DACs I have bought and sold...
Posted by: Mr Pierce on 09 May 2008
No questions just yet & not asking advice, just my $.02 to help future forum-searchers on the DAC-quest...
So, not long after taking possession of my new hifi set which consists of a Rega Apollo CDP, 72, 140, and Dahlquist DQ-20 speakers - and after bumblingly dealing with speaker placement issues - I decided I wanted to Never Alphabetize My CD Collection Ever Again. So, I bought a Mac Mini and a Stello DA100 (not the new "signature" model) DAC. Even after many emails to the US Stello rep and a two-week warmup/break-in period, it just didn't sound as good as my CDP. Brittle treble, and no bump & bounce in the dynamics. Totally lacked the thing that made me spend US $3K on a stereo in the first place when I'd planned to spend a third of that sum.
So I bought a used Benchmark DAC1 USB, kept the Stello long enough to do an A/B test, and sold the Stello to a headphone listener with an anime avatar on the forums whom I'm sure is now delighted with it. The Benchmark sounds noticeably better, but still doesn't make me stop what I'm doing and sit on the couch because the music compels me to. Again with the no dynamic liveliness. And again, my standard is the Apollo - I'm not trying to beat a CD555 at it's own game or nothin' - just want a DAC to sound as good as a CDP that costs less that itself. Repeat buy/compare/sell, this time with a PS Audio Digital Link III. This one is the best of the bunch so far, but still is left in the dust by the Rega - which was easily bested by the CD5i at the dealer's, but I only had so much to spend...
So I sell the PS Audio and am now DACless. In Seattle. Next stop I assume is to have Mr. & Mrs. Lavry send a DA10 across the Puget Sound so I can take advantage of their 30-day trial period. I am cautiously optimistic.
If the DA10 fails to deliver the goods the way I like 'em, my options narrow to rob a bank and get an HDX, wait for Rega to make a DAC since Naim says they won't make one, rob a smaller bank and get a SuperNait and use its DAC, get to alphabetizing, or consider more left-field stuff like a battery-powered Altmann, the Lessloss from Lithuania, or the Stealth Kukama...
YMMV, FWIW, OMG, etc - just wanted to post my findings so far.
So, not long after taking possession of my new hifi set which consists of a Rega Apollo CDP, 72, 140, and Dahlquist DQ-20 speakers - and after bumblingly dealing with speaker placement issues - I decided I wanted to Never Alphabetize My CD Collection Ever Again. So, I bought a Mac Mini and a Stello DA100 (not the new "signature" model) DAC. Even after many emails to the US Stello rep and a two-week warmup/break-in period, it just didn't sound as good as my CDP. Brittle treble, and no bump & bounce in the dynamics. Totally lacked the thing that made me spend US $3K on a stereo in the first place when I'd planned to spend a third of that sum.
So I bought a used Benchmark DAC1 USB, kept the Stello long enough to do an A/B test, and sold the Stello to a headphone listener with an anime avatar on the forums whom I'm sure is now delighted with it. The Benchmark sounds noticeably better, but still doesn't make me stop what I'm doing and sit on the couch because the music compels me to. Again with the no dynamic liveliness. And again, my standard is the Apollo - I'm not trying to beat a CD555 at it's own game or nothin' - just want a DAC to sound as good as a CDP that costs less that itself. Repeat buy/compare/sell, this time with a PS Audio Digital Link III. This one is the best of the bunch so far, but still is left in the dust by the Rega - which was easily bested by the CD5i at the dealer's, but I only had so much to spend...
So I sell the PS Audio and am now DACless. In Seattle. Next stop I assume is to have Mr. & Mrs. Lavry send a DA10 across the Puget Sound so I can take advantage of their 30-day trial period. I am cautiously optimistic.
If the DA10 fails to deliver the goods the way I like 'em, my options narrow to rob a bank and get an HDX, wait for Rega to make a DAC since Naim says they won't make one, rob a smaller bank and get a SuperNait and use its DAC, get to alphabetizing, or consider more left-field stuff like a battery-powered Altmann, the Lessloss from Lithuania, or the Stealth Kukama...
YMMV, FWIW, OMG, etc - just wanted to post my findings so far.
Posted on: 13 May 2008 by Guido Fawkes
quote:Originally posted by Jack Barron:
There is a chap selling a CD-555, together with a NAPS-555.
