Certainly there are practical variables. Both approaches have certain convenience factors. I’m primarily interested in the technical/implementation side. Some of the questions I’ve been wondering about:
1. Does combining a linestage, DAC, phono, etc. in one box allow you to share one power supply between them? Is this a good idea?
2. Are there potential interference problems to having multiple circuits in the same box?
3. Are the reductions in interconnect length between components, and additional shielding provided by being contained within a box, significant?
1. Does combining a linestage, DAC, phono, etc. in one box allow you to share one power supply between them? Is this a good idea?
2. Are there potential interference problems to having multiple circuits in the same box?
3. Are the reductions in interconnect length between components, and additional shielding provided by being contained within a box, significant?
Depends on execution. You can take advantage of better integration or screw it all up. Your choice.
Personally, I was thinking about taking the power supply out of my old Nak preamp and stuff a JDS Atom DAC in it along with my crossovers.
Getting rid of mechanical connectors and cables is always good, but improper layout, shielding and so on can negate any advantage. One case saves a lot of money which can be spent on mu-metal shields, better parts etc.
So the absolute definitive answer is the consultant's creed: " It depends"
Personally, I was thinking about taking the power supply out of my old Nak preamp and stuff a JDS Atom DAC in it along with my crossovers.
Getting rid of mechanical connectors and cables is always good, but improper layout, shielding and so on can negate any advantage. One case saves a lot of money which can be spent on mu-metal shields, better parts etc.
So the absolute definitive answer is the consultant's creed: " It depends"
Need to ask yourself what you need.
As an example I have a very complex system with two phono pre-amps, a DAC, two R2R tape recorders, a 3 head cassette recorder and a tuner. The line stage pulls this all together in one control center, except that there is a balanced source switcher for the reel to reel recorders and digital source. The output of the line stage goes balanced to a DSP based room/speaker equalizer, 3 way electronic crossovers and 6 channels of amplification. This is the extreme case. I am always fiddling with things so the lack of integration makes sense here.
What do you need? If you envisage a complex system with lots of sources and have a desire to mix and match phono stages for example you'd want to keep them quite separate, OTOH if one table, one cartridge and one phono stage rules the roost perhaps it makes sense to combine them?
Anything like a DAC that goes quickly obsolete, or is the possible subject of audiophilia nervosa (phono stage maybe?) should not go in the box.
As an example I have a very complex system with two phono pre-amps, a DAC, two R2R tape recorders, a 3 head cassette recorder and a tuner. The line stage pulls this all together in one control center, except that there is a balanced source switcher for the reel to reel recorders and digital source. The output of the line stage goes balanced to a DSP based room/speaker equalizer, 3 way electronic crossovers and 6 channels of amplification. This is the extreme case. I am always fiddling with things so the lack of integration makes sense here.
What do you need? If you envisage a complex system with lots of sources and have a desire to mix and match phono stages for example you'd want to keep them quite separate, OTOH if one table, one cartridge and one phono stage rules the roost perhaps it makes sense to combine them?
Anything like a DAC that goes quickly obsolete, or is the possible subject of audiophilia nervosa (phono stage maybe?) should not go in the box.
Yes, and yes - simpler, cheaper, fewer points of failure, only one switch to hit...
Not really if you know what you're doing and decouple properly, get the grounding right, and keep impedances nice and low. Having the PSU separate can be advantageous to reduce hum pickup from any transformer.
Wouldn't imagine so, audio signals can be run long distances if you want, but the advantage of not having connectors (unreliable) and cables (bulky, untidy) has a definite bonus - less environmental hum pickup, less chance of ground-loop issues.
DAC obsolete? Well a $100 DAC exceeded our hearing several years ago. Besides, a DIY, one can always update.
BTW, the phone stage belongs at the base of the tonearm and the head-shell should be a 10 gain buffer built on a thin film ceramic base. I was working on that about the time CDs came about, so I stopped. IMHO of course. And if one is doing DSP, it is best to digitize as close to the source as possible.
