The Opamp thread
Dec 7, 2021 at 12:23 PM Post #7,141 of 7,355
You likely won't see as much improvement with swapping out an OPA2604 for SE to Balanced duties.

Looks like you'd also need to re-solder in this case. I'd personally leave it alone in this particular amp/position.
 
Dec 7, 2021 at 12:34 PM Post #7,142 of 7,355
Thank you so much for the info. I did try to find info about this in the Xduoo thread as well, but i guess i didn't look well enough :p
Anyways, i do use the balanced inputs from my ADI-2 dac. So i guess there's no need to change anything. And i do have a pair of mullards on the way here, as well as some other tubes, can't even remember which ones atm. Sorry for hijacking this thread, i'll continue about this in the xduoo thread :)

-Pete
 
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Dec 23, 2021 at 11:07 PM Post #7,144 of 7,355
Hey all, I'm looking for an opamp that can be used in place of OPA2156 but has higher slew rate than it (which is 40V/us). Any suggestions?
 
Dec 23, 2021 at 11:22 PM Post #7,145 of 7,355
Hey all, I'm looking for an opamp that can be used in place of OPA2156 but has higher slew rate than it (which is 40V/us). Any suggestions?

Dare I ask why you need such a high slew rate?

The reason I ask, frequency capabilities relate to slew rate through the formula: Slew rate needed = 2 x Pi x frequency x voltage swing

Max safe voltage swing for an OPA2156 is probably 35V. At a slew rate of 40V/µs, you can reproduce music at full output up to 181 kHz.
 
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Dec 31, 2021 at 3:23 AM Post #7,147 of 7,355
My <US$40 Fosi Audio P1 tube preamp/buffer with bass, treble and volume dials has two TI NE5532Ps. While my tube research has indicated some good choices for tube rolling, my opamp research has led me here seeking advice, even after having read many posts in this thread.
Having eliminated the discrete opamp options and ICs such as the MUSE01 on cost, but prepared to pay ~US$20 for e.g. a pair of MUSES8920Ds from Digi-Key, I'm looking to try to eliminate any limitations of the signal through the device resulting from the NE5532P such that all (or as close as possible) the "flavour" comes from the tubes. I'm not interested in replacing any soldered components (yet).

Examples of the form of advice I'd find most useful are: "NE5532P is the best suited at that budget", "MUSES8920D will eliminate the severe dynamic range compression of the NE5532P", or "the OPA2134PA is as good as the MUSES8920D at 2/3 the cost and doesn't have the 1.6 kHz peak and 10 dB roll-off at 80 Hz of the NE5532P which makes all music sound like a car horn". If that's not too much to ask, then I'd also like precise and correct names, ideally with links to manufacturer or vendor product pages, because while you know how the "OPA" compares to the "34" and that one is better in the post-raphaelite stage, I don't (yet), and I need to be able to buy a thing, plug it into one or both of the 8-DIP sockets and have it work.

Other advice about or observations of the Fosi Audio P1 are welcome.

The device is between a Topping E30 and L30, so I have plenty of clean, low noise, linear, etc. signal.

PXL_20211224_155315121.jpg


More photos in the album.

PS. I know I'm not asking the right question, so if what I've asked is insufficient for a useful answer, then please let me know how I can improve it. I also know that results can vary.
 
Jan 8, 2022 at 12:01 AM Post #7,148 of 7,355
Hey all! I've a question for the more technical folks. LME49724, am I able to swap this for OPA1656 without any issue?
 
Jan 16, 2022 at 8:28 PM Post #7,149 of 7,355
My <US$40 Fosi Audio P1 tube preamp/buffer with bass, treble and volume dials has two TI NE5532Ps.
The device is between a Topping E30 and L30, so I have plenty of clean, low noise, linear, etc. signal.
More photos in the album.
Two dual Burson V6 Vivid fully discrete opamps arrived from Hong Kong courtesy of a generous offer from @John Burson at Burson Audio who asked only for "honest feedback and pictures of the upgrade posted in your frequent forums".

Since I am just starting my planned testing, I plan to split my review across multiple posts here, but first a photo of the V6 Vivids showing their neat packaging and how they might be a challenge to fit in the P1.

PXL_20220116_224543019.jpg


Caveats​

To properly review an opamp swap usually involves making the swap in an amplifier where the difference can be directly experienced, whereas I am swapping opamps in not only a pre-amp, but a tube pre-amp with stock tubes in which the two opamps operate across tone controls and volume in a way which I don't understand. Testing will involve twiddling bass, treble and volume dials on the pre-amp in order to try to discern the difference between the TI NE5532Ps and the Burson V6 Vivid. To make this harder, I am unable to effectively A/B test, so will rely on memory of impressions, approximate volume matching and comparable twiddling.

