[crapback]

I'm trying to remember the opamps with the best bass in my zero. I've had three earth's in it for a few weeks now which I think beat any combo of IC's I tried. My personal favorites in the amp section were the LT1361's and the LT1208's. IIRC, the 1208's had more punch.

 

[levin]

hehe i tried the HDAM earth but i prefer the HDAM sun v2 over it. i am trying HDAM moon at the moment.

 

[crapback]

The biggest bass improvement I found was when I put the two earth's in the amp section. I still haven't spent much time with the moon or sun yet. That and I couldn't fight the urge to buy a compass with the recent sale price.

I've done a few of the frankenzero mods to mine and with the treble improvements I found the sun v2 to be a bit too bright. I still have a few more mods to do to my zero yet. I have a $10 stepped attenuator coming and I'm going to replace my petp bypass caps with some pio caps. I'd recommend checking out the frankenzero thread when you get a chance.

 

[SpudHarris]

Quote:

Originally Posted by leeperry /img/forum/go_quote.gif well, after rolling the 1469 I started to hear the ugly side of the 1364...some nasty resonances in the trebles, that the 1678 simply doesn't have. the same sort of ugly stuff the 49720HA has too. I always wonder if the op-amps don't break-in...in a bad way. why would break-in always be positive ?! I often got that feeling w/ the 4562/49720 series. very nice for a few days, then either they broke-out, my brain suddenly refused to adapt or I dunno. anyway, the 1678 SS is way wider than the 1364, yet not artificial like the 49720

Well this must be a case of different circuits yealding different results as I still find the 1677's lacking in my P3+ with my current buffer and ground set up (which suits pretty much every other L/R chip). Don't get me wrong they don't sound bad as such but to my ears the 1363's are just more ballanced.

I may give them the benefit of doubt if you guys think they are worth it and try them with different or even bypassed buffers and/or ground.

 

[murrays]

Quote:

Originally Posted by Slash47 /img/forum/go_quote.gif Ah ok. It is generally accepted that using V- gives better results. See: Biasing Op-Amps into Class A

Tangent's article is a good reference, but it seems to be based on the assumption that biasing the output pins to -Vcc will load the NPN devices. While this is true for many chips where the NPN device is on the "positive" side of the output, there are some that their datasheet shows having the output transistors the around the other way, i.e. the PNP device is on the "positive" side (refer LT1677/78/79, AD823, OPA1611/12, etc).

I suppose if you are going to experiment with such biasing, you should probably try both +ve and -ve configurations, as Doug has suggested.

 

[murrays]

Quote:

Originally Posted by ecclesand /img/forum/go_quote.gif Yeah...I think I need to quit while I still have a working DAC. I'll solder up another set of single adapters with resistors between the OUT and V-. Then I can compare the 2. As for the dual socket....I'm done...stick a fork in me. EDIT: After an hour or so using the 2 single class A adapters on the BD adapter, the chips got just as hot as with the dual class A adapter. I guess that is a normal side effect of biasing?

The extra biasing draws current that will generate more heat within the chip. Ohm's law will tell you current and power, from voltage and resistance. e.g. 20mA x 15 volt supply = 300 mW.

If the heat is excessive it may be due to oscillation, by pushing the amp outside of its safe parameters. Those sockets stacked on the adapter could be enough to push a marginal setup over the edge. I don't know how output biasing would affect stability... ?

 

[bbbretzel]

Quote:

Originally Posted by levin /img/forum/go_quote.gif hey guys, i have received my Zero 2009 version and put in a HDAM Moon in the DAC section, what would you all reccomend to put in headphone section. i have tried LT1364 but i find them too be too sharp(?)( essentially really high treble, no bass at all ). is there a opamp i should try that would give it a better punch.

HI

I've got exactly the same configuration in mine, there are 2 LT1361 in the headamp section... I'll test with 2 x LME49860 after work, and I'm waiting for 3 pairs of samples from LT...

more bass with the LT1361 but the soundstage seems to be too "closed" for me... I'd like the open air soundstage ....

 

[leeperry]

Quote:

Originally Posted by SpudHarris /img/forum/go_quote.gif Well this must be a case of different circuits yealding different results as I still find the 1677's lacking in my P3+ with my current buffer and ground set up (which suits pretty much every other L/R chip). Don't get me wrong they don't sound bad as such but to my ears the 1363's are just more ballanced. I may give them the benefit of doubt if you guys think they are worth it and try them with different or even bypassed buffers and/or ground.

I'll try the single versions later...but so far -even w/ fresh ears- I still very much enjoy the LT1678.

trebles are clear(not resonating like 1364/1469/49720HA), SS is CRAZY(49720ish wide but not artificial), maybe only the low end percussion lacks a bit compared to the 1364...but it's still very much there.

1364 gave a "live" feeling, but this one goes even further I think...and Andrea I meant "loon" as there's several threads calling you a complete mad man, nothing personal...your advices have always been much appreciated here!

EDIT: the 1364 SS was too narrow, killing the extreme panned details...but the 1678 seems to miss the 1364 magic in the mids

maybe I'll try the OPA2107AP..

 

[ROBSCIX]

Quote:

Originally Posted by ecclesand /img/forum/go_quote.gif Yes. The LT1678 I have been listening to for the last several days and I know it well. The improvement with biasing was immediate. Again, I'm using these as the line out driver for a Peridot (PCM1793) DAC. OK...SCRATCH THAT!!! I have been burning the dual class a socket in for about an hour and decided to touch the top of the chip. OUCH....hot. I'm yanking this sucker now.

Some heat would be normal operation and some would be from the Class A modification.
I will do some more research into this subject and see what I can find out.

 

[ROBSCIX]

Has anybody here used the OPA6X7 series for I/V?

 

[levin]

Quote:

Originally Posted by bbbretzel /img/forum/go_quote.gif HI I've got exactly the same configuration in mine, there are 2 LT1361 in the headamp section... I'll test with 2 x LME49860 after work, and I'm waiting for 3 pairs of samples from LT... more bass with the LT1361 but the soundstage seems to be too "closed" for me... I'd like the open air soundstage ....

yea the LT1364 is quite good for stuff like classicals and vocals. but i listen to quite a few mix of different music so when songs with good bass or beats, they aren't there.

i usually listen to the same track with two different headphones for comparison. the AKG702 definitely have a huge soundstage in comparison to my Alessandro MS-2 but for both its still lacking the punch with these opamp.

i am trying to request for some AD797BRZ and OPA627AU samples but AVnet is asking me quite a few questions :X i think i also have some LME49720NA and a few LT chips coming in to test

 

[bbbretzel]

too difficult to have samples of TI chips....

 

[leeperry]

OPA2107AP ain't that ugly! I still got the 2277 to try afterwards

 

[SpudHarris]

Been rollin' most of the night and ain't gettin to enjoy the music and relax much because of this compulsion to find somthing better, arrrgh!!

Calling it a night now and I'm back to my old faithfulls the OPA132UA's. The LT1363's are still in the wings but for now I'm gonna chillax with my new Master Margherita album and a glass of Jameson's. Later taters!

 

[leeperry]

hahaha, luckily it's a major hassle for me to roll so I don't do it every 5 mins ^^

but the more you roll, the higher your expectations get....as you would want the good sides of all these chips, and the more of a let down it gets each time

PS: I think I'll put back the OPA2132P...HT.Omega recommends it for their AK4396 boards, and it wasn't too bad IIRC...the mids are dead on that 2107..