Hi salas. A quick update, replacing the output connectors with Audionote silver wasn't a scorching success. At this stage the DAC1 had the 100uF BG N-types as above and 150 ohm Mill resistors in series with the output bypassing the stock SMD resistive divider. To my ear it went dry as Death Valley, pushing the overall balance light and playing havoc with sibilance. Once again the change was so irrational I was checking and rechecking wiring and solder joints.
With extended listening the realization occured it was the same sound I thought had been partially addressed by adding the double 0.1uF BG N bypasses. Yanking the older, red BGs and replacing them with an extreme opposite, 0.1uF silver micas from the junk box, confirmed them as the cause. Dry is one way to describe is, slurring esses with a 'sshhh' texture is another. It becomes harder to differentiate the natural differences between male and female sibilants and fricatives. No wonder these caps are so divisive.
47uF BG NX Hi-Q which had been charging at ~2 volts for a couple days were next and a definite improvement. The top-end texture was reduced but still more than I want to live with. Replacing each with a pair of parallel 0.47uF BG NX Hi-Q was another jump up. Now the texture is audible but not at the level of being offensive. Bypass those with 0.1uF BG NX Hi-Q pairs made little difference so I left it as-is for now.
You're probably wondering, if I find the top end so inadequate why stick with them? Well, first because I bought them and want to see it through. 😉 More importantly, in most other aspects they're amazing. With the sum changes movies, nearly all recent movies, seamlessly fill the room ahead of the listening chair with sound. The sense of space is massive. Minimally mic'd musical recordings capture a great deal of that. Multi-mic'd pop mash remains a clothesline of sound from speaker to speaker so I'm quite certain it's not an 'enhanced effect'. Top of the list though is through the midrange down sounds can have a spooky, almost disorienting sense of realism like nothing I've heard. Elsewhere Jonathon Carr calls them 'coloured but spectacular'. My hope is that the smaller BG packages are more suited to the low offset voltage in this position (again, going entirely on the manufacturer's say about a charging requirement) and that with time the top end coulration will tame itself. From what I hear throughout the rest of the range it's worth the wait and see.
With extended listening the realization occured it was the same sound I thought had been partially addressed by adding the double 0.1uF BG N bypasses. Yanking the older, red BGs and replacing them with an extreme opposite, 0.1uF silver micas from the junk box, confirmed them as the cause. Dry is one way to describe is, slurring esses with a 'sshhh' texture is another. It becomes harder to differentiate the natural differences between male and female sibilants and fricatives. No wonder these caps are so divisive.
47uF BG NX Hi-Q which had been charging at ~2 volts for a couple days were next and a definite improvement. The top-end texture was reduced but still more than I want to live with. Replacing each with a pair of parallel 0.47uF BG NX Hi-Q was another jump up. Now the texture is audible but not at the level of being offensive. Bypass those with 0.1uF BG NX Hi-Q pairs made little difference so I left it as-is for now.
You're probably wondering, if I find the top end so inadequate why stick with them? Well, first because I bought them and want to see it through. 😉 More importantly, in most other aspects they're amazing. With the sum changes movies, nearly all recent movies, seamlessly fill the room ahead of the listening chair with sound. The sense of space is massive. Minimally mic'd musical recordings capture a great deal of that. Multi-mic'd pop mash remains a clothesline of sound from speaker to speaker so I'm quite certain it's not an 'enhanced effect'. Top of the list though is through the midrange down sounds can have a spooky, almost disorienting sense of realism like nothing I've heard. Elsewhere Jonathon Carr calls them 'coloured but spectacular'. My hope is that the smaller BG packages are more suited to the low offset voltage in this position (again, going entirely on the manufacturer's say about a charging requirement) and that with time the top end coulration will tame itself. From what I hear throughout the rest of the range it's worth the wait and see.
If they will not tame, keep in mind the 2uf Auricap. In my system only positive sound upgrade across the slate. And yes DAC1 can be spooky real when free from silly caps.
P.S. What kind of speakers do you use? Is there an easily excited tweeter or something?
