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 NEW  Bruce Heran outlines the details and construction of his simple DIY 6DJ8 (ECC88) Tube Hi-Fi Headphone Amplifier Project.

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It is currently 18 Dec 2014, 12:16

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PostPosted: 05 Dec 2014, 16:57 
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Joined: 05 Dec 2014, 16:08
Posts: 1
Why would I want to tube roll with an octal? Sounds like I should have chosen the Noval stereo board
I'm about 70% through with my first AUDIO build.
It is an Aikido Octal Stereo line stage preamp with 4x 6SN7's.
The power supply is a PS-14 which is currently configured to bring over 280VDC to the B+ pad (need to review notes) and B+ at tubes should be 250VDC.
I would like to try 12SL7GT's for the V1/V2 (or maybe all around) for an amp I'm considering building which requires more gain.
Following the manual, for 6SL7's all around and for 6SL7's at V1/V2 and 6SN7's at V2/V4 the differences are as follows, I'll list the 6SN7 all around first.
Raw B+ 280 vs 300
at tubesB+ 250 vs "same"
R3,4 680 [lq=6ma] vs 1k [1ma]
R12a 2k vs 3k

I had read some reviews that running the 6SN7's at 300v made for a better sound at the expense of tube life. To make things easy I decided to settle on 280 B+ at the solder pads, this has been confusing enough.
Back to complicate things...
How critical are these values? The first thing that came to my mind is at the extra solder pads for R12a, where there is a 2K resistor there must be a way to wire a switch with a resistor to have the option for 3K.
As far as R3 and R4 go, it gets messy as there are two of each and not redundant solder pads.

Any help with this is appreciated.
The alternative that hit me a few minutes ago was the alternative of building a box for the power supply and transformers (230VAC 100mA torroid and 12.6VAC separate), a passive box for selecting sources, tone and volume control. Then two boxes for separate Aikido boards built for purpose. Now I'm thinking about the ground, and... I'll stop writing...

It's the first subject I would like to try first but if the second one is better... then I could do part time bridged for the class A pair, and flip back and forth on which one to use with the class A/B...oh yeah, stop writing, first audio project and would like to wrap it up and listen to music! then i could put in a switch for capacitor selectors, oh, and why not a tube selector switch?


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