Yes, the rest of us will stare at the ground and drool.
The best analog designers out there have kept their skills up to date and are extremely knowledgeable about post-1968 digital.
Sadly I haven't been exposed to your products in such a way that would tell me they're award winning. I'll keep trying. At Axpona the KEF room sounded like crap; using all JC Parasound stuff. Why did it sound bad? That I'm not sure about. I didn't investigate heavily or anything.
I doubt that it was the electronics, either. It is sometimes very hard to get good sound at a show. I keep up-to-date by DESIGNING new analog audio products, I have 4 of them in process now. Two power amps and two phono stages. No preamps this year. Just as well. It keeps me continually finding alternative solutions as parts go obsolete, and replace them with surface mount dual jfets for example. Linear Systems is a good source for standard jfets, and then there are exotic complementary mosfets, etc.
Well it wouldn't be too hard to have a piece of equipment interacting poorly with your JC phonostage... from what I can tell, but I didn't notice anything but Parasound.
The Blades maybe we're not broke in? They sounded like that, and are not known to be just flat out bad... Helll, maybe they are.
I disagree with ease of sound at hotel, actually, but that's another story. However I can say that equipment to equipment to speaker matching isn't always good at shows. It's easy to get bad partnership/match if they don't check it before.
The Blades maybe we're not broke in? They sounded like that, and are not known to be just flat out bad... Helll, maybe they are.
I disagree with ease of sound at hotel, actually, but that's another story. However I can say that equipment to equipment to speaker matching isn't always good at shows. It's easy to get bad partnership/match if they don't check it before.
Let me guess (since you "stick with what's working"): all of them using a complementary Jfet input stage followed by a folded cascode.
For the power amplifiers, the folded cascade is bipolar and the output stage has 8 pairs of power devices, biased so that the amp is in class A up to 5-10W output power. Wide open loop bandwidth and using not more than 20dB of global negative feedback (probably around 12dB).
The phono stages are all Jfet, including the local source followers for the +/- 24V power supply, has passive RIAA correction, followed by a second gain stage, also using Jfets. The output stage is built using complementary cascoded lateral Mosfets.
> I will be dead before I run out of matched complementary jfets. I saved up! '-)
You and Nelson
And Mr. Hansen.
Open-loop all JFET phono stages sound fine to me, once you have vinyl artifacts how would you propose to separate them? I would skip the MOSFET's. I could listen to this all day long. Save the circuit sophistry to where it matters.
I wonder if NXP could be persuaded to pluck adjacent BF862 chips off a wafer and package them as duals? The matching is not perfect but probably an enormous improvement over non-adjacent devices. These are biting me a bit now, with EUVL's experience seeming to be a confirmation of wide Idss spreads. I have already widened the accommodation range of a d.c. servo for a preamp with the part in the front end, and today found it still not quite enough. I am trying to manage a design with minimal adjustments.
No folded cascode. Too exotic. One entirely IC, another all complementary jfet, but no folded cascode. One IC with digital power amp added. and Finally one super amp with 30W class A and 450W with 14 output pairs of bipolar transistors. Sorry, no microprocessors needed at the moment. Linear input always appreciated.
I've split the dual matched pairs into two groups -
-Low Vce , low cob , high gain - Panasonic DMA20403/20402
are touted at <2% Hfe . Other choice is BC807/817DS
-high Vce , low cob , medium gain.
....good old FMBM5551/5401. (@5% match)
I learned SSOT-6/SOT-23-6/SC-74 are the same pinouts/3mm footprint.
SMD dual packages are a full 3 different pinouts depending on package,
voltage , and OEM. Bases on pin 2/5 for low Vce and 1/3 for high Vce.
These are the bigger packages that might still be DIY friendly.
Even as JC would make fun of me for SMD'ing a standard "leach amp"
for my first foray into the SMD world , it's "daddy" (spooky)is my main amp now.
SMD should allow me to reduce it's area (and noise) much further.
I am also going to study the ground planing aspects of it's input stage
design.
Now , the trick is to refine this new SMD dual device tech to "play"
well with both CFA (P/N matches) and single ended topologies.
It should , since P/N mismatch is the bane for CFA and same gender
mismatch is the single ended issue.
The new fabs seem to (make better devices)than the present through-hole fabs
for 992/1845 and BC550/560 devices.
I only need one Jfet pair in SMD (can't find it) for my K-V2.1 (below).
This one- they are running at 200W with BJT. I'd like to hear it's Jfet
mod in person.
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