Everything posted by luvdunhill
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The ultimate DIY? A Stax SRM-T2!
"These" means the new production ones here.
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The ultimate DIY? A Stax SRM-T2!
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.
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The ultimate DIY? A Stax SRM-T2!
R31? Hence my request for clarification.
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The ultimate DIY? A Stax SRM-T2!
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...
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The ultimate DIY? A Stax SRM-T2!
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.
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The ultimate DIY? A Stax SRM-T2!
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
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The ultimate DIY? A Stax SRM-T2!
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?
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Ye Macce Threade
The previous gen quad-core mini isn't all that bad. I expect improvements with the OS upgrade, etc.
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And now what did you do TODAY?
Invite Reks over, I am sure he could find something to do with a turtle...
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And now what did you do TODAY?
A night seems like the most dangerous time to wear a watch... I would insist on separate bedrooms with arranged conjugal visits.
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And now what did you do TODAY?
Storage and security was a strange mix, even for a cocktail lover
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What are you smoking right now?
- And now what did you do TODAY?
Started down the road of another acquisition. Goodbye DHR, hello NTCT... Can't be worse than HP I guess?- Ipod Touch / Iphone
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..- What are you smoking right now?
Not sure what...one of these though.- Linux Distro
I am not sure about Win8, sorry.- Linux Distro
Yes.- And now what did you do TODAY?
I dunno, unlimited PTO with vacation stipends?- And now what did you do TODAY?
What sort of stuff do you do? Looking for a job now?- Speaker stands
I have reused ATC stands in the past with great success...- Linux Distro
Why would you want to downgrade to a useless fustrating user experience? Not seeing your osx desktop is much better than being forced to see a Linux desktop /reks- KG Balanced Dynahi build discussion thread
What is the output impedance of your source?- Ipod Touch / Iphone
But does it b(l)end?- Ipod Touch / Iphone
- kgst
I use a circular PCB. - And now what did you do TODAY?
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