May I suggest using a transformer to filter, keeping signal balanced and feed it to this:
http://www.diyaudio.com/forums/anal...eamp-well-balanced-volume-control-really.html
group buy here:
http://www.diyaudio.com/forums/group-buys/279981-bruno-putzeys-balanced-preamp-group-buy.html
Seems a very worthwhile project to me and it´s what I will be pursuing. Looking at options for transformers now....
http://www.diyaudio.com/forums/anal...eamp-well-balanced-volume-control-really.html
group buy here:
http://www.diyaudio.com/forums/group-buys/279981-bruno-putzeys-balanced-preamp-group-buy.html
Seems a very worthwhile project to me and it´s what I will be pursuing. Looking at options for transformers now....
I won't with the preamp because I already have one of these that does the buffer role I need.
BCF PCB and Kit
For an analogue attenuator for my nodac/BCF build I've narrowed it down to a K&K Audio balanced switched attenuator, installed between the LP filter and the BCF. K&K attenuator is at the bottom of this page;
K&K Audio | Digital Audio
But then I keep being drawn back to these, a combined filter/volume control...
SAC Thailand
Ray
I've been thinking about modifying the SE and flip-flop boards with Fabio's suggestion...
How about we take the mute function off the boards and put together a plug in mute daughter board. That way, as different ideas to address muting are developed they can be tried without having to rework the whole lot. The same mute daughter board could be used on both types of LP filter board, SE and flip-flop.
It'll mean a little more cost for the extra mute board and the SE and Flip-flop boards would be a bit sparsely populated but it's much more flexible.
I'm also thinking that I'll rationalise the mute circuit to eliminate the need for the TLP isolators by running it all, apart from the mute contacts, on the 'dirty' side of the JLSounds board
Thoughts/opinions?
Ray
How about we take the mute function off the boards and put together a plug in mute daughter board. That way, as different ideas to address muting are developed they can be tried without having to rework the whole lot. The same mute daughter board could be used on both types of LP filter board, SE and flip-flop.
It'll mean a little more cost for the extra mute board and the SE and Flip-flop boards would be a bit sparsely populated but it's much more flexible.
I'm also thinking that I'll rationalise the mute circuit to eliminate the need for the TLP isolators by running it all, apart from the mute contacts, on the 'dirty' side of the JLSounds board
Thoughts/opinions?
Ray
Sounds like a good idea.
I would go as far as to put a (tiny, for example an attiny85) uC on the mute board to make it fully programmable and thus compatible with as many USB to I2S boards as possible.
Definitely overkill, but in this hobby, what isn't?
I also think it's the best choice if less elegant. When I have done the nodac, I did it so. The filter directly output from jlsounds and the anti bump circuit apart. Then, I have done the new dac of Lyuben with akm 4490 that allows you to do the dsd direct, not using op-amp but after the filter lpf creating a balanced circuit FET. My amplifier is a jeff rowland focuses II, and the difference of use with balanced inputs with respect to those that use a transformer as a balancer, is remarkable. It 's also a very interesting solution, this ... although there is the dac.
Il bulgaro две (2) ..da "quasi" a dac - Pagina 14
My dac is the "real fake denon"
Il bulgaro две (2) ..da "quasi" a dac - Pagina 14
My dac is the "real fake denon"
An externally hosted image should be here but it was not working when we last tested it.
Bye, Fabio
For many years I used a relay-switched attenuator from Twisted Pear. I always felt the design was efficient and elegant. I will use it for this if needed...
You know, even they I have plenty of DSD files, I dont listen to them because I'm not really interested in the music , its a bit boring mostly, hi fi crap and pretentious rubbish.
But I do like the pcm- dsd conversion of my pcm collection, and using DoP I have no issues at all with pops , noise etc.
So I'm quite happy with the mute board as it is.
But I do like the pcm- dsd conversion of my pcm collection, and using DoP I have no issues at all with pops , noise etc.
So I'm quite happy with the mute board as it is.
I've reworked new versions of both the SE and flip-flop boards to use a plug-in mute module. I'm part way through a mute module that incorporates Fabio's delay circuit. Should be in a position to post images tomorrow. It's another five days until I can order anything anyway (Chinese New Year) so we're not delaying anything.
No problem Mick, I have some spare boards to the current layout that I can provide to you and others in the same boat.
Ray
No problem Mick, I have some spare boards to the current layout that I can provide to you and others in the same boat.
Ray
Fabio, I'm struggling to read some of the component values in your sketch, particularly the caps - could you clarify please?
Also, the 1M trimpot isn't going to be very precise and I'm wondering if you have measured to sort of R value that you have it set to in order to get the muting at 'Start'. A lower value trimpot, perhaps in series with a fixed resistor might allow more precision between muting and missing the start of the music?
Ray
giusta.jpg)
Also, the 1M trimpot isn't going to be very precise and I'm wondering if you have measured to sort of R value that you have it set to in order to get the muting at 'Start'. A lower value trimpot, perhaps in series with a fixed resistor might allow more precision between muting and missing the start of the music?
Ray
A my opinion about Dsd Sound. Some weeks ago, I have listened at friend's home the Jlsound dac with akm4490 complete all boards, max configuration possible. Mainly, only pcm to fly conversion dsd with Hqplayer. So, the Sound was very analog, but the stage was narrow and low when than compared with only Pcm. what do you think about this aspect?
Hi, @Ray
Emilio (Leon77) has already answered you for capacitors, I confirm they are microfarads. For the trimpod, it is a multi-turn, I have a mounted 1M but you can safely mount a 250k, there are no problems for its regulation between muting and missing the start of the music. I advise you to test the circuit, perhaps without the tlp185 on a sperimental board and see if you solve the problem before proceeding to build the pcb.
@Leon 77
My impression is opposed. I don't know if you have used it with DSD direct on. DSD direct on AKM4490, is another planet. The strong of this system is the stage, extended as a nodac but more precise. A other important thing, is the output stage. The best things I have heard with the original jlsounds akm4490 and lme49710 board were obtained with the substitution of lme49710 using a discrete opamp of Aurion audio,
Very best of burson and lme49710. In my system I use The R1,
a fet circuit from Ruggero Sanna. and it id fantastic for me. The stage is beautiful.
Piccoli Bulgari crescono: Il Diabolidak! - Pagina 14
Bye, Fabio.
Emilio (Leon77) has already answered you for capacitors, I confirm they are microfarads. For the trimpod, it is a multi-turn, I have a mounted 1M but you can safely mount a 250k, there are no problems for its regulation between muting and missing the start of the music. I advise you to test the circuit, perhaps without the tlp185 on a sperimental board and see if you solve the problem before proceeding to build the pcb.
@Leon 77
My impression is opposed. I don't know if you have used it with DSD direct on. DSD direct on AKM4490, is another planet. The strong of this system is the stage, extended as a nodac but more precise. A other important thing, is the output stage. The best things I have heard with the original jlsounds akm4490 and lme49710 board were obtained with the substitution of lme49710 using a discrete opamp of Aurion audio,
Very best of burson and lme49710. In my system I use The R1,
a fet circuit from Ruggero Sanna. and it id fantastic for me. The stage is beautiful.
Piccoli Bulgari crescono: Il Diabolidak! - Pagina 14
Bye, Fabio.
Thanks Fabio, but first things first. Would you care to check my schematic for the mute circuit?
An externally hosted image should be here but it was not working when we last tested it.
Cheers
Ray