelle


Hope you have an oxygen mask handy.

Gil

LOL! Well, I'll hold my breath just a little bit then...I started building amps basically to make me a SSS someday.....

Jelle

[Funkalicousgroove]

oxygen mask?

[Chris G]

oxygen mask?

Don't hold your breath!!!!!
Chris

[Funkalicousgroove]

Sorry, My other job is Driving the Short bus.

[Chad]

Sorry, My other job is Driving the Short bus.

[Chad]

I'm sure if anyone has a schematic of the SSS or any kind of info they would post it for us that would LOVE to take a shot at it RIGHT??!!.... PLEASE!! Not to sound like I'm beggin but PLEASE!!!!! JUST SOME INFO PLEASE!!! Maybe I could be more polite... MAY I have any INFO on the SSS PLEASE?? Chad

[ampdork]

Twin T filters?
[/i]

[Funkalicousgroove]

So I found a schemo for a tube driven Active Cut/boost bass and treble control that is supposed to go just before the power amp.

These controls use 1M pots instead of switches, so I wonder is it better to rig the switch up as 5 positions with different voltage dividers, or a fixed divider with 5 different capacitances?

The circuit says that with the knobs at the half way point it is bandpass with a 2.5v gain.

It's in the back of the RCA manual, and it's the only bass/treble control schemo there.

[ElectronAvalanche]

As far as I know, the Filters are indeed simply RC networks.

See the two pics attached.

Concerning the SSS PI. I have seen one specimen that had the following values:

0.02 input cap
820 Ohm cathode resistor
1M balancing
20k tail
240 fixed to ground from tail
0.1 uF from grid 2 to junction 270 Ohm 18k
100k plates
25k trimmer
68pF snubber
0.1 decoupling

0.1uF ------------grid of CF............... to CF cathode and Power tube grids
I.........................................................I
1M...................................................220k
I.........................................................I
to ground-120k--*---820k---------------<B- (300V)
I.........................................................I
1M...................................................220k
I.........................................................I
0.1uF-------------grid of CF............... to CF cathode and Power tube grids

Plates of CF to B+ approx. 380V

Maybe somebody can draw this up for all to share!

Cheers,

Electron

[FUCHSAUDIO]

I don't see any inductors, unless they are real tiny...

[novosibir]

I don't see any inductors, unless they are real tiny...

As he's already supposed:

As far as I know, the Filters are indeed simply RC networks.

And for building a network for tone shaping with a high edge steepness, it doesn't require inductors, when it's designed as an active topology around a tube.

Simply take a look onto the schems of some older 200W and 400W Marshall Bass amps, to see some examples.

Larry

[FUCHSAUDIO]

Many of the eclectic Hi Fi preamplifiers in the 50's and 60's (Harman Kardon Citation I, or some of the Fairchild stuff comes to mind) used R/C networks on rotary switches as high and low tone controls. Like many of HAD's other circuit adventures, I'm sure it's possible he looked at more than a few other products for "inspiration".

[novosibir]

I'm sure it's possible he looked at more than a few other products for "inspiration".

I'm even convinced about it

Btw. An interesting low-cut also might be the 'Slope Control' from the Marshall Bass amps - 3 RC networks cascaded and through a common pot to ground -> -12dB/Oct., although passive

Larry

[FUCHSAUDIO]

THAT is the question !

I believe Bill explained that the circuit was active, maybe using a triode or two, but I believe it's been maybe 5 yrs since we discussed it, so it's been quite some time.



The attached Harman Kardon schematic is a bit more complex that the SSS would appear to be, but it's clearly heading in that direction.

[FUCHSAUDIO]

Marantz Model 7