Hi,
It's easy and simple. Indeed, it is not a stereo volume regulator, it is just a input to the MCU to set the volume inside the DAC chip. So, connect G-Vol-V+ to one single potentiometer to 1-2-3 pins. Pay attention to it's curve - see my post https://www.diyaudio.com/forums/digital-line-level/314935-es9038q2m-board-90.html#post5421136
Yes, it will work. However, your pot, probably,
1. is a pair of pots
2. has a "audio" (i.e. log) curve.
Due to point 1 (if i'm right) you need to connect just 3 contacts (not 6) of that pot. Due to point 2 it may be not comfortable curve. Also, you do not need expensive pot like Alps, Alpha, and so on - any cheap 5-cents pot with the B or C (better) curve will be enough. Let me repeat myself - it is not in "sound flow", it is a just the source for voltage for MCU.
Oh, sorry, I have forget - you can try different orientation of pot, i.e. try a) connect V+ on the board to pin 1 of pot and Ground on the board to pin 3 of pot and b) connect V+ on the board to pin 3 of pot and Ground on the board to pin 1 of pot (connect Vol to pin 2 of pot in both cases) and check what way will be better for your ears (probably, you will have two different curves)
Hi all,
Major mishap on my output stage mod. Made the mistake of connecting the 15v dual in reverse! Smoke from one of the 10uf tantalum bypass cap. Checked and found shorts on all the tantalums on the opamp negative pins. Replaced them. Testing shows audio plays but with a lot of noise/distortion, kind of like radio with really bad reception. Any chance of salvage or is it done for good?
Any thoughts?
Cheers,
Kay.
Major mishap on my output stage mod. Made the mistake of connecting the 15v dual in reverse! Smoke from one of the 10uf tantalum bypass cap. Checked and found shorts on all the tantalums on the opamp negative pins. Replaced them. Testing shows audio plays but with a lot of noise/distortion, kind of like radio with really bad reception. Any chance of salvage or is it done for good?
Any thoughts?
Cheers,
Kay.
Hi Kay,
Sorry to hear about the mishap. Did it myself once, it it took me a couple of days to fix it. If you already replaced all output stage opamps and tantalum/electrolytic caps that may have been damaged (most likely all opamps without exception), then what about AVCC? Any damaged components there?
Do you have a scope? Are both left and right channels equally affected? What do power supply voltages measure? What do they measure with the meter on AC volts? Do you have any kind of a little amplifier that could be used for signal tracing? A tube guitar amp?
Sorry to hear about the mishap. Did it myself once, it it took me a couple of days to fix it. If you already replaced all output stage opamps and tantalum/electrolytic caps that may have been damaged (most likely all opamps without exception), then what about AVCC? Any damaged components there?
Do you have a scope? Are both left and right channels equally affected? What do power supply voltages measure? What do they measure with the meter on AC volts? Do you have any kind of a little amplifier that could be used for signal tracing? A tube guitar amp?
Hi Mark,
I don't have extra opamps. will take me weeks to get them. I do have ne5532's I guess can try them just to find out if other components are faulty. I don't have scope. As far as I can hear, both channels are affected. Voltages in DC seems to measure okay as far as I can tell. I'll try AC measurement. AVCC, Vref in DC seem to measure accurate. I do have a small tda7498 amp for testing.
So you think all the opamps will need replacing? the AVCC one too? Thanks for your commiseration.
Kay.
I don't have extra opamps. will take me weeks to get them. I do have ne5532's I guess can try them just to find out if other components are faulty. I don't have scope. As far as I can hear, both channels are affected. Voltages in DC seems to measure okay as far as I can tell. I'll try AC measurement. AVCC, Vref in DC seem to measure accurate. I do have a small tda7498 amp for testing.
So you think all the opamps will need replacing? the AVCC one too? Thanks for your commiseration.
Kay.
Hi Kay,
5532 opamps are fine for testing. Probably best to try that first. AVCC opamp likely also affected if it was connected to the same +-15v reversed power.
If need be, a signal tracing amplifier might be used to check the output of each I/V amplifier. A scope and a sine wave test signal might be better, but if no scope and still some puzzles after trying 5532 opamps everywhere, then maybe worth a try with the amplifier. Probably want to have a DC blocking cap and the volume turned down low at first, if it comes to that. Also, probably best to check all possibly affected polar caps (tantalum/electrolytic) along with all the opamps before trying signal tracing.
