I've watched this thread with interest, but that has now turned to dismay. How could this be developed to the point of release only to be pulled because of sound quality issues? Do Allo follow due diligence in their development process? Measure and listen and refine repeatedly. A design should never get to release without being ready.
The power supply requirement too is not properly developed... Multiple different connectors... Multiple possible configurations...
I'm thinking the pi stack makes no sense with this. Instead create a dac board with the required level of power supply sophistication on board. Plug in the isolator and pi to this providing optimum power in the process.
Think of the design as you would a commercial product. That discipline might help focus and define things to a better outcome.
The power supply requirement too is not properly developed... Multiple different connectors... Multiple possible configurations...
I'm thinking the pi stack makes no sense with this. Instead create a dac board with the required level of power supply sophistication on board. Plug in the isolator and pi to this providing optimum power in the process.
Think of the design as you would a commercial product. That discipline might help focus and define things to a better outcome.
@gazzagazza,
On one hand, I agree with you on the need for a better assessment of the SQ of the unit with all options and by external ears before finalizing the design. I’ve shared that opinion with Allo privately.
OTOH, I have a different view of the overall design and different options for configuration and power.
Allo’s product space is mainly RPi-stacked boards. They clearly wanted to stay in this space for the Katana. BUT the issue you quickly run into is limited real-estate. Allo (along with some other manufacturers who have developed high-end products for the RPi) addressed this problem with multiple boards, just as they have in the past with their Kali Reclocker and Isolator, which did wonders for the SQ of their Piano and original BOSS DACs.
BUT even with multiple boards, you still have the problem of separate power supplies, as there is not sufficient room on even those multiple boards for even 1 power supply. This is not so much of a problem with simpler setups as users in this space already have to provide a separate supply for their RPi. BUT to get the best out of any DAC, you will have multiple power domains and in almost all cases, multiple supplies.
IMHO, Allo has done a good job of providing a range of options for their customer with the Katana usable with a single supply powering the whole stack (including the RPi) to a ‘full-house’ 4-supply setup including +-15V for the output stages. Based on a lot of experience with a number of RPi DACs and different power configurations from single-supply / simple setups to more complex than most here will ever attempt, you’ll get the best SQ with the ‘full-house’ setup.
AND incorporating a USB-C power feed option means that a simple setup, with a high-current USB-C supply along or coupled with a separate supply for the RPi will provide a user with a quick and easy to implement starter setup for the Katana.
Allo is not trying to be the next Twisted Pear Audio with their Buffalo DACs, which are designed to provide options to obtain the best possible performance possible to high-end DIY’ers. Their units all take up more space than the limited square inches of an RPi-sized board. I suspect the Katana with good supplies will approach that level of performance and I intend to confirm that. I don’t expect they’ll get to the top of that level with the Katana, because of the limitations of an ‘RPi-mounted’ DAC system. BUT Allo HAS provided options to make anyone as happy as they want to be with the performance of the DAC. AND worked hard to make the performance hit one gets from something less than the ‘full-house’ solution as small as possible.
I can see room for improvement in presenting the options and the trade-offs between them. AND many of the more complex options will incorporate solutions from other sources. I don’t expect Allo to spend a lot of time and effort explaining those options, just as Twisted Pear Audio doesn’t discuss the pros and cons of using Dexa, Paul Hynes, Belleson, or Sparkos regulators with their DAC boards. That is something I hope to provide and hope others will chime in with other good recommendations.
My 2 cents.
Greg in Mississippi
P.S. One of my online friends who both DIY’s his DACs AND works in the Audio Industry has confided that his builds of the TP Buffalo DACs compare very favorably to the fairly high-end PS Audio Directstream DAC, a $6000 - $7000 USD DAC, based on comparisons in his own system. That says a lot to me about how good you can make a DIY setup nowadays. I don’t believe I have reached that level of performance with my own TP DAC builds yet, but feel I am close and only need some tweaking and adjusting to achieve it.
P.P.S. The one significant suggestion I've shared with Allo is to consider replacing the power connector on the DAC board with the 90-degree equivalent, to allow mating without separating the stack. Based on my personal experience, the type of inter-board connectors they chose are easy to damage with repeated disconnect/reconnect cycles. What different connectors are on what sides of the stack is a matter of personal preference IMHO... I'd like them all on the expansion-connector side of the stack, I can see the case for having the USB-C connector where it is, others will want something different. Allo is not going to make most happy no matter what they do with locating those connectors.