P.S. What kind of speakers do you use? Is there an easily excited tweeter or something?
Absolutely, Auricaps remain my favourite plastic caps to date. The latest changes - 2x 0.47uF NX Hi-Q in parallel + 2x 0.1uF NX Hi-Q in parallel - have actually less high frequency energy than an Auricap, perhaps too smooth. It's sounding thoroughly warm now and not at all dry. The problem with these Blackgates isn't level, it's a hard to describe 'texture' similar to that of cheaper full range drivers that augment an early HF rolloff with a response bump. Converting 'sssss' to 'ssshhhh' without altering level. That's the best I can do to describe it. The original 100uF N-types had it in spades well down into the voice range. These physically much, much smaller NX Hi-Q types push it well up to the high edge of sibilance and into cymbals.
This texture is gone with Auricaps or silver micas and is audble across a range of speakers so it doesn't appear to be a driver issue. That said, good guess, yes I use Tannoy Golds (pulled from studio monitors) precisely because their excitable top end pounds these changes home. Little hides from those ancient compression drivers.
This texture is gone with Auricaps or silver micas and is audble across a range of speakers so it doesn't appear to be a driver issue. That said, good guess, yes I use Tannoy Golds (pulled from studio monitors) precisely because their excitable top end pounds these changes home. Little hides from those ancient compression drivers.
Had mixed on such (in wall - half space) in a studio in England in 1991. They have an exciting and musical punchy sound.
FYI: Benchmark Announces First Native 96-kHz 24-bit "Advanced USB Audio"
Benchmark Announces First Native 96-kHz 24-bit "Advanced USB Audio".
More information about the DAC1 USB is available on Benchmark's website at:
http://www.benchmarkmedia.com/eupdate
High resolution photos are available at:
http://www.benchmarkmedia.com/dac1/photos
For all the latest product announcements, news, and information about Benchmark
Media Systems, subscribe to the RSS feed:
http://www.benchmarkmedia.com/press/index.rss
Benchmark Announces First Native 96-kHz 24-bit "Advanced USB Audio".
More information about the DAC1 USB is available on Benchmark's website at:
http://www.benchmarkmedia.com/eupdate
High resolution photos are available at:
http://www.benchmarkmedia.com/dac1/photos
For all the latest product announcements, news, and information about Benchmark
Media Systems, subscribe to the RSS feed:
http://www.benchmarkmedia.com/press/index.rss
USB is nice, but with wi-fi too, DAC-1 would be complete for home use.
Like Slim Devices Transporter.
Like Slim Devices Transporter.
Hi rdf,
I've only just seen your post here about sibilance problems associated with using BGs, and I (almost) gave up posting about these caps about 4 years ago, as my comments caused so much angst at that time.
However, I have been using these BGs for many years now and have picked up a few tips related to their application and I may have at least a partial solution for your problem here. Excellent though Non-Polarised BGs are (and I still haven't found any electrolytic which betters them overall, and this goes for 90% of plastic films, too) they are not perfect, and they do need some 'understanding'.
I found them to be 'microphonic' and damping their bodies can make quite a difference to their performance, especially in the manner which you seem to be having problems with.
If I understand you correctly, the effect is rather like a HF roll-off with a very high Q, where, approaching the upper frequencies, there appears subjectively to be an accentuating peak (about the region of sibilance) and thereafter the response drops like a stone, instead of gradually and smoothly tailing off into the stratosphere.
If so, I have found that vibrations can often be the cause of this phenomenon (either signal/self-induced within the cap, or due to air-borne or mechanical feedback via the enclosure) and there is a simple way of checking this out, and at very little cost.
Try sticking a blob of Bostic Blu-Tack or UHU White Tack on the end of any BGs in the circuit, which will help to damp out any of these vibrations. I don't know in Canada if this is as readily available as it is here in the UK from any stationery suppliers, but I have seen that Parts Connexion in your part of the world keeps Blu-Tack if your are stuck for this.
If your system is quite revealing, I would be surprised if you don't hear any effect from doing this, even if it doesn't provide a complete cure for the sibilance problems you describe, particularly as you seem to be sure this is related to the use of BGs in this circuit.
