The Caiman MKII: taking a bigger and better bite

[StanleyB]

When I started thinking about a MKII version of the Caiman DAC, the first thing that I decided upon from the outset was that it would have to be just as ground breaking in terms of price versus performance as the MKI. It is quite easy to fall into the trap of capitalising on the name of a successful predecessor, without any technical justification. But pushing the boundary even further is easier said than done. I often wondered if I had bitten off far more than I could chew.

In order to get an idea of what would make technical and audible differences versus what were just suggestions from couch potato experts, I decided to build a few prototypes and spend some time listening to them. Each build sounded good enough to sell in its own right, but the sound quality difference was in most cases merely a step up. But for the Caiman, I was only interested in improvements that were a substantial leap.

http://www.homehifi.co.uk/images/DAC/TC-7534/RnD-900.jpg
A selection of the prototypes that I designed and built to evaluate the performance and technical complexity of some parts that might be suitable for the final build.
Anyone who knows about the cost of designing and building electronic products would also know that the total cost of those prototypes would have been astronomical. Looking back, I reckon that I got possessed by an obsession for perfection, without keeping an eye on the R&D costs.


Things only got more complicated when some new components came on the market, and when some manufacturers gave me permission to use their parts in a consumer product, or use them in a manner that was not listed in their official datasheets. The ultra low noise regulators from the satellite communication industry made a significant difference especially. So much so, that I decided to try them in a 32 bit D to A configuration and compare that prototype against an otherwise similar 24 bit design and layout. The test results ended up costing me a year delay, partly due to a revised layout change that was optimized for 32 bit D to A number crunching.
Running in tandem to that were my tests on different types of USB audio conversion methods, and the added complication of software drivers. In the end I decided to settle with a 24/96 USB chip operating in adaptive mode that would not require any special drivers when used with different operating systems. Combined with my own async firmware routines, the outcome was actually better sounding than the alternatives I tried. Running the USB chip from the Caiman internal ultra low noise power supply, instead of using the BUS power, made even more of a difference.


http://www.homehifi.co.uk/images/DAC/TC-7534/TC-7534F-900.jpg

The addition of an I2C BUS will allow the Caiman to be expanded even further. But I am not looking that far ahead yet.
http://www.homehifi.co.uk/images/DAC/TC-7534/TC-7534R-900.jpg
My next goal is to get it all up on my website for a June launch.

[Theadmans]

Looks great Stan !:)

Will folks that have Anker and Ankaka batteries on their Bushmasters be able to use the same batteries to power the Caiman II ?

Also does the USB input work with a Squeezebox Touch (with EDO mod) ?

[RichB]

Looks great Stan !:)

Will folks that have Anker and Ankaka batteries on their Bushmasters be able to use the same batteries to power the Caiman II ?

Also does the USB input work with a Squeezebox Touch (with EDO mod) ?

Looks great Stan and interested to hear more about the USB implementation.

This is a question I've asked before on here but not had an answer yet. Why would anyone use the USB output of the SBT if you have a DAC with optical or other inputs. I just don't know what the advantages might be?

[StanleyB]

Yes the Caiman MKII works with the 12V battery pack and works with the Touch with or without EDO.

As for why anyone would use the USB out on a Touch: Not all DACs have an optical or coax input. Some only come with USB.

[marflao]

Hi Stan,
which native decoded PCM (DSD??) formats will be supported?
And how would you rank - from sonic perspective - the new Caiman compared to the BM1 / BM2?

[StanleyB]

Hi Stan,
which native decoded PCM (DSD??) formats will be supported?
And how would you rank - from sonic perspective - the new Caiman compared to the BM1 / BM2?
No DSD. Only PCM.
Where I rate it? That's a personal opinion, which I leave to the customers to express.

[Darren Cotter]

No DSD. Only PCM.
Where I rate it? That's a personal opinion, which I leave to the customers to express.

Hi Stan

I too would like to know where the new Caiman II fits in against a Gatorised Caiman, Bushmaster 1 and the Bushmaster 2.

I am thinking about getting an aftermarket power supply for my Gatorised Caiman, but may get a Caiman 2 or Bushmaster 2 instead, depending on where the new model fits in.

Regards

Darren

[StanleyB]

I too would like to know where the new Caiman II fits in against a Gatorised Caiman, Bushmaster 1 and the Bushmaster 2.
We are talking about a far higher level of quality musical reproduction. There is no comparison that I can think of. But you will need a respectable amp and set of speakers to be able to enjoy it to the full.

[Darren Cotter]

Hi Stan

Thanks for the quick reply.

