Bigger Not Better?
Hi
Yesterday I decided to try out the big K75-10 10uf Russian PIOs for output coupling. These are big and heavy caps (please see earlier post). As I had solder some screw connectors onto the board to facilitate cap rolling (ha ha), this was a very easy exercise.
I feel the DAC sounds a little different. For starters, it was not as forward as the KBGs. I think this is good, at least for vocals. Bass was about the same. Not much to sing about, so far.
However, I felt the most significant improvement was in the mids. It was even more refined and the presentation was sweeter, clearer and more lifelike. I think this cap is very easy on the ear, even on extended listening sessions.
I like what heard and I will definitely keep this on, at least for now.
How to fit this all into the case is another matter...
Ah well, you win some you lose some … and who says you need a case!!!
Thanks for reading …..
Best wishes
TC
Hi
Yesterday I decided to try out the big K75-10 10uf Russian PIOs for output coupling. These are big and heavy caps (please see earlier post). As I had solder some screw connectors onto the board to facilitate cap rolling (ha ha), this was a very easy exercise.
I feel the DAC sounds a little different. For starters, it was not as forward as the KBGs. I think this is good, at least for vocals. Bass was about the same. Not much to sing about, so far.
However, I felt the most significant improvement was in the mids. It was even more refined and the presentation was sweeter, clearer and more lifelike. I think this cap is very easy on the ear, even on extended listening sessions.
I like what heard and I will definitely keep this on, at least for now.
How to fit this all into the case is another matter...
Ah well, you win some you lose some … and who says you need a case!!!
Thanks for reading …..
Best wishes
TC
Hi Chris
I think therein lies the problem. Its not easy to find good ones at a reasonable price. I think (and I may be wrong) the best in-production mechanism is the Philips CD Pro. However, the top loading feature will not work for me as it needs to be placed into a middle shelf in the components rack!
Hmm... I guess I must be lucky as I have not had any problems with my Sony. In fact, it has been very faithful, other than for normal wear and tear (tray loading belt). The Sony is built like a tank and I particularly like the rubber sealing when the tray shuts. It is supposed to prevent stray light from affecting the laser pickup operations.
I stopped using the on board DAC long time ago as I felt that although it was sweet (I think it has a TDA1541A but not sure if crowned or not) it was not the ultimate in transparency and detail.
Is your DSD-S10 stock?
One thing is for sure, the CD format is a dying media. I think it is kept on life support now largely due to its large installed base.
I think Sendler is 100% right, media players are the way to go .... 24bit by 96Khz.... I don't think any CD player can beat FLAC files in detail, transparency and dynamic range and hence musicality. That was why I got a DAC capable of playing these flies.
I think CDs will be like those vinyls I used to cherish, played on a Thorens turntable using a SME 9 series ‘S’ arm sporting a Shure MM Cartridge!! Wow .. talking about a blast from the past!!!!!
That is progress, I guess .....
Have a good day!
Best wishes
TC
I think therein lies the problem. Its not easy to find good ones at a reasonable price. I think (and I may be wrong) the best in-production mechanism is the Philips CD Pro. However, the top loading feature will not work for me as it needs to be placed into a middle shelf in the components rack!
Hmm... I guess I must be lucky as I have not had any problems with my Sony. In fact, it has been very faithful, other than for normal wear and tear (tray loading belt). The Sony is built like a tank and I particularly like the rubber sealing when the tray shuts. It is supposed to prevent stray light from affecting the laser pickup operations.
I stopped using the on board DAC long time ago as I felt that although it was sweet (I think it has a TDA1541A but not sure if crowned or not) it was not the ultimate in transparency and detail.
Is your DSD-S10 stock?
One thing is for sure, the CD format is a dying media. I think it is kept on life support now largely due to its large installed base.
I think Sendler is 100% right, media players are the way to go .... 24bit by 96Khz.... I don't think any CD player can beat FLAC files in detail, transparency and dynamic range and hence musicality. That was why I got a DAC capable of playing these flies.
I think CDs will be like those vinyls I used to cherish, played on a Thorens turntable using a SME 9 series ‘S’ arm sporting a Shure MM Cartridge!! Wow .. talking about a blast from the past!!!!!