EDIT: Regarding OPA1612 opamps, you should only need four of them, 3 for the output stage and 1 for AVCC. Best to buy them from a reputable supplier rather than ebay or aliexpress, or you might end up with just more 5532 opamps but with some new letters printed on them. Just sayin'
5532 opamps are fine for testing. Probably best to try that first. AVCC opamp likely also affected if it was connected to the same +-15v reversed power.
If need be, a signal tracing amplifier might be used to check the output of each I/V amplifier. A scope and a sine wave test signal might be better, but if no scope and still some puzzles after trying 5532 opamps everywhere, then maybe worth a try with the amplifier. Probably want to have a DC blocking cap and the volume turned down low at first, if it comes to that. Also, probably best to check all possibly affected polar caps (tantalum/electrolytic) along with all the opamps before trying signal tracing.
EDIT: Regarding OPA1612 opamps, you should only need four of them, 3 for the output stage and 1 for AVCC. Best to buy them from a reputable supplier rather than ebay or aliexpress, or you might end up with just more 5532 opamps but with some new letters printed on them. Just sayin'
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Hi Kay,
Ceramic caps and resistors should be okay. Have you tried using 5532 opamps for everything yet? If still any problems, please use DVM to measure +-15v rails, AVCC left and right, and Vref left and right. Use DC volts, then AC volts and write down all measurements, then post them here.
Ceramic caps and resistors should be okay. Have you tried using 5532 opamps for everything yet? If still any problems, please use DVM to measure +-15v rails, AVCC left and right, and Vref left and right. Use DC volts, then AC volts and write down all measurements, then post them here.
Mark, you mentioned this a while back, do know the name of a chip like that?
I have an unused low jitter 100MHz clock and was thinking of dividing it down 25MHz, dividing the clock will only increase jitter but hopefully by an insiginificant amount.
What interesting is that dividing should decrease phase noise, which I have heard so many times is the most important parameter for audio.
laserscrape,
You might check out LT6954 or LT6950. One thing is they probably need, or work best with is LVDS or LVPECL clock inputs. Something to convert LVCMOS clock outputs to an appropriate divider input format could be something like MAX9110/MAX9112. However, if you could find a good clock with more suitable output capability, that might be better than using an intermediate chip to do it.
Or you could look at ICS542 which they claim has no added jitter (possibly optimistic claim).
A popular low-jitter clock buffer might come in handy: NB3L553
EDIT: Jitter and phase noise are two ways of looking at the same underlying thing, essentially they are different ways of measuring it.
EDIT: Where you quoted me in your post regarding my Iancanada FIFO speculation, I now have one of Ian's McFIFO boards. It turns out there are no tricks with dividers or multipliers. I looked at the chip part numbers on the FIFO and McClock boards. That was enough to tell me most of how they work, but out of courtesy to Ian I will refrain from going into more detail. However, I do plan to give them a try at some point. When I have a chance to do that I will report back with my sonic impressions.
You might check out LT6954 or LT6950. One thing is they probably need, or work best with is LVDS or LVPECL clock inputs. Something to convert LVCMOS clock outputs to an appropriate divider input format could be something like MAX9110/MAX9112. However, if you could find a good clock with more suitable output capability, that might be better than using an intermediate chip to do it.
Or you could look at ICS542 which they claim has no added jitter (possibly optimistic claim).
A popular low-jitter clock buffer might come in handy: NB3L553
EDIT: Jitter and phase noise are two ways of looking at the same underlying thing, essentially they are different ways of measuring it.
EDIT: Where you quoted me in your post regarding my Iancanada FIFO speculation, I now have one of Ian's McFIFO boards. It turns out there are no tricks with dividers or multipliers. I looked at the chip part numbers on the FIFO and McClock boards. That was enough to tell me most of how they work, but out of courtesy to Ian I will refrain from going into more detail. However, I do plan to give them a try at some point. When I have a chance to do that I will report back with my sonic impressions.
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I recently used original FIFO board in a project (not McFIFO) and it was very good.
I can only say it addressed everything that is important, being galvanic isolation, reclocking after isolation and separate power supplies for all. It also had a VG super low phase noise clock buffer.
