Just a further elaboration on above.
The correct resistor combo for 12v on a TL431 regulator would be 3K9 and 1K, for a 12.25v output.
A 3-pin regulator could replace easily the series resistor and the zener in powering the LM318.
The correct resistor combo for 12v on a TL431 regulator would be 3K9 and 1K, for a 12.25v output.
A 3-pin regulator could replace easily the series resistor and the zener in powering the LM318.
Again, I think that it's not exactly so...
What disturbed Mauro was that who proposed changes didn't do any calculation or fully understood the circuit, dispensing 'best practices' that could not apply to his design.
One example are the PS bypasses to ground, which are detrimental to sound in the Myref because they disrupt the floating ground.
Sorry, no.
But probably some opamps works without any mod.
I wouldn't be so sure, Mauro tried LM78xx and found them worse... Zeners are not so bad, poor PSSR but nice impedance.
TL431, Capacitance Multiplier, Salas Shunt should be better.
Thanks for the calculator!
I'll do some tests in the next months...
PS
Voltage should not exceed 12V because it can trigger SPIKE protection.
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I don't remember things too well: it was many years ago. What bypasses are you talking about?
The main things I remember are the regulators for the LM318, and the LM318 itself.
Why would exceeding 12v trigger the Spike on the LM3886?
The main things I remember are the regulators for the LM318, and the LM318 itself.
Why would exceeding 12v trigger the Spike on the LM3886?
In the original design no PS bypasses to ground was present.
In the TP version those bypasses were added by request of forumers.
When two years ago I started experimenting I've tried to remove them as per original design and the improvement was not subtle.
Rudy was one of the modders and tried higher voltage Zeners reporting good results but Mauro pointed out that doing so could trigger Spike protection (accordind to his calculations and experiments).
Initially Rudy changed LM318 PS with LM78xx reporting improvements but afterwards it went back to Zeners.
Awesome discussions going on again. Such a good circuit. It deserves to be revisited. The nice thing about one big massive thread is that it can be followed by all the subscribers. Obviously there are drawbacks. An input discussion might be a good thing.
My experience says that Dario is right but I dont think he knows why and Andrew was right on the money.
The smt passive probably sounds better because it is at an Rtot that sounds best with Dario's set up. There is NOT a magic Rtot for the MyREFC but there IS a magic Rtot for each system.
Dario, what you want to do is find ways to mess with the Rtot of the Lightspeed or if you have my Lighter Note ( I forget which you have) then you can adjust it even while its playing by following step 19 of my manual.
If you have the Lightspeed you can increase the current limiting resistors and increase the voltage and you will have a lower Rtot which to me usually sounds best. However if your source cant drive it it will sound terrible. So if you have a very low source output impedance then you can use a huge range of resistances on the Lightspeed as long as you find a way to control Rtot. If you want to increase the Rtot then lower voltage OR put a 10R trimmer after the LM317 but before the volume pot OR put a 100k trimmer from before or after the volume pot and have it act as a variable resistor from 5V to 0V. Careful not to go to low in resistance on it or it will burn but anyway, what you want to do to increase Rtot is to find a way to suck a tiny amount of power away from the LEDs so that when they hit higher resistances (this is when they suck only a tiny amount of power) then the resistor to ground (0V ) will actually play a large part in forcing resistance higher.
Higher voltage otherwise, if you want lower Rtot.
So if that smt attenuator sounds great then maybe this is a good Rtot to shoot for to do a comparison. The LDRs will not stay on that Rtot exactly. Their resistance curve will look like a smile but you can get in the vicinity and then do a comparison.
I have never had an LED die as a result of static electricity. Have you been walking around in fluffy slippers while rubbing your cat on the carpet again?! 🙂
Someone asked about sources. I suggest Audio-GD DACS if you can afford one. Best value I have ever found in a commercial DAC. Absolutely amazing.
I use JRiver as a server program on my computer. I enjoy it quite a lot and for Windows its the best full fledged program. If you want a very simple program you can control with your Android phone try VLC media player. Even more simple but a bit buggy is Stealth Audio Player. They all sound great. JRiver is the only one thats not free but at 50usd its a real good deal and they continue to improve it. Please at least download if for a month. Its got some wonderful features.
I wonder how wonderful things could get if we were to power the LM318 with the JLH Ripple Eater!
Uriah
My experience says that Dario is right but I dont think he knows why and Andrew was right on the money.
