EL82 in triode with silverstepper (TVC)

[ReinoutdV]

Good day all,

time for a new project. The big amps are finished (see the TB3/1000 and 833A threads) and they do sound very fine in the audio room. But in the living room....only her shocking plastic JVC-"thing" (i simply can not call that audio / hifi / music. So....the next project will be a small amplifier. Her wishes:
no funny anode connections; small; simple switch on/off.

I had some very nice parts still laying around. The most interesting was a silverstepper. This is a input transformer combined with a switch; a TVC (Transformer Volume Control). A very usable item; it oozes quality. Till now i always used a potmeter + inputtransformer....and this is combined in a very handsome package.
Sourced from www.silvercore.de

Picture of the silverstepper. My TVC is silver-wired; hence the name. This picture is from that website; the other pictures are from the amps itself.


The tube itself: the EL82. Not again a EL84; this tube is simply too crowded inside'pushed to their limit in the designer-years in quest for the most power from a small package. And everybody uses that tube.
The EL82 is lower in power....but sounds wonderfull. I sourced a complete box of 200 tubes. All made in the same manufacturing batch in August 1951 in the Blackburn-facility of Mullard.
These nice tubes will be used in triode; not as penthode.

[ReinoutdV]

Also available was left-over core material for an interstage. In the big amplifiers i used EI72 nickel laminations. For that application i stacked 1 3/4 inch of that stuff (interstage 6SN7 - 300B). But now i only had to 1 inch for each interstage left. For this application that was sufficient.
So the input is doen by the silverstepper; then the first stage by 6C45; then an interstage; and the output devices are EL82's in triode.

I had enough capacitors on the shelf. Just measuring them. That's always nice about quality oil-caps (mostly military stuff). After tens of years of shelflife....measure them: and within specs.

[ReinoutdV]

So component-wise i was heading in the good direction. But as this amplifier would be in plain sight in the living area the chassis must be nice too.

Also on the shelf are left overs from an amplifier design. These were interesting. It is a monochassis (2 avaliable) but with an integrated power supply. In essence each monochassis consist of 2 boxes; connected through massive metal piping. So the wiring is possible through those pipes.

One problem.....size....will it be too big to pass her judgement.......? But now i got all the components available and saw it fitted perfectly.

Decision made: order the top-plates.

On the pictures you can see the lay out of the powersupply and the audio-part. And this is mono.

[ReinoutdV]

Always a nice sight: the goodies on the shelf waiting to be used !

When the top-plates arrived i could start with the mechanical construction. These amps weigh 23 kgs each. Not surprisingly as the chassis is made out of 10mm aluminium; the top-plates of stainless steel and the bottom-plates of brass. Of course the transformers also add to the total.

[ReinoutdV]

Mechanical part over...start heating up the soldering iron.

In the pictures you can see the complete (mono-)amplifier. Very good visible is the connection between the powerssupply-part and the audio-part.

And two detail-pictures of these seperate parts.
Of course all free wired.

[ReinoutdV]

The final pictures of the acomplete amps and the first testrun.

They do look good; and they sound even better. Very nice soundstage; good in details and ABSOLUTELY silent when needed (and i don't mean that you have to switch of the amps....). Seriously: these amps are silent. So hum or other funny distractions.

In total i am very pleased. But i just found out that although they do sound good i can change them again for she thinks they are too big for the livinag area. I will not dismantle these fine amps !
I will start with another amp based on the same tubes and components. Just somewhat smarter build; more economic in space.

The advantage of the silverstepper TVC is nice. You simply hook it to an audio-source....music !
Next amp i will use more items from Silvercore. For the pragmatic reason because i do not have any trannies left (and i will NOT break up the current EL82 amps) and for the musical reason for the quality is seriously good.

And now starting with a cunning plan downsizing this set-up without sacrificing the quality.

Regards, Reinout

[Luke]

fantastic build quality. Nice rack too

[Tubes4e4]

Hi ReinoutdV,

Originally Posted by ReinoutdV

The EL82 is lower in power....but sounds wonderfull. I sourced a complete box of 200 tubes. All made in the same manufacturing batch in August 1951 in the Blackburn-facility of Mullard.
These nice tubes will be used in triode; not as penthode.

Triode strapped EL82 / 6DY5 / PL82 / 16A5 curves here: http://www.tubes.mynetcologne.de/roe..._as_triode.pdf

Regards,

Tom Schlangen

[planet10]

Originally Posted by ReinoutdV

the silverstepper TVC

Reinout,

What is the ballpark on the price of these? I couldn't find any info on that on the website.

dave

[revintage]

http://www.silvercore.de/index.php?stepper-11

Zin is low at 10k and there are only 12 steps. Looks great though!