Hi EC,
Always like to read about your adventures. I am still flabbergasted by the time you put in all this. Thanks for sharing also !
One comment from my side, I still object (remember I did before when you said the previous setup sounded like a transistor radio ?) to the way you report back on your modifications. Whenever you like what you do it is "major and spectacular". If you don't like it it is "sooooo bad...."
I would call for some modesty here. Doing this stuff (not as fast as you
) for more than 30 years, I know what impact tweaks like you do have and they can be absolutely worthwhile, you never want to go back, but they are NEVER so extreme
One other remark, since when are you chasing 0,0000000x% distoration rates ? I thought we left this behind in the eighties... Ever measured your speaker distortion when you are running some serious soundlevel ??? You know there is more than THD...
The thermal memeory thing you brought up recently was the best thing since sliced bread and more important than jitter, now it is dead. That is what I mean above. No hard feelings, just my observation and opinion.....
My 2 cents; Stay focuessed on the great things you do and keep it low key
doede
Always like to read about your adventures. I am still flabbergasted by the time you put in all this. Thanks for sharing also !
One comment from my side, I still object (remember I did before when you said the previous setup sounded like a transistor radio ?) to the way you report back on your modifications. Whenever you like what you do it is "major and spectacular". If you don't like it it is "sooooo bad...."
I would call for some modesty here. Doing this stuff (not as fast as you
) for more than 30 years, I know what impact tweaks like you do have and they can be absolutely worthwhile, you never want to go back, but they are NEVER so extreme One other remark, since when are you chasing 0,0000000x% distoration rates ? I thought we left this behind in the eighties... Ever measured your speaker distortion when you are running some serious soundlevel ??? You know there is more than THD...
The thermal memeory thing you brought up recently was the best thing since sliced bread and more important than jitter, now it is dead. That is what I mean above. No hard feelings, just my observation and opinion.....
My 2 cents; Stay focuessed on the great things you do and keep it low key
doede
dddac said:
Hi doede,
i must say some old tube radios sound fantastic, but it is not question of details, soundstage.... They can sounds natural, musical, live, hard to forget that sound.
Maybe John was thinking in that way.
Yes, Johns posts are really nice adventure. I am enjoying very much.
Since i will get that low jitter 48Mhz oscillator and few parts from Farnell, i will find out how DI-16 perform really and share my sound experience with it.
regards
coupling caps
Hello EC
For a reasonable while ago i posted also some mod results from my tube pre coupling cap upgrade. I bought some adyn cap plus 6.8uF to replace the standard audyn caps 10uF. I removed the plus, treble boost even with the plus caps. I figured out i don't like "series wounded" caps because a black gate NX test resulted in a terrible sound also, bypass of opamps cdp. I thought my cdp is playing a stereo cd, it sounded allmost mono, that bad with NX.
To me nothing can beat (NOS) paper in oil caps for coupling, for decoupling MKP (and simple low esr lytic) is fine. When no PIO available (testing equipment) In my personal taste MKC is rather good too, better then MKP.
http://www.fust-electronica.nl/ had some nice comparison-info in caps, but i couln not get on the site, maybe later on.
This nice chap Tony Gee has tested some regarded make caps also(good test):
http://www.humblehomemadehifi.com/Cap.html
Hello EC
For a reasonable while ago i posted also some mod results from my tube pre coupling cap upgrade. I bought some adyn cap plus 6.8uF to replace the standard audyn caps 10uF. I removed the plus, treble boost even with the plus caps. I figured out i don't like "series wounded" caps because a black gate NX test resulted in a terrible sound also, bypass of opamps cdp. I thought my cdp is playing a stereo cd, it sounded allmost mono, that bad with NX.
To me nothing can beat (NOS) paper in oil caps for coupling, for decoupling MKP (and simple low esr lytic) is fine. When no PIO available (testing equipment) In my personal taste MKC is rather good too, better then MKP.
http://www.fust-electronica.nl/ had some nice comparison-info in caps, but i couln not get on the site, maybe later on.