At the moment, I have a Yamaha RX-V3800 AV amp and Kef 3005 5.1 speakers that I use to play FLAC files into the Caiman. All power, HDMI, speaker and analogue cables (G2000HD) are from Mark Grant.

So not sure if I will see any benefit. Perhaps someone with a similar setup could help.

Regards

Darren

[Theadmans]

What is the Function button for Stan?

Also did I remember you saying the I2C bus might be for connecting a Raspberry Pi to the DAC as a streamer (or did I imagine that) ? I have a Pi in my second system connected to my old Bushmaster Mk1 (the Pi has the excellent new Wolfson audio card added which allows a coax digital connection to the BM).

Finally how does the Headphone amp on the Caiman II compare to the Bushmaster II? Using HD650s will the superiority of the Caiman II be apparent?

[StanleyB]

Hi Adam,

the function button is there to select a few additional functions.

The I2C bus is there to give access to the DAC chip I2C capabilities. That includes the 16 to 32 bitrates and 128 to 768kHz oversampling rates. The current maximum on other DACs is 384kHz. The Caiman II is capable of twice that. I am leaving it to the coders to come up with suitable software routines that can control the DAC chip via a RPi, or even a PC. A separate I2C adapter board under development will allow for additional functionality, including the use of an I2C LCD display, or a I2C remote control connected to a RPi.

The headphone circuit uses a higher voltage and is aimed at the midrange and above headphones with large drivers. Bass is also deeper and more pronounced due to the higher line voltage of the headphone circuit. So if you like low listening levels, a narrower dynamic range, and weak bass, then the headphone output on the Caiman might not suit you. The higher line voltage also results in a better extension of the treble. I can't say if you would hear a difference with your HD650. It all depends on how good your hearing is. But the deeper bass can cause the HD650 frame to rattle when you have the volume at maximum whilst listening to bass intensive music like reggae. It is OK with the HD800, which has a sturdier build quality.

[Theadmans]

Thanks for all that Stan - very informative - certainly food for thought. I will eagerly await further developments over the Summer (the Caiman II might make a nice Xmas present to myself!!).

[Old George]

Hi Stan,
At the moment (and for the foreseeable future) i'm using AKG 550 headphones, am i likely to find a tangible improvement running the Caiman 2 as opposed to my Bushmaster MK2?

I see the 12 volt battery packs are still usable on the Caiman 2, Will the Caiman draw more from the battery? I have to use a grain of wheat bulb to stop my battery cutting out.

Finally, what price bracket are we looking at for the Caiman 2?

[mkrzych]

When I started thinking about a MKII version of the Caiman DAC, the first thing that I decided upon from the outset was that it would have to be just as ground breaking in terms of price versus performance as the MKI. It is quite easy to fall into the trap of capitalising on the name of a successful predecessor, without any technical justification. But pushing the boundary even further is easier said than done. I often wondered if I had bitten off far more than I could chew.

In order to get an idea of what would make technical and audible differences versus what were just suggestions from couch potato experts, I decided to build a few prototypes and spend some time listening to them. Each build sounded good enough to sell in its own right, but the sound quality difference was in most cases merely a step up. But for the Caiman, I was only interested in improvements that were a substantial leap.

http://www.homehifi.co.uk/images/DAC/TC-7534/RnD-900.jpg
A selection of the prototypes that I designed and built to evaluate the performance and technical complexity of some parts that might be suitable for the final build.
Anyone who knows about the cost of designing and building electronic products would also know that the total cost of those prototypes would have been astronomical. Looking back, I reckon that I got possessed by an obsession for perfection, without keeping an eye on the R&D costs.


Things only got more complicated when some new components came on the market, and when some manufacturers gave me permission to use their parts in a consumer product, or use them in a manner that was not listed in their official datasheets. The ultra low noise regulators from the satellite communication industry made a significant difference especially. So much so, that I decided to try them in a 32 bit D to A configuration and compare that prototype against an otherwise similar 24 bit design and layout. The test results ended up costing me a year delay, partly due to a revised layout change that was optimized for 32 bit D to A number crunching.
Running in tandem to that were my tests on different types of USB audio conversion methods, and the added complication of software drivers. In the end I decided to settle with a 24/96 USB chip operating in adaptive mode that would not require any special drivers when used with different operating systems. Combined with my own async firmware routines, the outcome was actually better sounding than the alternatives I tried. Running the USB chip from the Caiman internal ultra low noise power supply, instead of using the BUS power, made even more of a difference.

http://www.homehifi.co.uk/images/DAC/TC-7534/TC-7534F-900.jpg

The addition of an I2C BUS will allow the Caiman to be expanded even further. But I am not looking that far ahead yet.
http://www.homehifi.co.uk/images/DAC/TC-7534/TC-7534R-900.jpg
My next goal is to get it all up on my website for a June launch.

