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Buffalo II & transformers

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C

canever

Member
Joined 2004
I investigate a lot and I posted in another thread because I think it is more pertinent.
http://www.diyaudio.com/forums/digital-line-level/117238-ess-sabre-reference-dac-8-channel-51.html#post4379164

Cannot be the wiring among USB interface and the ES9018 because in 6bits true and 7 bits pseudo differential everything is OK.
Distortion appear only from 7bits true to 9bits pseudo quantization.
And the behaviour is the same for IIS and SPDIF inputs.
Worse, the distortion is present only on the right channel (right channel means DAC2 + DAC4 + DAC6 + DAC8 hardware wired in the PCB).

Probably it depends on how the Quantizer works and how the harware wiring is done on the PCB.

I read about the Quantizer but it is not clear for me.

.... anyway, all these matters aren't pertinent for this thread reagarding the transformers so I moved this questions where wrote at the beginning.

Thanks in any case.

Ciao
 

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V

Vingborg

Member
Joined 2013
Good morning folks :)

Back on the track.. But just for a while.

Small kids, family, house and job are taking the time that it requires!

But here it is:

I have been testing, listened and testing over and over again, with several transformers with different tube output stages, no transformers and only coupling caps and tubes, and also the Legato output stage - And I really can't hear any significant improvement in the hole soundstage, compared to my modified XA50ES cd player!
I'm sorry to say! Maybe I'm deef some might say, but I don't care;)

A friend of mine has heavily modified a pcb with CS4398 dac chip - I have done the same thing with a pcb similar and I let the dac signal flow into a low gain tube stage.. And only in the test bench, the soundstages is allmost better than my modified XA50ES player! :)

So that's why I'm signing off this thread and I will thank all of you guys for the very helpful and nice answers:)

I will try sell my Buffalo III, LCDPS and my Legato stage on Ebay so if anyone is interested please let me know! :)

Best from Henrik
 
A

AudioDAC

Member
Joined 2010
all fet I\V converters

Hi
If it is not e secret could you tell me how is compared your I\V converters with Legato in sound quality?
As the transformers are very expancive, what is the cost of your fully discrete I/V conv. could you help me to make it? - schematics PCB.

regards
Andrzej






staccatiss said:
New Japanese ESS9018 IV Transformers –a mini review
Executive summary: these new Japanese transformers are the best sounding IV transformers that the author have ever listened to, and compared to a highly modified Legato and a fully discrete all-FET IV converter, these transformers are sonically hard to beat.


I have tried both the amorphous core Lundahl LL1684 and Sowther 9545e audio transformers applied as IV converters, and although the sound has been good with the LL1684:s, and OK with the 9545e:s, they did not sound as good as the discrete IV converters I have. I actually gave up on transformers even though they had something special sonically. Instead I started to modify and upgrade my Legato, IVY, and fully discrete FET IV converters with new components, and the power supply super shunt regulators were modified as well.

I thought that I´d given up on transformers as the ultimate IV converter, when a few months back, Bunpei wrote to me about a new Japanese transformer distributed by Feastrex*, that was made especially for the ESS9018 DAC, and that this transformer used a special type of core material called FINEMET, which is a nano crystalline soft magnet material. I checked out the new material and got a few photos of the transformers, and two weeks later, I had a pair of unusually heavy transformers hooked up with solid core silver wire to my reference DAC, the Buffalo II with the three Tridents installed, playing music from the SDTrans384 memory card player I use daily.

Compared to having a dual mono, discrete IV converter with dual toroids for raw power supply, and dual super shunt regulators to feed the converters, hooking up a similar transformer setup, is unstressingly easy. For each channel, just connect two (GND is not needed) short wires from the Buffalo2´s output to the transformer, connect the three or two wires (balanced or unbalanced) from the transformer outputs to the line amplifier, and voila, you are done! Well, OK, you need to have a load resistor on the transformer outputs and maybe a small capacitor across the secondaries, too.