The Plan​

My test plan has three stages:
  1. The Truth
    1. Create a demo playlist
    2. Choose review components excluding the pre-amp
    3. Listen to the playlist
  2. The Tubeth
    1. Connect the Fosi Audio P1 between the DAC and amp
    2. Listen to the playlist
  3. The Vivid
    1. Replace the two TI NE5532Ps with the Burson V6 Vivids
    2. Listen to the playlist

The Playlist​

A mix of aw-dee-oh-file demorific and familiar tunes to enable a suitable test of the highs, lows, wides, deeps and details with a mix of natural and synthetic sounds. Most files are 96 or 48 kHz 24 bit or 44.1 kHz 16 bit FLAC with a couple of 48 kHz Opus/Ogg. The fist uncontroversial choice.

  1. Yosi Horikawa - Spaces - Timbres
  2. Hans Zimmer - Dune Original Motion Picture Soundtrack - Dream of Arrakis
  3. Pink Floyd - The Dark Side of the Moon - Time
  4. How to Destroy Angels - Welcome Oblivion - Ice Age
  5. NIN - Hesitation Marks "Audiophile Mastered Version" - Came Back Haunted
  6. Daft Punk - TRON Legacy (The Complete Edition) - Solar Sailer
  7. GUNSHIP - Dark All Day - Black Blood Red Kiss (feat. Kat Von D)
  8. Public Service Broadcasting - The War Room - Spitfire
  9. Steven Wilson - THE FUTURE BITES - KING GHOST
  10. King Crimson - Radical Action to Unseat the Hold of Monkey Mind - Starless
  11. Dire Straits - Brothers in Arms - Brothers in Arms

The Gear​

Files on the PC played with Audacious go to EasyEffects where a full parametric EQ for Crinacle's Harman over-ear 2018 is applied with no further modification resulting in a 96 kHz PCM signal from PipeWire going to the Topping E30, which sends line level output to the L30 which powers my unmodified Sivga SV021. The intention here is accurate reproduction with a familiar sound signature in which the most components are neutral, i.e. do not significantly limit or colour the sound, leaving the colouring for the pre-amp stage. The second uncontroversial choice.
While an objective description of my hearing is impractical, mine has no noticeable damage and tops out somewhere around 14.5 kHz.

Impressions​

The Truth​

Neutral is far from boring. With the naturally bassy-V SV021 EQ'ed to the gently warm curve, all the available details of the tracks appear in their intended places. Low, high, loud and quiet and everything in between appear without great emphasis or evidence of distortion or limitation.
Since this is the reference listen, volume on the L30 stayed at a comfortably loud one o'clock for two playthroughs.
 
Jan 16, 2022 at 9:57 PM Post #7,150 of 7,355
The Tubeth
  1. Connect the Fosi Audio P1 between the DAC and amp
Before connecting the TUBE-P1 I thought I would practice removing the IC opamps and installing the V6s. I'm glad to I did, as unfortunately while one of them could be squeezed into one socket, the second is blocked by a capacitor.

Before removing the IC opamps it was clear that the V6 would be too tall to fit inside the case. This was not a surprise, however I hoped that wire pin connectors might allow them to be installed horizontally, but in any case [pun intended] I was going to test them with the case open.
PXL_20220117_015209551.jpg

Removing the IC opamps with large tweezers was easy.
PXL_20220117_015430068.jpg

The first V6 was a very tight squeeze between the capacitors, but alas the second was firmly blocked by a capacitor.
PXL_20220117_015927771.jpg

PXL_20220117_015828385.jpg

and the riser included in the case was insufficient to clear it (and the two risers don't stack).
While pin wires (which I don't have) could enable the V6 to be connected and lie vertically, there is insufficient clearance in the front of the case.
PXL_20220117_020638173.jpg

PXL_20220117_020657213.jpg

There are a few more photos from this effort in the album.

PS. Re-inserting the IC op-amps was not so easy as the pins did not align. I had to insert one side, then use the tweezers to gently push each pin on the other side into the holes before pressing down to fully insert it.
 
Feb 18, 2022 at 5:24 PM Post #7,151 of 7,355
I whole heartedly can recommend the sparkos ss2590 which I use 4 in my ray samuels Apache - I’ve tried a ton of op amps - I wrote a review on it
 
Mar 7, 2022 at 5:09 PM Post #7,154 of 7,355
Hi folks,
maybe you can help me with an upgarde to my OPA627 in an Ayon Skylla 2 DAC. The DAC is now 10 years old and it still sounds amazing.
Burson V6 Vivid and V6 Classic did not do the trick for me, the OPA627 sounded superior. A friend of mine suggested they were probably under-powered in my DAC.
Is there a modern upgrade to the OPA627 that is known to sound superior? It needs to be an op amp that fits straight into the socket without any modifications.
I love warm, natural and dynamic sound but I would not mind a change if there is an op amp available with higher resolution maybe?
Most threads concerning the OPA627 are rather old...any ideas?
Cheers
 
Mar 7, 2022 at 5:23 PM Post #7,155 of 7,355
OPA828 is the modern successor to the OPA627. Well, technically the 827 was the original successor, but the 828 has since replaced it, and it seems the 828 is preferable to the 827 from those who have tried both. I've not tried the 627, so I can't speak to that comparison.

I'm currently using dual OPA828 on this adapter within my upgraded WHAMMY, sounds awesome.
 
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