Hello all!
I am planning to build a Frankenstein of a preamp, of sorts, and I'm looking for some suggestions and help.
I have a setup that functions and sounds great to me. The problem is the sheer amount of individual appliances with the associated wiring is driving me crazy. Yeah, I'm a bit OCD like that. So, what we currently have is:
My plan is to combine these into one unit inside one chassis. Basically to have a preamp that has both analogue and digital inputs, LDAC Bluetooth and Dirac Live built in.
As far as I understand I already possess most of the components I need:
What I'm missing is:
I'm willing to DIY the needed modules, but I don't know how to design them. That is to say, I have built a few working tube amps, a speed controller for the turntable etc. However, all of these have been projects where the PCB, parts list and at least some sort of build guide have existed. I am not knowledgeable enough to work based on schematics alone. I'm not totally against buying ready-made modules either, if those serve the purpose.
There are so many options, particularly when it comes to the DACs, I'm totally overwhelmed. Could you perhaps point me in the right direction? Also, any feedback about my plan in general is much appreciated!
I am planning to build a Frankenstein of a preamp, of sorts, and I'm looking for some suggestions and help.
I have a setup that functions and sounds great to me. The problem is the sheer amount of individual appliances with the associated wiring is driving me crazy. Yeah, I'm a bit OCD like that. So, what we currently have is:
- Khozmo Acoustics passive preamp for input selection and volume control
- Hagerman Cornet3 phono stage
- Fiio BTA30 mainly for Bluetooth by currently also functions as a DAC
- MiniDSP DDRC-24 for room handles room correction
My plan is to combine these into one unit inside one chassis. Basically to have a preamp that has both analogue and digital inputs, LDAC Bluetooth and Dirac Live built in.
As far as I understand I already possess most of the components I need:
- The Khozmo preamp will provide the input selector and volume control with a remote controlled stepped attenuator
- Cornet 3 is a nice phono preamp, would incorporate as-is
- BTA30 would be used as Bluetooth only
- DDRC-24 would be installed between the volume control and RCA outputs.
What I'm missing is:
- Power supply. The BTA-30 needs 5V, everything else is 12V.
- DAC module to provide the digital inputs. I'd like a good quality HIFI sound, but no need for reference level, per se. A simple unit would do, no volume controls needed etc. No need to manually choose between digital sources, it is enough that the DAC automatically chooses the one where signal is coming from. If this is not possible, then a single optical input will suffice.
I'm willing to DIY the needed modules, but I don't know how to design them. That is to say, I have built a few working tube amps, a speed controller for the turntable etc. However, all of these have been projects where the PCB, parts list and at least some sort of build guide have existed. I am not knowledgeable enough to work based on schematics alone. I'm not totally against buying ready-made modules either, if those serve the purpose.
There are so many options, particularly when it comes to the DACs, I'm totally overwhelmed. Could you perhaps point me in the right direction? Also, any feedback about my plan in general is much appreciated!
Thanks for the reply! I actually have a DC3N-1205S for voltage regulation, should I want to go that route. I still need at least the 12V power supply, though. I'd rather build a proper one than use one of the wall-warts the current equipment uses. Bluetooth I don't need, as I can incorporate the BTA30. Besides, I have serious reservations about the sound quality of those $1.50 modules... 🙂
You will be surprised, there are videos on line, made by people with British voices...quite competent really.
Fair enough, I'll look into it! In any case, I'll need the DAC module, which seems to cause me most trouble to find. The problem being, there are too many to choose from. I like how the DDDAC would come as a kit, but it's quite expensive, perhaps overkill too.
OK, so what is your budget then? its kind of hard to help you with a request with so little information on your requirements and no budget.
Good point! I'm willing to spend a few hundred on the project. For example, if the DDDAC is in the end my best option I won't hesitate to buy it. I won't get into the thousands for this project probably, I assume that the point of diminishing returns lies well below four figures.
Please ask about the requirements, it might just be that I don't know how to communicate them. The other option is I don't know...
Please mention the currency.
You can convert an old computer to Linux, and do all sorts of things with it if you are talking Dollars, Euro or Pounds.
Difficult in Yen or Lira...
The software can do all sorts of audio signal processing.
You can convert an old computer to Linux, and do all sorts of things with it if you are talking Dollars, Euro or Pounds.
Difficult in Yen or Lira...
The software can do all sorts of audio signal processing.
I'm talking about euros/dollars. I would much prefer a hardware solution, the MiniDSP is enough software in my audio equipment for me. 🙂
There are so many changes in hardware these days that I prefer a software solution, you can always use another program if one does not satisfy you.
Basically, you are manipulating data in digital files, what better than a computer?
Old cell phone, and tablets will also do.
