Hi Paolo,
In the Denon DCD S-10, they used two PCM 1702 per channel. One of these was also fed inverted data, then the outputs which are 180° out of phase are combined in an op amp. Then you have single signal per channel. They are not in parallel.
Hi sendler,
You are generating twice the current, so you only need 1/2 the resistance to get the same levels.
-Chris
In the Denon DCD S-10, they used two PCM 1702 per channel. One of these was also fed inverted data, then the outputs which are 180° out of phase are combined in an op amp. Then you have single signal per channel. They are not in parallel.
Hi sendler,
No.
You are generating twice the current, so you only need 1/2 the resistance to get the same levels.
-Chris
Double the level
The idea was to double the level. But that is the other nice thing with the simplicity of the transformer I/V, you can change the resistor to get the best balance of sonics and output level by ear. I may still need to use an active output though as I use passive stepped attenuators for volume control.
anatech said:
The idea was to double the level. But that is the other nice thing with the simplicity of the transformer I/V, you can change the resistor to get the best balance of sonics and output level by ear. I may still need to use an active output though as I use passive stepped attenuators for volume control.
4 to 8
I'm sure 8 has been tried with diminishing returns. Now you are up to $500.00 just for the chips. You could post a new thread to ask. Demands on the power supply are increased with each additional chip of course.
inertial said:
I'm sure 8 has been tried with diminishing returns. Now you are up to $500.00 just for the chips. You could post a new thread to ask. Demands on the power supply are increased with each additional chip of course.
anatech said:
Understood, like push-pull amplifiers!😀
Indeed, that fantastic old DA-s1 transport + DAC was the same architecture I believe, exerpt they emploied a discrete devices output stage....... ( balanced also) but always the crappy 5532 to make I/V conversion!
thanks,
Paolo
Re: Double the level
Hi Sendler,
is it possible to use the 24 steps selector in order to select only one resistor ( instead of the only I/V resistor) at time before the transformer and use it like volume control?
Cheers,
Paolo
sendler said:
Hi Sendler,
is it possible to use the 24 steps selector in order to select only one resistor ( instead of the only I/V resistor) at time before the transformer and use it like volume control?
Cheers,
Paolo
Hi telstar,
Interesting🙂
So it is possible thus
What about "clicks" during the selection volume steps? Is it a real issue?
What about different bandwith in dependance of the selected step?
Cheers,
Paolo
Interesting🙂
So it is possible thus
What about "clicks" during the selection volume steps? Is it a real issue?
What about different bandwith in dependance of the selected step?
Cheers,
Paolo
Sowter may know
Sowter did a lot of testing with the pcm1704 to develop their transformer just for that specific application. If you write to them they may be able to tell you about the operating range of the I/V resistor and it's effects on the filtering.
Sowter did a lot of testing with the pcm1704 to develop their transformer just for that specific application. If you write to them they may be able to tell you about the operating range of the I/V resistor and it's effects on the filtering.
BTW somebody know the maximum bitrate and sample rate supported by these chips?
I'm thinking to feed 24/384 (or 32/384)...
I'm thinking to feed 24/384 (or 32/384)...
Hi Paolo,
These days people get all worked up over small numbers in a data sheet. The real performance difference may be another thing again, sometimes the difference is so small that it doesn't matter.
Denon is one of the few companies that knows how to do things right, just like Nakamichi did. I don't think they messed up using a 5532 op amp.
-Chris
The 5532 isn't that bad really. It's old, but still a good op amp. The 5534 is even better and it's the same age. If it really bothered you, they are easy to replace if you know how.
These days people get all worked up over small numbers in a data sheet. The real performance difference may be another thing again, sometimes the difference is so small that it doesn't matter.
Denon is one of the few companies that knows how to do things right, just like Nakamichi did. I don't think they messed up using a 5532 op amp.
-Chris
The Assembelage DAC 3.1 used the PMD 200 - as a 24/96 product with balanced pair of 1704 DACs per channnel - I use it with Borbely's all discrete jfet I/V converter and buffers., Dual mono Dexa 5 volt regulators with Blackgate NX caps for the 1704s, and Jung super regulators to power the Borbely Jfet board. The regulators made a big improvement to getting the best out of the all discrete Jfet design. it's isn't only the dac chip, but the I/V stage and buffers and how it's all powered that all contribute to the overall quality. changing each of these made significant improvements.
anatech said:
Hi Chris,
You have to excuse me , but I am a triode guy
and I can't see one IC of anything type !😀 Cheers,
Paolo
Hi Paolo,
No problem.
