The Opamp thread

[leeperry]

hehe, well the Earth sounds amazing...it really does, it's the same as the old burson(Kingwa was making it as OEM for them)...you can look up all the testimonials over the internet, it's not just in my head

anyway, time to ditch the Moon and put back the holy Earth again

next time I order, I'll be getting twice shorter extension leads indeed...it'll be less of a mess in my box, and maybe it'll also improve the SQ. anyway, I'm also getting a new burson w/ a mundorf cap, I wonder if it'll sound any better than the Earth

 

[leeperry]

yeah, one thing that's totally amazing on the Earth is the stereo coherence..just mind blowing!

you can see at the end of their webpage that they give perfect waveforms on an oscilloscope, unlike IC's: н¨ÍøÒ³ 1

another site did many more comparisons and came up w/ the same conclusions.

It's funny seeing manufacturers like Denon boast about dual-ended headphones to keep the stereo coherence spot-on, when most ppl will be using crappy IC's w/ lousy stereo soundstage to begin with..my cd1k is single-ended and I've never heard stereo this accurately, it makes my brain sooooooo happy in TrueHD binaural downmixed movies

I'll try 3*Earth but I'll prolly miss the vocal magic of the LT1364...but ya never know

 

[ROBSCIX]

Quote:

Originally Posted by 12Bass /img/forum/go_quote.gif Just looking at the photos, it is hard to imagine that running a bunch of long wires from a discrete op amp to a DIP socket can be helping performance any.... all sorts of inductance, RF pickup, and an open invitation for oscillation there. Just curious, leeperry, have you done any quasi-scientific testing, perhaps having a friend swap op amps so that you don't know which ones you are listening to? Expectation can have a huge impact on auditory perception.

Do you do any class A biasing work? just wondering if anybody has the proper formula for the bias resistors. I had it written down but cannot seem to find it. I am ordering about $100 in new parts for my opamps and want to get some biasing resistors.

 

[Slash47]

Quote:

Originally Posted by ROBSCIX /img/forum/go_quote.gif Do you do any class A biasing work? just wondering if anybody has the proper formula for the bias resistors. I had it written down but cannot seem to find it. I am ordering about $100 in new parts for my opamps and want to get some biasing resistors.

Figure out your supply voltage, your load impedance and how much power your opamps can deliver. Don't go below 1k or above 20k, else it's pointless/harmful.

If you're driving a buffer, 10k is plenty. If you're driving a headphone amp with 12k input impedance, go lower, like 3k3.

2k2 is a good value because pretty much nothing has less then 10k load impedance (except for headphones and speakers, of course) and high bias gives sweeter results. However, some (modern) opamps seem to prefer the higher load impedance to the bias current. Others can have a hard time coping with the heavy load, resulting in a loss of dynamics or even clipping/distortion.

 

[diditmyself]

Quote:

Originally Posted by ROBSCIX /img/forum/go_quote.gif Do you do any class A biasing work? just wondering if anybody has the proper formula for the bias resistors. I had it written down but cannot seem to find it. I am ordering about $100 in new parts for my opamps and want to get some biasing resistors.

You should use Ohm's law. R=U/I. A couple of mA is enough. Eg if the supply is +/- 10 V and you want 2 mA: R=10/0.002 => R=5k. I guess the recommended 2k2 or 3k3 is fine too.

Consider using constant current sources instead, like a JFET with appropriate source resistor. Look at how it's done in PIMETA, PPA or M3. You don't need cascoded JFETs.

 

[igor0203]

Quote:

Originally Posted by leeperry /img/forum/go_quote.gif ...it makes my brain sooooooo happy in TrueHD binaural downmixed movies...

Can you name some, please?

 

[leeperry]

Quote:

Originally Posted by igor0203 /img/forum/go_quote.gif Can you name some, please?

this one has a 24/48 TrueHD binaural track on BD: Bad Boy Bubby (1993)

I usually make my own 3D-ish stereo downmixes in ffdshow+Ozone4...I'd say the most impressive lossless soundtracks I have would be Transformers II/Nightmare Before Xmas/Kill Bill 1, always impressed by those

 

[leeperry]

Quote:

Originally Posted by 12Bass /img/forum/go_quote.gif it is hard to imagine that running a bunch of long wires from a discrete op amp to a DIP socket can be helping performance any.... all sorts of inductance, RF pickup, and an open invitation for oscillation there.

"We have added caps on the OPA, so it can reduce the effect of leads. -Kingwa"

I honestly can't hear any nasty artifacts, just some totally crazy stereo coherence..talk about surreal SS

PS: hahaha, Andrea has gone discrete too?? would explain his silence

Quote:

Hello, I'm Andrea from Italy. I purchased all of your discrete opamps, and after a 300+ hours or burn-in and deep listening I stick with the OPA Sun v2 as my favourite on my system (Zero DAC, Dussun DS99 amplifier, Tannoy Sensys DC2). I found it having the best dynamics and impulse response as you described it in your website, I feel it very fast and accurate, revealing a detail that the other two don't. I prefer the Sun v2 over the Earth under any aspect.

 

[Cynips]

Quote:

Originally Posted by leeperry /img/forum/go_quote.gif PS: hahaha, Andrea has gone discrete too?? would explain his silence

Why would that explain anything? Going discrete hasn't stopped you from coming here, has it?

 

[leeperry]

well, he went from 5 posts a day of "my favorite is this one, oh no this one...or maybe this one" to zero posts.

maybe the man finally found his favorite, once and for all

but yeah, IC's don't hold a candle to discretes(mushy SS is the worst offender)...I've just ordered some SUN V2, maybe I'll like it more than Moon.

I'm still waiting on my LT1028....but I'm rather doubtful these would crush discretes.

 

[diditmyself]

Now we just have to wait and see if he starts transistor rolling. SA970/SC2240 are kind of bright sounding, but on the other hand SK170/SJ74 are warm sounding and grainy when uncascoded.

 

[leeperry]

goodness gracious, this guy hacks standalone players...not to put discrete op-amps, but tubes!

Lampizator page index

sony227ESD

 

[ecclesand]

Quote:

Originally Posted by leeperry /img/forum/go_quote.gif PS: hahaha, Andrea has gone discrete too?? would explain his silence

When I had all 3 HDAMs, I too preferred the Sun V2. It was well suited to metal and progressive rock.

 

[Pluto2]

Andrea is happily residing on diyaudio these days..... : )

 

[K3cT]

Anymore Sun V2 to Earth comparison? The Sun is too bright for me now, considering selling it if it stays this way.