This nice chap Tony Gee has tested some regarded make caps also(good test):
http://www.humblehomemadehifi.com/Cap.html
dddac said:Hi EC,
One other remark, since when are you chasing 0,0000000x% distoration rates ? I thought we left this behind in the eighties... Ever measured your speaker distortion when you are running some serious soundlevel ??? You know there is more than THD...
My 2 cents; Stay focuessed on the great things you do and keep it low key
doede
Yes ECdesign is allways digging deep in the subject, nothing misses his attention.
I must agree with ECdesigns, about low distorsion figures, even it sounds like a 80's solution, this low dist. fig. story has become more important for me also. But in the 8ties they where aiming on the wrong, they achieved it with more, more and even more feedback, wich created an other sort of distorsion.
Hi DDDAC,
These are not adventures, but a systematic approach to achieve realistic (live) sound quality with an audio set.
I am not a robot (yet), so there are rare occasions where I might even show traces of enthusiasm, especially when the many hours invested in a project finally start to show some very promising results. In the same way I can sometimes get pretty frustrated when I loose a lot of time and money testing bad components, then taking everything apart and revert to the original situation, and start from scratch.
If you mention that improvements are usually not that spectacular, I can only comment that this depends on the characteristics of the audio set. If you hear a 3D soundstage opening-up, flooded with details, it's impressive enough to call it spectacular.
I am a modest guy, just reporting about my experiments here. But I also intend to back-up my claims, it's no use claiming something without proof. If all goes well, I will demonstrate my set in Brussles Belgium (HiFi 2007 show) next weekend. You are very welcome to come over and listen.
If you stick to a "safe" traditional approach, based on common knowledge of High-End audio, tweaks are likely not to be that spectacular.
I am trying to approach live sound as closely as possible, vanishing low THD helps, among other things like excellent phase, and transient response. I do realize very well that THD doesn't tell everything. That's why I spend so many hours listening, modding, and figuring out why one mod works well, and the other doesn't.
When a speaker distorts, it usually colours the sound significantly when turning up the volume. I don't use plain speakers but sonic resonators, they have a real-time correction system that prevents distortion increase at higher volume levels among other things.
About serious sound levels, during a demonstration last Monday I ran the set at approx 2 * 50W rms, with peaks of 80W rms. We listened to drum solo's and symphony orchestra recordings, the dynamic peaks were almost frightening. During a few music fragments, I got doubts if the sonic resonator structure would hold. The dynamic peaks were that extreme, and I wasn't even running the set at maximum power. During the whole listening test, regardless of volume, the sound remained absolutely transparent and natural.
Well in fact it's not dead at all, the circuit I removed from the power amplifier didn't perform optimally, as it reduced dynamics, among other things, it doesn't mean I simply abandon the thermal memory problem.
Remember the mixed-mode output? tubes have no thermal memory, so by running both tube OP-amp and semiconductor OP-amp in parallel, I basically reduce the effects of thermal memory.
I already started using resistors with very low temperature coefficient, in order to tackle thermal memory problems in the power amplifiers and attenuators. The effect is clearly audible (more detail, more liquid sound). The fully balanced setup, and the cascode circuits already tackle thermal memory problems too.
I look at it this way, the music flows through the audio set from source to acoustical sound waves. If there is a bottleneck anywhere in the system, it will prevent you from achieving ultimate performance. Mods will only have minor effect. When you fix one obstacle, the next will appear for sure, remove that and the next will appear. On a certain moment the audio signal starts to flow freely through the audio system (you notice this as the music reproduction starts to appear effortless, 3D sound stage starts to open up, and the sound gets very detailed and liquid). Then you can start worrying about smaller details. It's no use focussing on details while having major obstacles in the signal path.
These are not adventures, but a systematic approach to achieve realistic (live) sound quality with an audio set.
I am not a robot (yet), so there are rare occasions where I might even show traces of enthusiasm, especially when the many hours invested in a project finally start to show some very promising results. In the same way I can sometimes get pretty frustrated when I loose a lot of time and money testing bad components, then taking everything apart and revert to the original situation, and start from scratch.
