luvdunhill

Yay! Adjustment of this amp is like dancing on a blade's edge. What about the measurements in #3524 as recompense? :)

Now I am listening totally selfish request but is the 1K trimmer in the exact same location in reference to a mounting hole? I have a hole directly over trimmer locations (also TPs, and LEDs on the bottom, but that doesn't matter as much) as to adjust the amp with the lid on..

Slightly change the pot in one of the batteries and monitor the output. Find the point it jumps back down.

The 10V version has a max voltage noise of 6uV. LEDs should be an order of magnitude less. The things I am not sure of are current noise and tempco. Since LEDs share similar geometry to transistors, this might actually be a case to use LEDs. I just don't know enough to definitely declare the change a winner, other than the goals that JoaMat set out to achieve.

Yes, if you make the other changes to the batteries.

"These" means the new production ones here.

Yes Q32, sorry, but the measurements above would be nice to verify. If you flip the 6k2 resistor 180 degrees and flip 180 degrees the other transistor and move it behind the one on the little heat sink it might be a bit cleaner... If someone wanted to use 2sc3675 this also seems a bit safer. I will do a group buy on these transistors if people are interested. Can do a full kit or can do just the Fairchilds. Looks like a good savings can be had.

R31? Hence my request for clarification.

Q23 needs a heat sink. Also only one trimmer on the schematic that I can find (I assume the 10K value is the same?) Edit: oh you are only using the fine grain 2K control. Interesting. I assume the effect of changing R31, R32, RV1 allowing more adjustment range than the original RV1? To be clear, the 22K resistor is in a different place in this circuit and you only have a single adjustment point. So, are you saying you turn it on and then use the adjuster to set voltage drop across 22K resistor to 6.55v then the same adjuster to set the voltage to 740v? Or are you adjusting resistor values to get 6.55v? (Sorry it wasn't clear to me) I am not convinced this will perform better or equal to the KGT2 though. It is easier to build A simple board to switch between LED bias at LT ref might be fun, for existing T2 owners, similar to the one I did to add low bias, which sits perpendicular to the PCB...

It might be better to put the trimmer on the larger resistor. I have found 6.2K with 1K in series to work well. I can even get many of the tubes working that others couldn't with this setup, for example Amperex 6DJ8. I think in the original T2 transistors these two transistors were selected to have certain properties which are now lost to time (maybe... See more on this below) Using the third resistor has allowed me to get offset and balance in the mV range. The mystery I haven't solved is why others didn't need this and are still claiming 0 offset and 0 bias. Seems that transistors would have to be chosen exactly the same way as Stax did for this to happen. Regardless, evidence is there for example with Kerry's experience of setting things at 6.55V and everything zeroing out. Would it be possible to get a survey of your voltages across the 6.2K and 510R resistors? This will give the gain of the transistors. It would be useful (for me) to compare this to your original T2 as well. If the gain is as low as the datasheet suggests, I can't see them working in my T2 which means perhaps I have some other marginal component that is causing "problems" I haven't found. Again, just don't see a way for this circuit to be as well behaved as it is for people.

Seems they are much lower gain compared to the original. Anyways, I can just PM you as I am curious about a few related items

Wait, did the original from joamat have the servo trimmers? If so, crazy as that is what I did to my T2 to fix the biasing shenanigans... Assuming you did, can you describe your biasing procedure and give an idea of how far over the original 6.2K you went? I am glad to share pics of mine and procedure as well. How do the new darlington servo transistors fair in terms of gain? More or less than 2sc3675?

The previous gen quad-core mini isn't all that bad. I expect improvements with the OS upgrade, etc.

Invite Reks over, I am sure he could find something to do with a turtle...

A night seems like the most dangerous time to wear a watch... I would insist on separate bedrooms with arranged conjugal visits.

Storage and security was a strange mix, even for a cocktail lover

Started down the road of another acquisition. Goodbye DHR, hello NTCT... Can't be worse than HP I guess?

I thought there wasn't really a concept of "running" apps anymore? Everything essentially hibernated. At least I remember Reks mentioning that open apps and performance weren't related..

Not sure what...one of these though.

I am not sure about Win8, sorry.

Yes.

I dunno, unlimited PTO with vacation stipends?

What sort of stuff do you do? Looking for a job now?

I have reused ATC stands in the past with great success...