That is progress, I guess .....
Have a good day!
Best wishes
TC
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e-transports
Hi Scott
With you 100% here. I am actually not that advanced as you are (surprise, surprise!) and was looking at the Logitech iTouch. It is capable of 24*96 playback. At about $315 here, its value is difficult to beat, assuming you have a spare computer around and lots of HD space!!!
Hey, any other recommendations for a novice?
Best wishes
TC
Hi Scott
With you 100% here. I am actually not that advanced as you are (surprise, surprise!) and was looking at the Logitech iTouch. It is capable of 24*96 playback. At about $315 here, its value is difficult to beat, assuming you have a spare computer around and lots of HD space!!!
Hey, any other recommendations for a novice?
Best wishes
TC
Hi Scott,
You do realize that the gold CD recordable medium caused tracking problems with most CD players, don't you? Specifically, the reflectivity is well outside the CD standards. Data CDs use different specifications than music CDs did.
When CD burning first became popular, we suffered a few years where CD transports were damaged by the use of that medium. DJs were the worst for this, and exercise club instructors. It didn't matter how many times you told them this wouldn't work, they continued until I began charging them. Warranty is not insurance!
What would happen is that the servo would lose lock (RF waveform out of spec) and the head would get run forcibly to the far outer location past the last track. In fact, this was so violent that it often stripped the gears. 100% of the time, there was either a burned CD in the tray, or the user acknowledged that they were using blanks they recorded themselves.
What no one seemed to understand is that any departure from the standards (including "stabilizer rings" that threw the mass off) always resulted in sub-standard performance. Then most "improvements" would eventually end up caught in the transport, causing a jam and sometimes more damage. You have to understand that the CD servo filters are set up for a specific range of rotating mass. Same goes for CD thickness! Back then, manufacturers didn't make those crappy thin CDs. But these things also caused tracking problems due to both reduced mass and inevitable warping. The list of defects that CDs can have is extensive without messing with the media. The average person who just played music had years of trouble free service. The audiophile always ended up spending far more for maintenance than "normal" people simply due to all the accessories and "improvements" they bought. Almost every one of these people would swear their CD player sounded better after the messing around until I demonstrated (using a 'scope to monitor the RF test point) how it either degraded the signal, or made no difference. The green marker is still my all time favorite, with the green LEDs coming up a close second. BTW, the laser is in the near infrared part of the spectrum, not the green, yellow or blue wavelengths. Food for thought.
Now, I hate to bring this up, but the more expensive high end brands often used inferior CD transports. EAD never made their own mechanism, nor did they ever design their own servo section. What was often done was high end brands often used a very inexpensive transport and charged the world for it. In other words, you most likely had the same CD transport and servo section used in $200 players. Sorry about that. This means that your findings are expected.
How do you get your music into the computer? If they are MP3, your quality is inferior to what most CD players supply. However you seem to be using the system as background music anyway. In that case it makes perfect sense as well.
-Chris
You do realize that the gold CD recordable medium caused tracking problems with most CD players, don't you? Specifically, the reflectivity is well outside the CD standards. Data CDs use different specifications than music CDs did.
When CD burning first became popular, we suffered a few years where CD transports were damaged by the use of that medium. DJs were the worst for this, and exercise club instructors. It didn't matter how many times you told them this wouldn't work, they continued until I began charging them. Warranty is not insurance!
What would happen is that the servo would lose lock (RF waveform out of spec) and the head would get run forcibly to the far outer location past the last track. In fact, this was so violent that it often stripped the gears. 100% of the time, there was either a burned CD in the tray, or the user acknowledged that they were using blanks they recorded themselves.