I used a 4,02k TX2352 bulk metal foil resistor connected directly at the transformer outputs as load resistor to get 2,0Vrms at 0dBFS into the Buffalo2. A 10nF RIFA PFE210 film and foil polystyrene capacitor was also soldered to the outputs, as I, on my oscilloscope, noted a ringing when only a resistive load was used. The cap removed the ringing, and also made the treble sound as it should. For the experimental person, lower resistance values and made of other resistor materials, and ditto for the capacitor could be fun try out. If a lower output voltage is wanted, just lower the resistor value. One could even use a volume control of top notch quality connected at the secondary windings to get the master volume control for one´s complete hifi system.


To make the comparisons between - first the Legato and the transformers - and secondly between the all-FET IV converter and the transformers, I used two identical Buffalo2 DAC:s that were both powered by identical Placid super shunt regulators. The two Buffalo2:s were via I2S connected to a single SDTrans384 memory card player. One of the Buffalo2’s was always connected to the transformers, whilst the other Buffalo2 was connected either to the Legato or to the all-FET IV converter.

After a week’s burn-in of the transformers using the repeat functionality of the SDTrans384, I started out to compare my Legato, with Duelund VSF 10 uF caps and only film and foil polystyrene caps for the other caps, against the transformers. These transformers, in general, sound more clean or pure, less foggy, and less fat. The bass is deep and more articulated from the transformers but the Legato has more fattiness and more weight. About like from a high Q loudspeaker. Women´s voices are clearer to hear with the transformers but maybe they lack a bit of “body” in the voices – or this is how it should sound like if the fog is removed.


The transformers have more accurate energy in the treble which might be disturbing listening to for ex “Love over gold” which, IMO, is having a too harsh treble. The Legato smoothes this over and makes the song almost enjoyable. I am very sensitive to bad sounding s- and tch-sounds from voices and these sounds are better reproduced with the transformers. Listening to snare drums or steel stringed acoustic guitars there is more snap and attack.


Exchanging the Legato for my reference, the all-FET IV converter, which also uses a TX2352 resistor in the most critical position, I immediately noticed that it has the same accurate energy in the treble, that the transformers have more articulation in the bass, and as earlier with the Legato, the transformers do not have the sound of a high Q loudspeaker. I am really like the bass reproduction of these transformers. It is deep and firm but not even a tad dominant over mid or treble.

Compared to the transformers, the treble from the all-FET converter sounds a bit cloudy. For ex. cymbals and tambourines sound more real with the transformers, with less hash and more details. Male voices have a tad less body from the transformers but this is more and more feeling as correct. The all-FET converter has a more forward reproduction with more authority and I get the feeling of a demo type reproduction.


What made me decide to use the Feastrex transformers as my reference IV converter, was that when I listened to a duet between a male and female singer. They sing at the same time, and both singers were positioned at the same spot in the 3D image. With the all-FET converter (and also the Legato) it was hard for me to hear every word that the woman sang, but with the transformers I could pick out every word. They are very detailed.


Seems like I will be enjoying transformers for a while J. As I like to experiment, I will be trying an Audiocap Teflon and tin foil capacitor, and also a Caddock Mk132 as load resistor.



At the type writer - Staccatiss

*Feastrex, a Japanese full range loudspeaker driver company, is distributing the ESS9018 transformers, but the design of the transformer is made by Mr. Yasuo Suzuki - a “typical” Japanese audiophile. Primary DC resistance is 14 Ohms, and secondary resistance is 16 Ohms, and the turn´s ratio is 1+1:1+1. The transformers can be had with black urushi coating that is supposed to dampen against microphony.

Information about FINEMET can be found here http://www.hitachi-metals.co.jp/prod/prod02/pdf/hl-fm9-e.pdf.
Click to expand...
 
B

baMarek

Member
Joined 2009
Has anyone tried transformers in 8-channel mode and achieved good results? My aim is to not go crazy with the cost of the output stage and hopefully avoid opamps or tubes (various reasons for that). I already have a stereo version of ES9018 in voltage mode with LL1684 and it sounds great. But the cost of 8 LL1684 trafos exceeds my budget.