Interestingly, you may also find that it firms up the bass frequencies as well, as I always find this to be the case when applying such damping to BGs in a new circuit.
At least this stuff is cheap enough and can always be used for it's intended purposes (sticking things temporarily on walls etc) if there is no real improvement, but if things move in the right direction, it might be worthwhile investing in some better purpose-made damping material, maybe like Microsorb, Navcom or Sorbothane, which will probably have more effect here.
Also, as you acknowledge, these particular caps do need quite a bit of use (I won't say "burning-in" in view of the other thread where this is being ridiculed!) before they sound at their best, and this can take up to 3 months in total, although the most apparent changes will occur within a few weeks. Unfortunately, this sibilance problem (if it is due to the suspected vibration) will probably tend to seem rather worse as other matters improve, and, in my experience, will become more annoying because everything else sounds so good in comparison. I don't think it will improve just with use, if my experiences are much to go by.
I hope that this helps with your concerns here, but as advised, I have found this to be a virtually universal cure, always assuming that I understand the problems you have described correctly.
Regards,
I've only just seen your post here about sibilance problems associated with using BGs, and I (almost) gave up posting about these caps about 4 years ago, as my comments caused so much angst at that time.
However, I have been using these BGs for many years now and have picked up a few tips related to their application and I may have at least a partial solution for your problem here. Excellent though Non-Polarised BGs are (and I still haven't found any electrolytic which betters them overall, and this goes for 90% of plastic films, too) they are not perfect, and they do need some 'understanding'.
I found them to be 'microphonic' and damping their bodies can make quite a difference to their performance, especially in the manner which you seem to be having problems with.
If I understand you correctly, the effect is rather like a HF roll-off with a very high Q, where, approaching the upper frequencies, there appears subjectively to be an accentuating peak (about the region of sibilance) and thereafter the response drops like a stone, instead of gradually and smoothly tailing off into the stratosphere.
If so, I have found that vibrations can often be the cause of this phenomenon (either signal/self-induced within the cap, or due to air-borne or mechanical feedback via the enclosure) and there is a simple way of checking this out, and at very little cost.
Try sticking a blob of Bostic Blu-Tack or UHU White Tack on the end of any BGs in the circuit, which will help to damp out any of these vibrations. I don't know in Canada if this is as readily available as it is here in the UK from any stationery suppliers, but I have seen that Parts Connexion in your part of the world keeps Blu-Tack if your are stuck for this.
If your system is quite revealing, I would be surprised if you don't hear any effect from doing this, even if it doesn't provide a complete cure for the sibilance problems you describe, particularly as you seem to be sure this is related to the use of BGs in this circuit.
Interestingly, you may also find that it firms up the bass frequencies as well, as I always find this to be the case when applying such damping to BGs in a new circuit.
At least this stuff is cheap enough and can always be used for it's intended purposes (sticking things temporarily on walls etc) if there is no real improvement, but if things move in the right direction, it might be worthwhile investing in some better purpose-made damping material, maybe like Microsorb, Navcom or Sorbothane, which will probably have more effect here.
Also, as you acknowledge, these particular caps do need quite a bit of use (I won't say "burning-in" in view of the other thread where this is being ridiculed!) before they sound at their best, and this can take up to 3 months in total, although the most apparent changes will occur within a few weeks. Unfortunately, this sibilance problem (if it is due to the suspected vibration) will probably tend to seem rather worse as other matters improve, and, in my experience, will become more annoying because everything else sounds so good in comparison. I don't think it will improve just with use, if my experiences are much to go by.
I hope that this helps with your concerns here, but as advised, I have found this to be a virtually universal cure, always assuming that I understand the problems you have described correctly.
Regards,
Hi Bob, thanks for such an extensive post! I wouldn't have normally given much consideration to that sort of mod hadn't your description of the 'BG sound' exactly corresponded with mine. Without knowing which size caps you use it was also less certain to have the same effect on the smallest BG available (my DAC1 uses two pairs of two 0.47 Hi-Qs.) However Blue Tak is available in Canada, a forgotten pack in my stock and it's a very simple non-destructive thing to try.
