Bottlehead Forum
Bottlehead Kits => Legacy Kit Products => Topic started by: AudioDave on November 06, 2015, 02:21:30 PM
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I am in the process of rebuilding my Parabees as Paramounts per Doc and Pauls recommendation in a previous post earlier this year. Doc recommends changing to the PT-4 power transformer. Can these be purchased through Bottlehead?
Thanks!
Dave
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The Paramount kit is retired. There are no more transformers.
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Folks, per a previous thread it sounds like a few of you have rebuilt your Parabees as Paramounts in the larger chassis which is what I want to do. Per Doc's reply the PT-4 is no longer available so I will have to use the original PGP 8.1 Parabee power transformers for the rebuild. For those of you that have done this, what changes or additions to the Paramount instruction manual did you have to make?
Thanks!
Dave
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You'll have to make a new DC filament supply. I once posted a mod for the ParaBee to get a DC supply using the 6.3v winding, Schottky diodes, and a choke-input filter. The voltage was barely enough (I got 4.8 volts) but it worked pretty well. It may be practical to use the FC-1 choke wired for 2A3 (to get the DCR low enough) which would give a modest voltage increase over the specified 0.3-ohm Hammond 155B. Here's the post: http://bottlehead.com/smf/index.php?topic=4266.msg39280#msg39280
You'll also have to reproduce the ParaBee high voltage power supply instead of the Paramount's PC board. Tricky to get that over the transformer, especially if you do the filament mod.
I assume you are retaining the excellent Magnequest TFA-2004 and EXO-003 plate choke. You should have adequate room for the TFA-2004 on top (make sure it's centered fore-and-aft on the PGP8 centerline). That will leave some room where the Paramount OPT was, which you can use for the HV supply.
On the other side of the power transformer, it will be a tight fit to get the EXO-003 installed and centered, since it's larger. It must go under the chassis for safety reasons (exposed high voltage terminals).
With the "soft-start upgrade" kit for the driver, the rest looks fairly clear and easy if you are somewhat experienced.
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Thank You Paul !! I will get started on my rebuild and get back to you if I have any questions, which I am sure Iwill!
Dave
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Ok, I think I am finally ready to start my 300B Parabee rebuild as Paramounts but have a couple of questions for those of you that have already accomplished this. How did you attach the Magnaquest TFA output transformer which replaces the Paramount OT-1?, where did you position the Magnaquest EXO-03 plate choke which replaces the Paramount PC-2?, and I am assuming the Parabee Magnaquest RCG-6 filter choke is not used in the Paramount rebuild, but if it is utilized where is it positioned?
Thanks in advance for your help!
Dave
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Please disregard my question regarding attaching the TFA-2004, I was having a brain cramp. I would still be interested in seeing a pic of where the EXO-03 is positioned on the bottom of the chassis plate!
Thanks!
Dave