Dartzeel Preamp Hiss

[bonzo75]

Update. I just got in a home demo Trinity Golden Reference Preamp to compare with the Dartzeel. The Trinity is dead quiet so given that everything else is the same, it must just be how the Dart is. The Dart is, i remind you, not loud but it is audible for a short distance away.

More concerning, and i was warned, is that the Trinity is much more highly resolving than the Dart without being analytical, which is often the case. The Dart still sounds lovely and i could happily live with it, especially given i love its looks and wanted one for about a decade. But the Trinity is really something else. I am not sure if i like its looks that much but it is an incredible preamp that just sounds right. Even my 11 year old son and 10 year old daughter immediately asked me (without knowing which was playing) why one seemed muffled and less detailed (that was the Dart).

Unfortunately the Trinity is not cheap at all. MSRP is 53k Euros plus 20k Euros for the optional PSU. On sound alone it wins, unfortunately, as i so much wanted there to be no discernible difference.View attachment 55220View attachment 55221

Jazzhead has both trinity and Koda k15 preamps. He is now using the Koda. You can PM him for the difference as he is not very active on the forum.

 

[marty]

50 ohm BNC connectors are not a new idea and have been around for decades although not widely implemented. In the 80s I ripped out all the RCA connectors from my gear (Rowland) and installed them to great advantage. Their main benefit is that they make one's gear far less reliant on the quality and type of interconnect cables used. Due to better impedance matching of the preamp and amp, it sort of takes the interconnects out of the equation you might say. I think darT is onto something here and it seems curious why others don't implement this as well. Or course, when I tried to sell my gear with only BNC connectors, it was impossible so I had to put back the conventional RCAs. Thus, the lack of a standard using only BNC connectors is a drawback. Fortunately darT gear has options for both, but still, there is a lot of merit as to why a 50 ohm BNC connectors may offer a sonic advantage.

 

[howiebrou]

Howie
Wayt end of the year new CH L 10
I think you forget the pre for next years

Gian, please don't say that!

 

[howiebrou]

50 ohm BNC connectors are not a new idea and have been around for decades although not widely implemented. In the 80s I ripped out all the RCA connectors from my gear (Rowland) and installed them to great advantage. Their main benefit is that they make one's gear far less reliant on the quality and type of interconnect cables used. Due to better impedance matching of the preamp and amp, it sort of takes the interconnects out of the equation you might say. I think darT is onto something here and it seems curious why others don't implement this as well. Or course, when I tried to sell my gear with only BNC connectors, it was impossible so I had to put back the conventional RCAs. Thus, the lack of a standard using only BNC connectors is a drawback. Fortunately darT gear has options for both, but still, there is a lot of merit as to why a 50 ohm BNC connectors may offer a sonic advantage.

Whether it is correct or not i don't know but my Dart dealer says his Dart customers don't use the 50ohm connector from preamp to poweramp because it is inferior to good quality interconnects. Go figure. It would actually be great for me since my interconnects are around 7m long and the Dart ones are not too expensive (relatively).

 

[fbhifi]

The finest connection between the Dart preamp and Dart amp I’ve experienced is the one that Mike and I use- Evolution Acoustics 50 ohm BNC interconnect. I can’t speak to running BNC interconnects from a Dart pre to another manufacturers amp. However, if I’m not mistaken, I believe Mike commented a while back that his EA BNC interconnect with an RCA adapter on the amp end, when using a non Dart amp outperformed $20K Tara Labs RCA terminated “Uber Wire.”

 

[DaveC]

A couple issues... There are no grounding standards for audio gear wrt how signal and chassis ground are connected. There are no standards as to how AC power is delivered to the components. This leaves the possibility of large amounts of resistance between the grounds of components plugged into different lines. Power cable grounds and interconnect grounds may be one and the same (electrically speaking), or isolated in whichever way the designer thinks will work best using a wide variety of circuits and passive devices.

This leaves the possibility open for components to perform differently in different systems and combined with different gear, and leaves open the possibility that grounding "band-aids" will work, and will have variable results from system to system.