If you mention that improvements are usually not that spectacular, I can only comment that this depends on the characteristics of the audio set. If you hear a 3D soundstage opening-up, flooded with details, it's impressive enough to call it spectacular.
I am a modest guy, just reporting about my experiments here. But I also intend to back-up my claims, it's no use claiming something without proof. If all goes well, I will demonstrate my set in Brussles Belgium (HiFi 2007 show) next weekend. You are very welcome to come over and listen.
If you stick to a "safe" traditional approach, based on common knowledge of High-End audio, tweaks are likely not to be that spectacular.
I am trying to approach live sound as closely as possible, vanishing low THD helps, among other things like excellent phase, and transient response. I do realize very well that THD doesn't tell everything. That's why I spend so many hours listening, modding, and figuring out why one mod works well, and the other doesn't.
When a speaker distorts, it usually colours the sound significantly when turning up the volume. I don't use plain speakers but sonic resonators, they have a real-time correction system that prevents distortion increase at higher volume levels among other things.
About serious sound levels, during a demonstration last Monday I ran the set at approx 2 * 50W rms, with peaks of 80W rms. We listened to drum solo's and symphony orchestra recordings, the dynamic peaks were almost frightening. During a few music fragments, I got doubts if the sonic resonator structure would hold. The dynamic peaks were that extreme, and I wasn't even running the set at maximum power. During the whole listening test, regardless of volume, the sound remained absolutely transparent and natural.
Well in fact it's not dead at all, the circuit I removed from the power amplifier didn't perform optimally, as it reduced dynamics, among other things, it doesn't mean I simply abandon the thermal memory problem.
Remember the mixed-mode output? tubes have no thermal memory, so by running both tube OP-amp and semiconductor OP-amp in parallel, I basically reduce the effects of thermal memory.
I already started using resistors with very low temperature coefficient, in order to tackle thermal memory problems in the power amplifiers and attenuators. The effect is clearly audible (more detail, more liquid sound). The fully balanced setup, and the cascode circuits already tackle thermal memory problems too.
I look at it this way, the music flows through the audio set from source to acoustical sound waves. If there is a bottleneck anywhere in the system, it will prevent you from achieving ultimate performance. Mods will only have minor effect. When you fix one obstacle, the next will appear for sure, remove that and the next will appear. On a certain moment the audio signal starts to flow freely through the audio system (you notice this as the music reproduction starts to appear effortless, 3D sound stage starts to open up, and the sound gets very detailed and liquid). Then you can start worrying about smaller details. It's no use focussing on details while having major obstacles in the signal path.
Hi Bernhard
I tried Oxford Electrical Products Ltd 22R154C 6.3 + 6.3 : 1 + 1, 30 Hz...30KHz +/- 1% THD
Most transformers are unsuitable to handle the full-scale DI 8 core output current of 32mA, they are specifically designed for single or twin current output stages, and would go into saturation.
Configuration 1:
transformer secondary connected to both active I/V stages, transformer acted as differential to single-ended converter, and attenuator. 25mV output compliance is met
Configuration 2:
transformer primary connected to both DAC groups, I/V resistor on the primary. 25mV output compliance is violated.
Configuration 3:
transformer primary connected to both DAC groups, I/V resistor connected on the secondary (adapted to transformation factor). 25mV output compliance is violated.
I tried Oxford Electrical Products Ltd 22R154C 6.3 + 6.3 : 1 + 1, 30 Hz...30KHz +/- 1% THD
Most transformers are unsuitable to handle the full-scale DI 8 core output current of 32mA, they are specifically designed for single or twin current output stages, and would go into saturation.
Configuration 1:
transformer secondary connected to both active I/V stages, transformer acted as differential to single-ended converter, and attenuator. 25mV output compliance is met
Configuration 2:
transformer primary connected to both DAC groups, I/V resistor on the primary. 25mV output compliance is violated.
Configuration 3:
transformer primary connected to both DAC groups, I/V resistor connected on the secondary (adapted to transformation factor). 25mV output compliance is violated.
Hi EC,
I'm glad that you will share your system on a more massive way.