Depreciation is to be thought of, how much value and availability after say 5 years?
You can get parts for a car made on 2012, try finding DAC chips from that time!
Basically, you are manipulating data in digital files, what better than a computer?
Old cell phone, and tablets will also do.
Depreciation is to be thought of, how much value and availability after say 5 years?
You can get parts for a car made on 2012, try finding DAC chips from that time!
Hmm, it appears you have lost me, I'm afraid.
What I need is a DAC, DIY or complete, that will convert a signal from a TOSLINK S/PDIF to an analog signal, so that I can connect it to the input selector of the preamp. Preferably with a sound quality that is at least comparable to what I'm getting from the Cornet phono stage, for example. It could be my limited experience talking here, but I fail to understand why I would use a computer for this task.
What I need is a DAC, DIY or complete, that will convert a signal from a TOSLINK S/PDIF to an analog signal, so that I can connect it to the input selector of the preamp. Preferably with a sound quality that is at least comparable to what I'm getting from the Cornet phono stage, for example. It could be my limited experience talking here, but I fail to understand why I would use a computer for this task.
DAC = Digital to Analog Convertor...easy with a computer with the proper add-on cards.
Usually much better sound quality than dedicated units.
You can feed an amp directly, pre amp not essential.
Usually much better sound quality than dedicated units.
You can feed an amp directly, pre amp not essential.
Well, be that as it may, I don't see how it does what I'm looking for. If I can incorporate a computer into a device that has one ON/OFF-switch, one physical input selector, one physical volume control, digital inputs (including LDAC-capable bluetooth), analog inputs (including phono), tube phono stage and 4 analogue outputs with Dirac processing, I would be very happy to hear how this is done in a way that is easier than the plan I suggested in the original post: install a DAC module to handle the digital non-BT inputs (as all other inputs as well as outputs are already covered).
Otherwise, I would still like to get some suggestions for power supply units and DAC modules, because as far as I understand those are the only pieces of this puzzle that I am missing.
Idk if this helps but I’m building….
B-1t buffer preamp running a laptop PS,
Teabag I-select, PIzero w/hifiberry hat and led running moode a board to step the voltage down for the PI, the I-select board has 12v out to possible power phono stage in the future. It’s all working great but needs a case,
B-1t buffer preamp running a laptop PS,
Teabag I-select, PIzero w/hifiberry hat and led running moode a board to step the voltage down for the PI, the I-select board has 12v out to possible power phono stage in the future. It’s all working great but needs a case,
VIA and Gigabyte make embedded single board computers with pretty adequate specifications. I suppose others also do make them.
Even a cable TV box has a micro processor inside, so do most TVs. And those have on-off switches, and boot up fast due to a small OS, and that is stored on a solid state device.
Just a matter of looking in the right direction.
Even a cable TV box has a micro processor inside, so do most TVs. And those have on-off switches, and boot up fast due to a small OS, and that is stored on a solid state device.
Just a matter of looking in the right direction.
I'm sorry, this is simply not true and makes me doubt your experience with dedicated DACs and honestly digital audio in general. It is a whole lot easier to isolate an external DAC from computer noise and radiated RFI/EMI that is inherent and unavoidable in computers. there are a very limited number of PCI DACs that can compete in the same playing field and they arent cheap.
besides, its not what the OP is asking for. I've seen numbers of threads where you ignore what is asked for, suggesting what you think is acceptable and you dont stop when people try to politely inform you it isnt what they are wanting. Usually its about skimping on money and people spending more than what you think is required.
A little reality as well.
Dedicated DAC devices are designed around the same basic chips that are used in sound cards, and TVs, as TVs have moved to digital inputs (at least internally), for example in smart TV.
Even a satellite box has HDMI output, which I expect to be digital.
Spending a lot of money to filter noise is not justified in my opinion.
And many are made to price, and when they fail, just after warranty expires, the buyer realizes what happened.
I use a computer to store and play music, I have no issues with EMI or RF noises, I live 2 km away from a 10kW transmitter.
Of course, the show off factor, and the wow factor are always there.
Dedicated DAC devices are designed around the same basic chips that are used in sound cards, and TVs, as TVs have moved to digital inputs (at least internally), for example in smart TV.
Even a satellite box has HDMI output, which I expect to be digital.
Spending a lot of money to filter noise is not justified in my opinion.
And many are made to price, and when they fail, just after warranty expires, the buyer realizes what happened.
I use a computer to store and play music, I have no issues with EMI or RF noises, I live 2 km away from a 10kW transmitter.
Of course, the show off factor, and the wow factor are always there.
As for the original requirement, it is a Frankenstein type signal sensing pre amp that can take analog and digital inputs, and function as a input selector and so on.
And he has some bits, which he wants to combine in a single chassis.
