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Old 5th April 2013, 04:15 PM   #71
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Tea's boards are tough for V3, butif you start with half bias, say 250mV, then you are probably fine. Try mounting diodes to sink to. Thats what this V3 will be looking like
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Old 5th April 2013, 04:25 PM   #72
PKI is offline PKI  United States
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Indeed, thats why I do not want to mount them on the sink. They will be too close to each other and to the end on the sink(there are two per side). I will mount them on 10mm aluminum bar first and then all these on the sinks. It will help to spread the heat, but I have to prepare surfaces so they make a perfect contact along all the bars.
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Old 5th April 2013, 04:29 PM   #73
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So yes, 6L6, you say that your amp was blowing outputs because of these oscillations without this cap?
In what I have experienced, yes.

The first time I got it stable was with the 1000pF compensation cap ( marked C3 and C4 in the V3 schematic) and 680ohm gate resistors (R13-16 in the V2 schematic)
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Old 5th April 2013, 04:59 PM   #74
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How hot do those PSU diodes get out of interest ?

i think ill add the C3, C4 as well as C1, C2. do they have to be bi-polar ?
just a guess maybe wire length is making your amp more susceptible to oscillations.

Btw out of interest which type of caps are preferred by audio freaks ?
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Old 5th April 2013, 05:07 PM   #75
6L6 is offline 6L6  United States
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How hot do those PSU diodes get out of interest ?
10Deg F above ambient. Which is to say barely warm to the touch.

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I think ill add the C3, C4
I strongly suggest bigger gate resistors as well.

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just a guess maybe wire length is making your amp more susceptible to oscillations ?
Perhaps, but the original test rig had much shorter wire links.

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Btw out of interest which type of caps are preferred by audio freaks ?
New stock of the proper value and voltage rating.

I have had very good luck with the Panasonic T-HA series, as well as similar ones from Nichicon and Rubycon.
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Old 5th April 2013, 05:29 PM   #76
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It does make sense to increase them gate resistors a bit as they are increased in v3
680ohm tho thats quite a lot more ?

caps, the Nichicon and Elna i have liked. Now all is left is to find the best Sill Pads on RS electronics site.
Thanks for your help
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Old 5th April 2013, 05:37 PM   #77
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Oh also I can't figure out if that gate resistor Mod, modifies the gain of the amp
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Old 5th April 2013, 05:39 PM   #78
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Old 6th April 2013, 09:01 AM   #79
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Default What kind of matching needed for OT ?

Hi All,

I am seriously following all the Turbo threads but could not find any info on how crucial the matching both between the paralleled N and P is (ok, the closer the better I guess, but...) , and more important if the N should be matched to the P which is more time consuming and last but not least far more costly.

I'd appreciate any help on this matter.

Cheers,

Max
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Old 6th April 2013, 09:12 AM   #80
AndrewT is online now AndrewT  Scotland
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match N to N when used in parallel.
match P to P when used in parallel.
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