The smt passive probably sounds better because it is at an Rtot that sounds best with Dario's set up. There is NOT a magic Rtot for the MyREFC but there IS a magic Rtot for each system.
Dario, what you want to do is find ways to mess with the Rtot of the Lightspeed or if you have my Lighter Note ( I forget which you have) then you can adjust it even while its playing by following step 19 of my manual.
If you have the Lightspeed you can increase the current limiting resistors and increase the voltage and you will have a lower Rtot which to me usually sounds best. However if your source cant drive it it will sound terrible. So if you have a very low source output impedance then you can use a huge range of resistances on the Lightspeed as long as you find a way to control Rtot. If you want to increase the Rtot then lower voltage OR put a 10R trimmer after the LM317 but before the volume pot OR put a 100k trimmer from before or after the volume pot and have it act as a variable resistor from 5V to 0V. Careful not to go to low in resistance on it or it will burn but anyway, what you want to do to increase Rtot is to find a way to suck a tiny amount of power away from the LEDs so that when they hit higher resistances (this is when they suck only a tiny amount of power) then the resistor to ground (0V ) will actually play a large part in forcing resistance higher.
Higher voltage otherwise, if you want lower Rtot.
So if that smt attenuator sounds great then maybe this is a good Rtot to shoot for to do a comparison. The LDRs will not stay on that Rtot exactly. Their resistance curve will look like a smile but you can get in the vicinity and then do a comparison.
I have never had an LED die as a result of static electricity. Have you been walking around in fluffy slippers while rubbing your cat on the carpet again?! 🙂
Someone asked about sources. I suggest Audio-GD DACS if you can afford one. Best value I have ever found in a commercial DAC. Absolutely amazing.
I use JRiver as a server program on my computer. I enjoy it quite a lot and for Windows its the best full fledged program. If you want a very simple program you can control with your Android phone try VLC media player. Even more simple but a bit buggy is Stealth Audio Player. They all sound great. JRiver is the only one thats not free but at 50usd its a real good deal and they continue to improve it. Please at least download if for a month. Its got some wonderful features.
I wonder how wonderful things could get if we were to power the LM318 with the JLH Ripple Eater!
Uriah
I think you're right... 😀
Rtot is the pot resistance? If so mine was 10K.
I've the version you sold with MyRefC boards and kits.
Manual? Which manual? I've missed it!
In fact I wasn't able to perfectly balance it...
When the LS burnt I was trimming the series bal trimmer, then I've touched with the screwdriver one of the leads, static, now only one channel sounds (left) but at full volume.
Is also dead the same channel on the DCB1... 🙁
I've measured resistance between GND and output of the LS in one channel is ok, the other show 0 Ohm...
You caught me... 😀
No, I was sitting on my sofa, which is acrylic...
Well, the forum looks very odd on my computer right now. Having trouble with it so maybe the computer didnt load everything, but the text is there.
Dario, well there is a first for everything. You must be right about why it died.
Yes, then you will like the Rtot of 10k on the LS. There is a manual for the LS but there is no description of how to mess with Rtot. The LN has that.
If you build a LS again I will walk you through some ways to mess with Rtot. Rtot is the total resistance of the pot, measured from the left terminal to the right, skipping the middle(wiper).
Uriah
Dario, well there is a first for everything. You must be right about why it died.
Yes, then you will like the Rtot of 10k on the LS. There is a manual for the LS but there is no description of how to mess with Rtot. The LN has that.
If you build a LS again I will walk you through some ways to mess with Rtot. Rtot is the total resistance of the pot, measured from the left terminal to the right, skipping the middle(wiper).
Uriah
Hi Uriah,
I looked at the Audio-DG DACs and note the prices range from $399 to $2025. How far up the ladder do you have to go to get the best bang for the buck?
Also, let me add "Gold Wave" to the list of exceptional media players. It has almost all the features of big boy pro audio programs like Soundforge and the Steinberg offerings. Out of the box it has the warmest sound of those I have used. The EQ and editing features are first rate.
Bob M.
I looked at the Audio-DG DACs and note the prices range from $399 to $2025. How far up the ladder do you have to go to get the best bang for the buck?
Also, let me add "Gold Wave" to the list of exceptional media players. It has almost all the features of big boy pro audio programs like Soundforge and the Steinberg offerings. Out of the box it has the warmest sound of those I have used. The EQ and editing features are first rate.