I want to use 8 channel config , no pre-amps and ideally I do not want to have any extra outout stage past the TXs. I will end up with 780R internal impedance from the chip and 2.1mA current. 2.1mA seems super low to make it work in current mode by adding very low resistance to ground between primary and still have a decent gain on the output. Even serious step-up would not be enough. Or am I missing something?

Is voltage mode my only option???
If so, Marek metioned that in voltage mode the input impedance should be around DAC’s output impedance. But are there any stricter rules, do I need to look for say 600 to 1k Ohm? I saw positive reports from people who used 10K:10K trafos


Marek said:
There are two general rules depending on 'Mode"

-voltage mode: DAC should see infinity impedance. So it is not important what trafo you use*. It is important to load secondaries with very high impedance (ex. tube grid) so reflected impedance to primaries will not load DAC output. You have to choose right trafo turns ratio and/or active stage gain to meet your expectations.

*ofcourse primary inductance has to be suited to DAC output resistance.

Marek
Click to expand...
 
E

Erlend Sæterdal

Member
Joined 2007
Vingborg said:
Goodmorning people :)

Back from a little break from the dac project where I have focused on my family, house and a OTL amplifier project which is allmost finished :)

But yesterday I tried a little with the dac, loads and the two step up's that I have.. And now the matter:



The unknown British step up is way off! Absolutely bad sound! No bas respond what so ever. Boring highs and midrange may be useful, but not in this application.. Bas respond got better by loading the dac with 1 ohm, but certainly not good enough!

BeyerDynamic TR/BV 370 215 006 : Sound quality was very good, but there was some serious phase problems!
It sounded like a kind of artificial surround or spatial stereo.
I don't know what seems to be wrong - Measurement 1 kHz 0dB said 65mV from one side of secundary and ground and about 105mV from other side of secundary and ground?
The phenomenon changed a bit when I took ground away from faraday shield pin and when I solder of the load resistors..

The tranni's haven't been used when I received them so I don't think they are non functional.
If there is anybody in here who know's how to load or treat these BeyerDynamic TR/BV 370 215 006 transformers, You should be welcome to share that info with me:):confused::)

Best from Henrik
Click to expand...

Hi Henrik I will try the Joe solution with 330 ohm resistors and LL 1684 direct into a Holton NXV 200 balanced input. Only thing is that I am afraid the signal will not be high enough. Amp and dac in same enclosure.
 
V

Vingborg

Member
Joined 2013
Heey Erlend :)
It all sounds very exiting and go for it, but then again, I've tried with several resistor values and transformers and off couse your LL1684:) But with three different tube output circuits I could not find the Sound better than my modified Sony XA50ES cd-player!
And to my ears the Buffalo can't compete with my heavily modified CS4398 pcb with a low gain tube stage - sorry to say :)
With the CS4398 pcb and low gain tube stage the soundstage is so clear, smooth, powerful, wide and ultra analog!!
But again it's up to every person to like what he hears :)

Best from
Henrik
 
E

Erlend Sæterdal

Member
Joined 2007
Vingborg said:
Heey Erlend :)
It all sounds very exiting and go for it, but then again, I've tried with several resistor values and transformers and off couse your LL1684:) But with three different tube output circuits I could not find the Sound better than my modified Sony XA50ES cd-player!
And to my ears the Buffalo can't compete with my heavily modified CS4398 pcb with a low gain tube stage - sorry to say :)
With the CS4398 pcb and low gain tube stage the soundstage is so clear, smooth, powerful, wide and ultra analog!!
But again it's up to every person to like what he hears :)

Best from
Henrik
Click to expand...

Ok but you should hear my OPUS dac sometime. It is so much better than my results with Buffalo so far. Uses a silk volumetransformer after the dac. Then a Mantra buffer wich is very very good. Instead of the AVCC I use Belleson mini for the Buffalo SE. Almost finished.