The reason?
..................
The chap selling the CD-555 runs a Naim/Linn dealership.
When things like this are beginning to occur, a massive change is on its way.
Jack
Jack, aren't Naim dealerships supposed to sell Naim kit or am I missing something?
ATB Rotf
Posted on: 13 May 2008 by kuma
quote:Originally posted by ROTF:
47 Labs makes very interesting looking kit
Sexier looking version.
Posted on: 13 May 2008 by kuma
quote:Originally posted by Mr Pierce:
I'd prefer USB, as - per my understanding - there isn't the whole master/slave clocking issue, but - again per - Benchmark seems to be the only one with a handle on USB, and I don't like their sound.
Nah..
Wavelength has been a vocal advocate for a USB connection.
Cosecant USB DAC
And Bel Canto also is added the USB connection to their current DAC 3.
DAC3
Posted on: 13 May 2008 by jcs_smith
quote:Originally posted by Jack Barron:
There is a chap selling a CD-555, together with a NAPS-555.
The reason?
He has invested in a music streaming system. (He doesn't say which one). This means he can store all of his music on a hard drive and make his music accessible without a CD player.
The chap selling the CD-555 runs a Naim/Linn dealership.
When things like this are beginning to occur, a massive change is on its way.
Jack
That may not be that significant. I have met dealers and record shop opwners who never listen to music at home because they spend their whole working life dealing with it. Doing 9 to 5 6 days a week listening to music wouldn't you want to do something else on a night?
Posted on: 13 May 2008 by Guido Fawkes
quote:oing 9 to 5 6 days a week listening to music wouldn't you want to do something else on a night?
Can't think of anything I'd rather do at night.
Posted on: 13 May 2008 by James Lehmann
quote:Originally posted by daddycool:
Why don't you try a Firewire (to S/PDIF) interface instead of USB?
Absolutely.
You won't find USB interfaces in the pro-audio community - Firewire is a far more robust and reliable protocol for streaming audio.
Posted on: 13 May 2008 by jcs_smith
quote:Originally posted by ROTF:quote:oing 9 to 5 6 days a week listening to music wouldn't you want to do something else on a night?
Can't think of anything I'd rather do at night.
I can
Posted on: 13 May 2008 by daddycool
quote:Originally posted by James Lehmann:
Eek! My friend has had nothing but trouble with his TC interface and is selling it!
Sorry to hear that, James.
Mine's working smashing so far. It is 450 euro new, bought it used for half. I will try a RA PowerPak soon, see if it brings the same as others have reported concerning the Dynavector P-75.
The Metric Halo looks great, think it's a bit more pricey though.
Cheaper there is the M-Audio Audiophile Firewire, but haven't tried that. I know someone who has the USB version, but there's a FireWire socket on my Mac anyway, so...
Posted on: 13 May 2008 by daddycool
quote:Originally posted by ROTF:
47 Labs makes very interesting looking kit
Yes, looks great doesn't it? Especially on Kuma's pic. Sounds really nice too.
They do pop up pre-owned from time to time, just waiting.
Posted on: 13 May 2008 by Jack Barron
quote:Originally posted by ROTF:quote:
The chap selling the CD-555 runs a Naim/Linn dealership.
When things like this are beginning to occur, a massive change is on its way.
Jack
Jack, aren't Naim dealerships supposed to sell Naim kit or am I missing something?
ATB Rotf
Hiya, yes of course they are. But this gear is the dealer's own CD player and power supply. He says this in the advert he is using to sell the units.
It's a pity he doesn't mention which music streaming system he has invested in. I might try and find out.
Cheers,
Jack
Posted on: 13 May 2008 by Mr Pierce
Yeah, I'm aware there are many current DACs with USB ports in the back. I guess what I meant was "well implemented". Fer instance, I've read that the Grace Designs M902 sounds great via it's toslink input, and not so hot via USB. The Benchmark, they say, sounds its best via USB. But I don't like that sound. And the Wavelength site is what got me all worked up over this server issue in the first place! I just wanna stay SS and not go tube, since my Naim and Rega gear is SS, and I think those bits of kit sound just fine.
Posted on: 13 May 2008 by kuma
quote:I just wanna stay SS and not go tube, since my Naim and Rega gear is SS, and I think those bits of kit sound just fine.
