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 NEW  Matt presents bias and operation data for the 6V6 tube in SE operation - 6V6 Single-Ended (SE) Ultra Linear (UL) Bias Optimization.

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It is currently 26 May 2018, 12:58

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 Post subject: 807 Oddblock a bust
PostPosted: 25 Apr 2018, 08:13 
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Joined: 26 May 2009, 18:51
Posts: 129
Location: Lilburn, Georgia USA
I have 8 NOS 807 pentodes and about 5 years ago I built a complete 10X12X2 Oddblock with Edcors. What a waste of time. None of the 807 tubes would come even close to balancing and the sound was terrible. Plus the fact that I installed those big white ceramic 5 pin sockets. I have removed the big sockets, made a cover plate and installed octal sockets. Since I lowered the B plus to 360 volts with a 1K 25 watt power resistor I think I will try out some of my 36 6L6 tubes. 12 of them are the black metal military ones. Oddblocks are adaptable. My two original Oddblocks are going on 10 years now and have never faltered . They have the original KT88s. JJ brand. rparsh in Lilburn, Georgia


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 Post subject: Re: 807 Oddblock a bust
PostPosted: 25 Apr 2018, 09:51 
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Joined: 08 Aug 2009, 03:11
Posts: 2208
Location: Chilliwack, BC
Hi,

807's do sound pretty good, but they are pretty picky about operating conditions. Treat them like 6L6GC instead of KT-something's and you're OK :)

Cheers!

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-= Gregg =-
* Ratings are for transistors - tubes have guidelines*
Home: GeeK ZonE
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 Post subject: Re: 807 Oddblock a bust
PostPosted: 25 Apr 2018, 16:18 
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Joined: 04 Jun 2008, 20:59
Posts: 3649
Location: Arizona, USA
Hi, Remember the metal ones have a lower dissipation and that the case is attached to pin one. I made an "oddwatt" with type 832 tubes a while back and it was a bust as well. Tried two versions on with two tubes (parallel operation inside each) and one with a single tube with the balance adjusted with a small +dcv on the grids. Neither sounded worth a hoot. I would have thought that 807s would be OK, but then what I sometimes think is overrun by reality.

My original Oddblocks are running fine as daily drivers in my present system. I have done the updates to them though.

Good listening
Bruce

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