B1 with Korg Triode

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Steve Luck

Member
Joined 2012
Korg Channel imbalance?

What have other peoples experiences been with setting the voltages?

With one trimpot wound back to it's stop I can't get lower than about 10.5v the other is not near it's stop for the same voltage. I'm not sure but vocals seem off to the right of centre even with both all the voltages checking correctly. Re- checked ACA voltages too last night they where both running much higher than they should be after I rewired them with solid copper core wiring - 17 volts instead of 12 but with every thing adjusted things are still a little off centre.
 
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Steve Luck

Member
Joined 2012
Definitely the korg throwing things off centre. Soldered joints checked carefully. Resistors all look good. Voltages still the same - T8 wont go below 10.1 and T7 sits at 10.5 with both trim pots wound back.

Is it possible i've overheated the pins on the tube whilst soldering it off the board and cooked it?

Time to buy a replacement tube?
 
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dewdrop

Member
Joined 2004
Steve Luck said:
Definitely the korg throwing things off centre. Soldered joints checked carefully. Resistors all look good. Voltages still the same - T8 wont go below 10.1 and T7 sits at 10.5 with both trim pots wound back.

Is it possible i've overheated the pins on the tube whilst soldering it off the board and cooked it?

Time to buy a replacement tube?
Click to expand...
Do you hear music on both channels? Maybe use a mono content to test.
 
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happyrabbit

Member
Joined 2012
A little NuTube Luv ;). Thank you Mr Pass for introducing me to this lovely little tube. 1st version on right. 2nd on the left. 1 channel per pcb.
 

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Hikari1

Member
Joined 2012
Hikari1 said:
Tonight I experimented with additional capacitance in the PSU.

PSU is a big caged meanwell 10A switcher. Way overkill for this application but I had it.

Caps on board are 2700uf panasonic FM.

I added 33,000uf (!!!) bypassed with a 6.8uf poly cap between the meanwell supply and PCB. The meanwell did not shut down, didn't seem to care about the additional capacitance.

Soundwise, not much different. I was surprised. Maybe a tad bit more liquid but not a big difference. Bass was same. Amp did not seem less noisy. Really, nothing different to note.

Maybe the Korg doesn't care so much about PSU quality? This has made me rethink my plans for a well regulated linear supply. Maybe I don't need it.
Click to expand...

More PSU experiments:

I changed the 10A big meanwell psu to a 32V switcher followed by a lm317 reg set to 32V.

Sound is somehow a bit cleaner and smoother but less dynamic and edgy. Not a big change, but it is a change. Less lively with the lm317 but more refined.

I think my final psu will be linear w/a shunt.
 
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Steve Luck

Member
Joined 2012
dewdrop said:
Do you hear music on both channels? Maybe use a mono content to test.
Click to expand...

Yep just annoyingly of centre even when the trimpots set the voltage the same.
I've pulled the Korg from my system and fed the ACA direct from a Cambridge DAC Magic plus that has volume control and everything is centered. New Nutube ordered - this time ill see if the sill sockets I have can be used.

I've fried a few things lately I blame my new soldering iron tip - it works so much better than the old one :)
 
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Hikari1

Member
Joined 2012
ClaudeG said:
Hi Bullit

Oh, perhaps I wasn't clear, sorry. Short story: The Tocos is less than 10$ and works absolutely great in my case, I would say little risk to try and just make sure the seller garantees the channel tracking and job done, likely to have a good one.

TDK is an excellent recommandation.OK, of course in another price league. I would tend to be on Jim's side: a good pot can equal some very good stepped attenuators, although the engineer in me doesn't like saying it. That matches my experience and TBH once you have an excellent pot there isn't much more to gain, air gets thin...

Re caps, if happy with the sound, leave it as it is and enjoy ! If you want to give it a try, try replaceing the 2 (per channel) first caps in the signal path as per my post or if to expensive take the same values and take any PPP cap you fancy. Nothing can go wrong doing so and dead easy and you can have a flavour for little money of what it may add (or not) to your ears... and decide later on the 3rd cap or reverse.

Sorry if my long post may have been confusing, or the last one which replied to several posters in one go.

Fab hobby, nothing can really go wrong with the B1 Korg and there are non expensive solutions and paths out of the audiophilia which perhaps tend to magnify things a lot (me being contaminated aswell).

And you are welcome for any question, Jim / 6L6 having been more then patient wth my tons of questions when I gots started again

Claude
Click to expand...

I just got some 50K Tocos Cosmos pots. Very, very good. Crazy improvement in soundstage height and depth over the cheap alps pots I was using.
 
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