What builds will they work in, in general?
Sissy SIT R.3 has been mentioned in page 1 of this thread. It also has it's own thread here in the Pass Labs section here, plus a few pictures of competed builds and devices.
Otherwise, the crack scientific team is working on it.
There have been other designs (flexible designs that should be able to use unmatched pairs) in the works as mentioned by Nelson Pass. Read this thread from page 1 onwards and you will be able to pick up some of the hints and notes along the way.
And on top of all that, I am sure that Zen Mod will manage to find room on his laboratory bench to spawn a design or two.
Attachments
I believe - what I already spawned is - if not more than enough, it's at least enough
though, you can expect at least another one, from me, with Biguns
though, you can expect at least another one, from me, with Biguns
With quad THF51S and a pair of 2SK182 stashed and saved for this unknown project, I was looking around for other rare parts in the garage and found a pair of these things, which appear to be WE transformers with 15 terminals, and 6 mounting posts. About 7 inched long.
I not totally sure what they are, Western Electric GA-10654 Magnetic Amplifier. But hoping they are good for something in one of my builds.
Any ideas?
I not totally sure what they are, Western Electric GA-10654 Magnetic Amplifier. But hoping they are good for something in one of my builds.
Any ideas?
UTC LS-52
These puppies drove my DIY electrostats in the early 1980s. I bought them from some surplus place long since forgotten. ~7 pounds each. These might be nice for a Tokin SIT amplifier; high voltage, low current. They survived high voltage ESL duty for years. Secondary goes down to 1.2 ohms.
These puppies drove my DIY electrostats in the early 1980s. I bought them from some surplus place long since forgotten. ~7 pounds each. These might be nice for a Tokin SIT amplifier; high voltage, low current. They survived high voltage ESL duty for years. Secondary goes down to 1.2 ohms.
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What would people recommend here? 2SK180s or THF51S? And matched pair, not matched or quads?
What are the DIY designs most likely to use and what would deliver the best sound?
Cheers,
Jon
What are the DIY designs most likely to use and what would deliver the best sound?
Cheers,
Jon
There is all sorts of speculation. The currently available, or even about to be available designs are using one device per channel, matching not “required”.
Mr Pass has hinted (promised?, he keeps using the snail icon) of a new board for these devices, and mentioned matching not required. Then there was the possibility that he new SIT boards will be a modification of the VFET boards, using the modular input board system.
Not sure if anyone has done listening tests using matched vs unmatched SITs at this point. Mr Pass has repeatedly said that matching was not required. He mainly recommended that folks get some of these devices before they disappear, like some other devices have already.
Let audio-nervosa commence, we never let well enough alone.
Mr Pass has hinted (promised?, he keeps using the snail icon) of a new board for these devices, and mentioned matching not required. Then there was the possibility that he new SIT boards will be a modification of the VFET boards, using the modular input board system.
Not sure if anyone has done listening tests using matched vs unmatched SITs at this point. Mr Pass has repeatedly said that matching was not required. He mainly recommended that folks get some of these devices before they disappear, like some other devices have already.
Let audio-nervosa commence, we never let well enough alone.
I will quote Mighty ZM
I think you would need a pair with close Vgs to have similar behaviour of left and right channels.
That is one SIT per channel.
Does anyone have the LTSpice model for the 2SK180?
The 2SK182 is around, but Idss is much much higher. Though the mu is similar (10*)
try with this ( I believe I made it, you see how ....... I believe I didn't found any reason for doubts later)
edit: it could be easy that I simply took model from Mr. MR's site
Code:
*--------------------------------------------------
*2SK180
*GENERATED BY SIT MODELER @ AUDIOHOBBY.COM
*MODEL RANGE: 100V, 5A
*--------------------------------------------------
.SUBCKT 2SK180 D G S ; Drain Gate Source
+ PARAMS: MU=17 X=1.5 K=0.67 N=1.76 VCT=0 RG=2MEG
*--------------------------------------------------
B1 D S I=K*PWR(URAMP((V(G,S)+VCT)+(N*LN(V(D,S))+(V(D,S)/MU))),X)
*FOR MULTISIM COMMENT OUT ABOVE LINE (*) AND UNCOMMENT NEXT LINE
*B1 D S I=K*PWR(MAX((V(G,S)+VCT)+(N*LN(V(D,S))+(V(D,S)/MU)),0),X)
R1 G S {RG}
CGS G S 2000P
CGD G D 2000P
CDS G S 0P
.ENDS 2SK180
*--------------------------------------------------edit: it could be easy that I simply took model from Mr. MR's site
Thanks Guys,
I have spoke to Tomo-san and ordered matched Quads of 2SK180s and THF51S to be on the safe side and be future proofed.
Now I need to sell a Kidney.. or some gear.
When I received my THF-51S pair, I was astonished at how massive they look and feel. That is what I call an active device !
Roughly Matched
I got two pairs of roughly matched THF-51S from Watanabe san a couple of weeks back. All went smooth as silk. In the meantime I wanted to check what does roughly matched mean. So I put together a FrankenTracer (thanks to Mr. MR) and a Sweet Spot tester (thanks to Ihquam) and went to work. First I learned a lot, then generated a lot of data and then googled a lot about Excel data and charts. I added the reduced series data for each THF-51S to an Excel chart and finally came up with the graph attached.
From this amateur's point of view they look well matched.
Now to build something with them.
I got two pairs of roughly matched THF-51S from Watanabe san a couple of weeks back. All went smooth as silk. In the meantime I wanted to check what does roughly matched mean. So I put together a FrankenTracer (thanks to Mr. MR) and a Sweet Spot tester (thanks to Ihquam) and went to work. First I learned a lot, then generated a lot of data and then googled a lot about Excel data and charts. I added the reduced series data for each THF-51S to an Excel chart and finally came up with the graph attached.
From this amateur's point of view they look well matched.
Now to build something with them.
