The Official Guide to Converting your Quickie for Headphone Use

[bainjs]

If you sign up, the vendor will email you when they are available again.  That's how I got mine.

 

[Grainger49]

The MB Quart 400's are available again.  Check the discussion in Headphones for more info.  They are 300 ohm units. Great sound and comfortable.

Where are they available, please?

I think that when you find the thread there are links to several ebay auctions.  The seller should have a new auction up for them.

 

[kkcinc]

I got my specos today. They are the cheap ones that SPaulMac got. I am still going to try to make it work. If I wire it up exactly the way he did it will be 10w/.5w instead of 10w/.625w feeding 60ohm cans. Question is, what wiring would work better with 60ohm headphones? I really want to try to make this work. Secondary is red 8ohm only and black 0. Primary is black common, brown 10w, red 5w, orange 2.5w, yellow 1w, violet 0.5w, blue 0.25w. Any suggestions on the wiring, other than getting new transformers?

 

[Paul Joppa]

For cans 45 ohms to about 200 ohms, the best available option based on the turns ratios would be the highest impedance (0.25 watt, which is blue on my sample, and 600 ohms DC resistance to black=ground) to the preamp, and the lowest impedance (10 watt, which is brown on my my sample and 42 ohms to black=ground) to the headphone. Check the DC resistances to be sure you have the correct taps.

For cans below 45 ohms, use the 8 ohm secondary, and try different primaries - 0.25W, 0.5W, and 1W.

In both cases, listen for a lack of treble and/or bass. It might be worth changing these taps if one problem predominates over the other. You may find you have to choose between higher signal and better spectral balance, if your cans are not very sensitive.

I have not done a detailed study of this transformer, just measured the turns ratios so far. They seem to be as advertised (my earlier measurement of the 8-ohm tap was in error, or at least I got a different number tonight - and the new number agrees with the labeling.)

 

[kkcinc]

Thanks. The thing sounds fantastic using the .25w wiring. These are the cans, Audio-Technica ATHM40FS. I am not missing any range and no range is over emphasized. Volume is good. Normal listening is done at 3/4 of the volume pot. For me the cheaper Speco's are a happy accident. I highly recommend this mod and these phones for the budget conscious people.

 

[bainjs]

I tried wiring the new version of the speco 7010 with mixed results and have confused myself thoroughly. 

Would it be possible for someone to give me the correct wiring for a set of 300 ohm headphones?

  I need basic instructions like "blue goes to input jack, red on secondary side goes to..." and so on.  Which colors do you now tie together since there is no white wire any longer?

Thanks

 

[bainjs]

After looking at a photo of the old speco, it looks like the white is now the red on the secondary side.  Is that correct?  And would it still go to the black common on the other side?

Based on Paul's last explanation, will the blue go to the input and the red to the headphone jack?  Would the black on the secondary side go to ground?

Am I close?

Thanks

 

[Paul Joppa]

This is excellent news - thanks for posting it! I'll try to find some time to measure the transformer more carefully, since it appears to be worthwhile after all, at least in this application.

 

[kkcinc]

I tried wiring the new version of the speco 7010 with mixed results and have confused myself thoroughly.   

Would it be possible for someone to give me the correct wiring for a set of 300 ohm headphones?

  I need basic instructions like "blue goes to input jack, red on secondary side goes to..." and so on.  Which colors do you now tie together since there is no white wire any longer?

Thanks

If you look at SPaulMac's picture and description on page 2 of this thread, that is the one you would want to follow for 300 ohm cans. I think. Brown wire goes to headphone jack right to ring left to tip and make a wire from ground of the headphone jack to the the grounding bus wire on the quickie. Tie red 8 ohm wire to black common wire on the other side of the transformer. Solder the black wire (labeled 0 on the same side as the red 8 ohm wire ) to the ground bus wire of the quickie. Solder the violet wire to each of the output jack solder cups. Tape off all other leads. Should work fine.

 

[kkcinc]

This is excellent news - thanks for posting it! I'll try to find some time to measure the transformer more carefully, since it appears to be worthwhile after all, at least in this application.