As far as the BNC interface, it's not the BNC plugs and jacks that matter, it's the impedance. If you simply put BNC connectors on random components all you're hearing is the difference in how the connectors sound. The BNC 50 ohm interface used by Dart is to avoid impedance mismatch, which is a real issue because we don't have set standards for that either. This leaves open the possibility that sources, pres and amps don't ideally "match" for best results.

Now, there's no way standardizing the impedance and connection "removes" the dependence on interconnect quality, it's doing something completely different, impedance matching. This doesn't mean the cable makes no difference, if you think so then it's not possible for S/PDIF cables to sound different either.

One anecdote to illustrate the point. Not too long ago Burson paid a bunch of folks (or gave them free cables) to review their "cable", which uses Canare parts afaik, good but very basic parts and wire. But there was one massive difference... an active USB-powered buffer sitting in the middle of the cable. This resulted in large improvements in many people's systems, which they attributed to the cable, which is ridiculous. If the buffer had RCA jacks for in and out like a regular component then people would review a $10 USB-powered active buffer as making major improvement in their system, which few are going to admit, but seen as a cable with a weird hump in the middle and a usb cable attached, it was seen completely differently.

So, when you're connecting Dart > Dart the 50 ohm interface optimizes impedance match. But when you run a Dart Pre to any other amp the interface's advantages probably won't exist.

IMO there's no doubt that a really well made UPOCC silver 50 ohm BNC cable will sound VERY different vs a commodity 50 ohm coax cable used for the same purpose, but in comparisons the impedance advantage of the 50 ohm may or may not trump and differences in how the cable is made or what it's made out of.

 

[microstrip]

When I owned the NS18 and the NHB108 I tried several brands of 50 ohm BNC cables, from cheap to to top high bandwith laboratory cables and they all sounded different - I ended with the DartZeel supplied one, that came from a known CERN cable supplier. Impedance matching is not relevant at audio frequencies, but sources delivering signals to 50 ohm loads are supplying much higher current - some electronics have 50 ohm output impedance but are not able to drive 50 ohm input in a distortion free way.

 

[asiufy]

I've also experimented with RCAs and different BNCs when I had the 18NS/108 combo. At the time, I did not have access to the EA cables, so unfortunately that wasn't considered. But I did prefer darTZeel's BNC link, and that allowed me to purchase a 10 meter long cable, for not much money, as I wanted to move my sources off to the side and just leave the 108 in between the speakers.
No RCA I've tried at the time, including Odin, Transparent, MIT, etc. could touch darTZeel's BNC link, and I only wish I had the EA BNC cables back then
The idea behind the 50 ohm is not to eliminate the effect of the cable, but minimize the effect of the cable LENGTH, as the components are supposed to maintain the same impedance, regardless of the length of the cable.

howie,
Normally I'd say listen to your dealer, but in this instance, if you do try the combo 108/18NS, try the BNC link. Your 18NS will be absolutely dead quiet too.

 

[Mike Lavigne]

I've also experimented with RCAs and different BNCs when I had the 18NS/108 combo. At the time, I did not have access to the EA cables, so unfortunately that wasn't considered. But I did prefer darTZeel's BNC link, and that allowed me to purchase a 10 meter long cable, for not much money, as I wanted to move my sources off to the side and just leave the 108 in between the speakers.
No RCA I've tried at the time, including Odin, Transparent, MIT, etc. could touch darTZeel's BNC link, and I only wish I had the EA BNC cables back then
The idea behind the 50 ohm is not to eliminate the effect of the cable, but minimize the effect of the cable LENGTH, as the components are supposed to maintain the same impedance, regardless of the length of the cable.

howie,
Normally I'd say listen to your dealer, but in this instance, if you do try the combo 108/18NS, try the BNC link. Your 18NS will be absolutely dead quiet too.

before Herve Delatraz created the brand darTZeel or introduced his first commercial product, he wrote an article about flaws in interconnect geometry that appeared in the September 2001 issue of Stereophile. honestly that article is way above my head techncially; but in it Herve suggests that conventional interconnects (XLR and RCA) add echo's to the signal based on imperfect impedance matching. the article has lots of math and tech talk making his case.

his 50 ohm 'zeel' approach is an answer to his article.

i have that September 2001 issue of Stereophile, unfortunately that article is not on-line anywhere that i have seen.

i do have 15 years experience listening with the 'zeel' interface and am a big believer.

