Carlos, that's a pic of Max Headroom. I remember there was a TV show for a season or two as well as a somewhat famous Coke commercial which I believe preceded the TV show. Interestingly enough he was not computer generated but was played by Canadain actor Matt Frewer.
I really don't know if he was in an Art of Noise video or not...I was really more of a MARRS fan at the the time, remember Pump up the Volume? Sounds killer on vinyl!😎
I really don't know if he was in an Art of Noise video or not...I was really more of a MARRS fan at the the time, remember Pump up the Volume? Sounds killer on vinyl!😎
Just plugged in an AD826...
in place of the OPA2604 I was running in my homebrew headphone amp. The amp is a current-boosted Cmoy (a variation of the PRR Tori amp from Headwize). I had originally used the OPA2604 because I had some left from a work project. (Disclaimer: I build electronics for a living;-) I built the amp a little over a year ago, and while it sounded much better than my portable CDP huffing into a pair of AKG K271's, it didn't always reveal all the detail I knew should be in a particular recording.
After reading this thread, I ordered up some AD826 from the Analog website. I plugged them in today, and even with no burn-in, the difference was quite pronounced. The AD 826 was much more open and transparent than the OPA2604. Textures of the music were much more evident. Instruments merely heard before suddenly had presence. I even switched back and forth a few times. Definitely a big improvement. I'm looking forward to trying some others real soon.
a shot of my homebrew amp:
http://fractalbrewery.com/images/photos/amp.jpg
in place of the OPA2604 I was running in my homebrew headphone amp. The amp is a current-boosted Cmoy (a variation of the PRR Tori amp from Headwize). I had originally used the OPA2604 because I had some left from a work project. (Disclaimer: I build electronics for a living;-) I built the amp a little over a year ago, and while it sounded much better than my portable CDP huffing into a pair of AKG K271's, it didn't always reveal all the detail I knew should be in a particular recording.
After reading this thread, I ordered up some AD826 from the Analog website. I plugged them in today, and even with no burn-in, the difference was quite pronounced. The AD 826 was much more open and transparent than the OPA2604. Textures of the music were much more evident. Instruments merely heard before suddenly had presence. I even switched back and forth a few times. Definitely a big improvement. I'm looking forward to trying some others real soon.
a shot of my homebrew amp:
http://fractalbrewery.com/images/photos/amp.jpg
Gaucho said:
PHEW, am i relieved! A bit over a year ago i brewed-up a little dual OpAmp preamp for rolling chips to learn a bit more about these nifty critters. I rounded up the usual suspects, and a couple of ones that caught my eye. The OPA2227 and OPA2228 were two of the outliers with their notably low voltage noise specs, along with the LM6172 with its awesome slew rate and current capability.
One of the things that i sort for is the bandwidth of the flat phase response. Not all spec sheets dispense that information down into the audio frequencies, but it is there in many. The 2227 showed a remarkable 20-200,000 Hz bandwith - best of the group. The 2228 is shown to be 50-50,000 Hz, but it has a 4x slew rate advantage over the 2227... interesting. OBTW: the [prior to this thread] highly tauted 2604 is shown to be only 5,000 - 50,000 Hz bandwidth for flat phase -- could this be an indicator for the reported sonic deficits?
Anyway, my testing left me with the following impressions:
OPA2604 -- a bit boomy and too rounded, antithesis of harsh
OPA2132/4 -- very accurate, not objectionable at all, but maybe on the sterile side, could be a good candidate for active filters given the low offset and bias specs.
OPA2227/8 -- nice, real nice, liked the 2227 better by a hair, couldn't understand why all the fuss over the 2132/4, much less the 2604
LM6172 -- most musical of the bunch, little bug can really drive some current! some stability issues w/ low gain but tameable, used it as a headphone stage (at sane levels only🙂, also like it for driving cables... very fast chip
OPA627 -- on deck, got lazy making the dual-->single adapter
Since then i've spotted few posts regarding the 2227, and most were like the exchange in #192,3 in this thread. Thanks Gaucho for sharing your opinion -- it comforting to know that my ears haven't gone a completely daft as the stuff between them.
Cheers,
LarryO
lgo51 said:
Hi LarryO, I sort of hate to tell you but I've never used the OPA2227. I have however mentioned my initial experiences with the OPA2277 and when posting it wouldn't be hard to mix the two up, sorry if I did! The 2227 and the 2228 are on my 'to try list' even though the 2227 is painfully slow. The 1kHz unity gain THD+N spec is certainly very good.
lgo51 said:
Larry, I'm quite sure you've not gone daft! Boomy and rounded is exactly how I find the 2604, except that in a cd player at least, it is *not* the antithesis of harsh... In fact, it is very harsh, glary and reedy.