Thank you for the help. I had a chance to listen to two more albums last night. The 60 ohm cans work fine on the .25w tap plenty of deep bass and detailed highs. After further review, it might be missing a slight bit of lower mid-range and upper low-range. The cans could just be flatter than the mid-range heavy speakers that I am used to. I have no reference for the headphones, since they are brand new. Overall I am very happy.

 

[Paul Joppa]

Here is a first draft of wiring for the two versions of the Speco T-7010 output transformer. This is for the stock setup (not optimized for choke or PJCCS loads). I'll update it when I have done some more measurements and analysis.

 

[vanofmonks]

Hi just saw this and this is a reply to another question:


I commissioned this model originally, and it was confusing when I first saw it, but it was designed as an 8k winding that they put a CT in.  So for parafeed pin 1-4 is 8K  It is similar to all their other line output transformers in that it is push pull, but can be used as parafeed out.  They stated it should have about 15h inductance for what it is worth.  I have 10, but still have been to lazy to wire them in by quickie.  Hope this helps.

I finally got around to ordering the Edcor EM0735 transformers. Now that I have them before me, I have to admit that I probably have no business with a soldering iron in my hands. I have no clue as to how to hook the new transformers into my Quickie's circuit in place of the Specos. I'd imagined something like the signal ground going to both the C.T. and Common taps on the primary and secondary; the signal going to the 8K ohm tap on the primary and the output going from the 250 ohm tap of the secondary to the headphone jack, but I don't really look forward to smoking my little Quickie. I'd be very thankful for any help I can get on the proper wiring procedure for this transformer. The pin assignments for the EM0735 are as follows:

Primary

Pin 1    8K Ohm
Pin 2    Center Tap
Pin 4    8K Ohm

Secondary

Pin 5    250 Ohm
Pin 6    32 Ohm
Pin 8    Common

Thanks,
Stephen

 

[bainjs]

Thank you Paul for the diagram.  It made wiring it up much simpler.  Also, thanks kkinc to your suggestion.  They both worked pretty well, however, I think Paul's version has a tad more volume.

Paul:  Do you think there will be changes if the PJCCS module is installed?  I have one in my Quickie.

Joel

 

[Paul Joppa]

...
Paul:  Do you think there will be changes if the PJCCS module is installed? ...

Stock or modified, I recommend experimenting with adjacent output taps.

You should always use the lowest-power primary tap for the transformer input. That tap will use the entire winding, and have the most inductance (more turns = more inductance). Unless you hate bass, inductance is your friend!

 

[kkcinc]

Thank you Paul for the diagram.  It made wiring it up much simpler.  Also, thanks kkinc to your suggestion.  They both worked pretty well, however, I think Paul's version has a tad more volume.

Paul:  Do you think there will be changes if the PJCCS module is installed?  I have one in my Quickie.

Joel

I rewired last night with good results. I originally had the 8 ohm connection wired like the old one with 8ohm tied to common and 0 tied to ground, Now it is exactly as Paul has it in his diagram. Does seem to have more volume. Also, maybe a bit more balanced sound. Tried all adjacent taps as suggested and tried both chokes and pjccs. Blue wires on output and brown wires on headphone jack produce the absolute best sound and most volume for my 60 ohm cans.
Very little difference between chokes and pjccs. Big difference with an amp and floor standing speakers, since the chokes hum. No hum with headphones.

 

[denti alligator]

I've upgraded my SEX with MQ iron. Can I use the old transformers to convert a Quickie to a headphone amp?

 

[denti alligator]

I've upgraded my SEX with MQ iron. Can I use the old transformers to convert a Quickie to a headphone amp?

Anyone?

 

[bainjs]

I'm pretty sure they won't work.  You'll need to go with the Speco units as outlined in the instructions.  I believe I paid around $20 plus shipping for the pair. 

Joel

 

[Paul Birkeland]

Hello Sam,

Which stock SEX iron do you have?  If you have the old Specos, then of course you can.  If you have the OT-2, the step-down ratio will be pretty high.  You can try it as an 8K:32 ohm, but the available voltage at that tap will be pretty small.

-PB

 

[denti alligator]

Yes, I have the old SEX transformers.