P.P.P.S. I want the next several Marvel movies NOW too!
On one hand, I agree with you on the need for a better assessment of the SQ of the unit with all options and by external ears before finalizing the design. I’ve shared that opinion with Allo privately.
OTOH, I have a different view of the overall design and different options for configuration and power.
Allo’s product space is mainly RPi-stacked boards. They clearly wanted to stay in this space for the Katana. BUT the issue you quickly run into is limited real-estate. Allo (along with some other manufacturers who have developed high-end products for the RPi) addressed this problem with multiple boards, just as they have in the past with their Kali Reclocker and Isolator, which did wonders for the SQ of their Piano and original BOSS DACs.
BUT even with multiple boards, you still have the problem of separate power supplies, as there is not sufficient room on even those multiple boards for even 1 power supply. This is not so much of a problem with simpler setups as users in this space already have to provide a separate supply for their RPi. BUT to get the best out of any DAC, you will have multiple power domains and in almost all cases, multiple supplies.
IMHO, Allo has done a good job of providing a range of options for their customer with the Katana usable with a single supply powering the whole stack (including the RPi) to a ‘full-house’ 4-supply setup including +-15V for the output stages. Based on a lot of experience with a number of RPi DACs and different power configurations from single-supply / simple setups to more complex than most here will ever attempt, you’ll get the best SQ with the ‘full-house’ setup.
AND incorporating a USB-C power feed option means that a simple setup, with a high-current USB-C supply along or coupled with a separate supply for the RPi will provide a user with a quick and easy to implement starter setup for the Katana.
Allo is not trying to be the next Twisted Pear Audio with their Buffalo DACs, which are designed to provide options to obtain the best possible performance possible to high-end DIY’ers. Their units all take up more space than the limited square inches of an RPi-sized board. I suspect the Katana with good supplies will approach that level of performance and I intend to confirm that. I don’t expect they’ll get to the top of that level with the Katana, because of the limitations of an ‘RPi-mounted’ DAC system. BUT Allo HAS provided options to make anyone as happy as they want to be with the performance of the DAC. AND worked hard to make the performance hit one gets from something less than the ‘full-house’ solution as small as possible.
I can see room for improvement in presenting the options and the trade-offs between them. AND many of the more complex options will incorporate solutions from other sources. I don’t expect Allo to spend a lot of time and effort explaining those options, just as Twisted Pear Audio doesn’t discuss the pros and cons of using Dexa, Paul Hynes, Belleson, or Sparkos regulators with their DAC boards. That is something I hope to provide and hope others will chime in with other good recommendations.
My 2 cents.
Greg in Mississippi
P.S. One of my online friends who both DIY’s his DACs AND works in the Audio Industry has confided that his builds of the TP Buffalo DACs compare very favorably to the fairly high-end PS Audio Directstream DAC, a $6000 - $7000 USD DAC, based on comparisons in his own system. That says a lot to me about how good you can make a DIY setup nowadays. I don’t believe I have reached that level of performance with my own TP DAC builds yet, but feel I am close and only need some tweaking and adjusting to achieve it.
P.P.S. The one significant suggestion I've shared with Allo is to consider replacing the power connector on the DAC board with the 90-degree equivalent, to allow mating without separating the stack. Based on my personal experience, the type of inter-board connectors they chose are easy to damage with repeated disconnect/reconnect cycles. What different connectors are on what sides of the stack is a matter of personal preference IMHO... I'd like them all on the expansion-connector side of the stack, I can see the case for having the USB-C connector where it is, others will want something different. Allo is not going to make most happy no matter what they do with locating those connectors.
P.P.P.S. I want the next several Marvel movies NOW too!
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Everyone talks about making stack PCBs for the RPi but in reality, why not make a very good modular backplane where you could have enough space to put on the best PSUs, snap the RPi on the backplane and the DAC beside it on the same backplane. Why does it have to be as small as possible and on a tower stack? It could be a bigger PCB backplane that can fit into a larger chassis. After all, many audio components standardize on chassis width ~17". The backplane could allow for some nice PSU options that could be added or bypassed.
