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#11
12th April 2006, 09:01 PM
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Re: Pentode driven PT15 trioded for Stuart
Which in turn is very like a px4
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#13
13th April 2006, 08:40 AM
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Re: Pentode driven PT15 trioded for Stuart
which is a good place to start....
and the px 4 is close to the px25.. whose curves i refered to when setting up the pt15.. the curves show that the lower voltage, lower grid, but higher current are very linear I removed the pt15's cathode by pass cap last night.. listened for an hour..another cd frenzie... very, very slight loss in volume and i would say a very slight improvement.. more in the very fine detail.. then i removed the pt15.....and put a very rare valve in... 1st hour ..sounded like i'd put a really bad chinese valve in.... I'll listen again tonight ....I let you know on a new post.... cheers steve
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#14
15th April 2006, 05:13 PM
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Re: Pentode driven PT15 trioded for Stuart
Just done some measuring and checking on PT15 & KT66. Using both in triode mode they bias up almost identically and the anode curves track each other to about 15% (over the range I checked). These are a little way away from PX4 curves.
In fact given that the heater requirements for the KT66 & PT15 are identical you could plug and play between these two in the same amp and not have to tweak anything... Might be interesting to make the amp for the PT15 with a parallel connected octal socket and swop beteeen the two to see if the DHP sounds better than the IHP.... James
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#17
22nd April 2016, 03:43 PM
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Re: Pentode driven PT15 trioded for Stuart
I don't think James visits here anymore. You are more likely to have contact with him on The Audio-Talk forum and IslandPink may have contact details for him.
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#19
22nd April 2016, 07:47 PM
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Re: Pentode driven PT15 trioded for Stuart
I'm sure that somewhere on here, possibly in the archive, is a James D schematic for a trioded PT15 driven by a C3g.
I built one myself. I'll check my files for info.
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Philip. Everything in this post is my honest opinion based on what i thought I knew at that very moment in time. 
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#20
22nd April 2016, 07:57 PM
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Re: Pentode driven PT15 trioded for Stuart
This is the original PT15 amp I built, to Jame D design.
[IMG]  [/IMG]I still have some PT15, but I'm unlikely to use them as GM70 and GK-71 are better.
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Philip. Everything in this post is my honest opinion based on what i thought I knew at that very moment in time.
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