First official Bottlehead Quickie upgrade - the PJCCS

BNAL said:
I assume you can use the PJCCS with the headphone design?

Paul Joppa said:
I think I posted on the old forum but can't find it right now. Anyhow, the problem is the battery voltage will drop as they age. Using the fixed bias of an LED in the cathode will cause an exaggerated change in tube current as the battery ages; the cathode resistor provides negative feedback at DC to maintain the appropriate operating point.

A quick look at the curves shows the plate current dropping from 2.5mA to 1.0mA as the battery drops from 36v to 24v.

A reasonable solution would be to use a current source to replace the plate load - that way the tube maintains a constant operating point, and operation will cease suddenly when the battery no longer provides sufficient compliance for the current source. I'd suggest 1.5mA as a good value to use. Note this will not work well for headphone operation where a substantial output voltage is going to be needed, unless you also add more battery voltage. Now this is starting to get complicated!

Would the above long post apply with the PJCCS, too?

It's probably a moot issue, since many of us will be adding more battery power anyway (a milliwatt power binge!)
 
Len said:
BNAL said:

Paul Joppa said:

Would the above long post apply with the PJCCS, too?...
No, that post is old - it's actually what started me thinking about a self-adjusting current source. The PJCCS should work well and give fairly good battery life whether implemented as a preamp or as a headpone amp with output transformer.
 
Paul Joppa said:
Len said:
BNAL said:

Paul Joppa said:

Would the above long post apply with the PJCCS, too?...
No, that post is old - it's actually what started me thinking about a self-adjusting current source. The PJCCS should work well and give fairly good battery life whether implemented as a preamp or as a headpone amp with output transformer.

Cool!

Can it work with higher voltage?

 
Does the PJCCS offer the same gain increase as the Hammond choke modification?

I have a choke mod Quickie and can't give up a db of gain.
 
I'm having trouble with wiring up the PJCCS I just received.  The PCB is a bit different from the one pictured in the manual and some solder points are missing/not the same.  The partially stuffed board is here:  

http://picasaweb.google.com/103078014592468973736/Bottlehead#5537786106126040610

In short, p.13 talks about soldering a wire from points bA to bB with an "S" shaped wire.  My board has no such points, though it has all other solder points in different orientations from the manual.  I can't make sense of the solder points that DO exist to match them to the board as represented in the manual.  Can anyone help me figure out what points are the bA and bB on my board?

Thanks.

Edit:  Hnmm.  I can't seem to get the pics to post, so I've tried just posting the link.
 
I am currently working on a PJCCS myself. Follows the manual just fine.

The board you have looks nothing like mine. I am thinking you may have gotten the wrong board with your kit. 

Call the Queen - bet she needs to ship you a new/correct board. 
 
Wanderer is correct, there are two board designs. You have the older, more narrow one, but the Quickie manual is written for the newer version, developed for the Eros.

We are in the process of transitioning all uses to the new board, but that takes time as each manual must be modified and new pictures taken for it. Actually, there is a slight modification of the Eros board that will appear with the Paramount driver upgrade - this will be Version 4.4. Fortunately it is so similar to the current Eros/Quickie board that there should be no need to modify those manuals! All this work is intended to make the boards flexible enough for many different applications - they are MUCH less costly in higher volumes.
 
Thanks, guys.  In looking it over, I just assumed though different, the two boards could both be wired to work.  The only issues I figured I'd have are the "s-shaped" wire connector between bA and bB and the connections to the quickie circuit.  If there is a way to do this without the Queen having to send a replacement board, I'm happy to take instructions for how to wire this board properly.  If all traces are visible on the board I have, I may be able to figure it out from the manual photos and schematic.  If I can't work it out, I'll call her.

Oh, note too that the transistors I got don't have the metal ground plate on the back for orientation.  I assumed the side opposite the one with writing was the same as the metal plate (per most transistors I've used).  If anyone thinks I've got it wrong, please let me know.

Carl
 
Does your board look like the one in the first post?  If so, and the instructions are written with the new board nomenclature you are in need of better, more specific instructions. 