MP,
It's a silly reason to exclude valve offerings.
If it sounds good, who cares?
Posted on: 14 May 2008 by Mr Pierce
kuma,
Agreed. I thought this would be easy. I figured just throwing money at the problem would fix it! Since my CDP is (IMHO) the least expensive truly high-end machine, I thought that if I bought a DAC from the middle of the pack I'd be okay. But this return to the casino every payday and throw the dice until I'm broke again approach so far hasn't worked out, so I figured I'd see if anyone on this forum - you, for instance - had already solved this problem to his/her satisfaction (or at least to a reasonable degree for a reasonable price). So far, within my budget the consensus is Lavry, and you make a compelling case for 47 Labs. My plan at this point - since I've already ruled out the Cambridge Audio CDPs and their usability as DACs - is to try the Lavry, only risking a couple bucks in shipping charges, then to take one last blind leap and follow in your footsteps, first with the DAC & then possibly later upgrading the PSU.
Had YOU recommended the Brick, say, I would leap at it without hesitation.
But again, if I just cool my jets and listen to CDs for a few years, this problem will solve itself without my having to invest so heavily in the R & D.
Again, since you're still following this thread, did you try the fancier 47 Labs DAC, the one for which your PSU was intended?
Agreed. I thought this would be easy. I figured just throwing money at the problem would fix it! Since my CDP is (IMHO) the least expensive truly high-end machine, I thought that if I bought a DAC from the middle of the pack I'd be okay. But this return to the casino every payday and throw the dice until I'm broke again approach so far hasn't worked out, so I figured I'd see if anyone on this forum - you, for instance - had already solved this problem to his/her satisfaction (or at least to a reasonable degree for a reasonable price). So far, within my budget the consensus is Lavry, and you make a compelling case for 47 Labs. My plan at this point - since I've already ruled out the Cambridge Audio CDPs and their usability as DACs - is to try the Lavry, only risking a couple bucks in shipping charges, then to take one last blind leap and follow in your footsteps, first with the DAC & then possibly later upgrading the PSU.
Had YOU recommended the Brick, say, I would leap at it without hesitation.
But again, if I just cool my jets and listen to CDs for a few years, this problem will solve itself without my having to invest so heavily in the R & D.
Again, since you're still following this thread, did you try the fancier 47 Labs DAC, the one for which your PSU was intended?
Posted on: 14 May 2008 by James Lehmann
Good luck with the Lavry DA-10 Mr Pierce.
However, I remain sceptical that feeding such a device from the built-in optical out of a MacBook will give any definitive answers to the CDP vs DAC debate.
My reasons (gleaned from the pro-audio world in which I reside) are as follows:
1) However clever the slave D-A device (ie DA-10), it's only ever as good as the clock in the master device (the Mac) which is still essentially a consumer device
2) Jitter and noise-tolerance is substantially better via an AES-EBU interconnect rather than S/P-DIF
3) TOSlink cables are nothing like as robust as AES-EBU cables
4) When syncing two digital devices the best quality is obtained by syncing clocks over a dedicated Wordclock BNC connection, 'AES over black' is a close second. A digital stream that carries clock and audio data is always compromised and is always avoided in the professional studio world.
For these reasons I recommend anyone with a serious interest in high-quality computer-based playback & storage to get busy researching professional Firewire (forget USB) DAC interfaces for your Mac. These devices generate their own (usually super-accurate) clocks, thus removing all the critical parts of the D-A outside the Mac and into a dedicated external box, which is all good news for the conversion process.
The only issue you may be dealing with is that a most professional Firewire DAC's feature balanced XLR outputs, so you'd either need to convert to DIN or RCA to hook up with your Naim gear, but its a small price to pay for the improvement in D-A sound quality. (Although you won't really care because by the time you start replaying good 24/96k recordings through it you will be leaving anything achievable by a 16/44.1k CD player firmly in the dust.)
Then again, if Naim were to manufacture such a standalone Firewire DAC device it could feature the usual DIN output as standard... hint, hint...
However, I remain sceptical that feeding such a device from the built-in optical out of a MacBook will give any definitive answers to the CDP vs DAC debate.
