Decware Zen Plate Model ZSP1

[gni]

After careful study of the pictures on the Decware web site:




and




I noticed that the preamplifier uses the aluminum plate as
the signal ground (and possibly the PS ground).

I would think that would be bad. . . it seems that you would
only want the signal ground to contact the PS ground at one
place. . . .keep high current and signal currents away from each
other. . .

It also runs the filament wires to the tube on the bottom left first
and then goes clockwise. . . wouldn't that tube be the one taking
the most current at turn-on and kill it first. Wouldn't it be better to
run four A/C filament pairs from the power supply to each tube
so they each take the current. . . maybe even a resistor to
slow the inrush?

[Bas Horneman]

I would think that would be bad. . . it seems that you would

I would think that too. But since apparently it works for him. Why not. If it works it works.

[Hotsauce]

That amp is a kit, so you can make whatever changes you'd like.

Remember also that the posted picture might not be the full schematic. It may just be one point in the progress of completion.

The Decware amps that I've seen inside of all seem to have a 'Less wire is better' philosophy.

John C.

[mcs]

Originally posted by gni
It also runs the filament wires to the tube on the bottom left first
and then goes clockwise. . . wouldn't that tube be the one taking
the most current at turn-on and kill it first.

No. The resistance of the wire should be insignificant (unless it's too thin), so all the tubes get the same heater voltage at the same time.

maybe even a resistor to slow the inrush?

Why? The heaters were designed for this use. Most tubes can survive this daily for 20-30 years without any "protection". If a tube gets killed by the heater inrush current, it must have been defective from the start...

Best regards,

Mikkel C. Simonsen

[Alex from Oz]

G'day,

Did a search and found this thread.

I just completed this kit two days ago. The pics shown above are in fact the completed circuit.
The entire signal path is parts lead to parts lead.
Although, my layout is not quite as neat as the pictured one!

This is my first tube project - a toe in the water you might say.
This kit seems to me to be very transparent and brings out a lot more detail in the music.

My power amp is a Silicon Chip magazine kit (15w class A SS).

I'm very happy with the results so far and looking forward to seeing how good it gets when they get a few more hours on them.

Cheers,

Alex

[Jeb-D.]

Cool,
Do you need some Decware chassis to go with your project?
FS: Walnut tube amp chassis pair ; Decware

[Alex from Oz]

I got the US$20 aluminium box when I ordered the kit. The wooden ones are out of my budget.

Thanks for the offer though.

The kids are helping me burn in the preamp - I just keep the DVD's flowing through all day!

Mind you, had some nervous moments convincing my four year old son that tubes are NOT christmas lights that can be touched with fingers, food and toys!

Cheers,

Alex

[gni]

I guess my original question still applies: does the
signal ground the aluminum plate? Would it be better
to ground the plate to signal ground at one point only
and have a dedicated ground for signal? I am really
interested in this preamp and just haven't made
the jump. . .Glad to see the thread is still alive.

[Alex from Oz]

The plate is ground for the signal and for the secondary windings on the transformer.
As for the grounding layout, I also wondered about using a single star earth point.

I have no experience with tubes, so in the end I decided to trust the Decware design and built it as is.