I have the same problem, they quote yield issues which is perfectly understandible but there is no business argument in only supplying DIY audiophiles for phono circuits.
A bird told me they have OEM's and distributors waiting with massive orders.
This is the problem: buzzforb.
Audio amateurs are the biggest pita's that a manufacturer can have. They want small quantities, and low prices, (samples preferred) and they are VERY FUSSY about what they get.
Let us hope that Linear Systems will finally release the devices IN QUANTITY to distributors, who are set-up for this sort of customer. Today, no.
Audio amateurs are the biggest pita's that a manufacturer can have. They want small quantities, and low prices, (samples preferred) and they are VERY FUSSY about what they get.
Let us hope that Linear Systems will finally release the devices IN QUANTITY to distributors, who are set-up for this sort of customer. Today, no.
This is the problem: buzzforb.
Audio amateurs are the biggest pita's that a manufacturer can have. They want small quantities, and low prices, (samples preferred) and they are VERY FUSSY about what they get.
Let us hope that Linear Systems will finally release the devices IN QUANTITY to distributors, who are set-up for this sort of customer. Today, no.
Diyer's, fussy and cheap. Cmon
... an example of an ALTERNATE topology ...
John, I remember you posted an earlier version of this circuit with
additional mosfets in the output stage. In this version these are removed
and in turn the current through the BJTs increased somewhat.
My question is: were these mosfets removed because the extra current they
provide was not needed for the application (2nd stage of phono preamplifier)
resulting in fewer parts, or were you not satisfied with the mosfets versions performance ?
In other words, if one needs more current, is the "mosfet version" still a
valid approach or are there certain caveats ?
John, you keep mentioning j175 - j113 combo occasionally.. According to the datasheets:
j175 - Vgs(off) = 3-6 V, IDSS = 7-20 mA
j113 - Vgs(off) = 0.5-3 V, IDSS = 2-(?) mA
Are they really complementary? Or, does one, in order to get more or less complementary pairs, has to select from a large number of devices?
j175 - Vgs(off) = 3-6 V, IDSS = 7-20 mA
j113 - Vgs(off) = 0.5-3 V, IDSS = 2-(?) mA
Are they really complementary? Or, does one, in order to get more or less complementary pairs, has to select from a large number of devices?
Here is an example of an ALTERNATE topology that doesn't have pchannel jfets, that is akin to what Scott Wurcer used for his AD797.
I am very concerned about the availability of P ch jfets. Somebody, somewhere is grabbing ALL of them up. Please input here as to your problems and what you have done to find these pch parts.
Nice circuit. Just buffer it and there you have it. No complementaries needed.
OK, everybody. Let's look more carefully at the data sheets for the 'alternate' jfet devices:
John, which parameters specifically shall we look at "more carefully"?
I generally use IRF610 and IRFP510 devices of output followers or cascodes. For common source amplifiers, these devices have to be at least Harris (Fairchild) for the P's. Hitachi devices like the 2SK214, 2SJ76 work OK too.
The 'complementary' argument is sort of weak. It is not that true complementary devices would not be desired, but the lack of true complementary parts usually just means a bit more 2'nd harmonic. It must be remembered that usually the complementary part is working WITH the other part, not just being a parasite, just drawing current (at minimum) or even adding to the load, AND as well having a complementary distortion curve as well.
The 'complementary' argument is sort of weak. It is not that true complementary devices would not be desired, but the lack of true complementary parts usually just means a bit more 2'nd harmonic. It must be remembered that usually the complementary part is working WITH the other part, not just being a parasite, just drawing current (at minimum) or even adding to the load, AND as well having a complementary distortion curve as well.
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