That's a very good news since Caiman is superb sounding DAC. What DAC chipset you've used Stan and what OPAMP for HPA? What are the chassis dimensions?

[StanleyB]

Hi George, I have no idea if the K550 will sound better to your taste. But I have never heard my K701 sound any better with a more intricate bass and a true spatial analogue sound.
Now if you had a HD800 instead, you would be having a grin from ear to ear. I can see the Caiman MKII becoming a benchmark for HD800 owners. The Caiman headphone performance alone puts the Bushmaster I & 2 to shame.

The current consumption is a bit higher at 70 to 80mA, depending on whether it is a 16 or 24 bit file.

If you put £300 aside, you should be OK. The Caiman is about 30% bigger and heavier, which just about accounts for the extra 30% price increase over the BMII on a cost to weight ratio. I am not adding a premium to the price for the leap in performance.

[mr sneff]

Stan, does the MkII still have the muting relay that 'tweets' between tracks?

[Old George]

Hi George, I have no idea if the K550 will sound better to your taste. But I have never heard my K701 sound any better with a more intricate bass and a true spatial analogue sound.
Now if you had a HD800 instead, you would be having a grin from ear to ear. I can see the Caiman MKII becoming a benchmark for HD800 owners. The Caiman headphone performance alone puts the Bushmaster I & 2 to shame.

The current consumption is a bit higher at 70 to 80mA, depending on whether it is a 16 or 24 bit file.

If you put £300 aside, you should be OK. The Caiman is about 30% bigger and heavier, which just about accounts for the extra 30% price increase over the BMII on a cost to weight ratio. I am not adding a premium to the price for the leap in performance.

Hi Stan, thanks for the prompt response.
Price sounds very fair, i'll start saving.:)

[StanleyB]

Stan, does the MkII still have the muting relay that 'tweets' between tracks?
It is a completely different design. You'll have to look for a 2nd hand MKI if you miss those tweets :).

[mr sneff]

It is a completely different design. You'll have to look for a 2nd hand MKI if you miss those tweets :).
:lol:

[struth]

Me too Stan:lol:

[StanleyB]

Some of you might at some stage read about or even tried distinguishing between WAV, FLAC, and mp3. A relatively decent set of free test files can be found at: http://www.soundliaison.com/all-our-products/179-formats-to-compare-wav-flac-cd-mp3
But take note that the mp3 files have been marked out with a WAV extension by some careless person at Soundliason. So change the WAV extension to mp3 on those two files. If I need to tell you which ones then you are very likely not the PC audio playback type of person.
It is a very good test for the Caiman MKII, or any system for that matter. Give it a try in advance. And if and when you get a Caiman and want to see what it is capable of then these are the files to try again. I struggled with picking out 44.1kHz WAV from 96kHz FLAC. But the rest of them were easy to separate with the Caiman MKII in a totally blind test. The Caiman was not fooled by the change in format. If you can't tell the difference with your existing set up and then can't tell the difference with the Caiman in place, then the Caiman would be in excess of your needs. It's stern test, but a good enough one to clearly demonstrate the kind of distance there is between the new Caiman and other DACs, irrespective of price.

[Labarum]

It's looking good, Stan.

Will it drive my Quad 405-2 with no pre-amp?

How about my Quad 520f which has sensitivity pots on the front?

[StanleyB]

Hi Brian, it will drive your Quads and there are no problems with pots.

[Old George]

Some of you might at some stage read about or even tried distinguishing between WAV, FLAC, and mp3. A relatively decent set of free test files can be found at: http://www.soundliaison.com/all-our-products/179-formats-to-compare-wav-flac-cd-mp3

Are these files downloadable Stan? They want me to register and post the files to me FOC? :scratch:

Skip the above, after confirmation of order the files are downloadable.:rolleyes::D

[StanleyB]

