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Old 2nd July 2013, 03:52 PM   #791
redjr is offline redjr  United States
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Quote:
Originally Posted by AndrewT View Post
I don't see that emphasising that phrase changes my reply.
Those sources of interference still leave lots of potential to "colour the sonic character" of your equipment.
They might have the 'potential', but it's been my experience - with my gear and ears - none of them do to the extent my listening experience is compromised, or diminished.
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Old 2nd July 2013, 05:14 PM   #792
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Originally Posted by ivanlukic View Post
Hi Bob,

This is perfectly good explanation from an engineer's viewpoint. But there is also taste involved here. Even I must admit that j-fets sound better, if better means free from any nasty moments, aggressiveness, sharpness, edgy quality. But they are too polite, too bland for my taste. If you want to sooth yourself with music j-fets are way to go. But if you want drama (even if the price is occasional aggressiveness) and excitement, nothing beats bipolars. Great music performance involves a range of emotions, and performance sometimes contains anger, aggression, and negative emotional energy. J-fets seem to reduce everything to beauty. Listener remains calm all the time, unmoved enough by the musical performance. J-fets seem to be lacking in utmost realism, while bipolars sound thinner, sharper and more aggressive.
Interesting points. In the spectrum of devices, JFETs are more like tubes than BJTs, and some of what you say can be said about tubes. Some people prefer tubes, some people prefer solid state.

Cheers,
Bob
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Old 2nd July 2013, 05:19 PM   #793
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Maybe we just shouldn't be making preamps with 35-year-old op amps, whether they are JFET or BJT.

Cheers,
Bob
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Old 2nd July 2013, 05:32 PM   #794
kamis is offline kamis  Serbia
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For me J-fet based circuits, be it IC or discrete, always sound more neutral, less grainy and more dynamic , but not in the tube euphonic coloration way.
Comparing bad sides of tubes to J-fets is a wrong practice.
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Old 2nd July 2013, 05:45 PM   #795
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Quote:
Originally Posted by AndrewT View Post
Motors, both while running and during power ON/OFF.
Wireless gadgets, eg. mobile phone, WiFi, wireless house alarm, wireless landline, bluetooth, television
Dimmer switches, fluorescent lighting, LED drivers, SMPS.

It can be a very long list in most households !
I hear sonic signature of j-fets in any application including input stages of power amps, not only in opams. I remember when a friend of mine had Audio Analogue Paganini CD player. The sound was very soft and warm, like some old turntable, very analog-like. We opened it and in the analog section there was some TI TLE Excalibur j-fet. But that was the sound that reminded me of QUAD 34 preamp that I had 30+ years ago (with a lot of TL071 inside) and than there was no CD DACs, mobile phones, WiFi, SMPS, etc., to pollute audio signals. I never really liked the sound of that preamp and it took me a long time to understand that I am not a fan of j-fets.
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Old 2nd July 2013, 06:29 PM   #796
Zero D is offline Zero D  United Kingdom
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Several comments have been made as to being "more analog sounding"

I know what they mean but apart from Digi Synths etc, Everything else is Analog originally. I sure don't want to be exposed to "digi sounding" products !

The problem is, that are so Many variables involved i reproduction. The exact same gear in different rooms/locations WILL sound better or worse !

I've used & replaced combinations of Bipolar & Jfet OpAmps in mixers & other Pro gear over the years to improve performance. Jfet's "can" be beneficial in for eg usually higher impedance stages such as tone controls, to lower noise They all sounded great

*

Quote:
Originally Posted by Bob Cordell

Maybe we just shouldn't be making preamps with 35-year-old op amps
741's would do it
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Old 3rd July 2013, 12:09 AM   #797
owdeo is offline owdeo  Australia
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ivanlukic, I agree absolutely with both your recent posts - I think I can pick a jfet opamp easily, and same goes with power amps with jfet inputs (eg AEM6000). The smoothness is nice at first but gets boring quickly. So you were right, we're absolutely on the same page

Have you tried the OPA604 though? To my ears this is a nice compromise subjectively - it has the smooth "open" sound of fets while still maintaining some of the bipolar "drama".
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Old 3rd July 2013, 12:13 AM   #798
owdeo is offline owdeo  Australia
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Quote:
Originally Posted by redjr View Post
They might have the 'potential', but it's been my experience - with my gear and ears - none of them do to the extent my listening experience is compromised, or diminished.
redjr you've already stated that your preamp is the only high quality audio component in your system, so you would be extremely unlikely to hear any issues. I suggest you get yourself some decent speakers, power amp and source and another good preamp to compare to if you want to contribute to this discussion meaningfully.
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Old 3rd July 2013, 12:22 AM   #799
sandyK is offline sandyK  Australia
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Quote:
Originally Posted by owdeo View Post
ivanlukic, I agree absolutely with both your recent posts - I think I can pick a jfet opamp easily, and same goes with power amps with jfet inputs (eg AEM6000). The smoothness is nice at first but gets boring quickly. So you were right, we're absolutely on the same page

Have you tried the OPA604 though? To my ears this is a nice compromise subjectively - it has the smooth "open" sound of fets while still maintaining some of the bipolar "drama".
owdeo
Then why on earth are you still playing around with opamp based designs with their incredibly high open loop gain, when you could be further improving your discrete David Tilbrook based design from quite a few years back ?
Let's do a comparison between a couple of discrete preamps and the recent designs using 35 year old opamps.

Regards
Alex
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Old 3rd July 2013, 12:27 AM   #800
owdeo is offline owdeo  Australia
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Quote:
Originally Posted by Bob Cordell View Post
Maybe we just shouldn't be making preamps with 35-year-old op amps, whether they are JFET or BJT.
Hi Bob,

With all due respect I don't see any reason why not, if they are as good as or better than, objectively or subjectively, modern devices. Self has already argued the case for the objective reasons to use 5532s, but I have my own subjective ones also...

I bought some more LM4562s the other day so that I had enough to replace all the opamps in the main signal path of the Precision Preamp. I had a listen last night and oh dear, it's awful. Talk about a preamp that kills enjoyment of the music. It's hard to describe exactly why this is so, and presumably the distortion and noise would now be slightly lower than before. I don't understand why it's so bad, but I'm putting the 5532s back in - at least they are relatively harmless. The LM4562 might be regarded as "progress" for the test instruments, but as a device to faithfully reproduce music they are a big step backwards to my ears. At least in this design. And before anyone asks, I did check waveform with the scope and it appears stable so it's not that.

Cheers,
owdeo
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