Actually, for most people to tell me that the JC-80 was 'good enough' would be a mild complement. But in Scott's case, it can be contrived in two ways: One way is that he has a more 'forgiving' listening standard (probably so) or it could be that all my efforts with Vendetta, Parasound, the Blowtorch, and with Constellation Audio has been just a waste of time, or 25 years of added experience.
I have a JC-80 in my closet. Nearby, I have a Levinson JC-2. Neither is hooked up in any of my 3 sound systems. I KNOW the compromises that are in them, and they have been put aside. Just like an automotive designer might not want to drive an early version of one of their designs, and would prefer a later model, with the attendant improvements, that they worked so hard to do.
I have a JC-80 in my closet. Nearby, I have a Levinson JC-2. Neither is hooked up in any of my 3 sound systems. I KNOW the compromises that are in them, and they have been put aside. Just like an automotive designer might not want to drive an early version of one of their designs, and would prefer a later model, with the attendant improvements, that they worked so hard to do.
No not at all, John Dennisen had a Linn set up with his linear tracking arm and the JC-80, the sound was less colored than the typical all valve setup and I could live with it. The advances since are incremental to me, if the few dozen well heeled audiophiles out there think that the last drop of improvment is worth the dollars, fine.
So that a better understanding of what 30 years does to a preamp, let me briefly describe the JC-80, first designed in 1981. It was an 'all-out' design, made the best with what was available, at the time, including superior Toshiba devices, virtually impossible to get today in any quantity.
This was my second implementation of a 2 block phono stage, the first being for HK, that did not go anywhere, but was built in 1978.
The HK design was a simple dual jfet diff pair, cap coupled to a discrete transconductance amp second stage. We found that this sounded better than the origional 1 block phono stage in the Levinson JC-2.
In 1981, I added servos through-out, and a single folded cascode second stage, in order to completely remove any coupling caps from the audio thru-path.
This design was made with ONLY Nchannel jfets at the very input, in order to reduce capacitance (just one device, effectively) so that the input could also be used for moving magnet or moving coils. We added variable input loading, ranging from 10 ohms to 50Kohms or so. We used Rel. polystyrene or polypropylene caps for both EQ and power supply bypassing. We used a pair of P&G linear volume control pots for the volume and balance control. The line amp consisted of a full comp. diff jfet input stage, much like I like to use today, and even today, I consider it to be darn good.
This preamp did pretty well for about 10 years, including winning an award for preamp of the year, in one famous magazine in Japan.
Well, what was wrong with it?
First, within a year of designing this preamp, I started working on a full complementary jfet design that became the Vendetta phono stage. This replaced the simple jfet diff pair and was about 9dB quieter. However, the extra input capacitance limited its operation to MC cartridges only, being many times larger than the JC-80 input. The second stage of the Vendetta was a comp-diff input stage operating as a cascoded transconductance driver with partial RIAA EQ. This has served me well, until recently. By 1990, my best effort was the Vendetta with the JC-80 line stage, the JC-80 phono stage used for moving magnet, or a second phono input. (more later, only 15 years to go)
This was my second implementation of a 2 block phono stage, the first being for HK, that did not go anywhere, but was built in 1978.
The HK design was a simple dual jfet diff pair, cap coupled to a discrete transconductance amp second stage. We found that this sounded better than the origional 1 block phono stage in the Levinson JC-2.
In 1981, I added servos through-out, and a single folded cascode second stage, in order to completely remove any coupling caps from the audio thru-path.
This design was made with ONLY Nchannel jfets at the very input, in order to reduce capacitance (just one device, effectively) so that the input could also be used for moving magnet or moving coils. We added variable input loading, ranging from 10 ohms to 50Kohms or so. We used Rel. polystyrene or polypropylene caps for both EQ and power supply bypassing. We used a pair of P&G linear volume control pots for the volume and balance control. The line amp consisted of a full comp. diff jfet input stage, much like I like to use today, and even today, I consider it to be darn good.
This preamp did pretty well for about 10 years, including winning an award for preamp of the year, in one famous magazine in Japan.
Well, what was wrong with it?
First, within a year of designing this preamp, I started working on a full complementary jfet design that became the Vendetta phono stage. This replaced the simple jfet diff pair and was about 9dB quieter. However, the extra input capacitance limited its operation to MC cartridges only, being many times larger than the JC-80 input. The second stage of the Vendetta was a comp-diff input stage operating as a cascoded transconductance driver with partial RIAA EQ. This has served me well, until recently. By 1990, my best effort was the Vendetta with the JC-80 line stage, the JC-80 phono stage used for moving magnet, or a second phono input. (more later, only 15 years to go)
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I remember reading an interview with Carroll Shelby where he mentioned he had recently driven a restored AC Cobra. He couldn't believe what a pig it was and he felt the (then current) Dodge Omni GLH was a much better car.
For the record, I think Boulder amps sound awful.
John
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Cool, I've never had a chance to listen to them in fact the only big name SS amp I spent any time with were some Krells but the friend who owned them insisted on playing everything at 11 with lots of window rattling bass. An all Cello/Theil set up at a local hifi salon had me putting my hands over my ears as folks like to say. Do you like Cary?
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Jlsem
How can an amplifier that measures like this Boulder 2050 monoblock amplifier Measurements | Stereophile.com
sound awful?
vac
How can an amplifier that measures like this Boulder 2050 monoblock amplifier Measurements | Stereophile.com
sound awful?
vac
Depends on your expectations. If you prefer an amp which has audible coloration, one whose output is a replica of the input will not be satisfying. Likewise, if you want tubes and an amp has transistors, its technical capabilities will be secondary.
PMA's comment is irrelevant- the measurements provided go well beyond a single-number THD/IM measurement and quite nicely show the capabilities of this amp.
Sy,
Can you actually tell me which of these measurements is the one that shows that the Amplifier will sound good? Because this is what potential customers want to know.
To be honest, looking at the residue for the THD test is interesting, listening to it could be quite useful... What I see there does not necessarily please me, to be honest.
Ciao T
Can you actually tell me which of these measurements is the one that shows that the Amplifier will sound good? Because this is what potential customers want to know.
To be honest, looking at the residue for the THD test is interesting, listening to it could be quite useful... What I see there does not necessarily please me, to be honest.
Ciao T
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