What no one seemed to understand is that any departure from the standards (including "stabilizer rings" that threw the mass off) always resulted in sub-standard performance. Then most "improvements" would eventually end up caught in the transport, causing a jam and sometimes more damage. You have to understand that the CD servo filters are set up for a specific range of rotating mass. Same goes for CD thickness! Back then, manufacturers didn't make those crappy thin CDs. But these things also caused tracking problems due to both reduced mass and inevitable warping. The list of defects that CDs can have is extensive without messing with the media. The average person who just played music had years of trouble free service. The audiophile always ended up spending far more for maintenance than "normal" people simply due to all the accessories and "improvements" they bought. Almost every one of these people would swear their CD player sounded better after the messing around until I demonstrated (using a 'scope to monitor the RF test point) how it either degraded the signal, or made no difference. The green marker is still my all time favorite, with the green LEDs coming up a close second. BTW, the laser is in the near infrared part of the spectrum, not the green, yellow or blue wavelengths. Food for thought.
Now, I hate to bring this up, but the more expensive high end brands often used inferior CD transports. EAD never made their own mechanism, nor did they ever design their own servo section. What was often done was high end brands often used a very inexpensive transport and charged the world for it. In other words, you most likely had the same CD transport and servo section used in $200 players. Sorry about that. This means that your findings are expected.
How do you get your music into the computer? If they are MP3, your quality is inferior to what most CD players supply. However you seem to be using the system as background music anyway. In that case it makes perfect sense as well.
-Chris
Hi TC,
Computer CD transports are inferior to half decent, real CD player transports. Don't start talking about data CDs having zero defects, because they don't. What a data disc standard does have is far better error correction. This is not the same information that a music disc is made with.
There is a reason why this technician still uses real CD players. My wife and kids use MP3 players, but for enjoyment listening they use the real stereo system - by choice.
-Chris
Computer CD transports are inferior to half decent, real CD player transports. Don't start talking about data CDs having zero defects, because they don't. What a data disc standard does have is far better error correction. This is not the same information that a music disc is made with.
There is a reason why this technician still uses real CD players. My wife and kids use MP3 players, but for enjoyment listening they use the real stereo system - by choice.
-Chris
e-transport
Hi Chris
Hit a nerve, eh ha ha?
I still remember similar discussions in the early 80's when CDs were first introduced.... well they are still being had now!!
Whatever, I believe the internet has changed everything. There is no denying that they are more convenient although possibly not as good.
Best wishes
TC
Hi Chris
Hit a nerve, eh ha ha?
I still remember similar discussions in the early 80's when CDs were first introduced.... well they are still being had now!!
Whatever, I believe the internet has changed everything. There is no denying that they are more convenient although possibly not as good.
Best wishes
TC
Hi
Looks like we both have the same board!! The Balanced Mode DAC rocks.
You are going to have lots of fun with output caps!
I was with some friends yesterday and thought of this. Why not put some sort of simple on/off switch between the two points of the output caps and use it to toggle between OCL and non-OCL Cap Crazy mode!!! Best of both worlds at the flip of a switch.... I thought it was really cool.
... and the beautiful thing is it is not difficult!
I have also soldered a few of those blue screw connectors to the four output cap positions to facilitate cap rolling... really neat, in my opinion... However, those from Spencer are too big…
Welcome to the 1794A Club!!!
Have fun. I am ….
Best wishes
TC
Hi Victor
You too!!!
Pleae check out a later post I made on cap rolling, if you are keen ...
Best wishes
TC
Background
Well? I really don't care about CDRs and transports anymore but I must respond to all of that... I am sorry that apparently someone ruined your transport with a green ring?
.
Any transport die hard will have done comparative listening to different CDR blanks as they all sound a little different and burns always sound better than the original cd. This is well documented in other threads with the Mitsui Gold and Gold Audio blanks being two of the best sounding blanks.
.
Why would you think that I only use my system for background music? That actually makes me chuckle as most normal (non audiophile) people would consider me obsessed with comparative listening. Passive components, chips, cables, ect. Let alone complete circuit topologies. Can you believe there are still large numbers of people that argue that all good amplifiers sound "The Same"? You have prompted me to change my moniker. All (fill in the blank) do not sound "The Same".
.
Why also would you assume that everyone using a hard drive play back system would use digital file compression? Hard drives are cheap. I rip full wave. Some people actually use upsampling software to save upsampled files. The spdif out from my Firewire410 sounds better than my transport. Simple. And, now I have all of my favorite CDs (hundreds) stored as full rez on a portable hard drive that I can carry in my pocket! When that gets filled up, I will buy another one for $100.
