Best Schiit Bifrost 1 Multibit modification practice

I have been tried many different OP-AMPs and etc. and I found some interesting things.
This is the legacy Schiit multi-bit architecture and It is little bit noizy and too bright to me. On the other hand, the dynamic range is very good.
These modification steps also can be used by other Schiit AD5547 DACs

1. Upgrade USB card to Unison USB card

2. Replace OP-AMP from AD8512 to ADA4620-2 (this is the best IV op-amp nowadays).

3. Use iPad as USB source, set as headphone and turn on Headphone Safety. Simply go to Settings , then tap Sounds. Tap Headphone Safety. Turn on Reduce Loud Audio, then drag the slider to 100 db (as I think the Schiit does not design LPF)
The sound of Windows is a little strange. Specifically, the sound is relatively thin. It may be caused by system or signal jitter.

4. enjoy your music.

If you want better high frequency performance especially female singer vocal, AD826 is another better choice, ADA4620-2 is just good overall with better bass, and best surface cleaness.

 

After all modification, the incisiveness and sibilance almost disappeared. I think 20% high frequency grainy contributed by AD5547 or R2R, the 40% incisiveness and sibilance contributed by AD8512, and the rest is Digital filter cannot filtrate high frequence.

 

ipad mini A17 pro VS macbook pro intel

As a USB resource, ipad has better bass, clearer sound. Whether I set the macbook's MIDI to 16bit 44.1k or 192khz (trying to bypass the digital filter) the ipad always has better sound. What is certain is that the iPad's clock is much better than the MacBook's

ipad > macbook >>>> Windows

I admit that Apple has done some magic with the sound, but this magic is entirely beneficial to the sound.
The sound of Windows is always unpleasant to listen to, whether it is Wasapi or not, the sound has no thickness. The only available audio driver under Windows is ASIO, and Apogee does a great job in this regard. With their professional digital shaping technology, the voice can be very prominent and feel off the stage.

On the other hand, the disadvantage of Delta-Sigma is obviously It is manifested in that they will sacrifice the richness of bass as much as possible and use noise shaping technology to optimize the audio signal around 1Khz with limited bit depth, because it is obvious that 1K is the frequency that human ears are most sensitive to.

In general, you can get a fairly satisfactory sound by following steps 1, 2, 3, and 4 on the topic.

After replacing the DC servo op amp OPA2277 to ADA4620-2, the high-frequency grainy has disappeared, and the sound is as smooth as Delta-Sigma. The 3rd item, Reduce Loud Audio, does not need to be turned on..

 

Update: DC servo OPAMP replacement from OPA2277 to ADA4620-2, high frequency improvement is huge, high frequency grainy almost disappeared. Female vocal also improved.

 

In fact, any task involving differential, integral operation, and transconductance amplification can be completed by ADA4620, including IV and DC servo. And it really does excellent job.

After replacing the OPA2277 with the ADA4620, the sound was as smooth as butter. For a moment I thought I was listening to Delta-Sigma. The sound field is very deep, the 3D sense is very obvious, and many additional details can be heard
The details of the sound can be described clearly, rather than giving a jumbled or rough answer.
You can't imagine how magical this is, the smooth sound has a lot of details while retaining the 3D depth

 

Have you tried OPA1656?

Also, we already have a thread discussing op amp swaps in Schiit gear:
https://www.superbestaudiofriends.org/index.php?threads/hacking-schiit.11261/

 

Hi, I just came to this forum and didn't realize there was already a thread about modification

I just don't like CMOS or FET Opamps, I have tried 1656 on different devices, it just feel like lost a lot of details. It feels like listening to a filter. Same as your point, congestion. The quality of the bass also poor.

The high frequency of 1656 is really nice to listen to, and it is very friendly to female vocals, with a sweet feeling.

Update:
IV: AD826
DC-Servo: ADA4620-2

ADA4620 has a typical op amp sound, clean and delicate, while AD826 has a bit of a tube or transistor feel. Because of the ultra-high speed and large slew rate, the sound will be a bit rough.

For long time listen, I would recommend to turn on Reduce Loud Audio on iPad

 

ADA4620
Female Vocal: ⭐⭐⭐
3D depth: ⭐⭐⭐⭐⭐
3D width: ⭐⭐⭐
Cleaness: ⭐⭐⭐⭐⭐
bass: ⭐⭐⭐⭐⭐
warmness: ⭐⭐⭐⭐
details: ⭐⭐⭐⭐⭐

AD826
Female Vocal: ⭐⭐⭐⭐⭐
3D depth: ⭐⭐⭐⭐
3D width: ⭐⭐⭐⭐⭐
Cleaness: ⭐⭐⭐
bass: ⭐⭐⭐⭐
warmness: ⭐⭐⭐
details: ⭐⭐⭐⭐⭐

OPA1656
Female Vocal: ⭐⭐⭐⭐
3D depth: ⭐⭐⭐
3D width: ⭐⭐⭐⭐
Cleaness: ⭐⭐⭐⭐⭐
bass: ⭐⭐
Warmness: ⭐⭐⭐
details: ⭐⭐

5532
Female Vocal: ⭐⭐⭐
3D depth: ⭐
3D width: ⭐⭐⭐⭐⭐
Cleaness: ⭐⭐⭐
bass: ⭐⭐⭐⭐
warmness: ⭐⭐⭐⭐⭐
details: ⭐⭐⭐

In fact, I found that many OPAMPs with very pleasant treble have different degrees of lack of bass, such as OPA627, ADA4627, OPA1656, LME49720, AD826 is exception because it is ultra-high speed.

ADA4620 has a typical op amp sound, clean and delicate, while AD826 remind me a tube or transistor feel. Because of the ultra-high speed and large slew rate, the sound will be a bit rough.

