STAX: Their vintage SR3 & SRD-5 … and more


Hi Howard. Just found HFA;  full of useful stuff. I am interested in the differences between the electret and mains powered energisers. I have a pair of Stax headphones labelled "New" SR3 which originally (when I bought them in 1975) came with an SRD-5 energiser. The SRD-5 (which is mains powered) was changed for an SRD-6 (which is not mains powered, although it doesn't say "SB")

Question 1:  Can you tell me if using the SRD-6 is ok for the headphones or is the mains one a better match?

STAX were somewhat sloppy when it came to marking the type of power used in some of their energisers. In my office I use an SRD-6 which is not mains powered but is not marked ‘SB” (self-bias) either. Ho hum.

Now then, in my office system I use the SRX-Mk3 earspeakers. Both these and the SRD-6 these are quite old and yet have never given a moment’s problem. Curiously, this modest combination of SRD-6 and SRX Mk3 produces a sound characteristic that I can’t quite achieve with any modern STAX combination. There is a colouration with this old combination. It isn’t as neutral as say a 4040 II or Omega-2, but it sure is exciting. However ……

Using that SRD-6 with other earspeakers from that era, I’ve not been able to quite recreate that sound. I have no explanation for this.

In summary then, I cannot for certain say that all non-mains energisers are per-se ‘better’ than all mains-driven energisers. Different does not always mean better whereas better must always mean different! Moreover I cannot categorically state that ‘SB’ is better than non SB. It’s a suck-it-and-see situation. Three points to bear in mind:

Question 2:The sound in my opinion was better with the SRD-5 but it developed a fault and had a burn mark on the circuit board. Any thoughts and recommendations on your part would be greatly appreciated.

The stark reality is that there are no replacement boards for the SRD-5. Board repairs can only (and I know this for a certain fact because of work on my STAX SRA-12S) can only be done back at STAX HQ in Japan. The cost of 2-way transport alone makes this unrealistic. So, I guess your best bet is to buy a replacement dirt-cheap on eBay.

Howard Popeck