Am I right?

cpaul said:
I'm having trouble with wiring up the PJCCS I just received.  The PCB is a bit different from the one pictured in the manual and some solder points are missing/not the same.  The partially stuffed board is here: 

http://picasaweb.google.com/103078014592468973736/Bottlehead#5537786106126040610

In short, p.13 talks about soldering a wire from points bA to bB with an "S" shaped wire.  My board has no such points, though it has all other solder points in different orientations from the manual.  I can't make sense of the solder points that DO exist to match them to the board as represented in the manual.  Can anyone help me figure out what points are the bA and bB on my board?

Thanks.

Edit:  Hnmm.  I can't seem to get the pics to post, so I've tried just posting the link.
 
cpaul said:
Thanks, guys.  In looking it over, I just assumed though different, the two boards could both be wired to work.  The only issues I figured I'd have are the "s-shaped" wire connector between bA and bB and the connections to the quickie circuit.  If there is a way to do this without the Queen having to send a replacement board, I'm happy to take instructions for how to wire this board properly.  If all traces are visible on the board I have, I may be able to figure it out from the manual photos and schematic.  If I can't work it out, I'll call her.

Oh, note too that the transistors I got don't have the metal ground plate on the back for orientation.  I assumed the side opposite the one with writing was the same as the metal plate (per most transistors I've used).  If anyone thinks I've got it wrong, please let me know.

Carl
Yes, the board you have should work just fine. I'll dig up the board designs and try to describe how to hook it up, but it may take a few hours.

There's a sticky on the General Discussion board which describes the MJE350 changes.
 
OK, it didn't take that long after all.

The BIG DIFFERENCE is that the large MJE350 transistor is reversed between the boards. Coupled with the different transistors, this can be confusing - be careful there!!! If you look carefully, you will see that the three terminals of the transistor are labeled E, C, and B on the board, and they are reversed between the boards. Tiny print, hard to see!

Here's a map, going clockwise from the O terminal (which is the C4S output, in case you wondered) around the "A" end:

<pre>
old board    new board
O              OA
I                IA
-                (-reg)
K                Kreg
-                -reg
+                breg connected to rreg
G                bA

Of course for the PJCCS you only use the I, O, and G connections; the rest are for the shunt regulator function which is not used.
 
Paul,

Thanks a ton for looking into this.  So as I understand it, I'd solder a jumper wire between the two G points to replace the "s" wire, check and perhaps flip the transistors depending on how i soldered them (looks like I DO need to resolder them), and use the O, I and G points per the manual for connections to the quickie?  There are 2 solder points immediately to ether side of the 120k resistor at the ground side, one of which has a G next to it.  They appear to be so close as to be electrically connected.  Can I assume both are tied to the resistor so one can be used for the jumper wire and one for the connector to quickie?  Similarly the silkscreen O seems to span between two points suggesting either one could be used.  One is clearly connected to the collector pin of the transistor.  Can either be used for connection to quickie?

Carl
 
You got it, dude!

Look at both sides of the PC board to see the connections, but usually I have put multiple solder points that are connected together near each other. (The "-" points on the older board are an exception, but you can see that they are connected even though the "K" point is between them. I fixed that on the newer board.)
 
Oops, sorry guys. I have a faint recollection of "helping" in the packing room a while, back by packing PJCCS kits. Coulda been my bad. I'll ask Eileen to check the kits in stock to make sure we don't send out any more with the wrong board
 
Got my PJCCS finished and installed.

Just to recap - I am running the the Quickie as a headphone amp with Specos to power AKG 240M 600 ohm phones using the "5 watt/1k" taps.  I had been using plate chokes now replaced with the PJCCS.

I had enjoyed the QUICKIE rigged out as above but found "Stereo Spectacular" recordings sounded "okay" but lacking the spectacular. Telarc CD "The Stokowski Sound" was fine but not awesome.

With the PJCCS installed the spectacular is back. Through the AKGs the Quickie sounds warmer in the lower mids and upper bass. The dynamics that seemed compressed before are much more in evidence.

Less whiz bang CDs like MOZART Violin Concertos ARCHIV 477 7371 or Hesperus "Early American Roots" MMCD216 sound better as well. I am much more aware of center fill imaging and hear less emphasis of hard left and right information (headphones remember).

I have more listening to do and if you have a Quickie, even with the plate chokes, you should try the PJCCS mod.  

         

 
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