Paraglow

RPMac · 6746

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Offline RPMac

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on: December 11, 2014, 05:13:32 AM
I hope this is the right place to ask this, but I would like to try a parafeed version of PJ's  monkey amp that he has on AA.
I mentioned the 4P1L as a driver because of what I have read by Andy Evans who is a professional musician and accomplished amp builder. But I understand that implementing it may be beyond the scope of this project. Same for the 26 Paul mentioned as a driver. I would like to try an all DHT, but will go with what Paul recommends because I'm not a designer. Tubes I have...5670, 6N1P, 12at7

My iron-

MQ PGP 8.1  380-0-380VAC
MQ RGC-6
MQ EXO-03
MQ EXO-036Ni 2K5/8 ohm

Thanks, Robert
« Last Edit: December 14, 2014, 04:33:07 AM by RPMac »



Offline Paul Joppa

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Reply #1 on: December 11, 2014, 05:55:04 AM
What I recommend is (naturally) the design that I published. I won't be supporting it here, and I don't intend to support any particular variations - I don't object to variations but I expect the Asylum SET or DIY forums to provide the support community.

Paul Joppa


Offline Doc B.

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Reply #2 on: December 11, 2014, 09:16:27 AM
If you decide that you want to do some specific design that you have in mind you pretty much have three choices -

learn enough to design it yourself - after all, it's your idea of what would be cool

hire someone who designs things for a living to design it for you. They will change it from what you had in mind to what they think will work.

depend on the kindess of strangers - as PJ suggests, ask for help on AA or DIY Audio. Though if you thought the pro will change your design, hang on to your hat when some of those guys start preaching their religion.

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


Offline xcortes

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Reply #3 on: December 11, 2014, 10:40:43 AM
A design on the public domain by tucker, doc and (joppa?) is the direct coupled 45 published on valve and republished by positive feedback on line. Exact same iron except the opt but 3k should work great.

Xavier Cortes


Offline Paul Joppa

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Reply #4 on: December 11, 2014, 01:53:57 PM
It is not the EXACT same design! ... though pretty much all direct-coupled 2A3 amps are similar.  :^)

To be clear, I had nothing to do with the "direct coupled, active loaded, parallel feed output SE 45 amplifier" originally published in VALVE in 1997. That amplifier was the genesis of the Afterglow/Paraglow/Paramount 2A3 series of designs; I did only the Paramount ones, which were modest refinements of what Tucker and Doc B had developed over many years.

Paul Joppa


Offline RPMac

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Reply #5 on: December 12, 2014, 04:34:51 AM
I wanted to replace the CCS boards in my paraglows with plate chokes for reliability.
You are right, I need to learn this for myself.
I apologize for asking.



Offline Doc B.

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Reply #6 on: December 12, 2014, 05:44:45 AM
One important thing to do to a Paraglow for reliability is update the filter capacitors. The Paraglow is an old enough design that they will be reaching end of service life. We replace each single 100uF 450V cap with two 270uF 350V caps wired in series, with a parallel 100K resistor to balance the voltage wired across each one.

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


Offline Paul Joppa

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Reply #7 on: December 12, 2014, 07:31:20 AM
I wanted to replace the CCS boards in my paraglows with plate chokes for reliability.
You are right, I need to learn this for myself.
I apologize for asking.
Sorry, I misunderstood.

I will certainly support the Paraglow on this forum. If you would start a new thread that does not use the phrase "BB proof" in the subject line, I'd enjoy helping out. (The reason for a new thread is just to avoid having the thread show up in searches for the Asylum design.)

Meanwhile Doc B's advice is a good place to start.

Paul Joppa


Offline Paul Birkeland

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Reply #8 on: December 12, 2014, 12:48:11 PM
I have also implemented our current production C4S boards in the Paraglow for repair customers, and I'd be happy to share notes.

-PB

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man