Look at the Schitt Bifrost, Gungnir or Yggdrasil DACs internals
AMBs Gamma 3
The γ3 high resolution DAC
Soekris DAC backplane
Denmark Soekris dam1021 r2r dac decoder interface, display, control board | eBay
Just a few examples
Do
Look at the Schitt Bifrost, Gungnir or Yggdrasil DACs internals
AMBs Gamma 3
The γ3 high resolution DAC
Soekris DAC backplane
Denmark Soekris dam1021 r2r dac decoder interface, display, control board | eBay
Just a few examples
Do
@Markw4,
Agreed, but I also find it interesting that most 'high-end' manufacturers don't use SMPS'.
OTOH, I know they can be made to sound good. The iFi line has a good following, along with using DC-DC converters in 'i'-line gear needing a +- supply, such as their phono stages.
Also a number of recent good-sounding Class-D amps use them (I was listening to the Katana through one based on the B&O Icepower 1200AS2 until last night when I put my PS Audio BHK-250 back in. AND my 2 different previous amp models were SMPS-powered).
Then OTOH again, I remember a lot of people using the iFi supplies that were sold with devices such as the Uptone Audio Regen and Sonore uRendu finding linear supplies to be significant upgrades. I've recently modified some of the linear 5V & 12V 1A regulated supplies from Jameco, mostly to power network gear instead of the included SMPS wall warts. I lent some to a friend who compared them to the iFi 5V and preferred the cheapo modified Jameco to the iFi on his RPi DAC.
IMHO, this is an area where application and implementation matter a lot.
I have high hopes for Allo's new supply. We'll see. BUT in my experience a quick & dirty linear outperforms a generic SMPS... and even some engineered ones.
@pinnocchio,
That could be a great project for our community. 3 5V Salas Reflectors (RPi, DAC board, and Microprocessor board) and a +-15V pair of Salas UltraBiB (output stages) would work VERY well with the Katana. Sorry, I don't have any circuit-board design chops!
Greg in Mississippi
P.S. There's also David Berning who's been using SMPSs in his tube amps and preamps since the middle 1980s! I remember hearing his gear back in the late 80s and enjoying the experience a lot. I think they make a well-regarded and unusual OTL nowadays. Anyone else heard them?
P.P.S. Then there's the issues of the 'high-impedance leakage current' from SMPS's, as documented by former DIY Audio poster John Swenson. You can see more info on the Uptone Audio website or on Computer Audiophile, so I won't repeat that here. BUT the important thing is that for SMPS's used in audio, you want to connect the negative side of the output to ground, shunting most of it away.
Agreed, but I also find it interesting that most 'high-end' manufacturers don't use SMPS'.
OTOH, I know they can be made to sound good. The iFi line has a good following, along with using DC-DC converters in 'i'-line gear needing a +- supply, such as their phono stages.
Also a number of recent good-sounding Class-D amps use them (I was listening to the Katana through one based on the B&O Icepower 1200AS2 until last night when I put my PS Audio BHK-250 back in. AND my 2 different previous amp models were SMPS-powered).
Then OTOH again, I remember a lot of people using the iFi supplies that were sold with devices such as the Uptone Audio Regen and Sonore uRendu finding linear supplies to be significant upgrades. I've recently modified some of the linear 5V & 12V 1A regulated supplies from Jameco, mostly to power network gear instead of the included SMPS wall warts. I lent some to a friend who compared them to the iFi 5V and preferred the cheapo modified Jameco to the iFi on his RPi DAC.
IMHO, this is an area where application and implementation matter a lot.
I have high hopes for Allo's new supply. We'll see. BUT in my experience a quick & dirty linear outperforms a generic SMPS... and even some engineered ones.
@pinnocchio,
That could be a great project for our community. 3 5V Salas Reflectors (RPi, DAC board, and Microprocessor board) and a +-15V pair of Salas UltraBiB (output stages) would work VERY well with the Katana. Sorry, I don't have any circuit-board design chops!
Greg in Mississippi
P.S. There's also David Berning who's been using SMPSs in his tube amps and preamps since the middle 1980s! I remember hearing his gear back in the late 80s and enjoying the experience a lot. I think they make a well-regarded and unusual OTL nowadays. Anyone else heard them?
