Dual I/V stage implementation for Buffalo II & III

[pinnocchio]

I would like to start this thread to see if some of you would be interested in having a switchable dual I/V stage for the Buffalo II and III. Those are the DAC designed by TwistedPear Audio.

My thoughts on this is that some people love solid state I/V and some love Tube I/V. If you're like me, depending on the kind of music you're listening you might like one or the other.

What I'd like to propose is some sort of way to have both a Legato/IVY I/V stages from TPA and a third party I/V that could be selected with the press of a button or switch.

Now, I'm currently running a Dual Mono Buffalo II setup with Dual Legato 3.1 and I also have a tube I/V from DVBProjekt (Tube-I-Zator).

I was planning to have a switch board sandwiched between the Legato/IVY and the Buffalo II/III that would do the switching using latching relays. Latching relays to not induce EMI in the signal. And having this board sandwiched in between would allow for shortest traces as possible.

I hope this will bring some great ideas and a possible design. Since I'm no circuit designer, I would like to know if someone with experience would gladly provide help in designing the circuit. If not, I have a good source (a friend) that could do it but timing for him is not good at the moment.

Here's a drawing of what I was thinking

https://picasaweb.google.com/lh/phot...eat=directlink

There would also be a controller on a different board that would carry the electrical and electronics to switch the relays. I do not want to have any electricity flowing on the I/V circuit aside the balanced audio signals, hence the use of latching relays.

Of course we would need the right measurement of the PCB holes and connectors of both Legato/IVY and the BII/BIII to align things. I have sent a PM to Russ White and asked him for the Gerber files but only containing the holes and connectors alignments. I'm relying on their good heart for this help!

I was thinking of a group buy if enough people are interested!

Let's get this started!
Do

[pinnocchio]

As I would really like to have this started, I will be offering 100$ donation to the DiyAudio forum if someone will be interested in designing the board for me (for all of us).

I will provide the needed information and would love people to participate and share their ideas

Would also like to know who would be interested in such a board.

Thanks

[dvb projekt]

Hi Do,

as far as i see it on the attached wiring diagram, you need 6 lines per channel to do what you want to, correct?

[pinnocchio]

Hey Oliver!

I need 6 lanes per DAC (we have two BII/BIII) to connect the BII to the Legato/IVY and another 6 lanes per DAC to go to the third party I/V . In dual mono, please see diagram.

When they're installed, they stack perfectly on top of each others and the pins are aligned making a point to point connection. We'll need at least 4 latching relays, one for each "left and right" of each BII/BIII.

See diagram of what has to happen when using an external I/V in dual mono mode

https://picasaweb.google.com/lh/phot...eat=directlink

I'd like to have the relays as close as possible to the BII and legato as possible.

Please let me know if you have any questions

Thanks
Do

[qusp]

even a few cm and a fraction of an ohm will effect the resolution and dnr of the current output of the bII in a meaningful way, i dont think this is a great idea tbh. you should if you can avoid it and must push forward, try to avoid switching the return lines

[pinnocchio]

I have currently installed a Tube I/V and the setup is not final. I'm using all silver cabling.

Sure it can change the current output but trust me, I have good ears and it sounds amazing. The goal is to make the traces really short. We're all about experimenting.

I do however understand your concern.

Thanks

[pinnocchio]

Here's a quick hand drawn diagram for only one of the two BII DAC in the dual mono setup.

https://picasaweb.google.com/lh/phot...eat=directlink

I can put this on a better format if needed but it is the idea...

Thanks

[qusp]

good ears, silver cabling or not, using subpar methods to connect the IV stage like using relays, will singlehandedly remove any advantage gained by having a dual mono dac in the first place

[pinnocchio]

Originally Posted by qusp

good ears, silver cabling or not, using subpar methods to connect the IV stage like using relays, will singlehandedly remove any advantage gained by having a dual mono dac in the first place

Hi Qusp,

I do appreciate the feedback but if you could also provide some positive feedback, maybe tell us how you would do it instead of just pointing out the bad.

If using relays is not good then there must be tons of people wasting their times building / implementing R2R volume control using relays...

After all, this way of thinking would have never brought us to the moon!

Please don't be a show stopper and see the positive side of anyone interested to use an I/V stage of their liking. I do love the Legato / IVY stages but there's plenty of people that won't give up their tube I/V for SS output...

Lets just be innovative and find ways around this issue.

Thanks for your understanding

[pinnocchio]

Well, I have completed my dual mono BII with Tube-I-Zator tube output and it sounds incredible!

I will post picture later on.

I'm still looking for some good talent to create that board... I could split the bounty half and half... Half to DiyAudio and half to the person creating it... Or let me know what would motivate you!

Thanks