The Official Guide to Converting your Quickie for Headphone Use

[Doc B.]

       
    Here is the guide to modding your Quickie for use with high impedance headphones, courtesy of Caucasian Blackplate:

OK, since there have been quite a few questions circulating, I thought I would toss up the guide on how to convert your Quickie to headphone use.

    You will need:
    2 Speco T-7010 transformers
    1 headphone jack
    heatshrink tubing or electrical tape


    Step 1 (Preparing the Specos):
    Cut off the yellow, orange, blue, and gray wires from the Speco at the bobbin of the transformer. The black wire on the side of the transformer with the colored wires and the white wire must be trimmed, stripped, and soldered together. Cover the joint with heatshrink or electrical tape.

    (https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Flib.store.yahoo.net%2Flib%2Fyhst-76392764919929%2Fquickie1.jpg&hash=658ac0f7476649c1b52f7a403c98480ed4c28d99)

    Mount the Specos under the D cell battery holders as shown. Be sure the red/brown leads face the tube sockets.

    (https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Flib.store.yahoo.net%2Flib%2Fyhst-76392764919929%2Fquickie2.jpg&hash=a2f4c299053e4829a229b5e69ac3ffef2692611f)

    Solder the brown wires to the cups of each RCA jack. It may help to solder the wire to the cap lead that feeds into the solder cup instead of the solder cup itself. Solder the black wires to the ground buss.

    (https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Flib.store.yahoo.net%2Flib%2Fyhst-76392764919929%2Fquickie3.jpg&hash=e3b322dc71e8f8738431805859db6fa940a82157)

    On the 1/4" jack, run a wire from the terminal closest to the panel to the ground buss of the Quickie. The next terminal back is the "ring", and right is ring, so run the red wire from the right Speco to the ring terminal and solder. Run the red wire from the left Speco to the tip terminal and solder (remember, it's flipped over when you're looking at it, so check the jack colors just to be sure you don't mix them up).

    The jack shown is constructed so that when you plug in headphones the output disconnects. Although it is not installed in this application to perform such a task, be sure to solder the wires to the correct side, or to both sides if you are unsure.

    (https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Flib.store.yahoo.net%2Flib%2Fyhst-76392764919929%2Fquickie4.jpg&hash=3ec0f6fe37566137a97fb9f98d94e2d4d26879f5)

    Sit back and enjoy! For ordering a different transformer, we have the Speco wired as an 8k:500 autoformer.

[Wanderer]

Quickie headphone with Hammond plate chokes is working here.

Good News/Bad News situation:

Good news -
It works! Got my PCDP hooked in and just got done listening to Yes "Cans and Brahms" (how apropo) and have rest of "Fragile" sluicing past my ears right now.  Quite good sound given the limits of the PCDP. The unit (Memorex if anybody cares) does have a line out.

Phones are AKG 240M. In the past I have tried drivng these with a Total Airhead portable amp and found the sound thin and compressed. The Quckie sounds full with the 240Ms like they sound when driven off a good integrated amp. I do like the sound of the AKG 240M when I can find something able to drive them. 

Bad News -
Not enouph gain. Before the plate chokes the sound level as far to low. With plate chokes things are better but have to have the volume pot full open to get decent level. Seems more sensitive cans are in order.     

What phones are folks finding happiness with? Beyerdynamic KT-880s perhaps?  Any others? Seems high Z phones are not as common as in years past.                 

[Paul Joppa]

I think those AKGs are 600 ohms. In that case, try them on the 1K tap instead of 500 ohms - label of the Speco would say 5W instead of 10W. You'll get a little bit more output per volt input that way.

[Dr. Toobz]

Aren't the AKG's kind of hard to drive, notwithstanding the high impedance? My Beyers are 250ohms and work rather well on the 500 ohm taps, though they also seem a little more sensitive than some AKG's I've tried. Maybe the 1k tap will give you a little more gain, though - let us know, since I've been looking at their new K702 phones but have held off due to this reason.

[Wanderer]

Experiments with different taps on the transformer will have to wait for a new set of Specos as I trimmed unused leads off close to the windings as per instructions.

Oh well. At least they are cheap.

Any other suggestions on phones that work on a unit set up from the original instructions.

Sennheiser 580/600 have sounded a little closed in/lacking in air/dull when I have heard them in the past (with an X-Cans hybrid amp). Does the Quickie open them up?         

