yes but what of the sound and even measured performance of the TOSH's vs. Fairchilds??
_-_-bear
_-_-bear
My ears are burning, so kindly refrain from abbreviating Toshiba as 'TOSH.'
And why does having pairs of Toshibas permit having source R increased to 1R as NP said?
half the current through each mosfet... equals the same quiescent current.
I wouldn't but you can. 😉
_-_-bear
PS. Peter, is that you? Love ur music, mon!
I wouldn't but you can. 😉
_-_-bear
PS. Peter, is that you? Love ur music, mon!
No, same ~1.3A through each mosfet.
Here's a note I snipped about using the Toshiba 2SJ201 and 2SK1530, NP post 6408:
"Judging by the curves on those parts, when paralleling them
you can raise the Source resistor to 1 ohm and get greater
thermal stability yet."
Actually this thread may not be the best place for this Q, so I will prob bring it up later in cviller's F5 blog...
PS. Legalize it!
Here's a note I snipped about using the Toshiba 2SJ201 and 2SK1530, NP post 6408:
"Judging by the curves on those parts, when paralleling them
you can raise the Source resistor to 1 ohm and get greater
thermal stability yet."
Actually this thread may not be the best place for this Q, so I will prob bring it up later in cviller's F5 blog...
PS. Legalize it!
I will probably not update my blog the next few days, because I'll be doing sight seeing with visitors from denmark. 😉
Well if you adjust the bias you can set it anywhere pretty much with any reasonable value of resistor in the hole... but if you keep the bias setting the same and raise the R value... or made the total current the same 1.3amps no matter what then the amp still runs the same amount in class A into the same load. Or so it would appear...
...and the question in my mind is do you want/need better thermal stability or do you want a lower value resistor for sonic reasons?
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These words from Nelson have to be situated into the context when they have been said:
The question was about my tweeters dc coupled to the amp. A tiny offset was wished stable in this case. So the 1 0hm source resistors have been suggested.
At least, i think so.
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That does seem right, Bobo. And who wouldn't want lower DC offset? Did you get around to trying paralleled pairs of Toshibas?
Bear: I have the same Q as you...
Bear: I have the same Q as you...
As we're talking about resistors...........here's a page I found with some terrific information on why and what the differences are between ;film thick/thin/ foil/ carbon comp ect.
Precision Metal Film Resistors USA Manufacturers Electra Dale CGW TRW Mepco
Good reading.
Ron
Precision Metal Film Resistors USA Manufacturers Electra Dale CGW TRW Mepco
Good reading.
Ron
I use Toshiba outputs, sound wonderful, and w/o tempco they are very DC stable.
I think they are a bit more detailed than Nationals, while not sounding peaky or rough. They are smooth and refined. I use .47r, but lowered R3 and R4 to 1K to get a little more 'action' out of the 5K pot. They otherwise bias up very quickly.
I think they are a bit more detailed than Nationals, while not sounding peaky or rough. They are smooth and refined. I use .47r, but lowered R3 and R4 to 1K to get a little more 'action' out of the 5K pot. They otherwise bias up very quickly.
The blasphemous method to assure absolute minimum DC offset is the <gasp> dreaded DC servo circuit.
The question is where and how to apply such absurdity - if one was to do that.
Dunno, but maybe the idea I came up with back in post - oops in the F5 thread - I think, to use the current limiting transistor for something else, to control the bias via the thermistor. Which means that it could replace the trimmer pots. Which means it could maybe, perhaps get a voltage back around from a DC servo sensor to set the offset to nil??
But, as I said "that's a different amp"...
😀
_-_-bear
The question is where and how to apply such absurdity - if one was to do that.
Dunno, but maybe the idea I came up with back in post - oops in the F5 thread - I think, to use the current limiting transistor for something else, to control the bias via the thermistor. Which means that it could replace the trimmer pots. Which means it could maybe, perhaps get a voltage back around from a DC servo sensor to set the offset to nil??
But, as I said "that's a different amp"...
😀
_-_-bear
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Hi Tea-Bag,
glad to hear that your listening impressions with the Toshiba MOSFETs are the same as mine 🙂.
Regards, Uwe
Now if a guy could just find some Toshiba's I could get to work on my mono-blocks.
Stop teasing me with how good they sound. I'll never build it with the others this way.
Stop teasing me with how good they sound. I'll never build it with the others this way.
I think BLUES is putting together a GB for them. At least I will propagate the rumor for some time.
Of course the Austrian Audio guys convinced me they were worth it!
Of course the Austrian Audio guys convinced me they were worth it!
Thanks Mike!
Couple hundred are on my garage lab bench being tested right now...
sorry no timeline yet.
Couple hundred are on my garage lab bench being tested right now...
sorry no timeline yet.
Fwiw, my batch of Toshiba "K"s has just arrived... the "J201"s are not far behind. I will be matching them using my Tek curve tracer. I expect to get a few good quads out of it and a number of duals. I'll also sell "best pair" N & Pch singles... the quads of course are optimum for the Cviller 2 Mosfets per rail boards, although not essential since the bias can be set for each rail independently...
I figure about 2 weeks to slog through the batch and see what is what... the J's will not be in my hands until midweek...
When i am all set i will put a post up and link from these F5 threads...
If there is no demand, I'll just keep 'em around... 😀
_-_-bear
I figure about 2 weeks to slog through the batch and see what is what... the J's will not be in my hands until midweek...
When i am all set i will put a post up and link from these F5 threads...
If there is no demand, I'll just keep 'em around... 😀
_-_-bear