The Opamp thread - Page 284

The LT1363 never stayed too long in my gear as I always liked others more. My favourite amp with rolling capability is the Fi-Quest and I have yet to find anything better sounding than OPA1641's in this. I will swap them out tonight and give the 1363's a good listen, I know they were always one of Leeperry's favourites but I just never got it. Maybe my ears have matured now, we'll see....

My Favourites are OPA1641 / AD797B / OPA602BP + CM / ADA4637-1BRZ / OPA827 in that order.

Thanks for sharing SpudHarris, it was your picture of the LT1363 in the ground channel in the Warbler which made me buy two of them in the first place, so I am eternally grateful.

If you try them in the Warbler, use them x2 in L/R, a quality buffer x2, bypass virtual, bypass ground.

Oh Nigel!   Are you still rolling opamps?    

I was doing great until I cracked open my PB2 a couple of weeks ago, for the first time in about three months!  

It wasn't long before I got swallowed up in a downward spiral there for a couple of days - I'd call it a lost weekend, for sure - but when I started to twitch all over and get convulsions, I managed to pull myself together and call the op-amp rolling obsession prevention hotline.  They talked me down.  Good people, those volunteers.   

The next day, I flushed all my spares down the toilet. You should think about it Nigel - seriously.

Your friend,

Mike

That makes me feel better the OPA627SM's I bought are not that costly in alcohol terms.

Quote:

Originally Posted by zilch0md 

Oh Nigel!   Are you still rolling opamps?    

 

 

I was doing great until I cracked open my PB2 a couple of weeks ago, for the first time in about three months!  

 

It wasn't long before I got swallowed up in a downward spiral there for a couple of days - I'd call it a lost weekend, for sure - but when I started to twitch all over and get convulsions, I managed to pull myself together and call the op-amp rolling obsession prevention hotline.  They talked me down.  Good people, those volunteers.   

 

The next day, I flushed all my spares down the toilet. You should think about it Nigel - seriously.

 

Your friend,

 

Mike

LOL

Mike, I'm afraid I fell off the wagon last night but only for the LT1363 trial.

I listened for 3 hours and have to say they sound quite nice in my Fi-Quest but they are not the holy grail. Will try in the P4 tonight just in case.... I've been listening exclusively with my HE-6 of late and I think I've been a bit spoiled. I use a Topping TP60 speaker amp to feed them and boy does the extra power make a difference, none of my other amps/phones compare with the HE-6/Topping combo.

Will try the P4 and Fi-Quest with easier to drive phones for a fair comparison.

The HE-6 is quite different than the tiny Vsonic and TWFK IEM's I used to listen to the LT1363, just sayin'...

It doesn't deliver the power of a speaker amp, or the transparency of an OPA16XX, but what it does do for me, it does extremely well.

Quote:

Originally Posted by kiteki 

Well, I've had my amplifier on for over 10 hours at max volume (burn-in experiment), I just opened it up (yeah, I screwed it shut, that says somethin') and touched the chips... the LT's are like... a little under skin temperature, less warm than the skin on my neck, heh, I don't think there's any oscillation here. =]

 

It's the kind of intrinsic detail I've always ached for, no expectation bias since I wasn't expecting jack from them, lol.

 

No op-amp sounds perfect, unless you've been persuaded into reading specs, essays and dScopes, and delusionary thereafter.  Music isn't supposed to sound flat and neutral, OPA1611 with a STAX SR-009 and crystal cables is a joke...

 

"huh... I take it on and off... it sounds like... nothing!!  It's invisible!!  I can't hear any difference between this and... fresh air!!......  now all I need is a cloaking device and I won't even see it! ><"

 

 

Music is supposed to sound hyper-extended, hyper-detailed, with more distinct layering, closer intimacy at different frequencies, revealing in secret nuances within the music, with an intact, uplifting and unnatural tonal colour.

 

A karaoke room isn't "reference / flat" sound, it enhances the singers voice (just like studios), recording uses all kinds of microphones with tailored FR, to 'zoom in' on the right content.  Technology and spikes in your transducers will zoom in further for heightened perceptivity and impact.

 

 

As such, op-amps are all different flavours of soft-drink (except OPA627 which is tears in a vanilla milkshake), it's just most of them taste like Diet-Coke from a tin can, AD797 like Tonic Water, and LT1363 like Coke from a glass with ice and lemon.

kiteki your audio poetry continues to split my sides with laughter. Thanks for the chuckles, and for the artistic descriptions of sound signature. Much more helpful than trite audiophile jargon.

Could anyone tell me if 3.9k resistors are ok for an A class biasing of OPA2227? What resistor value would be the optimal for an operating voltage of 15V?

Thanks...
 

Resistors are not good for class A biasing...A CCS is the preferred method.

resistors can be OK depending - like everything in engineering

if you have high supply V re the actual headphone drive requirement simple R loading can be fine

also depends on whether you're trying for full Class A directly driving the headphone or if you're talking about a op amp + buffer circuit

simple R do load the op amp output more, reduce small signal gain - but if the added R are a much higher value than the headphone Z, within op amp load spec, then their added load may not really matter

if you need greater efficiency, are going to swing nearly to the amp Vsupply limits then active ccs is better - and led/bjt or bjt "ring of two" waste much less V than the (locally to head-fi) faddish jfet ccs

A qiuck question... are there any inherent flaws in using a chip like AD797 as a buffer?  If it sounds good, y not?