i don't know of a better way to describe this sound but it's found largely in vintage amps and valves- that dense saturated notes. of course everyone's interpretation will vary but thick sound is for me just that- thicker imaging, more substance to notes. what are some causes of it? mid-bass hump? slow, bloomy bass? or can it be just from having rich harmonics?
I know exactly what you mean by that statement...
I believe it's the distribution and level of harmonics... old gear and certainly tube stuff generally produce higher distortion than modern designs but it seems to be pleasing to the ear. It's often predominantly second harmonic too.
I always comment that it's no use having the best specced amp in the world if you don't actually like listening to it. Designing for specmanship has it's own appeal of course but it doesn't always tie in with what we like audibly. I have owned and built so called ultimate/blameless designs and although I tried hard to convince myself it had to be "right" I find I get far more pleasure from a system designed to actually reproduce music rather than numbers
I believe it's the distribution and level of harmonics... old gear and certainly tube stuff generally produce higher distortion than modern designs but it seems to be pleasing to the ear. It's often predominantly second harmonic too.
I always comment that it's no use having the best specced amp in the world if you don't actually like listening to it. Designing for specmanship has it's own appeal of course but it doesn't always tie in with what we like audibly. I have owned and built so called ultimate/blameless designs and although I tried hard to convince myself it had to be "right" I find I get far more pleasure from a system designed to actually reproduce music rather than numbers
High viscosity electrons?
If you're speaking of tube amps it's most likely a combination of low order distortion that many people enjoy and/or output transformers interacting with variation of the speaker impedance. As far as opamp rolling, don't get me started. Some folks just don't get it; you can't randomly substitute one opamp for another without adjusting the circuit around it. The results will be random at best, and no valid judgements or conclusions can be reached by doing things that way. Just my $.02 worth.
Mike
If you're speaking of tube amps it's most likely a combination of low order distortion that many people enjoy and/or output transformers interacting with variation of the speaker impedance. As far as opamp rolling, don't get me started. Some folks just don't get it; you can't randomly substitute one opamp for another without adjusting the circuit around it. The results will be random at best, and no valid judgements or conclusions can be reached by doing things that way. Just my $.02 worth.
Mike
Some opamps can be substituted, the OPA627 and AD8610 being two that can, unless of course you're using one in a *very* specific tailored application that pushes the opamp to its limits.
One thing about older equipment is that large format mid/bass drivers 8"+ we're coupled with tweeters @ high xover points. This causes a large dip in the off axis response around the presence region and depending on loudspeaker could occur from anywhere between 800-3khz. This will also contribute to a more relaxed sound as there's less of what makes a speaker sound 'forward' in the indirect/reflected sound field.
One thing about older equipment is that large format mid/bass drivers 8"+ we're coupled with tweeters @ high xover points. This causes a large dip in the off axis response around the presence region and depending on loudspeaker could occur from anywhere between 800-3khz. This will also contribute to a more relaxed sound as there's less of what makes a speaker sound 'forward' in the indirect/reflected sound field.
Distortion of any kind means that individual 'instruments' can no longer be cleanly separated by the ear, which I guess could be perceived as a thicker sound. One of the hallmarks of real hi fi, to me, is that each instrument occupies its own space, and is unaffected by whatever any other instrument is doing. This cannot happen with any appreciable amount of distortion, but is perhaps perceived by some as a 'thin' or 'cold' sound which needs thickening up with a fuzz box. I would just call it realistic.
I was assuming the power supplies are of an appropriate voltage. In audio applications the AD8610 should drop in to a circuit designed for the OPA627. Don't get me wrong on this, I do not advocate opamp rolling of the like commonly encountered, with things like the AD797 and high speed video opamps such as the THS4031 being plugged in and out of incorrectly designed circuits. Of course if people want an oscillator or a distortion generator they are free to do as they wish.
We are on the same page then. I'm amazed at how many times I'll see a comment like "I just replaced all of the NE5532s in my [whatever] with AD8620s on adapter boards, and installed DIL sockets to make swaps easy, and the detail I'm hearing...blah,blah,blah." Then they might notice the new chips seem to be running hot, oblivious to the idea the new "detail" they hear is due to Mhz oscillation.
Mike
Mike
Paragraph 9 came to mind,
http://www.diyaudio.com/forums/anal...u-have-checked-see-its-stable-havent-you.html
This reminded of an incedent I was unfortunate to get involved in. Several years ago one of the guys that worked at the same place as me found out I knew something about electronics and approached me about replacing the "crappy opamps" in his CD player. I told him I'd have a look if he'd pay me for my time, plus parts if necessary, but no promises. Well, he brought it to me (Rotel if I remeber right) and I took it home and hooked it to my system to give it a listen. I was impressed with the sound, I would have been happy keeping it as is. Anyway, I popped the cover and found what appeared to be a nicly done discrete output I/V stage with NE5532 as a DC servo. I took it back to him unmodified and explained that the only opamp in there wasn't likely to have any effect on the sound, and recommended he leave it alone and enjoy it. He got insulting, refused to compensate me in any way, questioned my intelligence, and said he'd take it to someone who knew what they were doing. I wished him well, but never heard what he ended up doing. I learned to politely back away from such requests from then on.
Cal I concur, low damping does create this effect. Damping factor of a transformer output stage is 1, which leaves the woofer to flap around until it comes to rest naturally.
Nico
It certainly has little to do with valves. Common to both SS and tube amps from the sixties are really bad electrolytics and in the tube amps also not so stellar PIO coupling caps. Other factors also contribute but i would point a finger at the caps, especially amps with capacitive coupling to the speakers.
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