 

Update:
IV replace with AD826
DC servo replace with ADA4620-2
I just tried with AD826 and it is perfect.
I just realized the noise is coming from the DC-Servo which is OPA2277, just replace it with ADA4620-2

So overall will be

1. Upgrade USB card to Unison USB card

2. Replace DC Servo OP-AMP from OPA2277 or TL082 whatever to ADA4620-2.

3. Replace IV OP-AMP from AD8512 to AD826

4. enjoy your music. Now it is the best DAC in the world

I even think that this solution should be quickly updated to Schiit's entire family of products, all products using AD5547

@schiit

 

Actually, Modi Multibit takes 14-16VAC wall-wart as input power, you can actually use ADP5071 as your power management IC and then just use a 12v DC as power supply, this will provide better compatibility with most power supplies on the market. Otherwise, once your power cord is lost or damaged, you will not be able to find a spare power supply for a period of time.

 

Interesting explorations, thanks for sharing.

 

Try this combo and you will addicted to it.

 

Why would you want to replace the onboard LPS with a generic 12V wall wart SMPS? Schiit has their wall warts all day long and I’ve never had one fail.

 

I mean just in case cable bit by mouse or throw it somewhere, then can grab a router power supply to use it.

 

AD826 for IV and the ADA4620 for the servo, and they completely cancel out each others flaws!

The strengths of the AD826 are its 3D soundstage and very pleasant high frequencies, but its weaknesses might be a lack of deep bass and slightly rough sound. The ADA4620 compensates for all of that. The ADA4620 has perfect low and mid frequencies, though its high frequencies—especially for female vocals—are not as pleasing. But, and here is the magic, when these two are combined, something amazing happens!!!

Let's talk about the accordatura first. The AD826 buffer combined with the ADA4620 servo gives a sound that's very similar to the 5532, at first listen you might think it's just a 5532, but like a super-charged version of it.

The treble have the soundstage of the AD826, with female vocals sounding very sweet, while the low have the ADA4620s deep bass with excellent texture. The clean nature of the ADA4620 completely eliminates the roughness of the AD826. These two are truly a natural match!

The overall tone is richer than the original AD826, maybe even stronger than the 5532's , but all frequencies are very clean and clear, with a soundstage that opens up, something the 5532 can't achieve. The separation between front and back, as well as left and right, is enhanced, and the microdynamics are very rich—not like the artificial cleanliness that comes from something like the OPA1656, which can feel a bit congested.

I highly recommend experts give this a try—these two op-amps are a perfect match!

 

Many people think that DC servo op amps does not affect the sound, but this is not true. I have tried the original OPA2277 with various op amps. Whether it is ADA4620 as IV, AD826IV, or AD8512 as IV, none of them can erase the roughness of the high frequency. I believe you have had a deep understanding of this.

The low and mid frequencies of ADA4620 are really good, very good, 100/100 points, deep dive, rich and clean taste, the only shortcoming is that the high frequency especially female vocal is too thin, the high frequency of AD826 is the gold standard, I didn't expect that these two op amps would produce the tone of 5532. Sure enough, the sound of the classic op amp is correct. Overall, it is a very enthusiastic sound without losing details, space and clean background. You won't be able to turn off the machine once you listen it.

 

Regarding source, from my subjective listening experience, turning on Reduce Loud Audio on iPad sounds better, the sound is more "correct", the high frequencies are brighter, and the overall music style is more suitable for long-term listening. Although some details will be lost, but the overall style of the music is uniformed and is very close to the characteristics of iPhone

Overall, iPad with Reduce Loud Audio turning on 100db is the best > iPad >> MacOS >>HQPlayer>>>>>Windows

My test environment is iPad -> Unison USB -> Bifrost 1 (AD826 for IV, ADA4620 for DC-Servo) -> Passive volume controller -> Aegir 1st edition

 

Update:
Now the ultimate music source for Bifrost 1 is below:

One way to turn off Reduce Loud Audio on iPad and now is the best source for Biforst 1
Because you can not configure sample rate for iPad, thus the only one way to bypass DF is to upsmaple music to 4x
Bifrost 1 and first gen AD5547 has megacomboburrito which will bypass any sample rate of 176.4k or 192k music.

The practice is:

Computer:
Use Foobar2000 upsample your music to 4x, configure the DSPs and click + to add the "MultiResampler" and configure it with select the Target samplerate "Upsample x4" Resampling quality: "Zero Order Hold".
And then, drag your music to convert by DSP, just right click your music -> Convert -> dsp
You can check your music sample rate after conversion by right click music -> Porperties
Believe me and don't use any other DSP, the MultiResampler is the best one.

iPad:
Download Foobar2000
use your iTunes on computer and drag music to Foobar2000 music folder. (You can also create a folder and then drag it )
use Foobar2000 as music player

Now, your Bifrost 1 is a beast, now is the best sound I've ever heard.

About Foobar 2000 HiFi & measurement mode
in Advanced -> High-definition audio output & measurement mode
Well, turn on the measurement mode the music is more smooth, but turn off will give more texture. I personally like to keep it off.
and also, turn off the high-definition gives more bass and vocal is more standout.
Maybe apple does some magic here, which is my personal preference. (I think Apogee and Apple acturally using the same DSP tech, Apogee is more conservative and focus on the spatial orientation of sound, Apple gives more dynamics and treble)

 

Would be interested in a loaner to trusted ears (not me).

 

I have plans to buy a Multibit card and modify the Asgard3, but I am not sure what kind of the digital filter is in.
If this plan works, it will be a small beast.
I don't have extra money recently, and I found that the DC servo in Asgard 3 is a single op amp, and the ADA4620-1 is not available now. and the ADA4620-2 in Digikey has out of stock.