Hi Guys,
The new build threat has been started! Please head over there for any build related questions or information. An updated BOM and schematic has been posted:
http://www.diyaudio.com/forums/digi...classic-pass-labs-d1-ess-dac.html#post2386563
I'll be posting the PTH parts BOM later tonight, along with the instructions for installing the two zeners correctly.
Cheers,
Owen
The new build threat has been started! Please head over there for any build related questions or information. An updated BOM and schematic has been posted:
http://www.diyaudio.com/forums/digi...classic-pass-labs-d1-ess-dac.html#post2386563
I'll be posting the PTH parts BOM later tonight, along with the instructions for installing the two zeners correctly.
Cheers,
Owen
New DI for Ess9018
I want to connect to my Buffalo II converter (Ess9018) your new D1. I ask if I can use the I/V converter also for ESS9018 or are necessary the modification. I saw that she has also designed another schematic I / V when using the Q1: Q4 mosfet FQA32N20C, new version D1 Pass labs for Ess. Which pattern would you recommend to use
Virginio
I want to connect to my Buffalo II converter (Ess9018) your new D1. I ask if I can use the I/V converter also for ESS9018 or are necessary the modification. I saw that she has also designed another schematic I / V when using the Q1: Q4 mosfet FQA32N20C, new version D1 Pass labs for Ess. Which pattern would you recommend to use
Virginio
Hi Virginio,
Please follow the link the post #741 for the build thread. The first post in the build thread has a link to the final schematic which is the best version to use with the Buffalo II DAC.
Best of luck with your build, and let me know what you think when you get it done.
Regards,
Owen
Please follow the link the post #741 for the build thread. The first post in the build thread has a link to the final schematic which is the best version to use with the Buffalo II DAC.
Best of luck with your build, and let me know what you think when you get it done.
Regards,
Owen
FS PCB and Parts .
Hi Gents ,
I'm sorry if this is the wrong place to offer this ,but I have an untouched kit for this build if anyone is interested . After a moment of clarity and a dose of reality ,I realise this project is way above my skill and understanding.
It seems a shame for it to sit here doing nothing . I ended up getting the young
DAC at a very reasonable price - the kit is from Owen .
Kind regards , Rich
PS, Also willing to trade for any parts for the Pearl 2 and B1 BOM .
Hi Gents ,
I'm sorry if this is the wrong place to offer this ,but I have an untouched kit for this build if anyone is interested . After a moment of clarity and a dose of reality ,I realise this project is way above my skill and understanding.
It seems a shame for it to sit here doing nothing . I ended up getting the young
DAC at a very reasonable price - the kit is from Owen .
Kind regards , Rich
PS, Also willing to trade for any parts for the Pearl 2 and B1 BOM .
spreadsheet
Ok, so I'm getting a 8 channel buffalo III for my multi-way horn system soon. I'll be needing to make 8 iv stages - possibly 16 when I get another Buffalo III to go multichannel! I plan to build an 'air-wired' monster on a BIG heatsink I picked up - should be enough for all the channels fets, regs and resistors....
In this age of austerity I'd like to re-use my collection of Lundahls as balanced/se converters.
I have 4 of Lundahl 1674 1:4 and 4 of Lundahl 9206 1:10. So, I'd like to adjust the circuit to suit various step-ups (or step-downs?) for various output levels for each of my drivers. I understand that there is a big range of output levels possible. What would be really great is a spreadsheet where I can play with the various resistor/psu voltage values vs output levels. I don't quite trust myself to do all the calculations. Could anyone help me with this?
thanks!
Maravedis
Ok, so I'm getting a 8 channel buffalo III for my multi-way horn system soon. I'll be needing to make 8 iv stages - possibly 16 when I get another Buffalo III to go multichannel! I plan to build an 'air-wired' monster on a BIG heatsink I picked up - should be enough for all the channels fets, regs and resistors....
In this age of austerity I'd like to re-use my collection of Lundahls as balanced/se converters.
I have 4 of Lundahl 1674 1:4 and 4 of Lundahl 9206 1:10. So, I'd like to adjust the circuit to suit various step-ups (or step-downs?) for various output levels for each of my drivers. I understand that there is a big range of output levels possible. What would be really great is a spreadsheet where I can play with the various resistor/psu voltage values vs output levels. I don't quite trust myself to do all the calculations. Could anyone help me with this?
thanks!
Maravedis
Hi Maravedis,
Sounds like an ambitious project to say the least. Unless you ramp down the power dissipation, running 8 channels is going to generate a lot of heat.