.
.
Well? I really don't care about CDRs and transports anymore but I must respond to all of that... I am sorry that apparently someone ruined your transport with a green ring?
.
Any transport die hard will have done comparative listening to different CDR blanks as they all sound a little different and burns always sound better than the original cd. This is well documented in other threads with the Mitsui Gold and Gold Audio blanks being two of the best sounding blanks.
.
Why would you think that I only use my system for background music? That actually makes me chuckle as most normal (non audiophile) people would consider me obsessed with comparative listening. Passive components, chips, cables, ect. Let alone complete circuit topologies. Can you believe there are still large numbers of people that argue that all good amplifiers sound "The Same"? You have prompted me to change my moniker. All (fill in the blank) do not sound "The Same".
.
Why also would you assume that everyone using a hard drive play back system would use digital file compression? Hard drives are cheap. I rip full wave. Some people actually use upsampling software to save upsampled files. The spdif out from my Firewire410 sounds better than my transport. Simple. And, now I have all of my favorite CDs (hundreds) stored as full rez on a portable hard drive that I can carry in my pocket! When that gets filled up, I will buy another one for $100.
.
.
EAC and HiFace
The simplest way to get a great spdif out from your pc would be with a HiFace usb stick. They are a little pricey for the amount of hardware you get but should be worth it in the long run as one of the few usb solutions that can pass hi rez. If not that, then you would need an internal soundcard with coax out or a firewire external card. Coax still sounds better than optical with a good cable such as the twisted pair taken from Belden 1701A. Rip your CDs full rez with Exact Audio Copy. Be sure to set up a nice, uniform file structure where each CD is in it's own folder labeled : Artist (last name first), date of release, and album title. Label each song: track number (start with 01 as many players think 1 means 10 and comes after 9) and title. EAC has data base look up which does all of this automatically. I am a newbie. There are many threads about hard drive music.
.
The simplest way to get a great spdif out from your pc would be with a HiFace usb stick. They are a little pricey for the amount of hardware you get but should be worth it in the long run as one of the few usb solutions that can pass hi rez. If not that, then you would need an internal soundcard with coax out or a firewire external card. Coax still sounds better than optical with a good cable such as the twisted pair taken from Belden 1701A. Rip your CDs full rez with Exact Audio Copy. Be sure to set up a nice, uniform file structure where each CD is in it's own folder labeled : Artist (last name first), date of release, and album title. Label each song: track number (start with 01 as many players think 1 means 10 and comes after 9) and title. EAC has data base look up which does all of this automatically. I am a newbie. There are many threads about hard drive music.
.
Dac gain adjustable?
Can the gain of the I/V and buffer stage be adjusted? You may already have a great pre built in. I use passive stepped attenuators at the amp and or gain optimized digital volume control with the amps and dac gains matched to deliver my reference listening level at -0db volume control.
Hi Scott
If that were the case, that would be superb ... However, I am not sure how easily the I/V gain can be adjusted. I think it can be but would require some work. Spencer said that there is a 4.99ohm resistor that links the DAC analog output to the I/V. Maybe something can be done here???
I guess the best person to answer whether this is possible would be Spencer...
Hello Spencer....
Best wishes
TC
Hi TC,
The actual issue was that their reflectivity was far too high. This threw off the expected RF pattern amplitude and many earlier CD servo sections had adjustable "slice" levels (a reference for determining what was a low and high). So when set for normal CDs, no problem. Stick one of these other types in and it might track, and it may just lose lock. Then the rotational velocity would go way up (All is lost now) and if you were very unlucky, the tracking servo would run the sled right into and beyond (well, it tries) the end. This often destroys the gears outright. Unfortunately for some people it wouldn't rip the teeth right out, but rather split or crack them. This resulted in many machines labeled as "not worth repair" simply because the white grease hid the damage, and unobservant technicians didn't check.
