2 Headphone sockets on an HD83?

[NickW]

All,

Wonder if you can help on how one might fit two headphone sockets on a WAD HD83 or Headphone-II? This idea has arisen as a "nice to have" in an exchange with Black Stuart on upgrades to the WAD Headphone amp.

The question is really how to wire the output transformers? I have HD650 phones at 300 ohms impedance, and have thus wired the output transformers accordingly for the highest output impedance configuration. However, if I were to fit a second set of HD650 phones in parallel, what would that do to the load impedance and thus the output transformer/phone matching?

Why? - I bought my lovely wife a pair of HD650s of her very own when I convinced her that my very old HD565s needed replacing.....and it would be great to share the same souce at times.

Can anyone help?

Many thanks, NickW

[John Caswell]

Hi Nick,
Not being familiar with the HD83 this a generic type of answer. However I can see no reason not to try the following:
Leave the windings as is and wire the second socket in parallel with the first.
or separate the secondary windings into two so that you have two windings of approx 125-250R and wire each of these to a separate socket and see which sounds the best.
I don't think that there will be a noticeable difference at these low power levels but as usual am prepared to be proved wrong.

Regards

John aka Dr John

[Richard]

This would be the quick way to try,



http://www.maplin.co.uk/module.aspx?...o=989&doy=24m1

There's also a volume control you could use to adjust (lower) the vol to one set,

http://www.maplin.co.uk/module.aspx?...33144&doy=24m1

I would use the "125R - 250R" setting for the output as this will match 2 sets of phones ( = 150R) and one set alone will present a load a little higher (300R) which will result in a little less power to the phones but will not affect frequency response. (The amp will be happy to drive a higher load rather than a lower one).

Rich

Hi

If was for only the odd occasion you could always make up a flying lead and wire the two in series my HD 83 easily powers my 650’s and I would think there would be enough to power them both this way

[NickW]

All,

Many thanks for the ideas. I think the best thing will be to "suck it and see".

As I expect that the majority of the time the unit will operate on only one set of phones, a simple solution might be the better. A quick trial with a single-to-dual converter plug is certainly a good idea.

Thanks again,

NickW