john curl said:
Sometimes yes, sometimes no, depending on your mood and interest
So today you are saying we should not target better than 0.01% distortion 3rd harmonic because it's not audible?
I don't like to use large amounts of negative feedback to get very, very low numbers, when I can do OK without it. It is my deliberate choice for the Vendetta Phono Stage.
You do what you want, and we shall see, what wins in the audio world. Anyone can use an IC op amp to get extra gain, what is unique about that?
You do what you want, and we shall see, what wins in the audio world. Anyone can use an IC op amp to get extra gain, what is unique about that?
john curl said:
Well John, we are not competing 😀 I just proved that it's in the DIYer hands to beat the **** out of your old Vendetta design performance using feedback, opamps and a better, modern topology. What sells it's a different story, and I let that in your trustful hands. Certainly, handmatched (TM) JFETs are still a good marketing catch 😀
Otherwise said, your Vendetta phono stage is an overpriced piece of hardware and this price has no relationship with the quality or performance.
The second phrase pretty much proves your understanding of opamps. Pretty good for your age and experience 😀
Syn08, your designs are not new in any way. What makes you think they are? IC's have been around for 45 years or so. I could take a uA709, use 2 diodes and 2 complementary output devices and virtually match what you are getting today.
I just might do that with the parts I got in 1966. Maybe I will get lazy and use a 709 with a NH2002. That would be OK too. It's like falling off a log, it is so easy.
I am not here to discredit your efforts, they are significant and useful, BUT they are not unique.
Now, please don't attempt to discredit me, and I will not be forced to respond in kind.
I just might do that with the parts I got in 1966. Maybe I will get lazy and use a 709 with a NH2002. That would be OK too. It's like falling off a log, it is so easy.
I am not here to discredit your efforts, they are significant and useful, BUT they are not unique.
Now, please don't attempt to discredit me, and I will not be forced to respond in kind.
I wish to say something about pricing:
When I built the Vendetta Research SCP-1 and later the SCP-2, I was pushing the envelope of what I could do with jfet design. IF I could have made a living making the Vendetta phono preamp, I would have continued to do so. However, I couldn't make it economically.
Now, Syn08 thinks that I am crazy to match. Well, instead of using 4 unmatched parts, I used factory matched pairs with the same effective surface area. All I had to match was the Idss of the complement part pair. One easy measurement. What did I get? Easier 2'nd harmonic cancellation, less servo control needed, balanced current draw from the power supplies.
Now, what does it cost to make something like this.
Well, what is YOUR TIME WORTH? Throw in a decent (pretty case) and good quality connectors, and it gets pretty expensive.
Try building a Mercedes sometime from Ford parts. I DARE YOU!
When I built the Vendetta Research SCP-1 and later the SCP-2, I was pushing the envelope of what I could do with jfet design. IF I could have made a living making the Vendetta phono preamp, I would have continued to do so. However, I couldn't make it economically.
Now, Syn08 thinks that I am crazy to match. Well, instead of using 4 unmatched parts, I used factory matched pairs with the same effective surface area. All I had to match was the Idss of the complement part pair. One easy measurement. What did I get? Easier 2'nd harmonic cancellation, less servo control needed, balanced current draw from the power supplies.
Now, what does it cost to make something like this.
Well, what is YOUR TIME WORTH? Throw in a decent (pretty case) and good quality connectors, and it gets pretty expensive.
Try building a Mercedes sometime from Ford parts. I DARE YOU!
One of the most important resistors in a MC RIAA amp is the input resistor. I use a TX2352 or TX2575 for that position.
The 1 Ohm resistor I would special order from Texas Components and the type would be the same as above. If SMD types are needed they have that in bulk metal foil, too.
Sigurd
The 1 Ohm resistor I would special order from Texas Components and the type would be the same as above. If SMD types are needed they have that in bulk metal foil, too.
Sigurd
john curl said:
I also match JFETs. Not in absurdum, and only for Idss.
Not even the best chefs can make three star Guide Rogue meals 😉
/S
Not even the best chefs can make three star Guide Rogue meals 😉
/S
john curl said:
john curl said:
Oh, yes you are, as you are with anything/anybody that dares to challenge your 40 years old view of audio technology 😀
I use a tantalum pot in series with an old Holco 1/4W 10 ohm resistor. You are right, it is important.
john curl said:
Yep, that's what primarily defines the audio quality. Forget about those stinkin' numbers, and take care of the customer and reviewer eyes and pockets with directional silver wires wrapped in unbleached cotton, solid metal cases, $2000 power cables, gold connectors at $200 a pop, etc...
Sigurd Ruschkow said:
Your call, but I would bet it wouldn't do the slightest difference in a blind test to a good quality metal film like the Vishay/Dale.
Anybody have a favorite? Mills, Resista, Caddock, ...?