We had notices from most distributors that stated that the warranty was null and void if recordable CD blanks were being played. My concerns are simply that the gold coloured CD blanks were off spec as far as audio machines are concerned. Using these in an audio CD player will result in many more read errors as a result. Yes, they still play these days (servo controlled everything now), but I'm not sure about the error rate.
Hi Scott,
Just look at yourself. You gave up on CD players and use hard drives now. That's an intelligent choice I think, and I certainly can't fault you for it. A hard drive would probably be the best playback device for automotive use. I'd spring for that, none lossy storage of course.
Sound quality is directly related to the BLER rate on the disc. So the fewer the errors, the better it should sound. The result of having varying error rates on a disc will depend greatly on both the mechanism, it's calibration/performance (or setup and how new is the head) and how much money went into the error correction area. That's it, that's all that will differ. The DAC simply converts what it is fed and the audio section remains constant for everything. Or it should, it's entirely possible that some manufacturers may play there to make disc errors less noticeable.
The one thing to remember too, the information coming off the original CD is the perfect standard as for as the information you are about to burn is considered. It doesn't get any better, only worse. However, the original CD may have disc errors that a machine has problems tracking. Taking the data over to another medium frees those issues, so for the case of a poor quality CD, the copies may sound better. But you can not say that blanks are better. All you can say is that some store bought CDs are of poor quality. On that, I completely agree with you.
The amount of mis-information about CDs and how the information comes off the disc is appalling. We can thank the self appointed experts, "white papers" and other marketing ploys. Once you know how stuff actually works, there are many products that you will know can not work, at least in the way they are promoted. I've been servicing CD players since the first ones were released (those were grim days), up to and including the present. The one thing I am grateful for are all the problems with the early machines, because we got an excellent education from the engineering departments. Most of todays machines are "continuous setup via servo" machines. They self correct until they can't anymore. This means that the average performance is probably better, but the extremely high performance that hand tuning can produce is no longer possible.
Give me the storage and I'll do the same. BTW, up-sampling on the way off is at least as good, and more efficient for storage (as you should know). The trick is to get the information off the original media without errors, so a good transport makes sense there.
Finally, I'm well aware that amplifiers, preamps, tape decks and everything else sounds different between various devices. I've never once said they sound the same, and I do a fair amount of work improving the performance and sound quality of amplifiers. You must be thinking of another "Chris". I also listen to my CD player for enjoyment, or a turntable. I also use both tube and solid state equipment. You're talking to another person who listens extensively.
-Chris
No, not in any way. Made a lot of money from damaged transports due to many off-spec CDROM blanks. While they are in spec for data cdroms, they certainly weren't for audio CD player use. I just hate to see people cost themselves money is all.
The actual issue was that their reflectivity was far too high. This threw off the expected RF pattern amplitude and many earlier CD servo sections had adjustable "slice" levels (a reference for determining what was a low and high). So when set for normal CDs, no problem. Stick one of these other types in and it might track, and it may just lose lock. Then the rotational velocity would go way up (All is lost now) and if you were very unlucky, the tracking servo would run the sled right into and beyond (well, it tries) the end. This often destroys the gears outright. Unfortunately for some people it wouldn't rip the teeth right out, but rather split or crack them. This resulted in many machines labeled as "not worth repair" simply because the white grease hid the damage, and unobservant technicians didn't check.
We had notices from most distributors that stated that the warranty was null and void if recordable CD blanks were being played. My concerns are simply that the gold coloured CD blanks were off spec as far as audio machines are concerned. Using these in an audio CD player will result in many more read errors as a result. Yes, they still play these days (servo controlled everything now), but I'm not sure about the error rate.
Hi Scott,
No, not me. I have had to remove them (the rings) from CD player mechanisms on occasion. Just think, it cost some people real folding stuff to impair the performance of their machine. There was an entire industry built up out of lying to the public to sell useless crap. That industry is alive and well.
Just look at yourself. You gave up on CD players and use hard drives now. That's an intelligent choice I think, and I certainly can't fault you for it. A hard drive would probably be the best playback device for automotive use. I'd spring for that, none lossy storage of course.
No, it's not well documented. It's called anecdotal replies.