Continuing with the "teasers" the Caiman MKII, two features of note are:
1. A more advanced AUTO function that can distinguish between a digital signal with no "life" data transmission, and a standard digital signal. This is particularly useful for such things as satellite and cable boxes that have a permanent output on the digital signal even when the box is switched to standby. The advanced function needs a separate set up method which will be described in the Advanced Operating instructions on my website (still to come).
2. The headphone section has a more advanced headphone response detection circuit. It was first introduced in the BMII, and further perfected in the CII. Basically what it does is to measure the frequency response of the headphone voice coil in real time and adjust the voltage output accordingly. To give an idea of how that works, plug in something like a HD650. This headphone is well known for its pronounced sloppy bass and shaved off treble. The BMII and CII correct these problem to a certain extent with my own circuitry. So the HD650 is now far better in the bass and treble (as existing owners of a BMII with a HD650 or K701 can testify). If you plug in a K701 or HD800, you'll notice the opposite operation of the circuit. Those headphones are known for poor bass and ear piercing treble. The auto response circuit detects the incorrect movement of the headphone drivers, and adjusts its voltage output accordingly in order to maintain a linear correlation between the input signal and the signal fed to the headphones. It is basically a voltage and current feedback circuit as used in some power amps to drive difficult speaker loads. I adapted it for use in the headphone circuit of the CII. It's also one reason why the CII headphone output impedance is a ridiculously low <0.1 Ohms.

[StanleyB]

One of the things that I discovered when working on the idea of adding a USB input on the TC-7520 was that the USB section performed far better if it was on a separate PCB. I therefore made the USB circuit on a separate PCB as result of those findings. I had however dismissed that discovery as a probable coincidence from using the particular chip I had decided upon at the time. Nobody else had ever raised that issue before or since, and USB equipped DACs have had the USB chip on the same PCB as the rest of the circuit without attracting any questionable comments about performance losses.
But when I had ended up at quite an advanced state in the R&D of the Caiman MKII I suddenly remembered my earlier discovery. By then I had already completely integrated the USB circuit into the main PCB.

http://www.homehifi.co.uk/images/aos/t1.jpg

But I had to convince myself that gains could be had in terms of audio quality if the USB section was put on a separate PCB. So at more great cost I redesigned and built a new main PCB that had a separate USB PCB attached. It might seem a bit over the top to go to such great cost and length in order to confirm or reject a suspicion, but it was my intention after all to try to design the near perfect sounding DAC.

http://www.homehifi.co.uk/images/aos/t2.jpg

After another prolonged set of comparisons and evaluation I had to agree that mounting the USB circuit away from the TOSLINK and Coax circuit did indeed offer benefits. It might be something for other designers to consider, but modern day pressures on cost savings is unlikely to see low and medium cost designs going to such length as I did n the Caiman.

[mkrzych]

Continuing with the "teasers" the Caiman MKII, two features of note are:
1. A more advanced AUTO function that can distinguish between a digital signal with no "life" data transmission, and a standard digital signal. This is particularly useful for such things as satellite and cable boxes that have a permanent output on the digital signal even when the box is switched to standby. The advanced function needs a separate set up method which will be described in the Advanced Operating instructions on my website (still to come).
2. The headphone section has a more advanced headphone response detection circuit. It was first introduced in the BMII, and further perfected in the CII. Basically what it does is to measure the frequency response of the headphone voice coil in real time and adjust the voltage output accordingly. To give an idea of how that works, plug in something like a HD650. This headphone is well known for its pronounced sloppy bass and shaved off treble. The BMII and CII correct these problem to a certain extent with my own circuitry. So the HD650 is now far better in the bass and treble (as existing owners of a BMII with a HD650 or K701 can testify). If you plug in a K701 or HD800, you'll notice the opposite operation of the circuit. Those headphones are known for poor bass and ear piercing treble. The auto response circuit detects the incorrect movement of the headphone drivers, and adjusts its voltage output accordingly in order to maintain a linear correlation between the input signal and the signal fed to the headphones. It is basically a voltage and current feedback circuit as used in some power amps to drive difficult speaker loads. I adapted it for use in the headphone circuit of the CII. It's also one reason why the CII headphone output impedance is a ridiculously low <0.1 Ohms.

That is neat idea Stan. BTW, for the pot, did you use something better than regular stock potentiometer used in the original Caiman, like ALPS pot? If so, is it linear or logarithmic? I have changed the pot as you know in my Caiman to ALPS mini, but coudn't find 20kLog, instead 10kLinear was used.

[StanleyB]

I trust the current supplier of my pot ;). It's log.

[mkrzych]

Hello Stan,
Could we get information what sampling rates and over which interface are supported on CII?

[Butuz]

This looks great. Even though I use my Quad CDP2 as my dac - I've still got my 7520 and my Caiman 1 sitting on my shelf, can't bear to part with them - they really introcuced me to the idea that a DAC can make me enjoy music more! Still sometimes use them with headphones.