P.P.S. Then there's the issues of the 'high-impedance leakage current' from SMPS's, as documented by former DIY Audio poster John Swenson. You can see more info on the Uptone Audio website or on Computer Audiophile, so I won't repeat that here. BUT the important thing is that for SMPS's used in audio, you want to connect the negative side of the output to ground, shunting most of it away.
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Hi ,
Sound is good coming out of Katana. Still I have found (and others as well) that with smaller speakers there is a bit of "fatiguing sound"
Right now we are testing small changes to the PCB (making low pass filter have a lower cut off frequency) and more.
Please wait a few more days and we will post our findings.
"Quick and dirty linear..." more of this stuff -- please!
You've got a talent to get people exhausted. For me it's that simple. A <=$50 whatever linear supply will have a hard
time to beat an iFi iPower SMPS at $50. (I have two Sbooster supplies (>$100) over here and I still prefer the iFi)
Bottom line. $50 is the ticket into the rather serious power arena.
Even the Youtube audio prophet (HB) is in line with that.
I'm not saying it can't get better than that.
That's a message that IMO matters to the folks around here.
An SMPS messes with the mains - the usual argument against it - who cares!?!? There's so much dirt on the mains anyhow.
Does that mess even has any/much impact on the sound?? I havn't seen any prove of that.
Of course - having a proper grounding scheme in place is a different subject
and probably even more important than the PS discussion "linear vs. SMPS".
And than I can't imagine that anybody is interested in your very special super tweaked $800+ boutique power solutions for a PI tower. If I add it all up
we'll probably hit the 2k border you spent on your unique power solution.
Most people are just not interested to spent that rather insane amount of money and time on HiFi gear - and PS in particular.
If you have a power solution at hand that's applicable and/or affordable to most of us - shoot! With all your experience that shouldn't be a problem!
And please no BS and no prose!
Thx.
I agree with soundcheck, it does not make sense to me to feed a 250 EUR DAC with 4 PS with a value of the same price as the DAC or much higher. People who buy this DAC want a simple but not too expensive solution otherwise we end up at the DAC 3 price level and the question comes up if such complete and proven solution would not make more sense to buy.
It is also not clear to me why a big board with better grounding and shorter traces is worse than a stack in Pi format with 4 PS - if grounding over 3 planes is that difficult it should be considered making a big board to stick the PI on top (probably already including the PS) as a big housing would be needed anyway for all the 4 PS you need with the stack solution.
It is also not clear to me why a big board with better grounding and shorter traces is worse than a stack in Pi format with 4 PS - if grounding over 3 planes is that difficult it should be considered making a big board to stick the PI on top (probably already including the PS) as a big housing would be needed anyway for all the 4 PS you need with the stack solution.
No problems with Greg's approach here either - how can you assess the best approach unless all options (however OTT for most users) have been tried and tested? It sounds like Greg plans to scale back from the multiple expensive supplies to ascertain the best bang for your buck option(s) which should make PSU choices easier
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HW revision is not the same as our own 1.2Katana. Sorry for the confusion.
Just a small recap.
We improved the LPF on summing opamp. Small improvement in SQ
We improved filtering before analog stage . Medium improvement in SQ
We improved noise escaping DC/DC convertor. Not quantified yet
We connected earthing to board (with Nirvana PSU it will be automatic). Removal of some HF and better trebles . I would say small improvement but clearly audible
Adding some 220uF caps to analog stage. No improvement
So far we are happy with SQ
Just a small recap.
We improved the LPF on summing opamp. Small improvement in SQ
We improved filtering before analog stage . Medium improvement in SQ
We improved noise escaping DC/DC convertor. Not quantified yet
We connected earthing to board (with Nirvana PSU it will be automatic). Removal of some HF and better trebles . I would say small improvement but clearly audible
Adding some 220uF caps to analog stage. No improvement
So far we are happy with SQ
Hello
"We improved filtering before analog stage . Medium improvement in SQ"
I guess that you were playing with feedback capacitor which can caused some instability or help to stabilize input od analog stage.. and also it has impact on sound.
Am i right, or you did some other changes..
Thanks
Vita