I'll admit first that I cheated a bit. Your suggestion reminded me of another intended mod to reduce the effect of vibration so both were done simultaneously. I think few realize that the greatest source of mechanical excitation on a piece of gear is almost always the power transformer. An ear on the Benchmark's chassis confirmed it so along with a pea of Blue Tak on the caps I stood off the toroid on three soft rubber feet and inserted a rubber isolator between the central potting material and the chassis hold-down nut.
Really hate to say it about any of these kinds of mods but it appears to have helped. Time will tell, it's too soon to say and I currently have a bit of an allergy which affects my hearing. The impression for now though is sibilance, which had been slowly improving, became a leap less 'generic' and more revealing of tiny details. My system can't tell me anything about bass but everything above it seems to have cleaned up too. All in all the results were encouraging, and safe, enough to take it to the next step. There certainly are more effective ways to damp those cap bodies and in a few days they'll be encased in steel epoxy, which dries extremely hard but never goes brittle. I'm sure somewhere around here I have some softer Sorbothane as well to replace the relatively hard rubber bumpers.
Thanks again for suggestion Bob! The pic below shows the mods so far (Mills wiring is temp until I decide on a final config), minus the Blu Tak. The sleeves around the cap pairs were used to hold them for soldering and I just didn't bother to remove them.
I'll admit first that I cheated a bit. Your suggestion reminded me of another intended mod to reduce the effect of vibration so both were done simultaneously. I think few realize that the greatest source of mechanical excitation on a piece of gear is almost always the power transformer. An ear on the Benchmark's chassis confirmed it so along with a pea of Blue Tak on the caps I stood off the toroid on three soft rubber feet and inserted a rubber isolator between the central potting material and the chassis hold-down nut.
Really hate to say it about any of these kinds of mods but it appears to have helped. Time will tell, it's too soon to say and I currently have a bit of an allergy which affects my hearing. The impression for now though is sibilance, which had been slowly improving, became a leap less 'generic' and more revealing of tiny details. My system can't tell me anything about bass but everything above it seems to have cleaned up too. All in all the results were encouraging, and safe, enough to take it to the next step. There certainly are more effective ways to damp those cap bodies and in a few days they'll be encased in steel epoxy, which dries extremely hard but never goes brittle. I'm sure somewhere around here I have some softer Sorbothane as well to replace the relatively hard rubber bumpers.
Thanks again for suggestion Bob! The pic below shows the mods so far (Mills wiring is temp until I decide on a final config), minus the Blu Tak. The sleeves around the cap pairs were used to hold them for soldering and I just didn't bother to remove them.
Attachments
rdf said:
That is quite correct, and one way to lower the coloration is to use smaller cap values that have been used originally in a circuit.
Bobken looks to have hit on another way. His recommendation was taken to an extreme by skinning the caps, cleaning the metal surfaces (only!) with methyl hydrate to assure a solid stick and encasing pairs completely in standard epoxy. See the not-pretty pic below. The sound remains spectacular and the colourations drop through the floor. The only quibble I have with Bob's original description is it's too cautious. Damping these things would appear to retain all the positives while removing huge swaths of texture top to bottom. The sound is now incredibly detailed and fast-fast-fast without punishing you when the source material gets rough.
I'm not going into elaborate much because it I know how daft it sounds. However, taking advantage of the flu and a day off work I listened to a number of very familiar recordings for the first time since these mods began. The different microphones used on various tracks of the Cash recordings, for example, stand out in bold relief. Yep, hearing things I've never heard before after hundreds of listens too. The overall sound is far more natural while differences between recordings are far more obvious, which has one downside. The Benchmark DAC1 has a reputation for being a 'space master', throwing huge soudscapes. At this point I think it's part colouration, a combination of an overall dark resentation coupled with fast transients that come out of the 'black' (which to my mind is another, popular, colouration.) These mods will reduce the depth of image of typical multi-mic pop recordings to pancake flat if that's how it was recorded. Conversely dual or simply mic'd recordings in natural spaces blow the back wall out better than ever and heavily DSP'd movie surround tracks reproduced over two speakers take the rest of the room with it. (Yes, I know how that sounds.)
