English Plus Starter Second Edition Audios

[Claribel Szwaja]

Nowthe 4 output sockets were setup to make sure Tyll to could test pretty much anything out there. From the right there is a regular Pro bias socket, a normal bias socket (230V bias), a Sennheiser HE90 socket (500V bias and the correct ballast resistor) and finally, an extra 5 pin socket. This has a special PSU on the side of the amp which feeds a 0-1000V DC/DC converter. Simply plug probes into those sockets on the side and adjust the trim resistor above to set the bias. This means the amp can run Jecklin Floats and other oddball designs plus there was talk of higher bias voltages back then so it was a way to future proof the amp.

This is a stock Stax SRD-7Mk2 with the original box. This is the last, upgraded,version of the SRD boxes and suitable for both Pro and Normal bias headphones. This is a good way to drive electrostatic headphones off speaker amps as these units provide the bias supply and use transformers to step up the audio signal to the right level. It comes with a US/Japan power plug but is universal voltage so it can be used anywhere in the world.

Here is a second, very early SRM-313 amp, but in much nicer condition. Same external voltage selector and this unit has been fully refurbished as well with new electrolytic caps. Some light marks on the back of the mousing but this is close to mint condition.

The SRM-3 was the follow up from the SRM-1 Mk2 and a far more modern design. This is a great starter amp and puts some more expensive amps to shame. This unit has been refurbished with new capacitors, the volume control cleaned and lubricated plus I updated the bias supply to the modern standard. It can be set to any voltage before shipping it out.

Here is a nice Stax SRM-1 Mk2 amp, fully recapped and cleaned so that it will work perfectly for years to come. These are a great beginner amp and pair well with either the vintage Stax sets or the newer L series. There are some scuffs on the back covers but over all in very nice condition. As with all of these, it can be set to any voltage before shipping it out.

Here is a near mint SRM-1 Mk2 P.P. which was a special edition with improved internal wiring and resistors. These all have dual pro bias outputs with no normal bias. It is a great starter amp and drives any of the Lambda, L series or Koss ESP950 with ease. This unit was fully refurbished with new electrolytic caps, volume control cleaned and lubricated plus the bias supplies brought up to the newest standard. There are a couple of marks on the chassis (as pictured) but over all condition is very good. It can be set to any voltage before shipping it out.

Now here is a rare one, the Sound Tech MC7 Pro bias amplifier. I got this one with the headphones (which is what I wanted) but these sold almost exclusively in China a few years back. The circuit is a variation of am old Stax design but updated so this makes for a good, budget tube amp. RCA and XLR inputs (with a proper input selector switch) and the classic ECC83/6SN7 tube layout. This is no monster in terms of power output but it works well with all of the Stax L series, Lambdas, SR-009 and X9000.

This SRM-1 Mk2 started out life as the normal bias only version but since they use the same PCB as the Pro bias units, I just populated all the missing parts on the PCB so this one now has one of the outputs converted to Pro bias. The amp has been fully refurbished with new capacitors, updated the bias supplies and cleaned the volume control so it works perfectly.

This unit has the voltage selection hard wired so I can set it to any voltage before shipping it out. The amp is in over all nice condition, some marks on the painted back panels but they all suffer from that. Over all though, it is a nice little amp which will drive most electrostatics perfectly well.

Here is a small amp project which dates back to 2019 but never really went anywhere. The plan was to look into cheap (sub 1k$) amps and a simple way of making them quickly. I had known about the Little Dot units for years so I bought a couple of them, stripped them down and replaced pretty much everything to turn them into an electrostatic amp. The main chassis, transformer cover and the back panel are all Little Dot Mk2 but the holes for the tubes were enlarged, a new transformer fitted inside the cover and a new PCB designed for the chassis.

This is another stock Stax SRD-7Mk2 in very nice condition. This is the last, upgraded,version of the SRD boxes and suitable for both Pro and Normal bias headphones. This is a good way to drive electrostatic headphones off speaker amps as these units provide the bias supply and use transformers to step up the audio signal to the right level. It comes with a US/Japan power plug but is universal voltage so it can be used anywhere in the world with adapters.

The SRM-300, the weirdest looking amp Stax ever made. This one was in a sorry state when it arrived, most the paint had flaked off the cover and it was bent out of shape due to shipping damage. The amp it self was just fine, measured great so I adjusted it and bent the covers back into shape and painted them. I had to sand them completely down so I tried a new way to a textured paint finish (as it was stock), it is a coarser than it should be but I think it looks nice.

The amp is a neat design that acts like a headphone stand and the circuit is really a scaled up version of the portable SRM-001. Very neat design and even features a small R-core transformer. I can set the amp to any voltage before shipping it out.

This is a SRM-1 Mk2 amp that has been fully refurbished with new capacitors, updated the bias circuit to the new standard and cleaned/lubricated the volume control. The amp can be set to any voltage before shipping it out and it is in over all good condition with some marks on the paintwork.

This SRM-T1 has been shitting on a shelf for years here as it arrived with a missing volume knob and the volume control was broken. I was always on the lookout for replacements but nothing has shown up so I just did it my way. The amp was fitted with a new Alps RK27 volume pot and then I found pretty much the only available volume knob which fit in that cutout. Due to the length of the volume control shaft and the height of the knob, the control is not as pronounced on the front panel as it was with the Stax units but it works perfectly.

The amp was then treated to my usual mods, the output protection added for the amp channels, bias supplies updated to the latest spec, all electrolytic capacitors were replaced and the amp fitted with a CCS for the output tubes. Cosmetically the amp is pretty good condition for a 35 year old unit, with not too many marks on the front panel or the back cover. This one can be set to any voltage before shipping it out.

Here is a classic, a Beyer Dynamic N1000 energizer for the ET1000 system. The set I received had some serious issues with the headphones so I replaced the cable with a Stax normal bias unit so this energizer is surplus to requirements. It will with two adapters as well, one which allows Stax normal bias headphones to be used with it and adapters from the DIN inputs to banana sockets.

A completely original Stax SRA-8S preamp/amplifier from 1967. This one is completely untouched and while it came from Japan the transformer does have a provision to run on 117V as well. Simply move one wire and you are set. Now this amp needs to be refurbished but I have so many that I just want to sell it. These are super rare and a great match for anybody with a SR-1 set or even the super rare SR-2.

I bought this when they were first released and it only arrived with the Euro plug on the PSU, even though they can be easily swapped out. I stripped it down, ran tests on it and then designed a new PCB which adds protection to the output as the stock unit has none. This amp has been fitted with that fix that did require me slightly moving on of the transformers and drilling an extra hole. Other than that, the unit is fully stock and even has the plastic cover still on the front panel. It comes with the original box and manual.

Musician Pegasus dac which is an excellent R2R design from China. It is multi voltage so can be used anywhere in the world. There are some marks here and there on the silver chassis but it is in overall good condition and works perfectly.

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