Belleson regulators are dangerous.
 
Joe Rasmussen

Joe Rasmussen

Member
Joined 2003
customanalogue.com
Vingborg said:
With the CS4398 pcb and low gain tube stage the soundstage is so clear, smooth, powerful, wide and ultra analog!!
But again it's up to every person to like what he hears :)
Click to expand...

Another Dane here, ensconced Down Under. :D

The CS4397/8 works great with 1:1 transformer because it has a low output impedance unlike the Sabre DAC which has to see a very low impedance to sound at its best. Note, one has and the other needs - but the Sabre's output is then very low into low Z - the Sabre is more variable and difficult to get right, but when you do - great.

Send me a PM, something off topic (?) I want to tell you about the CS4397/8.

Cheers, Joe
 
V

Vingborg

Member
Joined 2013
Erlend Sæterdal said:
Ok but you should hear my OPUS dac sometime. It is so much better than my results with Buffalo so far. Uses a silk volumetransformer after the dac. Then a Mantra buffer wich is very very good. Instead of the AVCC I use Belleson mini for the Buffalo SE. Almost finished.

Belleson regulators are dangerous.
Click to expand...

Hello Erlend :)

You know, that Sounds quite exiting! Just throw me an invitation and I'll be there!:)

Joe Rasmussen said:
Another Dane here, ensconced Down Under. :D

The CS4397/8 works great with 1:1 transformer because it has a low output impedance unlike the Sabre DAC which has to see a very low impedance to sound at its best. Note, one has and the other needs - but the Sabre's output is then very low into low Z - the Sabre is more variable and difficult to get right, but when you do - great.

Send me a PM, something off topic (?) I want to tell you about the CS4397/8.

Cheers, Joe
Click to expand...

Mr. Joe Rasmussen:) I'm allways happy when you drop by in this thread! I will try and create a PM for you this evening when the children is into there beds :)
I really look forward to see what you got for me.. :D

Best from Henrik
 
M

mjock3

Member
Joined 2011
Erlend Sæterdal said:
Ok but you should hear my OPUS dac sometime. It is so much better than my results with Buffalo so far. Uses a silk volumetransformer after the dac. Then a Mantra buffer wich is very very good. Instead of the AVCC I use Belleson mini for the Buffalo SE. Almost finished.

Belleson regulators are dangerous.
Click to expand...

Erlend,

Could you tell me more about the use of Belleson mini for the AVCC? I really like Belleson would be grateful if you could share how they are used in this application.

Thanks,
Mark
 
Joe Rasmussen

Joe Rasmussen

Member
Joined 2003
customanalogue.com
Coris

Coris

Member
Joined 2009
Paid Member
AVCC (DVCC) adjustable regulator based on ADM7151, lowest noise level available on marked. Also similar regulators based on LDLN015 for the rest of the ESS9018 power lines (1,2v - VDD L/R, VDD).
 

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Coris

Coris

Member
Joined 2009
Paid Member
By the way powering ESS9018 chip. There is not only AVCC rail which it may have a high quality power supply to make the chip to perform properly (for its analogue stage). All the required power (digital stages) rails of the chip must have the same highest as possible power quality (lowest noise level), to have the appropriate high quality of the signals out of this DAC chip.
When thinking at the power supplies for this chip, one should consider the same high quality for all its power rails, for the best results (in this area).
 
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E

Erlend Sæterdal

Member
Joined 2007
Coris said:
By the way powering ESS9018 chip. There is not only AVCC rail which it may have a high quality power supply to make the chip to perform properly (for its analogue stage). All the required power (digital stages) rails of the chip must have the same highest as possible power quality (lowest noise level), to have the appropriate high quality of the signals out of this DAC chip.
When thinking at the power supplies for this chip, one should consider the same high quality for all its power rails, for the best results (in this area).
Click to expand...

I use Belleson mini they are really good. But take care if not done right they are oscillating. Burned a sabre chip
 
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