[friendly]

Hi Stan,

What's the price of the new Caimen? I looked on your site but couldn't find a price.
I am so impressed with the Bushmaster MKii with battery supply, this coming from a Youngs with psu. To me it is just more musical, if the Caimen is another jump forward it must be very special indeed.
Gwyn

[mkrzych]

Can anyone who already own Caiman MKII can check out if Integer Mode with A+ works with it?

[mkrzych]

Hello Stan,
Just for my curiosity, you've put two optical toslink inputs on MKII, does it mean that you're still believe in optical transport instead of USB? Asking, becasue there is a lot of discussion on the web, that USB is superior to optical because jitter free (at least less jittery) than optical etc? BTW, old Macs are not able to send 24/192 over the toslink as well - up to 24/96. Do you think that optical can sound similar to USB?

[StanleyB]

The inputs have nothing to do with what I believe. It has everything to do with what customers need so that they can connect their equipment to my DACs.
As for what is discussed on the net as to what is best: I introduced surface mounting to the medium and low cost DAC market. I also introduced the idea of a twin optical and twin coax to the DAC market. So I am a trailblazer not a copy cat.
So as far as what is discussed on the internet: I don't have time for advise from couch potato. Let them put their money where their mouth is. I do my own research and follow my findings. And I now keep most of my findings to myself. Everyone else does.

[mkrzych]

The inputs have nothing to do with what I believe. It has everything to do with what customers need so that they can connect their equipment to my DACs.
As for what is discussed on the net as to what is best: I introduced surface mounting to the medium and low cost DAC market. I also introduced the idea of a twin optical and twin coax to the DAC market. So I am a trailblazer not a copy cat.
So as far as what is discussed on the internet: I don't have time for advise from couch potato. Let them put their money where their mouth is. I do my own research and follow my findings. And I now keep most of my findings to myself. Everyone else does.

Yes, I suppose that optical is there because customers want them - this is clear to me. However, I was just curious about your opinion about it since there is a lot of heat discussions that optical is not able to reach the quality of USB. In my case I am still using MKI with toslink and I am pretty happy, but thinking if indeed USB is so superior to optical.

[Labarum]

mk, if both are competently engineered you wont hear the difference; and that's all that matters.

[mkrzych]

mk, if both are competently engineered you wont hear the difference; and that's all that matters.

That's very good answer, but not so often cited on the web :-/ I saw that you have MKI SEG - do you use optical? On this device USB is limited to redbook.

[StanleyB]

As far as I am concerned, the people who say USB is superior are talking from thye back of their head. Signal break ups, interrupt delays, special audio drivers, noise isolation, etc. are just a proportion of things that USB audio suffers from. TOSLINK and coax are true plug, play, and forget. USB still has possibly years to go before it is of the same reliability of TOSLINK or coax. Anyone suggesting that USB is better is telling lies.

I really don't have time for these sort of discussions. I got better things to do in my life.

[mkrzych]

As far as I am concerned, the people who say USB is superior are talking from thye back of their head. Signal break ups, interrupt delays, special audio drivers, noise isolation, etc. are just a proportion of things that USB audio suffers from. TOSLINK and coax are true plug, play, and forget. USB still has possibly years to go before it is of the same reliability of TOSLINK or coax. Anyone suggesting that USB is better is telling lies.

I really don't have time for these sort of discussions. I got better things to do in my life.

Strong statement Stan, thank you.

[Wakefield Turntables]

Aaah the great coax / toslink debate, which is better:scratch:

[Clive]

My view is the USB can sound better but it's not necessarily so, a lot depends on the details. Coax and Toslink need to be done well too but they are better understood so it's easier to get them right. For sure USB is more finicky and has caused me to tear my hair out. When using a computer USB is ubiquitous whereas coax/optical are not. For the user it's a balancing act between pros and cons. For a designer I can see that USB is an even bigger pain than it is for the user.

[worrasf]

Aaah the great coax / toslink debate, which is better:scratch:

Well I for one am unable to hear any difference - I used both coax and optical outputs from my CD player into the DAC and just kept switching between the 2 and I couldn't tell any difference
Steve

[Wakefield Turntables]

Well I for one am unable to hear any difference - I used both coax and optical outputs from my CD player into the DAC and just kept switching between the 2 and I couldn't tell any difference
Steve

Me neither, I was stirring things a little (sorry just a guilty pleasure) :mad: I bought Coax because it was slightly cheaper and the results are excellent, I'm not going to be worried about cable swapping between coax and optical as I dont do enough CD listening.

[Xaval]

I have a Mark Grant linear PSU with sbooster on the BM I. Is the plug compatible with the Caiman?

[StanleyB]

I have a Mark Grant linear PSU with sbooster on the BM I. Is the plug compatible with the Caiman?
They are the same size.