Paraglow 2 with Tucker's board...question and help

Nutube · 7732

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Offline Nutube

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System seems to run fine except for loud hum/buzz until I throw my signal switch. Then things are relatively quiet. I decided to do some re soldering (gnd) to reduce hum further on my unit since that cleanup (mostly re solder of ground points)  really helped my Bottlehead 300B.
Upon re familiarizing myself with the Paraglow2 and re reading Tuckers instruction Booklet; I noticed that once there was a wire from Terminal 10 to the "I" Pad of the Bottlehead board. (C4s). The Tucker deconstruction instruction  was to remove this original board and the wire from I pad to terminal 10. It then reminded us to resolder the Electrolytic +ve leg back on to Terminal 10. This puzzles me...terminal 9 is the ground where the black stripe of the electrolytic is attached.....then the right +ve leg on T 10 has no wire going to or from it. Shouldn't there be something there wire wise? Otherwise isn't the T9;T10 essentially not used at all? If I missed a step please help. What does the electrolytic on T9 and T10 do functionally? With just the negative soldered to ground and nothing on the T10 as the caps +leg- seems like I missed something here...but  both the amps are the same yet other that loud hum before throwing my second switch First switch is my power to the filaments it plays music fine. Point is I don't think the electrolytic cap with just the -ve hook to ground cant be in the circuit. I might as well take it out ,,,right?help appreciated thanks in advanced

FP 1,2,3, Seduction, 45, Paramount 300B, Paraglow2A3; Dehavilland 845, Eico pp 805,Adcom 555 mono, Sota star saphire ugraded Nova motor & bearings,  Et 2.5 carbon wand on Shelter 901, Koetsu rosewood Sig., on magnesium wand, grado sumiko etc. Custom Edgarhorn with Seismic sub


Offline Paul Joppa

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Reply #1 on: May 14, 2010, 05:49:02 PM
Do you have circuits that you can share? I'm not familiar in detail with Tucker's board (only in general terms) and I don't know what your "first" and "second" switches do. And there were different versions of Paraglow.

Paul Joppa


Offline RPMac

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Reply #2 on: May 15, 2010, 02:55:17 AM
The cap on terminal 9 & 10 is the 2A3 cathode bypass cap. There should be a wire from ter. 10 to the top of 2A3 cathode resister( center of hum pot). In the original Paraglow, B+ for the driver C4s came from ter. 10(like the "Free Lunch" amp)...this is the wire that was removed. If this cap is still the 250V cap, I would replace it with 400V+ rated cap. Hopefully, Doc will confirm I correct.
Paul, the original Paraglow was essentially the J. Epstein "Free Lunch" amp with C4S replacing the driver plate choke and is parafeed.



Offline Nutube

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Reply #3 on: May 15, 2010, 06:20:40 AM
Paul and RPMac
Upon re reading my Paraglow manual - yes a wire needs to go from Center of hum pot to T10. That is the one missing! I must have remove that as well as the T10 to original Bottlehead board. I re read  John Tuckers deconstruction and he did say to remove not only the old board but to also remove the wire from T10 to "I" (input?) pad of riginal Paraglow board . Apparently I have not utilize the cathode bypass cap as my wire is not there period. Since I am waiting for the parts (expected  next wednesday.What sonic difference should I expect to hear with  the Cathode bypass cap hooked up-just curious till the parts .
RPMac- For the Cathode bypass attached to  T9;T10 , I upgraded the stock to 220uf to Panasonic TSHB rated 450V paralleled two 220uf . making a 470uf 450V. This over kill of mine is it harmful to the circuit?[ Should I just use the one 220uf 450V since I am working under the hood.
In JT's parts supplied he uses a 1.8k and a 1.5k ohms WW 10 watt;  connected in series. I am replacing those as the ceramic is cracking and in some cases exposing the internal coils. I bought Ohmite 3.3k ohm single reisitor WW 10 watt. Question is using 2 in series better at heat dessipation  over a single 3k3 and that is why it was supplied with 1k8 and 1k5 ?

PAUL- I have sent an email to Eileen's email; ( Doc's email may be log jammed : )) attaching a PDF file of  the complete John Tucker Paraglow upgrade manual. Please ignore my scribbles all over the pages.
Thanks gentleman

FP 1,2,3, Seduction, 45, Paramount 300B, Paraglow2A3; Dehavilland 845, Eico pp 805,Adcom 555 mono, Sota star saphire ugraded Nova motor & bearings,  Et 2.5 carbon wand on Shelter 901, Koetsu rosewood Sig., on magnesium wand, grado sumiko etc. Custom Edgarhorn with Seismic sub


Offline Doc B.

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Reply #4 on: May 15, 2010, 06:52:33 AM
The original Paraglow circuit came from the Afterglow, and that basic design is something that JT and I cooked up in early 1997, sitting in a crummy Chinese restaurant in Vegas. Jeremy came up with the Free Lunch some time after we had been working with the circuit, IIRC. There were also variations floating around called "Monkey on a Stick".

Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.


Offline RPMac

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Reply #5 on: May 15, 2010, 08:49:37 AM
Nutube, I think you will are fine with the bypass caps.
In the thread below, "Paraglow Output Transformer to 2A3 Cathode?"  , PJ recommends 50 watt cathode resister.

http://www.bottlehead.com/smf/index.php/topic,578.0.html



Offline Paul Joppa

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Reply #6 on: May 15, 2010, 11:08:13 AM
Nutube, I think you will are fine with the bypass caps.
In the thread below, "Paraglow Output Transformer to 2A3 Cathode?"  , PJ recommends 50 watt cathode resister.

http://www.bottlehead.com/smf/index.php/topic,578.0.html
As I said, there's a long history of Afterglow and Paraglow and Paraglow II circuits; none of them are my designs though they are the basis for the current Paramount 2A3 circuit. One of the big changes was the power supply voltage, which increase when we went to the PGP8 power transformer. That meant the 2A3 cathode voltage had to rise, and therefor the cathode resistor had to dissipate a lot more power. It also meant the voltage rating on the cathode resistor became more marginal. I believe we have seen a few incidents where various problems with the driver would raise the direct coupled 2A3 grid voltage so high that the cathode bypass capacitor was damaged. That's why the Paramount uses a 450v rated part, even though in normal operation the voltage is half that.

Paul Joppa