New amp in the making

[Rob N]

For dynamic headphones from Singlepower

Power supply:

2 x 45 sec. Delay Relay tubes per power rail with switch for circumventing delay circuit
2 x 323 W.E. rectifier tubes, 2 x 4B27 Tungar tubes with adjustable loading
6 x Voltage regulator tubes 0A3 types, interchangeable with 0C3, 0D3, 0B3
2 x Voltage Pass Regulator tubes

Audio Section:

Drivers selectable between Type 27, 6SN7, 15E, 717 and others with adapters
Output tubes 6SN7, 6BL7

Inputs/outputs/switches

1 pair RCA input
1 pair balanced input
2 pairs Pre-amp out-RCA and balanced
2 pairs loop out - RCA and balanced
Switch between RCA and balanced inputs
2 x Shallco stepped attenuators 45 step 1.5 db per step
Heater voltage switch selection
Voltage selection
Bias selection driver
Bias selection output
Fixed Bias adjust on selection 1 of bias switch
Capacitor bleed tactile button with W.E. 395a indicator lamp/lock thyratron

 

[NoPants]

=O any pictures? is this supposed to be lumped into the same tier as the SDS XLR because it packs so many features into a single chassis...

 

[romanalexander]

wow nice info. thanks

 

[Rob N]

No pics yet.

It's really an extension of the two box SDS-XLR

 

[Rob N]

Mikhail is still buiding this but I thought I would do a little update.

It's being built into the ES2 type chassis.
There's actually going to be upto 8 0A3 type regulator tubes,4 per channel.Shorting adapters will be provided so that other regulator tubes can be used
It will now have an additional 2 x U707 tubes acting as damper diodes.
Delay relays are now 75 second octal 6NO75.
Mikhail has told me that pretty much any 4pin rectifier tubes from the 1920's to early 1950's can be used (4b27's do need an adaptor)

A quote from Mikhail on startup up procedure:-

"The first power switch is engaged and allowed to warm up the rectifier
heaters, regulator heaters, and final smoothing tubes (U707). Then the
second power switch is engaged. It allows power to flow to the relay
tubes, and this in turn takes about 45 to 120 seconds depending on the
type of relay installed. I prefer the 75 second relay tubes which allow
just enough time to let the other parts of the circuit warm up. Then,
all of a sudden the relay starts to engage with a slight flash
internally, one two three and possibly a fourth time in fast succession
the relay finally engages. The momentary flashes from the relay
provides just the right amount of critical ionization potential (photon
excitation of the noble gas) to ignite the voltage reference tubes."