iBasso PB-2 Pelican fully balanced portable, DB-2 Dac . . HiFlight recommended op amps page 16. .
Aug 31, 2013 at 6:24 PM Post #917 of 1,604
Quote:
Oh, sorry to add fuel to the fire!

Not at all Nigel, another configuration I've got to try so thankyou. I'm not after perfection, I'm just after general enjoyment
 
Have you heard the OPA2134? What do you think of them?
 
Also, what's a class A mod? Is it an adapter?
 
Tom
 
Aug 31, 2013 at 6:32 PM Post #918 of 1,604
I'm after a sound that's slightly warmish in the low end but clear in mids and highs and bass does not bleed into the mids. I really liked the sound of the stock chips AU797 x 4 and the BUF634P but it had a mettalic twang in the bass on some tracks which I didn't like about.
 
Tom
 
Aug 31, 2013 at 7:43 PM Post #919 of 1,604
Well I to am selling my Slate JDS Labs C5, to buy this amp xD, going to run a Beyer Dt 880 Pre 600 ohm portable balanced [mine's already been recabled] out of a Hm 801 and then into this
 
What would be the leanest set of Op amps and Buffers, The Hm 801 is going to have all warmth I need now I just want the amp to be as clean lean and tight as I can get er! 
 
Also any one selling one ;3
 
Aug 31, 2013 at 7:47 PM Post #920 of 1,604
The class A mod is in the form of a DIP socket with a resistor across two pins (4 and 7???). Sorry Tom it's been a while :rolleyes:.

Not sure I have pics on this Ipad but will post some for sure if not from the home PC.

I think that configuration will cover your needs and you can always swap the buffers for stacked BUF634P if you need to smooth it out slightly.
 
Aug 31, 2013 at 7:59 PM Post #921 of 1,604
Quote:
I'm after a sound that's slightly warmish in the low end but clear in mids and highs and bass does not bleed into the mids. I really liked the sound of the stock chips AU797 x 4 and the BUF634P but it had a mettalic twang in the bass on some tracks which I didn't like about.
 
Tom

You know... looking at your portable rig are your using an iPhone as a source? That Metallic Twang is something I heard when I owned and amp'd my old iPod Nano... if you want a slightly warmish sound but clear mids and highs... try going for a Hifiman DAP. The bass is nice and smooth Great speed and tightness with a warm sound to it, mids r touch forward and a little sparkle in the treble. The DAP might be a tad to warm for the mad Dogs, but honestly i'd imagine a better source might yeild better results, if your feeding your amp a sub par signal, there's nothing the amp can do to make crap into gold 
 
I used to own a iDevice and the sound pretty bleh, Still I'm happy to hear the stock sound at the very least has that issue to it, the Dt 880s have such a big fat resonnace in thier low end some metallic twang might balance em out lol 
 
Aug 31, 2013 at 8:45 PM Post #922 of 1,604
You know... looking at your portable rig are your using an iPhone as a source? That Metallic Twang is something I heard when I owned and amp'd my old iPod Nano... if you want a slightly warmish sound but clear mids and highs... try going for a Hifiman DAP. The bass is nice and smooth Great speed and tightness with a warm sound to it, mids r touch forward and a little sparkle in the treble. The DAP might be a tad to warm for the mad Dogs, but honestly i'd imagine a better source might yeild better results, if your feeding your amp a sub par signal, there's nothing the amp can do to make crap into gold 

I used to own a iDevice and the sound pretty bleh, Still I'm happy to hear the stock sound at the very least has that issue to it, the Dt 880s have such a big fat resonnace in thier low end some metallic twang might balance em out lol 
funnily enough I actually like the warmth of the bass on the iPhone but it just won't give me the volume for that mad dogs. I've run the PB2 via the pc and I believe the metallic twang is from the PB2. Non of the amps I've tried from the iPhone had this sound. I really did like the warmish bass when I used the 797 op-amps as buffers but the bass ate into the mids too much and I lost all details in the mids and highs
 
Aug 31, 2013 at 8:49 PM Post #923 of 1,604
Quote:
funnily enough I actually like the warmth of the bass on the iPhone but it just won't give me the volume for that mad dogs. I've run the PB2 via the pc and I believe the metallic twang is from the PB2. Non of the amps I've tried from the iPhone had this sound. I really did like the warmish bass when I used the 797 op-amps as buffers but the bass ate into the mids too much and I lost all details in the mids and highs

again if ur using the on board mother board sound your not going to have any details to begin with, but you might be right. Still any one have pictures of what the OP amp swaping and Buffer swaps look like? How would I change the op's and buffers in my unit? [Obviosuly open it up but aside from that then what...]
 
