The transformers are on ebay now.
Up for sale are the last of my Stax SRD-6 and SRD-7 transformers, all fitted with my Pro bias board and have had extensive mods done to shorten the signal path. The mods consist of wiring one side of the the transformers directly to the Stax sockets bypassing the jumper leads in many of these boxes. On the input side I've discarded the old umbilical input cable, bypassed the selector switch and all the jumper wires, resistors, thyristors and wired the transformers directly to the old loopout terminals on the back of the boxes. On the SRD-7 units those terminals have been replaced with nice 5-way binding posts and on the SRD-6 I've scrapped the old connectors for some nice Sony part I had.
All of these boxes are a big upgrade over the stock units, not only by offering Pro bias but a much cleaner signal path. Now neither of these boxes were designed to drive anything as demanding as the SR-007 but the SRD-7 can give promising results and only bettered by much larger and more expensive transformers. The SRD-6 has smaller transformers so I'd only recommend it for use with any of the Lambda series of phones but it will work as a cheap way to drive a SR-007. One advantage these boxes have over any of the Stax made units is that the bias supplies in these feature the recommended updates Stax put into all of their gear after the SR-Omega was released. This means better performance for any post 1993 models.
Now going from left to right in the pic above:
1: This is a late model SRD-7 fitted with two Pro bias outputs and plugs in the output sockets so that normal bias phones can not be connected. It has the newer Stax sockets and the transformers are identical to the other SRD-7's. The switch on the front works as a power switch but like I said above, all input switching has been disconnected. The amber neon light is fully functional. The top of the unit had some rust damage so I sanded it down and applied some black spray paint to it. It's not a good paint job and more to stop corrosion then to be pretty. The cover is easy to take off should the owner want to refinish it. The rest of the chassis is in ok condition for its age. The power cord is fitted with a US power plug but the transformer can be used anywhere in the world without any modification.
2: This is an earlier model SRD-7. Same transformers as above and this unit has one Pro bias output and one normal bias output. A plug has been fitted so that a normal bias model can not be plugged into the Pro output. The switch on the front works as a power switch but like I said above, all input switching has been disconnected. The amber neon light is fully functional. The top of the unit had some rust damage so I sanded it down and applied some black spray paint to it. It's not a good paint job and more to stop corrosion then to be pretty. The cover is easy to take off should the owner want to refinish it. The rest of the chassis is in ok condition for its age. The power cord is fitted with a US power plug but the transformer can be used anywhere in the world without any modification.
3. This is a standard SRD-6 and since it has only one output, it is Pro bias only. These boxes never had any power switches so none is fitted plus there is no power on indicator. The boas is in ok condition with a nasty scrap on the upper right hand corner of the faceplate and some marks on the black top cover. Such is to be expected of 30+ year old gear. The power cord has a US plug but the transformers can be used anywhere in the world.
Thank for looking.
Edited by spritzer - 7/4/10 at 2:22am
