Ultra high spec. opamp MC/MM phono, warp "elliptic" filter, line, headphone amps.
- Thread starter wyn palmer
- Start date
A quick update on he remote version (hopefully in the correct thread). Work is progressing slowly. I'm the bottleneck - Wyn has been very patient. It's been determined that all functions that are manually switched on previous version will be able to be remotely controlled, including cart loading. This version will support 2 inputs, each can be either MM or MC. Input, type and loading will be done by reed relays on main board (yes it will be wider). There will be an auxiliary board to facilitate different enclosures. This board will contain its own PSU, Arduino, and relays for gain, mono,warp and automatically mute during certain updates. LEDs will be used as indicators. It will be possible to drive a small LCD display with IIC but this could well increase noise so it will be subsequent development. All updates that have been discussed in this thread and the build thread will be incorporated.
Functions can be controlled by IR remote or front panel butto s or rotary encoder.
A lot of this is probably gilding the lily but it's DIY after all..
Functions can be controlled by IR remote or front panel butto s or rotary encoder.
A lot of this is probably gilding the lily but it's DIY after all..
wyn palmer
Addicted Member
Yes, this is the correct thread.
A bit more background for some of the choices made.
Firstly, the power supply for the digital, which is on the Aux board, is taken directly off the large smoothing caps in the analog supply at 24v.
A synchronous buck converter with enhanced EMI protection, switching at c. 2.2MHz is used to produce 5.64v from the 24v with c. 80% efficiency. The buck converter inductor is surface mount and shielded. The max output current is 600mA, the max input current is 176mA.
The 5.64v is then distributed using a pair of TPS7A2050 ultra-low noise low drop out regulators (an order of magnitude lower than the analog channel regulator noise), each producing a max output of 300mA at 5.0v.
The digital supply ground is star connected to the global supply ground.
This should be sufficient to drive all of the digital/5v relays/LEDs and is well within the capacity of the Analog supply.
As Bill mentioned, the load/input switching is not using the small telecom relays of before.
This is because the signal levels are too small to meet the contact wetting requirements of the telecom relays. Reed relays have no such requirement.
The main analog board has enhanced power supply rejection for the RIAA stage compared to the present design.
The enhanced power supply rejection for the input buffer stage was a feature of the prior design, which was intended to reduce the feedback from the output stages to the input stages and potentially improve "temporal smearing". There is, some, anecdotal evidence that this has indeed helped. This change, which can be bypassed, takes the process one step further. Beyond this I can envisage no additional benefit.
At some point I'm sure that Bill will provide more details on the digital operation. We have discussed the requirements extensively, but he's the digital designer for this and ultimately is responsible for the final choices and implementation.
j!m
Super Member
Mine has two inputs... two discrete boards inside the box. I could probably very comfortably fit a third if I wanted to.
Now, Wyn, the "improved" PS filtering you just mentioned... Is this something that could be built stand-alone as a drop in to replace the current line filter you developed for the SPS output? If not that's fine, and frankly my current set up is such crap it doesn't do justice to the current design anyway, but just asking.
Now, Wyn, the "improved" PS filtering you just mentioned... Is this something that could be built stand-alone as a drop in to replace the current line filter you developed for the SPS output? If not that's fine, and frankly my current set up is such crap it doesn't do justice to the current design anyway, but just asking.
wyn palmer
Addicted Member
Howdy good people,
I built a WP v2.0 board a few years ago and it's still center of my system. I love the sound of the phono section - very clear and clean but still smooth - and the line amp is great. I've also got the headphone amp in it, which I also love.
I have an extra v2.0 board that I'd like to build for my brother, but just as a mm phono stage. No preamp. Not sure about the warp filter.
Does anyone have the build docs for v2.0? I wasn't able to access them at the dropbox link. I wouldn't be surprised if there were links somewhere in this thread, but I couldn't find them with search and it is 155 pages long... I would be very grateful if someone could share them with me.
I don't remember which components are required for which constellation of features you choose.
Thanks, and let me know if you need more info!
Best,
Dan
I built a WP v2.0 board a few years ago and it's still center of my system. I love the sound of the phono section - very clear and clean but still smooth - and the line amp is great. I've also got the headphone amp in it, which I also love.
I have an extra v2.0 board that I'd like to build for my brother, but just as a mm phono stage. No preamp. Not sure about the warp filter.
Does anyone have the build docs for v2.0? I wasn't able to access them at the dropbox link. I wouldn't be surprised if there were links somewhere in this thread, but I couldn't find them with search and it is 155 pages long... I would be very grateful if someone could share them with me.
I don't remember which components are required for which constellation of features you choose.
Thanks, and let me know if you need more info!
Best,
Dan
Have you got any yet? If not, I could send them to you this evening.
I've got the build doc's. thank you!!!
Dan