The difference between them all for audio is undetectable, the bridge measurements looking for -150dB differences are an exercise better suited for NIST or a calibration lab. Dale RN60's for me right out of the stock room. Does anyone out there want to put this stuff to the test once and for all?, didn't think so.
The difference between them all for audio is undetectable, the bridge measurements looking for -150dB differences are an exercise better suited for NIST or a calibration lab. Dale RN60's for me right out of the stock room. Does anyone out there want to put this stuff to the test once and for all?, didn't think so.
Nice work .. if you can get it!
John,
Your preamp was absurdly expensive at the time. It's not too hard to see that the profit margin was large (to be kind about it).
It's not hard to get cases milled out of a solid billet of aluminum. That is the silly expensive way to get there. A more intelligent path is to use investment casting and finish machining. Don't even breathe about defects - that's how they make the most expensive production engines in the world, and Chevy's too. Of course, you could get a special person to do this in an inefficient manner. But that is your problem and shouldn't be passed on to customers.
Matching? Yeah, it's work. I do it all the time and I'm just repairing equipment. Yes, it does sound better. Yes, I feel my time is worth something, and so do my customers.
So, how much did you cost your time out for? Development time doesn't count. That's what you learn as a job skill. Actual design time is charged out a bit at a time over the production.
I've seen enough product to know over the years John. But then, I don't care how much your pre sold for. It's just your constant references to it. Keep referring to it and you might be called to account for the costs. You don't want to do that.
-Chris
John,
Your preamp was absurdly expensive at the time. It's not too hard to see that the profit margin was large (to be kind about it).
It's not hard to get cases milled out of a solid billet of aluminum. That is the silly expensive way to get there. A more intelligent path is to use investment casting and finish machining. Don't even breathe about defects - that's how they make the most expensive production engines in the world, and Chevy's too. Of course, you could get a special person to do this in an inefficient manner. But that is your problem and shouldn't be passed on to customers.
Matching? Yeah, it's work. I do it all the time and I'm just repairing equipment. Yes, it does sound better. Yes, I feel my time is worth something, and so do my customers.
So, how much did you cost your time out for? Development time doesn't count. That's what you learn as a job skill. Actual design time is charged out a bit at a time over the production.
I've seen enough product to know over the years John. But then, I don't care how much your pre sold for. It's just your constant references to it. Keep referring to it and you might be called to account for the costs. You don't want to do that.
-Chris
Blind test for the input resistor was made a few months ago. We used carbon film, standard metal film, and the TX2352. MC RIAA amp was a 10+k Euro German line amp. Cartridge was Lyra Skala.
We were six highly trained persons who have "rather" expensive hi end audio stuff at home. Most favored the TX2352 but one person liked the carbon type.
I was a bit amazed that just one resistor in a special position would make such a big difference. I usually use TX2352:s all over a design.
Not sure what you would want more for a "proof". Surely repeated my many previous resistor experiences....
Why not make your own blind testing?
BTW,
do you imply that a good quality metail film like the Vishay/Dale (light brown RN55 I presume) sounds different form a normal metal film resistor???
Sigurd
We were six highly trained persons who have "rather" expensive hi end audio stuff at home. Most favored the TX2352 but one person liked the carbon type.
I was a bit amazed that just one resistor in a special position would make such a big difference. I usually use TX2352:s all over a design.
Not sure what you would want more for a "proof". Surely repeated my many previous resistor experiences....
Why not make your own blind testing?
BTW,
do you imply that a good quality metail film like the Vishay/Dale (light brown RN55 I presume) sounds different form a normal metal film resistor???
Sigurd
syn08 said:
My Vendetta Research box set cost ME $200. My best price that I ever got for a completed Vendetta was $1500, and I usually had to sell it for less. It was difficult to make for a number of reasons. In fact, we are working on making a BUILDABLE version at this very time. We finally found some solder resist that we liked, and this makes it infinitely easier not to make mistakes. We also have silkscreen ID's now.
Still, the Blowtorch dual chassis cost us $3000 a set, and we didn't like it. This is the fact of the matter, and I hold to it.
Still, the Blowtorch dual chassis cost us $3000 a set, and we didn't like it. This is the fact of the matter, and I hold to it.
Differences by listening alone do not exist. Sorry if that offends anyone and you can just ignore it, but I will stand by that claim that a precision resistor can not have an audible artifact in its transfer function. Held under strict scrutiny all results to the contrary will not hold up.
OK Scott, I will take your word for it. I am asking for inputs on the wrong thread, to be sure.
john curl said:It is NOT undetectable, it is just difficult to measure. You presume to lecture ME on this?
And of course is important to use the best and most expensive. They are audible, in particular in a 0.01% distortion design.
I measured quite a few metal film resistor brands and never got any difference over -130dB. That is, 0.00003%
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