I did not test this board with Sabre DAC *BUT from ppl I know that have done considerable development on Sabre DACs, the clock buffering is a good thing.
I can definitely recommend the FIFO board.
IME from a number of projects, the galvanic isolation and reclocking *after isolation is important.
PS - someone here probably should give one of the many 100MHz OCXO's on ebay a go. I'd most likely try a Wenzel, you can pick them up pretty cheap. There are no phase noise specs available but they are usually SC-cut based OCXO's with their own internal shunt reg PS. They may be a real benefit for these Sabre DAC's for not too much money.
Terry
The ICS542 looks about the only option that is worth it with this clock, as you say itll be better to buy new clock instead of the others options.
I managed to grasp that ''lower phase noise'' is a only a technical truth, phase noise scales down when the frequency is divided but nothing has improved, the impact of jitter on what you hear would be the same.
a lower frequency version of same clock should still have lower jitter and lower phase noise than divided clock.
I managed to grasp that ''lower phase noise'' is a only a technical truth, phase noise scales down when the frequency is divided but nothing has improved, the impact of jitter on what you hear would be the same.
a lower frequency version of same clock should still have lower jitter and lower phase noise than divided clock.
the theory was that low ppm clocks have little benefit for audio, and OCXO in particular have high amounts of jitter due to their design.
What sort of benefits do you mean?
Its an interesting suggestion, to hear how one of these ultra low ppm clock effect the sound,.
laserscrape,
Not quite on the clocks. True that phase noise (jitter) is the most important thing for audio, and OXCOs are primarily more for longer term frequency accuracy than we care about for jitter, but at least a few SC-cut OCXOs have very good phase noise too. Just depends.
However, I don't recall seeing any OCXOs that have significantly lower jitter at 10Hz or 1Hz offset than the typical ultra-low jitter dac clocks we use. Seems like OCXOs are usually are worse for jitter.
By the way, Wenzel has a website with specs on their clocks: 1 MHz to 25 MHz |
Didn't find it all that interesting myself.
Not quite on the clocks. True that phase noise (jitter) is the most important thing for audio, and OXCOs are primarily more for longer term frequency accuracy than we care about for jitter, but at least a few SC-cut OCXOs have very good phase noise too. Just depends.
However, I don't recall seeing any OCXOs that have significantly lower jitter at 10Hz or 1Hz offset than the typical ultra-low jitter dac clocks we use. Seems like OCXOs are usually are worse for jitter.
By the way, Wenzel has a website with specs on their clocks: 1 MHz to 25 MHz |
Didn't find it all that interesting myself.
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WRT not that interesting, that doesn't suprise me. It's not quite as simple as you might think. Wenzel have been making some of the best clocks available for many years but it's not just a case of reading some published phase noise plot.
SC cut crystals have some fundamental (no pun) advantages such that when it comes to ultimate phase noise performance, they will be used.
Also there is always a trade off between LF phase noise and HF noise floor.
Then there is the general trade off that as you move away from 5 - 10MHz,
the phase noise will suffer, even taking freq into account.
It's getting a bit beyond this threads discussion but for lowest 1 to 10Hz
phase noise, it will be a special type of SC cut, OCXO with a super low spec
Allan Variance over 1 sec. If you want this performance at 100MHz, then they will use a multiplier or phase lock the 100MHz clock to a 10MHz one.
A few years ago I had batches of 11.2896 OCXO's made for CD player upgrades. The supplier was not able to achieve the spec using AT cut crystals, so they were SC. I was focusing mainly on LF 10Hz phase noise.
Interestingly they all sounded a bit different and It is worth noting that one parameter that varied was Allan Deviation (Variance). Also some had more spurs than others.
When you buy a Crystek clock, you are hoping that they all meet spec but from people I've spoken to that measure them, that is not necessarily the case.
I haven't had too much direct experience with 100MHz clocks but there has been a bit of discussion by people that tried quite a few including SC cut OCXO's and the general concencus was despite their sometimes seemingly poorer specs, they generally sounded better.
This may be due to a few things including fewer spurs, lower G sensitivity,
the fact that SC cut has much higher Q - I'm not sure....
So considering the price of these OCXO's on ebay, it's worth a try just to see.
That's my 10c worth... well. more like a dollar
T
