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The Opamp thread - Page 10

post #136 of 4402
7/15/09 at 5:47pm
Anyone noticed much (any?) difference between LME49710 (single) and LME49720 (dual)?
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post #137 of 4402
7/15/09 at 5:49pm
ok cool! well I've seen some ppl being more inventive than using these...and that'd have been far easier to solder.

anyway, I've been using the 2111 for +1 day, the bass is simply fantastic....but the mids lack something, I don't really know what it is...they're not "astonishing" as they are on the 4562/49720

I'm hoping the 1358/1364/1028ACN8 that I should get anytime soon will be a nice in-between the 4562 mids and the 2111 killer bass
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post #138 of 4402
7/15/09 at 5:55pm
Quote:
Originally Posted by 12Bass View Post
Anyone noticed much (any?) difference between LME49710 (single) and LME49720 (dual)?
I don't have the dual version to compare but in theory there shouldn't be a noticable difference unless you run the singles in Class A which I find makes a difference in a good way to all singles I've tried.
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post #139 of 4402
7/15/09 at 8:31pm
Thread Starter 
Quote:
Originally Posted by 12Bass View Post
Anyone noticed much (any?) difference between LME49710 (single) and LME49720 (dual)?
I have both and I prefer the 710's.
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post #140 of 4402
7/15/09 at 8:38pm
Quote:
Originally Posted by ROBSCIX View Post
I have both and I prefer the 710's.
Okay, I'll bite. Why?
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post #141 of 4402
7/16/09 at 3:49pm
Thread Starter 
Quote:
Originally Posted by SpudHarris View Post
I don't have the dual version to compare but in theory there shouldn't be a noticable difference unless you run the singles in Class A which I find makes a difference in a good way to all singles I've tried.
Your using a adapter, with some resistors to bias the opamps into Class A operation?
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post #142 of 4402
7/16/09 at 4:35pm
Yes but you can do a neater more permanent job with the smd resistors but as they are about as big as a grain of sand I prefer these.

I thought I had some pics but don't. If anyone wants to see them Ill take some and post them up.
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post #143 of 4402
7/16/09 at 4:40pm
Quote:
Originally Posted by SpudHarris View Post
I don't have the dual version to compare but in theory there shouldn't be a noticable difference unless you run the singles in Class A which I find makes a difference in a good way to all singles I've tried.
Is there a reason to believe in a difference between a single or a dual opamp in this respect or any respect at all? Is there a reason to believe "class A" biasing of opamps will improve the sound? If a typical buffer is used, with an input impedance of at least 10 MOhm, wouldn't the opamp already be operating in class A?
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post #144 of 4402
7/16/09 at 4:54pm
Since here is an Op-amp thread, I won't be off-topic. I'm looking for the cheapest op-amp to use in the Dynalo power supply. What kind of characteristics should I be looking at ? (slew rate, output current...)
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post #145 of 4402
7/16/09 at 4:55pm
If you say so diditmyself
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post #146 of 4402
7/16/09 at 5:44pm
Quote:
Originally Posted by bidoux View Post
Since here is an Op-amp thread, I won't be off-topic. I'm looking for the cheapest op-amp to use in the Dynalo power supply. What kind of characteristics should I be looking at ? (slew rate, output current...)
A good deal of output current. The alternative is to use any opamp and buffer it. Since the opamps are sinking and sourcing the return currents I guess it should sound good as well.
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post #147 of 4402
7/16/09 at 11:20pm
Thread Starter 
Quote:
Originally Posted by SpudHarris View Post
Yes but you can do a neater more permanent job with the smd resistors but as they are about as big as a grain of sand I prefer these.

I thought I had some pics but don't. If anyone wants to see them Ill take some and post them up.
Sure I would be interested in seeing those Mods...
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post #148 of 4402
7/17/09 at 5:14am
Ok, now where did I put that flame proof jacket?

Let me start by saying I am not a technical bod but I do have a gift (or a curse), which is a critical ear. I don't know if it is a thing learned over time or just the fact that I have a highly perseptive sense. Either way it's there.

I was once told that if it sounds good to you then it's good. Even if on paper (spec sheets) it shouldn't. Now with that covered and all you test geeks at the ready with your Multi Meters & Flame Throwers here are some pics of some Class A and some OBCA (Output Bypassed + Class A) AD744's.

Obviously there are neater ways of doing this especially if you are using SOIC on Brown Dogs. HiFlight (Ron Kerlin) makes and sells the nice neat modules and is far more qualified to comment on the pros and cons of using them.

Just for reference I have only ever used these in my P3 and P3+ so can't tell you how they fair in different circuits or amps.

Class A Adapters (AD8610's)


OBCA AD744's


Favourites
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post #149 of 4402
7/17/09 at 5:48am
I also think I have a critical ear, like most of us do, and I used to believe my amps sounded a lot better when I class A biased the opamps. Then I realised that it's very easy to do this trick live, going back and forth between "class A" and "AB". So I did and now I'm a nonbeliever. There was absolutely no difference at all. I've tried it with both a simple resistor and with active current sources - no difference. Belief is a mighty power. One more thing, just because a trick is audible doesn't mean it's for the better.
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post #150 of 4402
7/17/09 at 6:01am
Quote:
Originally Posted by diditmyself View Post
So I did and now I'm a nonbeliever. There was absolutely no difference at all.
To your ears.
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