Sound quality is directly related to the BLER rate on the disc. So the fewer the errors, the better it should sound. The result of having varying error rates on a disc will depend greatly on both the mechanism, it's calibration/performance (or setup and how new is the head) and how much money went into the error correction area. That's it, that's all that will differ. The DAC simply converts what it is fed and the audio section remains constant for everything. Or it should, it's entirely possible that some manufacturers may play there to make disc errors less noticeable.
The one thing to remember too, the information coming off the original CD is the perfect standard as for as the information you are about to burn is considered. It doesn't get any better, only worse. However, the original CD may have disc errors that a machine has problems tracking. Taking the data over to another medium frees those issues, so for the case of a poor quality CD, the copies may sound better. But you can not say that blanks are better. All you can say is that some store bought CDs are of poor quality. On that, I completely agree with you.
The amount of mis-information about CDs and how the information comes off the disc is appalling. We can thank the self appointed experts, "white papers" and other marketing ploys. Once you know how stuff actually works, there are many products that you will know can not work, at least in the way they are promoted. I've been servicing CD players since the first ones were released (those were grim days), up to and including the present. The one thing I am grateful for are all the problems with the early machines, because we got an excellent education from the engineering departments. Most of todays machines are "continuous setup via servo" machines. They self correct until they can't anymore. This means that the average performance is probably better, but the extremely high performance that hand tuning can produce is no longer possible.
Give me the storage and I'll do the same. BTW, up-sampling on the way off is at least as good, and more efficient for storage (as you should know). The trick is to get the information off the original media without errors, so a good transport makes sense there.
Finally, I'm well aware that amplifiers, preamps, tape decks and everything else sounds different between various devices. I've never once said they sound the same, and I do a fair amount of work improving the performance and sound quality of amplifiers. You must be thinking of another "Chris". I also listen to my CD player for enjoyment, or a turntable. I also use both tube and solid state equipment. You're talking to another person who listens extensively.
-Chris
Hi TC,
...Made a lot of money from damaged transports due to many off-spec CDROM blanks. While they are in spec for data cdroms, they certainly weren't for audio CD player use. I just hate to see people cost themselves money is all.
The actual issue was that their reflectivity was far too high......
-Chris
Hi Chris
Good for you! I remember those days of using these 'enhancers'. They were fun though. Frankly, I also bought those black 'audiophile' disc to record and I still have some.. he he.
If I am reading you correctly, the silver audio CDs have a lower reflectivity index than CDROM ones? Just from purely looking at surface, it seems to be the opposite. The silver ones seem to reflect light better. I always thought that was why some DVD players cannot read CDROMs.
So, any suggestions on a good transport other than the Denon?
Best wishes
TC
OCL Rules!
Hi
After a few weeks of rolling output coupling caps, I came to the conclusion that OCL gives the most accurate and hence best sound. My rationale was that the top of the chain should be as accurate and faithful as possible, leaving the personalization to the pre and power amps. As I have a complete tube setup, this is possible. That way, I can hopefully ensure that as little of the intricate nuances of the music is lost.
Although I do appreciate the risks involved in running the DAC in this mode, I think in my set up, these are minimal; well that is the theory anyway. Ah well, what is life without some excitement, right?
Tubes Died!
When I first configured the DAC to OCL, there was some harness in the highs. At first, I thought it was the DAC. I then tried the system with another pre amp and the harshness was not there. What gives?
It was then that I decided to test my preamp tubes with my trusty TV7 and hold and behold, 3 of the 4 6V6 GECs were testing marginal! Ouch! These were smoked coke bottled with black bases! I bought these about 8-9 years ago and they cost more than the whole DAC then!!! Ouch again….Fortunately, I still have four (NOS matched Quad) so I am fine but maybe I should just sell them for a tidy profit!! Ha ha… Open to offers ...ha ha ha ha!!
Anyway, I am now using Sovtek 6L6 as their temporary replacement. Of course, the Sovtek can’t come close to the finesse, smoothness and refinement of the GECs but they will have to do for now. Anyway, the edginess of the highs is gone and the soundstage is much more open.
