The Official Guide to Converting your Quickie for Headphone Use

[Paul Joppa]

... Can anyone confirm that the diagram is correct for 32ohm for the New Speco?  And is it right, then, that it's using the Speco as a transformer? ...

Yes, you have correctly described the "new Speco" diagram - though it says "less than 50 ohms" actually. (Calling it 32 ohms led to some misunderstanding of which diagram you meant.)

You should hear something from the labeled 8 ohm secondary, but it will be very low, about 18dB lower than the 10W tap. Suitable for extremely sensitive IEMs, perhaps.

[cpaul]

Thx, Paul.  Yes, you're right of course.  It is the <50ohm wiring I was talking about.  Glad I now understand it.  I may try it again b/c I can't figure out why I didn't hear anything.  Cheers.

[cpaul]

Back in post 84, I mentioned a similar transformer to the old Speco that's available for $4.99 (http://www.mcmelectronics.com/product/555-7120).  Same specs except it's a dual voltage transformer.  Well, despite PJ's concerns, I went ahead and ordered it and it arrived yesterday so I clipped it together today.

WHOA!  Much better than the new Speco.  Quite a lot of extra bass, and cleaner nicer throughout the (my  ) audible spectrum.  I don't know if the high end is any better (my old ears aren't so good up high), but it's still quite good.  So overall it's a big improvement over the current Speco.  I wired it essentially the same, blue/0.625w to the RCA outputs, Brown/10w to the headphones, black to ground.  Wiring is similar to the new Speco, wired as autoformer. 

I can definitely recommend this as a cheap way to a headphone amp.  Ultimately I hope to wire it with a switched jack so I can just leave it in place and still use it as a preamp while I build a 27-based linestage.

Photo of the two transformers (Speco is the smaller):

[bourbonator]

CPaul - do you still stand by the recommendation for that transformer?  Sorry, I'm very late to this thread. Looking particularly for what to use for Grado 80 headphones

[cpaul]

Yes, it's far better than the Speco (well, I haven't tried either in a little while as I'm working on some other projects at the moment).  Keep in mind, though, that my Speco is the new one that is quite small, and I haven't tried the older version (which I've never seen available despite the photos that some places are using that makes it look like they're selling the old version).  The older Speco could be better than the ones I use, I just don't know.

In short, unless you know you're getting the larger old Speco, I'd use the one I mentioned.

[mcandmar]

I would be interested to hear what the BH guys think of these as an option https://www.edcorusa.com/pcw10k-7k_300-32

Planning on ordering a pair to experiment with, but thought i would ask in case there is some good reason why they wont work.

Cheers,

Mark

[AudioDave]

CPaul -  Back in post #92 you described how you connected your transformer from mcmelectronics.  Just so I am clear,  are these connections for 32 ohm headphones?
Thanks!
Dave

[cpaul]

Whoa, Dave, I never got a notification of your post and must not have looked back at this thread.  Sorry about that.  I suppose you've figured it out by now.  In short, I was describing how I wired it for my Grado SR-60 phones (32ohm).   So yes, you are correct.