My reasons (gleaned from the pro-audio world in which I reside) are as follows:
1) However clever the slave D-A device (ie DA-10), it's only ever as good as the clock in the master device (the Mac) which is still essentially a consumer device
2) Jitter and noise-tolerance is substantially better via an AES-EBU interconnect rather than S/P-DIF
3) TOSlink cables are nothing like as robust as AES-EBU cables
4) When syncing two digital devices the best quality is obtained by syncing clocks over a dedicated Wordclock BNC connection, 'AES over black' is a close second. A digital stream that carries clock and audio data is always compromised and is always avoided in the professional studio world.
For these reasons I recommend anyone with a serious interest in high-quality computer-based playback & storage to get busy researching professional Firewire (forget USB) DAC interfaces for your Mac. These devices generate their own (usually super-accurate) clocks, thus removing all the critical parts of the D-A outside the Mac and into a dedicated external box, which is all good news for the conversion process.
The only issue you may be dealing with is that a most professional Firewire DAC's feature balanced XLR outputs, so you'd either need to convert to DIN or RCA to hook up with your Naim gear, but its a small price to pay for the improvement in D-A sound quality. (Although you won't really care because by the time you start replaying good 24/96k recordings through it you will be leaving anything achievable by a 16/44.1k CD player firmly in the dust.)
Then again, if Naim were to manufacture such a standalone Firewire DAC device it could feature the usual DIN output as standard... hint, hint...
Posted on: 14 May 2008 by gary1 (US)
James thank you I couldn't agree more and this is the intermediate solution I will be following until the Firewire DAC from Naim you mentioned becomes available? The other issue however becomes the ripping of the current 16 bit material to your PC/NAS whatever since we all have substantial quantities of CDs which we don't want to disregard. From what I've have researched the manner in which this is done is critical to the ultimate quality of the playback so not all programs either free on the internet or for purchase are really equivalent.
Posted on: 14 May 2008 by 555
quote:... this gear is the dealer's own CD player and power supply.
He says this in the advert he is using to sell the units.
2+2=5?
Posted on: 14 May 2008 by Steve S1
James,
I'm interested in your cable discussions.
I have been playing with iTunes 7 on the latest Mac OSX and getting very impressive results with an optical cable from AE. Far better than a coax feed from a CD transport.
The important things seem to be to take iTunes volume control out of the equation and make sure "sound enhancer" and "sound check" are both off (in iTunes "preferences"). The OSX Audio MIDI settings has the output at 44khz 2ch-24bit. Sounds very good to me, are you saying a different cable from AE to DAC would be better?
Mr P, the DAC1 under this arrangement sounded better than I've ever been able to get it before and exceeded my expection considerably. Very early reaction to the Lavry is that it is a further improvement, but mainly presentational - they both sound really good. I will enjoy reading about your experience.
Steve
I'm interested in your cable discussions.
I have been playing with iTunes 7 on the latest Mac OSX and getting very impressive results with an optical cable from AE. Far better than a coax feed from a CD transport.
The important things seem to be to take iTunes volume control out of the equation and make sure "sound enhancer" and "sound check" are both off (in iTunes "preferences"). The OSX Audio MIDI settings has the output at 44khz 2ch-24bit. Sounds very good to me, are you saying a different cable from AE to DAC would be better?
Mr P, the DAC1 under this arrangement sounded better than I've ever been able to get it before and exceeded my expection considerably. Very early reaction to the Lavry is that it is a further improvement, but mainly presentational - they both sound really good. I will enjoy reading about your experience.
Steve
Posted on: 14 May 2008 by James Lehmann
quote:Originally posted by Steve S1:
The important things seem to be to take iTunes volume control out of the equation and make sure "sound enhancer" and "sound check" are both off (in iTunes "preferences").
Oh for sure, yes - don't touch any of that nonsense, even the iTunes volume! The minute you do you are screwing digitally with the original data which, assuming you want to hear what the mastering engineer intended the material to sound like, you most certainly don't want to mess with.
quote:Originally posted by Steve S1:
I have been playing with iTunes 7 on the latest Mac OSX and getting very impressive results with an optical cable from AE.
Sorry Steve - I'm not quite sure what you mean by AE?
quote:Originally posted by gary1:
The other issue however becomes the ripping of the current 16 bit material to your PC/NAS whatever since we all have substantial quantities of CDs which we don't want to disregard. From what I've have researched the manner in which this is done is critical to the ultimate quality of the playback so not all programs either free on the internet or for purchase are really equivalent.