As for the gain, it's more or less independent of the supply voltage, and fully dependent on the resistor values. If you run the Buffalo III in 8 channel mode, you'll only get about 4mA p-p per channel of current output, as opposed to the 16mA p-p you would get in stereo mode. In a sense, that would work out perfectly with your 4:1 Lundahl transformers, as you'd be right back up to about 2VRMS output at 0dBFS, which is the same as the stereo version.
As for the 10:1 transformers, I suppose you could halve the resistor values to lower the gain by a factor of 2, and then use the 10:1 as step-up which would give you a little more output than the other setup, around 2.5VRMS.
The downside to this is that your output impedance will be higher than usual, at around 1500 ohms for the 4:1 version, and about 1800R for the 10:1 version. If you know that your amplifiers or preamp (whatever is next in the chain) has a high impedance input, then you'll be fine and it won't make a difference.
Rather than a spreadsheet, you're best to download LTspice and run some simulations. It's easy to use, and you can easily model in your transformers and check everything before you build it. If you start changing the resistor values, you'll need to keep an eye on power dissipation and what rail voltage gives you the desired idle current. I can send you the design file to get you started.
Regards,
Owen
Sounds like an ambitious project to say the least. Unless you ramp down the power dissipation, running 8 channels is going to generate a lot of heat.
As for the gain, it's more or less independent of the supply voltage, and fully dependent on the resistor values. If you run the Buffalo III in 8 channel mode, you'll only get about 4mA p-p per channel of current output, as opposed to the 16mA p-p you would get in stereo mode. In a sense, that would work out perfectly with your 4:1 Lundahl transformers, as you'd be right back up to about 2VRMS output at 0dBFS, which is the same as the stereo version.
As for the 10:1 transformers, I suppose you could halve the resistor values to lower the gain by a factor of 2, and then use the 10:1 as step-up which would give you a little more output than the other setup, around 2.5VRMS.
The downside to this is that your output impedance will be higher than usual, at around 1500 ohms for the 4:1 version, and about 1800R for the 10:1 version. If you know that your amplifiers or preamp (whatever is next in the chain) has a high impedance input, then you'll be fine and it won't make a difference.
Rather than a spreadsheet, you're best to download LTspice and run some simulations. It's easy to use, and you can easily model in your transformers and check everything before you build it. If you start changing the resistor values, you'll need to keep an eye on power dissipation and what rail voltage gives you the desired idle current. I can send you the design file to get you started.
Regards,
Owen
yeah for 8 channels running as we have it, youll have about 200W and then another 200W for the second dac (plus whatever your power supply puts out). airwiring that mess will net you a pretty serious decrease in performance and you will have already taken a hit with only using 1 dac per channel and then another hit from the transformers.
ambitious is one word for it i guess
ambitious is one word for it i guess
hot
Owen and qsup, thanks for your input!
The scale of a project has never put me off before...
I'm not worried about the output impedance as we are talking valve grid resistors here. But looks like I will have to lower the current a bit. The Time Has Come to bite the bullet and get to grips with LTspice. Deep breath. Owen, could you please post the LTspice file?
I'm unclear about what sort of a (subjective) performance hit I will get from not paralleling the ESS outputs - will just have to listen to various options I think. (and I need to evaluate the internal digital attenuator before I proceed too). But this is not for this thread I suppose.
I don't necessarily see why air-wiring (or perf board) is quite so inferior. 3d path lengths can be short and neat. Maybe I'm just naive, but its not a very complicated circuit is it? err..onthe other hand, anyone have a spare bunch of pcbs?
Another option I have is to use opamp ivs on some of the uncritical channels, and save the heat for the critical midrange/midbass. 4 channels would be more manageable.
thanks,
Maravedis
Owen and qsup, thanks for your input!
The scale of a project has never put me off before...
I'm not worried about the output impedance as we are talking valve grid resistors here. But looks like I will have to lower the current a bit. The Time Has Come to bite the bullet and get to grips with LTspice. Deep breath. Owen, could you please post the LTspice file?
I'm unclear about what sort of a (subjective) performance hit I will get from not paralleling the ESS outputs - will just have to listen to various options I think. (and I need to evaluate the internal digital attenuator before I proceed too). But this is not for this thread I suppose.
I don't necessarily see why air-wiring (or perf board) is quite so inferior. 3d path lengths can be short and neat. Maybe I'm just naive, but its not a very complicated circuit is it? err..onthe other hand, anyone have a spare bunch of pcbs?
Another option I have is to use opamp ivs on some of the uncritical channels, and save the heat for the critical midrange/midbass. 4 channels would be more manageable.
thanks,
Maravedis
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.