5D4 with KT88s

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Markusv
Posts: 393
Joined: Wed Dec 21, 2005 3:16 pm
Location: Toronto, Canada (yes it's friggin cold!)

5D4 with KT88s

Post by Markusv »

Folks

I have some spare iron kicking around
And I feel like a deluxe ish vibe but with KT88 type output

my question,is: will the PI in that design hit the output hard enough for modest breakup like in a deluxe?
Alternatively has anyone ever tried say 2 small pentodes in paraphase PI format? What I am aiming at is a preamp,with relatively few gain stages and a PI that will kick the output squarely in the teeth

Please educate me

Markus V
.........Now where did I put it?
matt h
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Re: 5D4 with KT88s

Post by matt h »

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Last edited by matt h on Fri Mar 27, 2015 1:59 am, edited 1 time in total.
TUBEDUDE
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Re: 5D4 with KT88s

Post by TUBEDUDE »

The 6u8 is a great idea. They make strong drivers. Another way to get more drive from a PI is to give it a higher plate voltage, or tie the tail to a negative supply voltage. It complicates the power supply a little though.
Markusv
Posts: 393
Joined: Wed Dec 21, 2005 3:16 pm
Location: Toronto, Canada (yes it's friggin cold!)

Re: 5D4 with KT88s

Post by Markusv »

Thanks to both replies for these insights
I really do mean 5D4 . But I do notice that in my Aspen Pittman book both the early deluxe as well as a super have that number.
its the same circuit except for the output tubes

that's right- maximizing the output is not a critical factor for me
Running the 88s at around 400 should be more than enough. I'm really just curious about what I can achieve tonally.
So I'm hoping a soft power supply at the output tubes will perhaps provide big sounding but smooth overdrive- that is- if I can get them to clip with enough oomph from the inverter

Thanks for the 6u8 suggestion
I have a few I can use

will keep updated

Markus
.........Now where did I put it?
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jon
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Re: 5D4 with KT88s

Post by jon »

Another option is to use a split load PI with an anode driver post PI. Look at a Gibson Super 200,300,400 Gibson GA100. And they are pentodes not triodes. Should give even more FLAVOR
Last edited by jon on Tue Aug 06, 2013 9:32 am, edited 1 time in total.
Markusv
Posts: 393
Joined: Wed Dec 21, 2005 3:16 pm
Location: Toronto, Canada (yes it's friggin cold!)

Re: 5D4 with KT88s

Post by Markusv »

Thanks Jon

Never done anything like that before- I will investigate

M
.........Now where did I put it?
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