I speak hollow state as well.
Both tubes and solid state thingys each have their strengths and weaknesses. If you play to the things each does well, then you are doing it right as far as I'm concerned. I think that an I/V converter is not a strength of a tube type technology. Sure, you can build them that way. There are endless ways for accomplishing a goal, some are better than others. Ever see someone try to drive a nail in with a screwdriver? How about a screw with a hammer? Actually, one of my daughters did have someone in her woodworking class that did drive a screw in with a hammer. He got about 1/2 way before the screw bent over. True story. The point being is that each job does have tools appropriate to that job.
-Chris
No problem.
I speak hollow state as well.
Both tubes and solid state thingys each have their strengths and weaknesses. If you play to the things each does well, then you are doing it right as far as I'm concerned. I think that an I/V converter is not a strength of a tube type technology. Sure, you can build them that way. There are endless ways for accomplishing a goal, some are better than others. Ever see someone try to drive a nail in with a screwdriver? How about a screw with a hammer? Actually, one of my daughters did have someone in her woodworking class that did drive a screw in with a hammer. He got about 1/2 way before the screw bent over. True story. The point being is that each job does have tools appropriate to that job.
-Chris
You are right Chris🙂
I'm intrigued also from active I/V stage , solidstate.
I am looking at the Pass D1 I/V stage but I am perplex.....maybe I would be something even more simpler, to say a single transistor ( plus another to " fix" the point of work).🙄
Someone kind guy can suggest me a schematic like this ( unbalanced only) ? 🙂
Cheers,
Paolo
I'm intrigued also from active I/V stage , solidstate.
I am looking at the Pass D1 I/V stage but I am perplex.....maybe I would be something even more simpler, to say a single transistor ( plus another to " fix" the point of work).🙄
Someone kind guy can suggest me a schematic like this ( unbalanced only) ? 🙂
Cheers,
Paolo
Re: Several parts not needed with the AK4395
Hmmm, I found that on my deq2496, a nice Oscon directly on the AVDD pin improves the sonic (I am using tranny direct out).
I found the deq2496 poorly decoupled. Eg, for the ak4393 on the datasheet, the Avdd and Vrefh should have separate caps, but the deq only only have 1 ceramics for both pins.
sendler said:
Hmmm, I found that on my deq2496, a nice Oscon directly on the AVDD pin improves the sonic (I am using tranny direct out).
I found the deq2496 poorly decoupled. Eg, for the ak4393 on the datasheet, the Avdd and Vrefh should have separate caps, but the deq only only have 1 ceramics for both pins.
Attachments
Can't hear bypass in my DCX
I've done most of my work on the DCX2496. Never looked at that on the DEQ. It's interesting that the supply around the dac is different between these otherwise similar units. The DCX has a separate 47uf and bypass for Avdd and Vrefh. I have a DCX board with every electrolytic bypassed with an oscon and a film cap and honestly don't know if I could tell it apart from a board without.
.
Still, either Behringer offers amazing sound for the money (at any price?) with a direct out mod using either high quality transformers or caps. I like the extra detail of the caps and, with the 4395, don't need the filtering of the expensive transformers, which really adds up times 6 channels in the DCX.
.
You will also want to try the AK4396 which is a drop in for the 4393. It is night and day better especially if you don't want to bother with the clock.
.ChuckT said:
I've done most of my work on the DCX2496. Never looked at that on the DEQ. It's interesting that the supply around the dac is different between these otherwise similar units. The DCX has a separate 47uf and bypass for Avdd and Vrefh. I have a DCX board with every electrolytic bypassed with an oscon and a film cap and honestly don't know if I could tell it apart from a board without.
.
Still, either Behringer offers amazing sound for the money (at any price?) with a direct out mod using either high quality transformers or caps. I like the extra detail of the caps and, with the 4395, don't need the filtering of the expensive transformers, which really adds up times 6 channels in the DCX.
.
You will also want to try the AK4396 which is a drop in for the 4393. It is night and day better especially if you don't want to bother with the clock.