Bob M.
I have RE5 and RE7 at a price of 1k and 1k7. They use the PCM1704 chips which I prefer to the Sabre32 which I have ONLY heard at RMAF so take it with a grain of salt but these DACs seem to me to outperform the Sabre implementations I heard. Head-Fi.org has lots of Audio-GD fans and so lots of information but they are really really argumentative folks so you may want to just browse the information. A great review is found here Audio-gd Reference 5 ~ A PCM1704UK-based DAC with DSP seattleite
I will check out Gold Wave.
I apologize for OT stuff.
HERE IS A NEW THREAD about experimenting with surrounding equipment
http://www.diyaudio.com/forums/chip...touched-sources-experimented.html#post2588988
I will check out Gold Wave.
I apologize for OT stuff.
HERE IS A NEW THREAD about experimenting with surrounding equipment
http://www.diyaudio.com/forums/chip...touched-sources-experimented.html#post2588988
I spoke to Stanton from Jim's Audio about the Buffalo II before I bought the unit I mentioned above. He has several friends in his group who have the Buffalo and they are all disappointed. Not so much with the unit itself but with all the extras and tweaking needed to connect and configure it. Stanton has one himself but hasn't been enthused enough to implement it. I understand he is a DAC seller but he sounded honest in his opinion.
Just passing on what I was told.
Just passing on what I was told.
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The problem is that the 470k gain-limiting resistor is between the output and the compensation pin of the LM318. If you substitute the LM318 with an internally-compensated opamp (without the comp pin), some other way to limit the gain has to be found. Without it, most opamps seem to latch-up low (in LTSpice simulations) e.g. almost all LT single opamps, LME49710, OPA134, etc. LT1028 is unstable, i.e. oscillates.
The only one that even works in the simulation is:
LT318A (with C10 reduced from 22p to 3.3p)
Perhaps NE5534 will work, but I don't have a reliable LTSpice model of it, and it's slower and has lower slew-rate than the LM318 at any rate.
Never say never... if LinuxGuru or others find a universal compensation network...
The real question is that you need a fast and very stable chip for that place, and it has to be musical at the same time. The 318 was used on one of the first DAC mods in The Audio Amateur that was different from anything being done elsewhere.
The 5534 is another chip that is also very nice to the ear, and the reason why it was everywhere in high quality professional mixing desks. But it's not fast enough I think.
Did you try the AD825 on that LTSpice simulation?
The 5534 is another chip that is also very nice to the ear, and the reason why it was everywhere in high quality professional mixing desks. But it's not fast enough I think.
Did you try the AD825 on that LTSpice simulation?
Just downloaded and tried the AD825 5V model from Analog Devices - it is stable with C10 in the range of ~2.2..6.8 pF, doesn't latch up but oscillates for higher values of C10. Caveat: I'm using an LM1875 model for the Howland current pump for these simulations, so it's just an approximation. However, odd-harmonic distortion seems to dominate.
OTOH, OPA134 is almost stable even with C10=22pF and THD20 FFT spectrum looks nicer, with H2 dominating.
I think the chip better be a fast one, with high slew-rate. The 318 is 50V/µs, the 825 is 125V/µs.
Not good going for expensive chips either, or difficult to get. We would be buying a problem. Same reason for picking a DIP chip and not a SOIC.
Not good going for expensive chips either, or difficult to get. We would be buying a problem. Same reason for picking a DIP chip and not a SOIC.
OPA627 and 827 look stable in the sim with C10 in the range 2.2pF..10pF. OPA1611 seems impossible to stabilize with any reasonable value of C10. The THD20 FFT spectrum of the OPA627 looks the nicest, with H2, H3, H5 and H7. OPA827 shows only H3, H5 and H7, like the AD825.
An opamp with better sonics than the LM318 in this application, which is stable, relatively easy to obtain and not too expensive, seems to be elusive. The initial experimenters with the Rev C must have rolled a few opamps and come to the same conclusion.
The OPA134 seems to be the closest, but may not be stable as a drop-in replacement.
An opamp with better sonics than the LM318 in this application, which is stable, relatively easy to obtain and not too expensive, seems to be elusive. The initial experimenters with the Rev C must have rolled a few opamps and come to the same conclusion.
The OPA134 seems to be the closest, but may not be stable as a drop-in replacement.
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