Quickie 1.0 manual correction - battery reversal

[Paul Joppa]

There is an error in the manual for the original Quickie kit, v1.0. The D cells, which power the filaments of the tubes, are wired in reverse. The preamp still operates (actually sounds quite good) but the voltages and the battery life are not optimal.

If you have already built the Quickie, the easiest solution is to install the D cells in the holders backwards.

If you have not built it yet, I recommend that you exchange the connections to the tubes. On page 21, connect the black wires to A5 and B5 (NOT A1/7 and B1/7). At the bottom of page 24, connect the black wire from terminal 2L to socket pins A1 and A7. Similarly connect the black wire from 4L to B1 and B7.

We will eventually post corrected voltage measurements, and produce a revised manual.

[JONO]

I posted my mesurements in http://www.bottlehead.com/smf/index.php/topic,594.msg3810.html#msg3810. Can anyone confirm?

[Paul Joppa]

Sorry, I should have posted when that appeared. I just did so and said:

The voltages with "D negative to pin 5 (schematic diagram)" are almost exactly the theoretically expected voltages, as designed.

I picked up a kit last week but haven't built it yet. Until I do, the tube voltages should be:

pin 1 3.5v
pin 2 28v
pin 5 2.0v

Pin 5 is the top of the 1K cathode resistor, and 2.0v indicates 2.0mA cathode current.
Pin 2 is the plate and indicates the plate is at about 75-80% of the high voltage battery (nominally 36v when new)

The 9-v batteries will last a bit longer, and the headroom will be a bit greater and more symmetrical, with the correct orientation. In most cases you won't hear a lot of difference - tubes are pretty tolerant that way.

Once I am done with my build and measurements, I'll be posting some variations, optimizing for different situations - particularly using output transformers with headphones.

[denti alligator]

I followed these changes and got different voltages at 1, 5, and 7 (and not 2):

A/B1: 2.757/2.530

A/B5: 1.216/0.963

A/B7: 2.777/2.534

Are these OK?


EDIT: It certainly sounds good.

[Paul Joppa]

I assume that "(and not 2)" means you got close to 28v at the plates, pin 2?  If your 9v batteries are also fresh (36 volts), then I would guess your tubes may be a bit worn since the current is a bit low. If the tubes are very new, they may get a little more current as the cathode finishes its forming process.

[denti alligator]

So does this alter how I install the PJCCS?

[Paul Joppa]

So does this alter how I install the PJCCS?

No, the PJCCS adapts itself to varying voltages fairly well. Check the battery and plate voltages after it's installed and report them here if they are less than 5 volts different - in which case we might want to make some adjustments. But it's not especially likely.

[Zimmer64]

Hi,

I have just built a Quickie incl. the PJCCS and only now read the manual correction post.....

I have a question: Was the manual corrected for your latest shipment?

Best regards,

Michael

Edit: Just figured. Tha October manual is still wrong. I will switch the batteries around as suggested.

[4krow]

Soooo, I left my Quickie on by mistake for a few days....if I reverse the batteries, will it work again? Seems like it did on Star trek...

[2wo]

NO Don't do it! You will suck the music right out of the room...John

[earwaxxer]

'I've done that man!' - Cheech & Chong - It shuts itself off after the D-cells go dead.

[proud indian]

At the end of the day, the battery's + side does not really sit on the springs properly and you may have to rotate the battery for better contact. I reversed the wires. If there is a mistake correct it!!! Reversing the batterys is more of a "Band aid" solution. After doing the wires the other way, it sounds much better and I find better channel balance and even sound stage width.

shreekant

[4krow]

Eric, did you bait shreekant? hmmm must have been 2TWO

I want to invent the 'anti-bulb'. When you turn it on, it sucks all the light from a room, just like a regular bulb sucks all the darkness from a room. Then, I will turn them both on and let 'em fight it out.

[pushbroom]

I am currently building a quickie 1.1...are these changes reflected in the manual?  the page numbers don't coincide with the earlier post, and my browsing hasn't sufficiently answered.

- josh

[jimiclow]

I think it only applies to version 1.0.
The 1.1 version was only released in February.