Thanks for sharing your impressions. Now that I am well accustomed to 2132 I am itching to try some of these others out! 😎
for Carlosfm
Hi ,today i try to bias opa627 with resistor to class A,looks I suceed.Actually extremely simple upgrade make sound much better.Especially on classic music and voices.
Have question.I biased in my Rotel 991 opa627 in out cascade.Can I also do same thing in I/V,filter?
Can Class A negative slowdown opa627 in i/v? Have you expirience with it?
Hi ,today i try to bias opa627 with resistor to class A,looks I suceed.Actually extremely simple upgrade make sound much better.Especially on classic music and voices.
Have question.I biased in my Rotel 991 opa627 in out cascade.Can I also do same thing in I/V,filter?
Can Class A negative slowdown opa627 in i/v? Have you expirience with it?
Re: Just plugged in an AD826...
What tool did you use to make those round cuts in the vero board that leave the centre coppered?
beerguy0 said:
What tool did you use to make those round cuts in the vero board that leave the centre coppered?
Re: Re: Just plugged in an AD826...
Vector makes a pad cutter tool, specifically for this. It'a hand tool but I have mine attached to a cheesy battery operated drill. It's a lousy drill, but is low power enough to cut pads without trashing the board. Makes for very neat boards.
Cheers,
IanAS said:
Vector makes a pad cutter tool, specifically for this. It'a hand tool but I have mine attached to a cheesy battery operated drill. It's a lousy drill, but is low power enough to cut pads without trashing the board. Makes for very neat boards.
Cheers,
Gaucho said:
Darn that lesdixia
Want to trade a couple of 2277's for a 2227 and a 2228 ? Seems that we each have some sonic homework.
Regards
LarryO
lgo51 said:
I just have the one 2277 and would like to keep it. I plan on getting some 2227s and 2228s before long. As for homework I also want to give the AD827 a try as well as few more Linear Technology op-amps. I also need to buy some of the Brown Dog adaptors (single-to-dual) for the OPA627s/637s and see what all the fuss is about. 🙂
Brown Dog
Gaucho said:
I know the OPA2228 for long, and it's not bad at all.
On a phono stage it gives very low hiss.
It sounds good, but not up to a well implemented OPA2132 or LM6172.
Curiosly, I've even tested the OPA2228 at unity gain, with no issues at all.
Works fine.😱
AnthonyAsh said:
AnthonyAsh said:
I have never tried it biased to class-A in I/V.
Try it if you want, but for me there are better op-amps for that role.
Very fast op-amps are better for I/V.
I'm using LM6171 with great results.
carlosfm said:
I know the OPA2228 for long, and it's not bad at all.
On a phono stage it gives very low hiss.
It sounds good, but not up to a well implemented OPA2132 or LM6172.
Curiosly, I've even tested the OPA2228 at unity gain, with no issues at all.
Works fine.😱
I have never tried it biased to class-A in I/V.
Try it if you want, but for me there are better op-amps for that role.
Very fast op-amps are better for I/V.
I'm using LM6171 with great results.
carlosfm said:
That is an opamp that really improved by biasing it with about 2mA which I tried it with....
Nicke said:
Thanks, Nicke.😎
I may try it, on my Audio Alchemy DDE 3.0 dac.
From the AD1862 dacs to the output RCA plugs it has a new board I made.
I've quit tweaking the original I/V and output stage, no use.
High-end now.
These AD dacs are very good, and the PMD100 digital filter (HDCD) is the best thing I know, I won't go NOS on this one.😀
AnthonyAsh said:
I use the OPA637😱 biased to class-A on the output stage of my TDA1541A NOS dac.
Direct I2S from my Philips CD650.
The biasing is just a resistor from V- to output.
Bias at close to 10ma for great results, with the OPA627/37.
Gentlemen, are you thinking, that biasing of an integrated opamp to class A is universal medicine and that manufacturers are only idiots ?
Upupa Epops said:
Specially when the biasing of an op amp is done , with a resistor to the power rail...it will inject power supply noise in the signal...
Some people seems to like "dirty sound"...😉
Jorge
Upupa Epops said:
I don't think so ,but in my case it works fine.Actually 99% procent of today commercial manufactures think only about profit,stock price etc...Please compare today equipment with equipment was made by same companies 10 years ago.All questions will gone🙂
That is other side of global capitalism🙂
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