Difficult, but with enough time and money anything is possible.
Question is, what makes you happy?
Making something, or listening to music?
My preference is listening, your choice may not be the same as mine, tastes do differ...let it be.
And he has some bits, which he wants to combine in a single chassis.
Difficult, but with enough time and money anything is possible.
Question is, what makes you happy?
Making something, or listening to music?
My preference is listening, your choice may not be the same as mine, tastes do differ...let it be.
Now we are on the right track, although I would rephrase the question as "what problem are you trying to solve"? For me, the problem is not audio quality, I am already more or less happy with my listening experience. My problem is that I hate the clutter and untidy mess that my audio equipment currently is. I like simplicity, order and minimalism, at least in the visual space.
By integrating all these little boxes into one bigger box I can eliminate at least 8 RCA interconnects, and at least 4 power supplies and their cables. The prospect of getting rid of all that clutter makes me feel all warm and fuzzy inside. Someone else might not care one bit. I happen to.
Secondly, making stuff myself (in this case it might be more modifying than actually building, but still) adds a lot of value. Surely this is something we can all appreciate since we are all reading a forum called diyAudio. 😀
So, in order to solve my problem I arrived at the conclusion that I need a DAC module. Why? Because currently I use the BTA-30 for that purpose and in the future it will be dedicated to Bluetooth only. Why? Because it will be inside the chassis and I cannot reach the switch, and I want to have all the inputs in one input selector anyway.
Secondly, I concluded I need a power supply. Why not use one of the existing ones? Mainly because I want to make sure there is enough good quality juice to power all the separate boards that are inside the device.
I'm curious about why you say this project seems difficult and expensive? I might be missing something, and that is why I ask. To me it seems rather simple, and consists of following tasks:
- Obtain suitable chassis
- Install power switch, input selector, volume control and a USB socket to front panel (USB is for convenient access to control the MiniDSP)
- Install inputs and outputs on back plate. In a best case scenario, there is suitable space to install the associated boards in a way that the terminals can remain on the boards.
- Connect outputs of the DAC, BTA-30, Cornet3, and additional RCA inputs into the input selector
- Connect input selector to volume control input
- Connect volume control output to MiniDSP input
- Connect MiniDSP output to RCA outputs on the back panel
- Connect all boards to power supply
- Connect power supply to power switch
- Connect power switch to IEC inlet
Of course cost is always relative, but in terms of difficulty it doesn't seem bad even if I would solder the power supply and DAC myself (assuming there are PCB's and guides available). It might be a time consuming task for a reward that someone else might consider completely not worth it. For me, it is worth it, and I would very much appreciate if we could steer the discussion towards finding ways to get the ball rolling in terms of finding the pieces I am missing, and not so much about solving the problem in a completely different way, or solving another problem entirely.
I understand I might not have given enough information for others to give meaningful input. The problem here is, I don't know enough about DAC's for example to be more detailed, and I'm hoping that you'll bear with me and ask me for some missing details/choices if that is the case. One option is of course just to take an existing DAC and do the same as with the other components, yank the board from it and install it. I'd just much rather build it.
Whatever you say @NareshBrd
Look at the pro audio world. for the most part, serious interfaces are not built in and it is a fact that the majority are not. If you are talking plain vanilla consumer low end dacs? sure some might. Many are just using the dacs built into the SoC and not using a dedicated dac at all, some will use midrange modern dac chips, using the top shelf is pretty much unheard of. In particular, while the DAC performance of some of the cheaper cards is almost useable, the ADC performance is often NOT, if you are going to use it with the preamp he has.
Indeed the DDDAC uses one that was very popular in soundcards, but that is quite an old chip. The DDDAC wouldnt be my choice; but thats a preference thing. It is also a fact that a computer case is a hostile electromagnetic environment; you saying it isnt, doesnt make it so.. I guess you are talking about not being able to hear noise? can you hear -90->115dB noise? I cant, but that is not the point. The SINAD performance on the AE-5 soundblaster for example is -70dB on the ADC input ... This is where all these things tend to fall down and you can bet the ADC chip is capable of much better than that in an external chassis. It is possible to do much better but it'll cost you. It would still fall short vs the same circuit externally. The stuff from UAD does quite well, but aint cheap.
Remove or distance the noise source, the noise gets smaller and easier to manage, funny that ...
consider also that he is using DSP for room correction, which often involves quite a bit of bass correction, some boosts to correct for dips can be quite steep and significant in the frequency band of interest, meaning that you should have considerable headroom in performance to account for it being boosted. Then you have the possibility of using digital volume control on top of that, more headroom required.
