The Official Guide to Converting your Quickie for Headphone Use
- Thread starter Doc B
- Start date
You could hang them off the output of your BeePre.boulos said:Alright, thanks!I'll find a different use for them.
600:600 or 600:150. On the downside, they will load the output of the BeePre if they are installed, even if nothing is hooked up to them.
-PB
-PB
I've finally decided to convert my Quickie 1 to a headphone amp. I'm using nothing special for cans and they are low impedance. Edcor no longer makes the EM0735 (I suppose one could custom order it and pay the setup fee) so I bought a pair of the Specos to wire for 32ohm (they are the new ones and weigh in at 4.75oz). They were quite cheap so I'll give them a try, but they are VERY small so I have my doubts. Then I took a quick look this morning and found this: http://www.mcmelectronics.com/product/555-7120. It sounds virtually identical to the old Specos, weighs just about 10oz (according to the specs) and costs $4.99. Any thoughts? I'll probably order a pair to try out.
In both cases I'll post back if/when I have success.
In both cases I'll post back if/when I have success.
Paul Joppa
Moderator
Seems unlikely - those dual-voltage (70 and 25v compatible) line transformers usually don't have enough inductance for decent bass. But until someone tries it, we'll never know for sure!
Thanks, Paul. Transformers are a big black box to me, and I certainly didn't know that about dual voltage (I don't really understand how a dual voltage would be wound in the first place...). And frankly, I hadn't even noticed that it was dual voltage. It came up as 70v and I went straight to the specs. Now I see that.
Tonight I hooked up the tiny Speco transformers per the wiring diagram on post 65 by mcandmar (thanks!) and had a listen. Quickie performs reasonably with these transformers. I don't notice substantial loss of bass, midrange is full and clear, and the high end is certainly good if not quite good. At the same time nothing is outstanding. Now, this is with Grado SR60s (old version) and Fostex T50RP, both of which are on the low side of impedance (32ohm and about 60ohm respectively).
I got the best performance using the 0.25W tap as the input (attached to the RCAs) and the brown tap (10W) connected to the headphones. I tried the recommended 32 ohm wiring per the diagram in post #65, but there seems like there's something wrong with that. When I inadvertently left out the jack ground, I got a small amount of very hollow sounding audio. When I put it back in, I got nothing. Checked and re-checked but found no problems.
As I read the diagram (see image), the ground is pulled off of the transformer BEFORE the headphone output. Wiring is input to 0.25W tap, common on the multi-tap side tied to the ground on the 8ohm side and that connected to Quickie ground, followed by the output attached to the 8ohm tap That would seem to be a recipe for no sound output even ignoring what the core is doing to the 8ohm "secondary."
Am I misunderstanding something here? Anyway, I tried a number of variations on the 32ohm wiring to no avail. I got little or no sound out each time. But since I was getting reasonable performance with the brown/50-200ohm wiring, I just went with that. I may experiment more, but reasonably satisfied with the way it is. I did try the red and orange taps (5w and 2.5w) and they weren't bad, but not as good as the brown/10W tap.
These Specos cost me less than $6 each plus small amount of shipping. At that cost, it's well worth experimenting. And I have a reasonable headphone amp to boot. I'm new to headphone amps, so not sure I have a good baseline to compare, but it's better than the output of my CD player (and OLD Pioneer PO-M6) which is no doubt op-amp based.
I got the best performance using the 0.25W tap as the input (attached to the RCAs) and the brown tap (10W) connected to the headphones. I tried the recommended 32 ohm wiring per the diagram in post #65, but there seems like there's something wrong with that. When I inadvertently left out the jack ground, I got a small amount of very hollow sounding audio. When I put it back in, I got nothing. Checked and re-checked but found no problems.
As I read the diagram (see image), the ground is pulled off of the transformer BEFORE the headphone output. Wiring is input to 0.25W tap, common on the multi-tap side tied to the ground on the 8ohm side and that connected to Quickie ground, followed by the output attached to the 8ohm tap That would seem to be a recipe for no sound output even ignoring what the core is doing to the 8ohm "secondary."
Am I misunderstanding something here? Anyway, I tried a number of variations on the 32ohm wiring to no avail. I got little or no sound out each time. But since I was getting reasonable performance with the brown/50-200ohm wiring, I just went with that. I may experiment more, but reasonably satisfied with the way it is. I did try the red and orange taps (5w and 2.5w) and they weren't bad, but not as good as the brown/10W tap.
These Specos cost me less than $6 each plus small amount of shipping. At that cost, it's well worth experimenting. And I have a reasonable headphone amp to boot. I'm new to headphone amps, so not sure I have a good baseline to compare, but it's better than the output of my CD player (and OLD Pioneer PO-M6) which is no doubt op-amp based.
Attachments
Thanks, mcandmar. I'm curious, though, about the diagram even if it's for the "old" version. The first drawing (where it says "New") shows wiring for 32ohm cans. As I read it, it ties together the two black "common" taps, connects that point to ground, and pulls the signal off of the red 8ohm tap (on the secondary). So it seems the signal would come in via the blue 0.25w tap, go out the common on that side and get tied to ground. In that configuration, I suppose it could be using the Speco as a true transformer instead of an autoformer? If that were true, I'd expect to at least hear some output, but I got nothing. Maybe I'll try that again.
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? I have some other configurations I may try out for learning purposes, but I'm happy enough as it is.
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? I have some other configurations I may try out for learning purposes, but I'm happy enough as it is.
Paul Joppa
Moderator
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.)cpaul said:
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.
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 :-X) 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):
WHOA! Much better than the new Speco. Quite a lot of extra bass, and cleaner nicer throughout the (my :-X) 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):
Attachments
bourbonator
New member
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
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.
In short, unless you know you're getting the larger old Speco, I'd use the one I mentioned.
mcandmar
New member
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
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
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