All in all I'm delighted with the results and more than glad to leave cap-skinning behind and return to biasing, load lines and harmonic spectra. One caveat, the mods I describe relate to the V1 version of the DAC1 only. From salas' measurements later versions have lower interstage input impedances and require much larger cap values. On the other hand V1's can be had at fire sale prices now, a tremendous value when combined with $50 worth of parts.
I'm not going into elaborate much because it I know how daft it sounds. However, taking advantage of the flu and a day off work I listened to a number of very familiar recordings for the first time since these mods began. The different microphones used on various tracks of the Cash recordings, for example, stand out in bold relief. Yep, hearing things I've never heard before after hundreds of listens too. The overall sound is far more natural while differences between recordings are far more obvious, which has one downside. The Benchmark DAC1 has a reputation for being a 'space master', throwing huge soudscapes. At this point I think it's part colouration, a combination of an overall dark resentation coupled with fast transients that come out of the 'black' (which to my mind is another, popular, colouration.) These mods will reduce the depth of image of typical multi-mic pop recordings to pancake flat if that's how it was recorded. Conversely dual or simply mic'd recordings in natural spaces blow the back wall out better than ever and heavily DSP'd movie surround tracks reproduced over two speakers take the rest of the room with it. (Yes, I know how that sounds.)
All in all I'm delighted with the results and more than glad to leave cap-skinning behind and return to biasing, load lines and harmonic spectra. One caveat, the mods I describe relate to the V1 version of the DAC1 only. From salas' measurements later versions have lower interstage input impedances and require much larger cap values. On the other hand V1's can be had at fire sale prices now, a tremendous value when combined with $50 worth of parts.
Attachments
Bravo RDF, amber bliss I see!
I am happy 4U, it was an annoying mishap battling with the BGs.
I agree 100% for the way it sounds now and the 'black' stock popular coloration. Well verbalized.
-Bobken, you are a good sport.
I am happy 4U, it was an annoying mishap battling with the BGs.
I agree 100% for the way it sounds now and the 'black' stock popular coloration. Well verbalized.
-Bobken, you are a good sport.
Bobken... THANKS!
I just want to say thanks for this and all your other posts. Of all the people who post here, you have provided the most concise and useful info while being beyond the edge of high-end audio design by most people's yardstick.
I've read most of your posts and rarely find don't find something to note and try.
Greg in Mississippi
P.S. BTW, I'd love to correspond with you. I notice you don't accept emails from the group... and seeing how some respond to your wisdom, I can see why you have done that. If you're willing, please send me an email via my profile.
Bobken said:
I just want to say thanks for this and all your other posts. Of all the people who post here, you have provided the most concise and useful info while being beyond the edge of high-end audio design by most people's yardstick.
I've read most of your posts and rarely find don't find something to note and try.
Greg in Mississippi
P.S. BTW, I'd love to correspond with you. I notice you don't accept emails from the group... and seeing how some respond to your wisdom, I can see why you have done that. If you're willing, please send me an email via my profile.
It's like an itch you can't scratch now. Has anyone looked at replacing the ceramic compensation caps around every opamp?
Hi salas. Thought you might enjoy the next experiment, transformer coupling. In decommissioning one of our broadcast facilities I found a pair of UTC Ouncer isolation transformers. The impedance ratio is 600:500, an early concern, but a 5532-full M-Audio Firewire had no problem generating very impressive numbers from it. Installed for testing below. At maximum SPDIF input level THD worsens to 0.012%, IMD to 0.007%. The output RC network was tuned on the bench for flat to 100 kHz response, mostly used to pull down a small peak. In other words from any know measured criteria for audibility the UTC is transparent in this application.