Absolutely! But this is where my experience (and time to research) runs a bit thin. Fortunately there are others here - "pcstockton" comes to mind - who appear to have done a great deal of detailed research on this and can advise on some solutions. Unfortunately, his conclusion is at the moment the Mac doesn't offer the perfect ripping solution yet - iTunes is not up to scratch on things like 24/96k support, PQ codes, indexes and track gap times. He cites non-support of FLAC as another strike against iTunes, but this is irrelevant if, like me, you intend to rip your music to industry-standard WAV's. Obviously, there are many of us who hope this state of software affairs will improve for Mac users, because in terms of reliable Firewire streaming, remote control and GUI, Mac hardware is more than viable as an excellent music-server platform. If it wasn't then 95% of the world's professional recording studios wouldn't be using one!
Posted on: 14 May 2008 by Steve S1
quote:Sorry Steve - I'm not quite sure what you mean by AE?
Hi James,
Airport Express.
Mac streams to AE. AE is connected via optical to the DAC. DAC to Amp by the usual ic.
Steve
Posted on: 14 May 2008 by Jack Barron
quote:
Then again, if Naim were to manufacture such a standalone Firewire DAC device it could feature the usual DIN output as standard... hint, hint...
Thanks for all of the info you have provided James and Kuma.
I am using a Mac > Airport Express > Beresford DAC > Nait 5 > Flat-Cap 2x > Linn Kelidhs.
I know it can be bettered and that is why it has been interesting to read this thread.
The guy who is selling his CD-555 and 555PS is doing so because he has bought a Linn Klimax DS system.
He has emailed me to say that a Linn Sneaky DS, the bottom of their digital-file player range, will produce higher quality output of music than my Naim CD5.
I can believe this is possible. When I play digital files at the moment the music is nearly as good as using the CD5.
Given that I am thinking about buying a Logitech Duet, and setting up a NAS system, your idea about Naim manufacturing a standalone Firewire DAC device is bang on.
In the interim I will try and go to tomtom audio's Naim Roadshow at a hotel in St Albans next month. This will give me a chance to listen to the HDX and also the highly rated Guru QM10 speakers.
Jack
Posted on: 14 May 2008 by kuma
quote:I thought this would be easy. I figured just throwing money at the problem would fix it!
I think it depends on how much money you throw at it.
quote:I thought that if I bought a DAC from the middle of the pack I'd be okay.
Yeah. Me too.
And Shigaraki combo isn't exactly cheap ( as for me, the PSU upgrade was mandatory ), at least I am in the ballpark of where I want to be.
quote:did you try the fancier 47 Labs DAC, the one for which your PSU was intended?
I haven't tried it but then talking to the US distributor, he told me that the PSU upgrade is a better VFM. The Progression DAC apparently is something akin to going from an X series CD player to S players in a Naim hierarchy.
Posted on: 14 May 2008 by kuma
munch,
I thought it would be cool to ditch all the CDs and store the music on a computer. But then I realised it's just too pain in the arse so I stopped.
I have to admit it was a cobbled together effort and every piece of aspect was compromise.
In order for me to ensure everything was up and up, it seemed too great of a learning curve as well as when I reliased my itune rip ( wav ) was not as good as others, I sort of threw my hands up in the air called it a quit. ( I guess I wasn't anal retentive enough to go through with it again ! )
It was sort of like owning a turntable but worse.
But yes, it was an *interesting* experience.
I thought it would be cool to ditch all the CDs and store the music on a computer. But then I realised it's just too pain in the arse so I stopped.
I have to admit it was a cobbled together effort and every piece of aspect was compromise.
In order for me to ensure everything was up and up, it seemed too great of a learning curve as well as when I reliased my itune rip ( wav ) was not as good as others, I sort of threw my hands up in the air called it a quit. ( I guess I wasn't anal retentive enough to go through with it again ! )
It was sort of like owning a turntable but worse.
But yes, it was an *interesting* experience.
Posted on: 14 May 2008 by Keith L
Kuma,
During all your attempts at achieving Nivarna with streamed audio, did you actually stream aiff/wav audio to your sb2 to a Benchmark Dac1 via a Naim dc1, and the Dac1 to your pre-amp via a hiline?