It is kind of boring to speak only between us about the sound of DI16...
From my part, I can say that real life is still showing its ugly face around here...mid-September I will have a small vacation. Perhaps then I will be able to finish the DI8*4 TDA1543 DAC (IF the 100nF caps are kind enough to arrive ) and also play with my horn project.
So my PRP resistors are "100ppm" and Riken are "700ppm"
Well, all I can say is that, when our system is not ideal a "good coloration" makes things interesting sometimes...what would you prefer in the morning, Cindy Crawford with or without make-up?
I'm kidding...
I am using now "Vishay" Draloric at 20cents/each (partsconnexion.com)
The sad part is that some of us are sensitive to cables
In order to avoid bankruptcy I began also my own experiments with interconnects and power cables. I share your feeling that screening, though technically correct, takes some of the life of the music away.
My favorite material so far is OCC copper (Ohno continuous cast copper) which combines the transparency of silver and the warmth of copper, IMHO. I only use what I can source, solid core cable:
I am burning-in an interconnect formed with 4 strand of solid, enameled 26AWG OCCC braided, for each polarity (8 strands total only because I don't have more). This is the exact wire that forms Stevens & Billington's attenuation transformers. It sounds very, very detailed but lacking midbass yet.
The power cable is also solid OCCC, 3 leads, braided, 14AWG. Again, very fast and detailed cable but takes looong to burn-in. Cost is +/- US$1.1/foot. There is a multistrand fat OCCC wire but it costs +/-20 times more!
These are cheap experiments and I exhort the people that don't believe in those things to try them against plain vanilla fat copper cable. I'm not saying it's better (which I think) but different.
(End OT)
About class A bias, you increased current to 3.3mA...can I try a current regulator diode instead...or maybe a 4K5 resistor. I'm still no good with discretes
(or maybe you can post a drawing)
Thanks for the link!
Bye,
M
I'm glad that you will share your system on a more massive way.
It is kind of boring to speak only between us about the sound of DI16...
From my part, I can say that real life is still showing its ugly face around here...mid-September I will have a small vacation. Perhaps then I will be able to finish the DI8*4 TDA1543 DAC (IF the 100nF caps are kind enough to arrive
) and also play with my horn project.So my PRP resistors are "100ppm" and Riken are "700ppm"
Well, all I can say is that, when our system is not ideal a "good coloration" makes things interesting sometimes...what would you prefer in the morning, Cindy Crawford with or without make-up?
I'm kidding...I am using now "Vishay" Draloric at 20cents/each (partsconnexion.com)
The sad part is that some of us are sensitive to cables
In order to avoid bankruptcy I began also my own experiments with interconnects and power cables. I share your feeling that screening, though technically correct, takes some of the life of the music away.
My favorite material so far is OCC copper (Ohno continuous cast copper) which combines the transparency of silver and the warmth of copper, IMHO. I only use what I can source, solid core cable:
I am burning-in an interconnect formed with 4 strand of solid, enameled 26AWG OCCC braided, for each polarity (8 strands total only because I don't have more). This is the exact wire that forms Stevens & Billington's attenuation transformers. It sounds very, very detailed but lacking midbass yet.
The power cable is also solid OCCC, 3 leads, braided, 14AWG. Again, very fast and detailed cable but takes looong to burn-in. Cost is +/- US$1.1/foot. There is a multistrand fat OCCC wire but it costs +/-20 times more!
These are cheap experiments and I exhort the people that don't believe in those things to try them against plain vanilla fat copper cable. I'm not saying it's better (which I think) but different.
(End OT)
About class A bias, you increased current to 3.3mA...can I try a current regulator diode instead...or maybe a 4K5 resistor. I'm still no good with discretes
(or maybe you can post a drawing)Thanks for the link!
Bye,
M
-ecdesigns- said:
A properly implemented transformer I-V, with the right
transformer will have less distortion than the tube part of your
OP stage <0.01% over a large part of the freq range and
=<0.001 above a few hundered Hz.