Interesting contrast to a cap for sure, especially since this change halves the number of coupling caps in my playback system. At first I thought the small DC trickle current on the primary was causing a bottom end roll-off in such a small trannie but it's 0.5 dB down at 10 Hz. Not as razzle-dazzle as the BGs, cleaner up top, movie surround effects opened up again. Unsure if they'll stay yet, if not it'll be more for system matching reasons than lack of performance.
I'm thinking headers and a four barrel next.
Interesting contrast to a cap for sure, especially since this change halves the number of coupling caps in my playback system. At first I thought the small DC trickle current on the primary was causing a bottom end roll-off in such a small trannie but it's 0.5 dB down at 10 Hz. Not as razzle-dazzle as the BGs, cleaner up top, movie surround effects opened up again. Unsure if they'll stay yet, if not it'll be more for system matching reasons than lack of performance.
I'm thinking headers and a four barrel next.
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Interesting...see how it comes out in the long term. Hey! Don't post a 5687 based tweak with some Tango choked supply and a 274 rectifier next!
Sorry, it was a dry motor-head joke. I forget sometimes it's an international forum and not everyone spent teen years under the hoods of 1960's American cars. It's like salas' 274 recommendation, a joke when he really knows 8008s MV rectifiers in Graetz Bridge are the ticket. 😉
rdf said:
If you like what that transformers do and want to pursue
that path, it is worth checking out the Cinemag line of transformers.
Very linear, at midband less than 0.001%, very good HF extension
and very good LF distortion performance. Pretty much the same as
Jensns but at a fraction of the cost.
It's also worth noting that once using an OP transformer then only
1 opamp per dac phase is required purely to do I-V, this can then
feed straight into transformer. The transformer will do the required
summing of each phase whilst rejecting common mode noise
and distortion generated in the dacs.
The tranformer will also negate much of the low pass filtering
otherwise required. At a guess I would say a single order at 80kHz
+ transformer would be enough.
It's definately a path worth pursuing if you are prepared to pay
for very high qual trannies.
cheers
Terry
Thank you so much for this thread. I just purchased a dac-1 on audiogon for $750, i'm quite excited. Chris's mods in the past are the only mods I trust, partsconnexion is a gift to mankind, transforming my silly jolida equipment into giant killers (Chris did Sonic Frontiers, and people are still sending their 10-15 years old SF equipment to him to keep them up to date). That was before a power outage took out all my mullards in 1/100th of a second and i'm back into SS again 🙂 I will definately be sending mine dac up to him soon. The previous owner said the dac was two years old, does anyone have a timeline on upgrades for the dac? I've heard the pcb board has been improved upon a few times, I suppose i'll just email them with my model and they'll know. I almost regret buying a 500 gig 'request' music server recently since the benchmark now has a 1.1 usb option, and I could have just played all my flac's on my computer with killer sound and saved myself 3 grand. But that requires a dedicated computer, but seriously don't buy a music server with the bechmark usb in existence. I'm considering leaving the endless audiophile upgrade game behind and just going from the benchmark to some pmc aml-1's, it's what they master the cd's with that we spend endless grands on trying to improve, so why bother. I've noticed Rick Rubin uses the benchmark and Stevie Wonder uses the pmc aml. If anyone out there wants some platinum audio duo's and solos for sale let me know 🙂
P.S. Before you diss someone who charges for upgrades to existing equipment, remember they are the ones out there for public scrutiny, for better or for worse, and until someone gets their diy work reviewed by a few magazines, i'll stick with the reviewed ones, no offense. I never did well in calculus like all you folks 🙂 lol my wife says I have to stop writing this book now. Cheers.
P.S. Before you diss someone who charges for upgrades to existing equipment, remember they are the ones out there for public scrutiny, for better or for worse, and until someone gets their diy work reviewed by a few magazines, i'll stick with the reviewed ones, no offense. I never did well in calculus like all you folks 🙂 lol my wife says I have to stop writing this book now. Cheers.
tuffgong420 said:
We are not making recommendations to the buying public we DIYers. We just expose our work. Its for fellow hobbyists to try out if they get intrigued. The professional asks for $, he gets the flack or the praise. Fair enough. As for the press, I would take it with a huge pinch of salt.
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