He may also wish to watch TV, or stream movies, with DSP. How d you plan to handle those sources in your PC and soundcard? Yes you can buy a PCI card with a TV receiver ... but would you? You would want an HDMI input somewhere. hardware DSP and IIR correction (rather than FIR) is going to make that much more straight forward with regard to minimising delay for lip sync. Otherwise you will need to account for the delay caused by the FIR; which is generally not possible with streamed movies. Are you suggesting he build the preamp into a full blown PC chassis? really? Do we know its RF hardened like any PCI card would have to be?
Here are 2 examples to illustrate my point, with a 10 second google.
Asus STX II PCI Sound Card
Both of these, while reasonable, dont compete with USB dacs in the same pricerange. the AE-5 ADC input at -70db noise, plus say 15dB headroom for DSP, plus another 12-15dB for volume control. how does worst case -40db SINAD performance sound to you?
Today, I would recommend the COSMOS ADC, from one of our Members IVX, which is designed for measurement, but will do just fine here. USB C powered and very nice performance, some 50dB better than the Soundblaster ADC input. For the dac, you could use one of his very competitive DACs while wipe the floor with the above for $100, especially when calibrated with the COSMOS. There are many options for DAC, thats just an easy suggestion as its cheap, IVX is one of the few designers in the more entry level especially that has solved the ESS IMD distortion hump problem. I will make some more DIY suggestions on dacs, including some you may wish to build, bare PCBs etc, but I would recommend the COSMOS ADC regardless. The little DAC dongle looks like a toy and uses an ESS chip that was originally designed for high end smart phones, but punches well above its weight and does a good 10-15dB better than even the metric HALO and UAD high end studio PCI gear mentioned.
Look at the pro audio world. for the most part, serious interfaces are not built in and it is a fact that the majority are not. If you are talking plain vanilla consumer low end dacs? sure some might. Many are just using the dacs built into the SoC and not using a dedicated dac at all, some will use midrange modern dac chips, using the top shelf is pretty much unheard of. In particular, while the DAC performance of some of the cheaper cards is almost useable, the ADC performance is often NOT, if you are going to use it with the preamp he has.
Indeed the DDDAC uses one that was very popular in soundcards, but that is quite an old chip. The DDDAC wouldnt be my choice; but thats a preference thing. It is also a fact that a computer case is a hostile electromagnetic environment; you saying it isnt, doesnt make it so.. I guess you are talking about not being able to hear noise? can you hear -90->115dB noise? I cant, but that is not the point. The SINAD performance on the AE-5 soundblaster for example is -70dB on the ADC input ... This is where all these things tend to fall down and you can bet the ADC chip is capable of much better than that in an external chassis. It is possible to do much better but it'll cost you. It would still fall short vs the same circuit externally. The stuff from UAD does quite well, but aint cheap.
Remove or distance the noise source, the noise gets smaller and easier to manage, funny that ...
consider also that he is using DSP for room correction, which often involves quite a bit of bass correction, some boosts to correct for dips can be quite steep and significant in the frequency band of interest, meaning that you should have considerable headroom in performance to account for it being boosted. Then you have the possibility of using digital volume control on top of that, more headroom required.
He may also wish to watch TV, or stream movies, with DSP. How d you plan to handle those sources in your PC and soundcard? Yes you can buy a PCI card with a TV receiver ... but would you? You would want an HDMI input somewhere. hardware DSP and IIR correction (rather than FIR) is going to make that much more straight forward with regard to minimising delay for lip sync. Otherwise you will need to account for the delay caused by the FIR; which is generally not possible with streamed movies. Are you suggesting he build the preamp into a full blown PC chassis? really? Do we know its RF hardened like any PCI card would have to be?
Here are 2 examples to illustrate my point, with a 10 second google.
Asus STX II PCI Sound Card
Sound BlasterX AE-5
Both of these, while reasonable, dont compete with USB dacs in the same pricerange. the AE-5 ADC input at -70db noise, plus say 15dB headroom for DSP, plus another 12-15dB for volume control. how does worst case -40db SINAD performance sound to you?
Today, I would recommend the COSMOS ADC, from one of our Members IVX, which is designed for measurement, but will do just fine here. USB C powered and very nice performance, some 50dB better than the Soundblaster ADC input. For the dac, you could use one of his very competitive DACs while wipe the floor with the above for $100, especially when calibrated with the COSMOS. There are many options for DAC, thats just an easy suggestion as its cheap, IVX is one of the few designers in the more entry level especially that has solved the ESS IMD distortion hump problem. I will make some more DIY suggestions on dacs, including some you may wish to build, bare PCBs etc, but I would recommend the COSMOS ADC regardless. The little DAC dongle looks like a toy and uses an ESS chip that was originally designed for high end smart phones, but punches well above its weight and does a good 10-15dB better than even the metric HALO and UAD high end studio PCI gear mentioned.
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