I have been listening to various dacs over the last few months, including a Cambridge Audio Dacmagic (dual TDA1305), Chiurutu's discrete logic ladder dac, and a Topping E30 dual AKM 4493. Years ago I built an Audio Note DAC1 (single AD1865) and valve output stage.
But then I go back to my dual TDA1541a dac, and realise everytime that I it prefer over all the others although I can't explain why. I think it's like comparing fresh water with distilled water - they are both H2O but the distilled water is bland.
I built it with Nichicon UKL ultra low leakage 100uf dem caps and use IanCanada's Fifo II and I2S to PCM board to supply the +- data for simultaneous mode. The dem clock runs at the specified frequency. I2S comes from a DIR9001 coax/optical interface. (or originally, direct from a CD player modified to provide I2S)
I/V is thanks to a pair of Sowter 1465 I/V transformers with 75r resistors. (there is no issue with the output offset current)
Power is from a Lithium battery bank with onboard low noise regulators.
I now want to experiment with other dem caps so have ordered 20 boards and 15 will be available to members.
If anyone wants one, please let me know. The cost is about £5ea + postage. (cost confirmed when they are delivered in case taxes are added)
The design is below and it is what it is and is far from perfect but cannot be changed. There are no surface mount parts.
But then I go back to my dual TDA1541a dac, and realise everytime that I it prefer over all the others although I can't explain why. I think it's like comparing fresh water with distilled water - they are both H2O but the distilled water is bland.
I built it with Nichicon UKL ultra low leakage 100uf dem caps and use IanCanada's Fifo II and I2S to PCM board to supply the +- data for simultaneous mode. The dem clock runs at the specified frequency. I2S comes from a DIR9001 coax/optical interface. (or originally, direct from a CD player modified to provide I2S)
I/V is thanks to a pair of Sowter 1465 I/V transformers with 75r resistors. (there is no issue with the output offset current)
Power is from a Lithium battery bank with onboard low noise regulators.
I now want to experiment with other dem caps so have ordered 20 boards and 15 will be available to members.
If anyone wants one, please let me know. The cost is about £5ea + postage. (cost confirmed when they are delivered in case taxes are added)
The design is below and it is what it is and is far from perfect but cannot be changed. There are no surface mount parts.
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I also have one unused IanCanada I2S to PCM board for £40 to members if bought with a pcb. (on ebay for £60)
Now selling a Fifo II v6 and Dual XO clock board with 45 & 49Mhz XOs with the above I2S PCM board.
Selling as a set so the I2SPCM is not available seperately.
https://www.diyaudio.com/community/...-fifoiiv6-dual-xo-clock-interconnects.404132/
I now have the new batch of PCBs. £4.20 each (cost price) + postage.
NB the pcbs are a previous design without L1,2,3,4 or the pin 16 jumper.
Selling as a set so the I2SPCM is not available seperately.
https://www.diyaudio.com/community/...-fifoiiv6-dual-xo-clock-interconnects.404132/
I now have the new batch of PCBs. £4.20 each (cost price) + postage.
NB the pcbs are a previous design without L1,2,3,4 or the pin 16 jumper.
Hey I would be interested in a board, I use an old DacMagic that has been recapped as they all have leaky capacitors by now in my experience.
Do you have any photos of boards that are complete, and where do you source your TDA1541a from?
Thanks - should I just PM you?
Do you have any photos of boards that are complete, and where do you source your TDA1541a from?
Thanks - should I just PM you?
Attached is a photo of my own dac.
I used Nichicon UKL ultra low leakage 100uf dem caps.
My TDA1541s came from a Dutch member who is selling them on ebay. (for much more than they cost a few years ago)
https://www.ebay.co.uk/itm/225636566889
There is a seller with some allegedly new ones but his prices are almost as steep. They seem to be Chinese unbranded ones so be wary - no photo from above.
https://www.ebay.co.uk/itm/384770773444
However, I do have two spare 1541As for £90 the pair. Used by me for a few years so known to be good.
Please pm me if interested in a pcb and/or the chips.
I used Nichicon UKL ultra low leakage 100uf dem caps.
My TDA1541s came from a Dutch member who is selling them on ebay. (for much more than they cost a few years ago)
https://www.ebay.co.uk/itm/225636566889
There is a seller with some allegedly new ones but his prices are almost as steep. They seem to be Chinese unbranded ones so be wary - no photo from above.
https://www.ebay.co.uk/itm/384770773444
However, I do have two spare 1541As for £90 the pair. Used by me for a few years so known to be good.