So, after more tests, OCL vs non-OCL, I feel that with OCL the system is more detailed and open and with more punch. It continues to be very easy on the ears but much more dynamic and faster. The soundstage is larger and as quiet and the bass is fantastic; more in quantity and quality … lower and more extended. I feel the improvement in the bass is most pronounced.
With the GECs, I am sure these improvements will be even more apparent. I think I will eventually put these in ….. I also have some Tungsol Reissues to try too…. . Its going to be another fun week.
This little DAC continues to amaze. It is capable of reproducing incredible musical detail. Truly amazing ….
So, the conclusion is OCL for this 1794A DAC rules….
Thanks for reading.
TC
Ps. A picture of the DAC with the big K75-10 10uf, Jensen PIO and Silmic …
Hi
After a few weeks of rolling output coupling caps, I came to the conclusion that OCL gives the most accurate and hence best sound. My rationale was that the top of the chain should be as accurate and faithful as possible, leaving the personalization to the pre and power amps. As I have a complete tube setup, this is possible. That way, I can hopefully ensure that as little of the intricate nuances of the music is lost.
Although I do appreciate the risks involved in running the DAC in this mode, I think in my set up, these are minimal; well that is the theory anyway. Ah well, what is life without some excitement, right?
Tubes Died!
When I first configured the DAC to OCL, there was some harness in the highs. At first, I thought it was the DAC. I then tried the system with another pre amp and the harshness was not there. What gives?
It was then that I decided to test my preamp tubes with my trusty TV7 and hold and behold, 3 of the 4 6V6 GECs were testing marginal! Ouch! These were smoked coke bottled with black bases! I bought these about 8-9 years ago and they cost more than the whole DAC then!!! Ouch again….Fortunately, I still have four (NOS matched Quad) so I am fine but maybe I should just sell them for a tidy profit!! Ha ha… Open to offers ...ha ha ha ha!!
Anyway, I am now using Sovtek 6L6 as their temporary replacement. Of course, the Sovtek can’t come close to the finesse, smoothness and refinement of the GECs but they will have to do for now. Anyway, the edginess of the highs is gone and the soundstage is much more open.
So, after more tests, OCL vs non-OCL, I feel that with OCL the system is more detailed and open and with more punch. It continues to be very easy on the ears but much more dynamic and faster. The soundstage is larger and as quiet and the bass is fantastic; more in quantity and quality … lower and more extended. I feel the improvement in the bass is most pronounced.
With the GECs, I am sure these improvements will be even more apparent. I think I will eventually put these in ….. I also have some Tungsol Reissues to try too…. . Its going to be another fun week.
This little DAC continues to amaze. It is capable of reproducing incredible musical detail. Truly amazing ….
So, the conclusion is OCL for this 1794A DAC rules….
Thanks for reading.
TC
Ps. A picture of the DAC with the big K75-10 10uf, Jensen PIO and Silmic …
Attachments
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How much dc?
How low can you get the dc offset on the output with the adjustment. Is it stable during warm up?
DC Offset
Hi Scott
Hope you are having a good weekend.
The DC offset is set by 2 (5K, I think) variable resistors on each board. So far (touch wood), the offset is close to 0 with a variation of about +/- 2mV but hovers around +/- 1mV most of the time. It doesn’t vary much though, even during use (on my set, at least) but that could be because my Fluke can't detect it! Its resolution is only up to 1 mV.. Ha ha.
I think if it stays within this range, it should be ok, right? Anyway the speakers and amps are still functioning, which is always a good sign.
Oh, OCL is also slightly louder. I guess this is because this is the path of least resistance.
Best wishes
TC
Hi Scott
Hope you are having a good weekend.
The DC offset is set by 2 (5K, I think) variable resistors on each board. So far (touch wood), the offset is close to 0 with a variation of about +/- 2mV but hovers around +/- 1mV most of the time. It doesn’t vary much though, even during use (on my set, at least) but that could be because my Fluke can't detect it! Its resolution is only up to 1 mV.. Ha ha.
I think if it stays within this range, it should be ok, right? Anyway the speakers and amps are still functioning, which is always a good sign.
Oh, OCL is also slightly louder. I guess this is because this is the path of least resistance.
Best wishes
TC
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