It can be configured for any amount of DAC OP swing, and
provided the DC dac OP bias is compensated for will not result
in any core saturation. The 32mA dac OP just means that the I-V
resistor must be of very low value. This is in fact a good thing for
transformer linearity.
The only problem is - if all these parameters are met there is no
way you can get enough OP level from a transformer alone as
ultra high ratio transformers are out.
So in the end, an active stage will be required to further boost
the voltage level so - why use a transformer anyway?
There are some instances that could be worth trying - a) using
the transformer in a fully differential balanced active circuit where
the transformer secondary is common mode servoed to allow
a DC coupled circuit following it. b) Using a transformer
followed by a fully differential tube stage of low gain to allow
better linearity than the tube stage alone. c) using (b) config
and bringing transformer secondary some point say -100V or so
to allow direct coupling of OP. This would also require servos to
adjust the tube OP's.
These are all costly and complicated.
You could of course just use a transformer and 2 opamps for a
fully balanced OP. The transformer will do wonders for filtering
RF from IP of opamps.
In all cases the most appropriate transformer would be a moving
coil type and these, of the brands mentioned, are very expensive.
cheers
Terry
Terry Demol said:
With transformer and 500 ohm I/V on primary I did not have any harmonics down to -94 dB @ 1 kHz.
Terry Demol said:
I think a 1 + 1 : 2 used to convert from balanced to single ended is a good thing.
In balanced you can get away with half of the resulting voltage on the DAC, compared to using only one DAC in single ended.
Bernhard said:
Hi Bernard
I think this 1:12 Jensen moving coil is about as good as it gets
for low level low impedance.
http://www.jensen-transformers.com/datashts/346ax112.pdf
<0.001% from just a few hundred Hz.
Very expensive though.
cheers
Terry
Bernhard said:
If there runs no current through the primary (signal current), how would you get an output at the secundary ?
If you run a 1:12 every secundary load will be seen as an I/V "resistor" 144 time smaller. So a 47k Volumepot wil do 326 Ohm load primary. For sure there will run current !
Battery power for the DI 8?
EC, have you ever considered doing away with AC and go with battery power? I've heard battery powered DAC and preamp, and the ambient noise is vanishingly low compared to most AC powered gear. I've been saving up for the fully built DI 8 DAC - getting close but not quite there yet. If battery power can be easily implemented, may be in a separate box with automatic recharging when the unit is off, it would really improve the sound, me thinks.
EC, have you ever considered doing away with AC and go with battery power? I've heard battery powered DAC and preamp, and the ambient noise is vanishingly low compared to most AC powered gear. I've been saving up for the fully built DI 8 DAC - getting close but not quite there yet. If battery power can be easily implemented, may be in a separate box with automatic recharging when the unit is off, it would really improve the sound, me thinks.
Battery power
Hi Chris, I've heard that said by some also, but my experience tells me battery sounds better. Besides, I live in a major city were AC line noise becomes a significant problem - I get noticeably better sound late night than during the day when energy demand is high in this hot humid city.
Hi Chris, I've heard that said by some also, but my experience tells me battery sounds better. Besides, I live in a major city were AC line noise becomes a significant problem - I get noticeably better sound late night than during the day when energy demand is high in this hot humid city.
Hi MGH,
Well, both an AC supply and a battery supply require regulation and noise removal to be at their best. So either way you need to do some work. The issue of battery purchase, replacement and disposal is a bother and harmful to our environment. For myself, I'd sidestep that one. Charging a battery set is not efficient either.
The reason you thought the battery one was better sounding was probably due to a number of factors. Different circuits for one. Poor power supply design for another. The more you know, the less capacitance over the minimum you will use.
-Chris
Well, both an AC supply and a battery supply require regulation and noise removal to be at their best. So either way you need to do some work. The issue of battery purchase, replacement and disposal is a bother and harmful to our environment. For myself, I'd sidestep that one. Charging a battery set is not efficient either.
The reason you thought the battery one was better sounding was probably due to a number of factors. Different circuits for one. Poor power supply design for another. The more you know, the less capacitance over the minimum you will use.
-Chris