In addition I always found the Mad Dogs to be really  warm... and hearing that a Fully Balanced Amp results in losing detail in the mid range and highs sounds alittle off... Still I'd like to tinker with it my self, although I hold to the idea that the iPhone and the Pc [if your using the Stock DACs in both] are teh culprit.
 
My old iPod had no mid or high details, and my on board pc audio was the same. You really need a better source to accurate judge the sound of an amp as nice as that. But if all you have is Stock Mother Board Sound and n iPhone it's not a wonder you'r having issues with quality. 
 
Sep 1, 2013 at 2:30 AM Post #924 of 1,604
again if ur using the on board mother board sound your not going to have any details to begin with, but you might be right. Still any one have pictures of what the OP amp swaping and Buffer swaps look like? How would I change the op's and buffers in my unit? [Obviosuly open it up but aside from that then what...]

In addition I always found the Mad Dogs to be really  warm... and hearing that a Fully Balanced Amp results in losing detail in the mid range and highs sounds alittle off... Still I'd like to tinker with it my self, although I hold to the idea that the iPhone and the Pc [if your using the Stock DACs in both] are teh culprit.

My old iPod had no mid or high details, and my on board pc audio was the same. You really need a better source to accurate judge the sound of an amp as nice as that. But if all you have is Stock Mother Board Sound and n iPhone it's not a wonder you'r having issues with quality. 


I was using the audio gd 15.32 as a dac via usb. It drives the HE500s via the Topping TP60 really well.
 
Sep 1, 2013 at 2:35 AM Post #925 of 1,604
hmm and there was no mid detail... did u check ur gain my matrix gets a thick bass n no details when i run my beyers at 18 gain... n they r 600 ohms at that
 
Sep 1, 2013 at 2:39 AM Post #926 of 1,604
The class A mod is in the form of a DIP socket with a resistor across two pins (4 and 7???). Sorry Tom it's been a while :rolleyes:.

Not sure I have pics on this Ipad but will post some for sure if not from the home PC.

I think that configuration will cover your needs and you can always swap the buffers for stacked BUF634P if you need to smooth it out slightly.


Spud what combo of ops n buffers would yeild the most linear sound
 
Sep 1, 2013 at 3:48 AM Post #927 of 1,604
Sorry meant to expand a bit on that. I have that metallic artificial twang sound in the bass with the PB2 even though connected to a the Audio GD DAC via USB from my PC so I don't believe its the source. For me trying to reduce the twang (not sure if its even a word but you understand right) increases the warmth in the bass which I like but it ends up always affecting the mids and highs.
 
My topping TP60 (speaker taps) via the same source beats the PB2 in every way via the same source and headphones (HE500s). I didn't like my old ipod nano either (no mids and no highs) and didn't like the sound of the iphone 5 (bass is bloaty and it clips on some of my iems), I'm not sure if there are any differences inside but I actually like the iphone 4 and 4s which I use both as a standalone player and to drive the PB2s. I might purchase another DAP but at this stage I still like the iphone 4 and will later consider an upgrade once I feel like I'm ready.
 
Sep 1, 2013 at 4:47 AM Post #928 of 1,604
Damn it Mshenay, now listening to my desktop rig again, you got me thinking I might need a new DAP. Any recommendations on a decent DAP that will do the PB2 and Mad Dogs justice? The bigger the storage available the better also. 
 
Sep 1, 2013 at 6:07 AM Post #929 of 1,604

 
P1010115.jpg

 
Class A DIP mod for Dual and single OpAmps
 
Sep 1, 2013 at 6:30 AM Post #930 of 1,604
Geez, I better learn how to solder
 

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