The results I get from the above are nothing but outstanding. Have I inadvertently stumbled across great sounds? It is matches my cdx2/xps2/hiline.
I cannot understand comments about the Dac1 being sterile. I've heard similar said about a bare cdx2, but the addition of a xps2 usually sorts that out. Similarly in the case of the Dac1, could the addition of a Naim dc1 and hiline have changed this "sterile" presentation?
Keith
During all your attempts at achieving Nivarna with streamed audio, did you actually stream aiff/wav audio to your sb2 to a Benchmark Dac1 via a Naim dc1, and the Dac1 to your pre-amp via a hiline?
The results I get from the above are nothing but outstanding. Have I inadvertently stumbled across great sounds? It is matches my cdx2/xps2/hiline.
I cannot understand comments about the Dac1 being sterile. I've heard similar said about a bare cdx2, but the addition of a xps2 usually sorts that out. Similarly in the case of the Dac1, could the addition of a Naim dc1 and hiline have changed this "sterile" presentation?
Keith
Posted on: 15 May 2008 by kuma
quote:Originally posted by Keith L:
During all your attempts at achieving Nivarna with streamed audio, did you actually stream aiff/wav audio to your sb2 to a Benchmark Dac1 via a Naim dc1, and the Dac1 to your pre-amp via a hiline?
The DAC1 was tried with an EAD DVD transport only. No SB2 was involved since i haven't bothered putting it back in the system.
I have tried the Shigaraki/Dumpty on the same transport as well. And still.. somehow, a DAC1 is missing in funkiness. ( hard to explain )
Hell, Krell DAC was more organic sounding than the Benchmark!
I've been using a Naim DC1 as my reference digital cable.
It adds some grooves.
My Krell CD player benefits from it yet it does not change the player's inherent character. Naim leads will help but they will never change their core personality. I'd rather start from something closer and use cables to further enhance the kit's strength.
I haven't used a RCA/DIN HiLine on any of those DACs. (only Chord Chrysalis cable )
The preamp was the same old Nait 3R/SC.
I also did a lot of headfone listening via NAHA/AT W5k as well.
quote:The results I get from the above are nothing but outstanding. Have I inadvertently stumbled across great sounds? It is matches my cdx2/xps2/hiline.
That's great!
quote:I cannot understand comments about the Dac1 being sterile.
Listener preference as well as a system make-up.
I won't expect everyone to like my systems.
Seriously, when I did a coax digital cable shoot out in friend's system ( this one consists of all Audio Note UK DAC 3.1/matching transport ), his favourite was the Siltech G5. My favourite was still with the DC1. We value different things which is cool.
quote:I've heard similar said about a bare cdx2, but the addition of a xps2 usually sorts that out. Similarly in the case of the Dac1, could the addition of a Naim dc1 and hiline have changed this "sterile" presentation?
I got spoiled by using a 555PS on a CDX & CDS3 up in my office system.
And I am aiming for something beyond a CDX2/XPS2 level at this point if I were to switch over to a HD/DAC arrangement.
Shigaraki DAC will never get there. It does not produce that type of sound. But the *funky* bassline or naturalness are there at least which I don't hear from an XPS2 PSU. The bass dynamics are there, of course, but there's something missing and artificial about an XPS2 compared to a 555PS.
Hence the attraction of a HDX. You can use a 555PS!
I'm sure Naim can make a Superline level killer DAC that can be powered off a 555PS. ( one can hope )
But that's up there in terms of price, but one thing I know is that a good digital don't come cheap. And inevitably, the VFM is smaller once you pass a certain point.
Trying to find something *good* ( this is subjective, mind you ) at around 2-3k is tough and it all seems some sort of trade offs rather than definitively better for me. And the part of the reason I've settled on the Shigaraki is that I realised that the next performance leap will be costly when I tried the valve DAC costing around 6k.
Sure you can always band-aid something with cables tailored to a system need. I've done it many times and sometimes I still do it!
oh.. be sure to add Powerline(s) to your system as well.
Posted on: 15 May 2008 by Keith L
quote:Sure you can always band-aid something with cables tailored to a system need. I've done it many times and sometimes I still do it!
If my cdx2/xps2/hiline qualifies for the band-aid title, I don't mind the same being said of my sb3/BM dac1/dc1/hiline. In the context of cables, I give my streamed audio the same level playing field as my cd replay.
Keith