BTW, the phone stage belongs at the base of the tonearm and the head-shell should be a 10 gain buffer built on a thin film ceramic base. I was working on that about the time CDs came about, so I stopped. IMHO of course. And if one is doing DSP, it is best to digitize as close to the source as possible.
If you're combining pre-built boards inside a case, then the potential for a ground loop exists. Bluetooth boards are notorious for this.
The remedies are
1) Use a power transformer with multiple secondary windings so the power ground is not shared between boards, or
2) Use interstage coupling transformers on the outputs of the boards, or
3) Employ ground loop breaker circuits ( a real hassle).
The fourth remedy, which I chose for Bluetooth because I didn't want to use the remedies above, is to use an external Bluetooth unit with its own wall wart. This ensures no ground loop through the power ground.
The remedies are
1) Use a power transformer with multiple secondary windings so the power ground is not shared between boards, or
2) Use interstage coupling transformers on the outputs of the boards, or
3) Employ ground loop breaker circuits ( a real hassle).
The fourth remedy, which I chose for Bluetooth because I didn't want to use the remedies above, is to use an external Bluetooth unit with its own wall wart. This ensures no ground loop through the power ground.
Ground loops can usually be eliminated by proper star point grounding. Some board layouts may be so bad as to make it worse.
Transformers are very non-linear. Best to avoid.
Transformers are very non-linear. Best to avoid.
Bluetooth boards will often cause a bad ground loop no matter how you wire them, because they have both power and noise grounds. When both grounds are wired, it's a loop.
I don't know if DACs are the same way, but I do know that line level transformers are not unheard of in DACs.
So 1960s and so noisy. Use a ground plane on the audio board with the volume control grounds soldered directly to the plane.
Transformers are in mixing boards and pro audio equipment. The only reason to avoid them in this day and age is price. Jensen JT-11P-1 Premium Line Input Transformer 1:1
I don't know if DACs are the same way, but I do know that line level transformers are not unheard of in DACs.
So 1960s and so noisy. Use a ground plane on the audio board with the volume control grounds soldered directly to the plane.
Transformers are in mixing boards and pro audio equipment. The only reason to avoid them in this day and age is price. Jensen JT-11P-1 Premium Line Input Transformer 1:1
They _were_ used, but were pretty much dropped like a stone when semiconductor technology allowed, as they are large, heavy, non-linear, non-flat response, _very_ expensive (when you factor in hardware and enclosure costs particularly) and limited bandwidth, although good transformers manage to get pretty good, they are not really viable competition for modern low-noise amps in most cases. There are a few niche uses still, and the galvanic isolation can be useful, and sometimes being passive can be very handy.
So, no, there are several reasons to avoid them other than price, which is why they are seldom used.
Yes, they are all that.
There is some renewed interest in line level transformers. With modern designs employing embedded solutions (like the Bluetooth board which can be found in both consumer and DIY equipment), transformers have been used as the easiest and most effective way to cure the dreaded ground loop. I've seen DACs that used transformers too.
And now Triad offers a line level transformer that isn't that expensive. I haven't used it but I will check it out. I did notice that Mouser was out of them a couple years ago when I was looking for a pair but now they stocked up on them.
Finally, I think some experimenters use them for euphonic reasons. I've read where people claimed it made their DACs more "analog" sounding, for what it's worth. Maybe that belongs in another thread. 😉
There is some renewed interest in line level transformers. With modern designs employing embedded solutions (like the Bluetooth board which can be found in both consumer and DIY equipment), transformers have been used as the easiest and most effective way to cure the dreaded ground loop. I've seen DACs that used transformers too.
And now Triad offers a line level transformer that isn't that expensive. I haven't used it but I will check it out. I did notice that Mouser was out of them a couple years ago when I was looking for a pair but now they stocked up on them.
Finally, I think some experimenters use them for euphonic reasons. I've read where people claimed it made their DACs more "analog" sounding, for what it's worth. Maybe that belongs in another thread. 😉