Please pm me if interested in a pcb and/or the chips.
Attachments
Is this the place to sale stuff ??
have a look at there : https://www.diyaudio.com/community/forums/swap-meet.2/
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have a look at there : https://www.diyaudio.com/community/forums/swap-meet.2/
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I have one of these PCB's on the way from another forum member. I like the transformer I/V setup so I'll order a set from sowter. How to I connect the transformers?
You'll need 75-100r I/v resistor on each output and then connect the primaries across each pair of resistors. You can fine tune the sound with secondary load resistors.
The orange & brown are joined and connected to 0v, this ensures the magnetising effect of the 2ma offsets cancels due to the bifilar winding.
https://www.sowter.co.uk/specs/1465.php
PS I still have a few pcbs left.
The orange & brown are joined and connected to 0v, this ensures the magnetising effect of the 2ma offsets cancels due to the bifilar winding.
https://www.sowter.co.uk/specs/1465.php
PS I still have a few pcbs left.
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Sorry, I never made one.
I used Nichicon UKL ultra low leakage 100uf 16v for the dem caps but you can use whatever you want, same goes for the dem oscillator.
The rest are decoupling caps - I used Panasonic or Tantalum and 100n film.
The voltage regulators can be on board or off board and either 78/79xx type, or one of the very low noise TO220 alternatives (LT3045/3094)
The datasheet might be helpful.
I used Nichicon UKL ultra low leakage 100uf 16v for the dem caps but you can use whatever you want, same goes for the dem oscillator.
The rest are decoupling caps - I used Panasonic or Tantalum and 100n film.
The voltage regulators can be on board or off board and either 78/79xx type, or one of the very low noise TO220 alternatives (LT3045/3094)
The datasheet might be helpful.
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Thanks, I will most likely use iancanada's supercap power supplies. I'll have to research if I need the regulators or not
I used my own Lithium battery pack to provide raw 8v and 20v to the on board regulators which were from Ldovr (https://www.ldovr.com/).
How do you go about safety and charging with Lithium is it automated so that the battery will recharge in standby mode, low battery & over charge cutout. I haven't seen any ready made solutions but haven't looked in a while.
I built an external DAC psu which uses two banks of 5 cells, in a separate housing, with taps after 2cells for the +,-5v regulators & after all 5 for the -15v.
They are 8000mahr so don't need recharging too often but I do have to remove them and charge two at a time in separate Li-ion compatible chargers. (they are 22650 cells which are too large - the charger is meant for 18650 cells and could charge 4 of them at a time.)
I bought a multi cell charger / BMS with sensors for each cell but haven't fitted it yet. It would avoid the need to charge them outside of the DAC psu.
Quick blow fuses provide short circuit protection.
They are 8000mahr so don't need recharging too often but I do have to remove them and charge two at a time in separate Li-ion compatible chargers. (they are 22650 cells which are too large - the charger is meant for 18650 cells and could charge 4 of them at a time.)
I bought a multi cell charger / BMS with sensors for each cell but haven't fitted it yet. It would avoid the need to charge them outside of the DAC psu.
Quick blow fuses provide short circuit protection.
@batteryman whats the best way to feed I2S to this board? I was looking at these but I think the output is simultaneous mode so I don't think it'll work but I could be wrong. I could also use iancanada's DDCPi and FiFo board but not sure how to split that signal
http://www.jlsounds.com/i2soverusb.html
https://electrodac.blogspot.com/p/i2s-to-tda1541a-converter-tutorial.html
http://www.jlsounds.com/i2soverusb.html
https://electrodac.blogspot.com/p/i2s-to-tda1541a-converter-tutorial.html
I use Iancanada's I2s to PCM board and you need to set the dacs to simultaneous mode by connecting pin 27 of both to -5v. The point of simultaneous mode is that all latches are updated at the same time and then the bit clock is stopped which also keeps digital noise out when the actual digital to analaogue happens.
I haven't tried any others.
I did also have a FIFO II and dual clock between the I2S in and PCM board, but sold these. The FIFO II has the advantage of two switchable I2S inputs.
I just supply the PCM board with I2S from a spdif interface (switchable from coax to optical)
I haven't tried any others.
I did also have a FIFO II and dual clock between the I2S in and PCM board, but sold these. The FIFO II has the advantage of two switchable I2S inputs.
I just supply the PCM board with I2S from a spdif interface (switchable from coax to optical)