[Paul Birkeland]

Aren't the AKG's kind of hard to drive, notwithstanding the high impedance? My Beyers are 250ohms and work rather well on the 500 ohm taps, though they also seem a little more sensitive than some AKG's I've tried. Maybe the 1k tap will give you a little more gain, though - let us know, since I've been looking at their new K702 phones but have held off due to this reason.

The 702's are indeed quite tough to drive, the 600 ohm K240M's are not. 

[Paul Joppa]

Now I am really confused.

I did a little searching. Found the "headphone.com" site which seems to have lots of specs. There, I see the AKG240 MKII at 55 ohms (I think the original poster did not have the Mk II). Anyhow there the 240M MkII is spec'd at 91dB SPL/v and the 702 is 105dB/v (at 62 ohms). At the AKG site, there's a (discontinued) 240 Studio (55 ohms, 91dB/mW,  104dB/v), the 240DF (600 ohms, 88dB/mW), and the Mk II (55 ohms, 91dB/mW,  104dB/v). I didn't find any K240M at all.

The Quickie will not drive a low impedance phone very well with the Speco, and my advice about bumping up the output tap applies to 600 ohm phones, not to 60 ohm phones. I'm really lost here...

[Wanderer]

Spec for the 240 Monitor here:


http://www.akg.com/site/products/powerslave,id,429,pid,429,nodeid,2,_language,EN,view,specs.html

These were contemporary with the 240DF (diffuse field) and have about the same specs, 600 ohms, 88 db SPL/mW

[Wanderer]

I am about to order another pair of Speco xformers to experiment with different taps.

Would there be any issue with adding a second headphone jack to connect to the 1K tap while the 500K tap is still connected to the other? No plans to use them both at once, just to swap back and forth for quick A/B.

Seems to me there would not be an issue, but might as well ask.     

[Len]

I am about to order another pair of Speco xformers to experiment with different taps.

Would there be any issue with adding a second headphone jack to connect to the 1K tap while the 500K tap is still connected to the other? No plans to use them both at once, just to swap back and forth for quick A/B.

Seems to me there would not be an issue, but might as well ask.     

I expect you'll get an official answer.

I had thought of that myself, and figured that if no circuit was made unless a headphone was plugged in, then it would be alright. But one can forget down the road and plug headphones into both jacks (I least I could).

I decided to use the input selector switch instead. Using one jack, I think the switch can be used to change taps. Worst case, the hole can be used for a different switch.

I plan on using it as a dedicated headphone amp, so I don't expect a need to switch between sources.

[Paul Birkeland]

I am about to order another pair of Speco xformers to experiment with different taps.

Would there be any issue with adding a second headphone jack to connect to the 1K tap while the 500K tap is still connected to the other? No plans to use them both at once, just to swap back and forth for quick A/B.

Seems to me there would not be an issue, but might as well ask.     

You could indeed add the second jack, as long as you don't put two pairs of headphones on at once.  You could also use a DPDT switch to select the different taps. 

[Wanderer]

You could indeed add the second jack, as long as you don't put two pairs of headphones on at once.  You could also use a DPDT switch to select the different taps. 

Headphone Quickie with AKG 240M: 

Okay, new Specos on board. Per Paul Joppa's suggestion using the "5 watt/1k" taps. Quick back and forth and, yes, the "5 watt" taps are just a jot louder. This with the PCDP line out. I have no idea the output volts from this jack. With the CD of "Kind of Blue" I have just a little volumn control left till things get too loud. Loud enouph for me but perhaps not for a real head-banger.   

 I rigged jacks to both "5 watt" and "10 watt" taps. I will not hook up two sets of phones (How drunk would I have to be to do that? - let's not find out!!). I have cut just ONE hole in my home brew wood base so whichever current tap I wish to use that jack will get mounted.   

So far - SOUNDS GREAT!!! HAPPY HAPPY JOY JOY.       

[cvandyke]

I have an older pair of the Speco T-7010 transformers which were removed from the original Paramours during an upgrade. These older transformers did not have the same color coding as the new production ones. For installing these in my Quickie, I developed the table below and thought this might be useful for other bottleheads with older Speco transformers.

--Chris

{Editted from original post which was badly worded}{Editted again to fix stupid error in table}

[Wanderer]

Your chart shows .5 k and/or 1 k cut. Aren't one of those headphone connections? 

[cvandyke]

You're right - that's a stupid mistake. I fixed it in the post above. Thanks.