 

[microstrip]

before Herve Delatraz created the brand darTZeel or introduced his first commercial product, he wrote an article about flaws in interconnect geometry that appeared in the September 2001 issue of Stereophile. honestly that article is way above my head techncially; but in it Herve suggests that conventional interconnects (XLR and RCA) add echo's to the signal based on imperfect impedance matching. the article has lots of math and tech talk making his case.

his 50 ohm 'zeel' approach is an answer to his article.

i have that September 2001 issue of Stereophile, unfortunately that article is not on-line anywhere that i have seen.

i do have 15 years experience listening with the 'zeel' interface and am a big believer.

Nothing new on the maths of impedance matching - it is spread in many textbooks, every electrical or electronic engineer must go through it once in his bachelor studies. The echos are just reflections - they can be easily seen in a fast oscilloscope. We have debated the subject several times in WBF. However these echos exist in the nanosecond scale and their influence in the audio band has never been proved.

More than one decade before the 2001 Stereophile article Bob Stuart of Meridiam wrote a similar article and implemented a terminated topology in his 100 series - but using 75 ohm . We can see the reference to the optional 75 ohm module in the technical literature of the 101 preamplifier. Users could buy 75 ohm terminators to use with their higher impedance electronics. The promise was the same - no cable sound, just perfect transmission with standard long inexpensive cables! This was particularly attractive with their active speakers.

Anyway there are other advantages of the 50 ohm mode - for example the low impedance makes it much less sensitive to interference. It is why professionals use the 600 ohm balanced interface in telecoms, studios or adverse conditions.

BTW, being a believer in the high-end is a consequence of years of listening and experience, not of technical papers filled with maths!

 

[Ron Resnick]

I find the use of a BNC connector a little puzzling. In amateur radio (and commercial radio too, actually) the standard connector interface for high frequency (“HF”) radio communication is the ubiquitous PL-259.

The standard connector interface for very high frequency (“VHF”) radio communication is the BNC connector. The BNC connector offers a lower power loss through the connector than does a PL-259.

The standard connector interface for ultra high frequency (“UHF”) radio communication is the N connector. The N connector offers a lower power loss through the connector than does a BNC.

PL-259s and BNCs and Ns are used generally with co-axial cables.

But the signal attenuation at audio frequencies is so low for the lengths audiophiles deal with I don’t see the rationale for using the low-loss BNC connector in the first place.

What am I missing here?

 

[adyc]

I would like to ask more technical person in this forum about impedance matching. Given the length of interconnect is around 2m and the frequency of audio signals is up to 20kHz. The wavelength is much much longer than the length of interconnect. From standard textbook, the circuit can be considered discrete elements. There is no need for impedance matching. What is the fuzz of impedance matching between pre and power amp?

 

[howiebrou]

Try what I suggest first. Doing so will eliminate a lot of variables. Changing the power source adds more.

You could even see if gain affects it the same without the powercord connected, but being on.

If you try it, I'll stay on top of this thread to see what can be done - or if there is anything necessary to be concerned with.

Dartzeel connected: Hiss from 12 inches sometimes further. It is audible as you walk past.

Dartzeel on mute: same as above.

Dartzeel with PSU turned off: same as above.

Dartzeel with PSU disconnected: same as above.

Dartzeel disconnected: Hiss only audible if you put ear to tweeter.

Trinity Golden Reference Preamp: Hiss only audible if you put ear to tweeter.

 

[Folsom]

Interesting, that's very useful information! It would seem that the floating nature of it raises the stakes for controlling the loop more. I suspect DartZheel's amps compensate for that.

Thank you!

 

[howiebrou]

Interesting, that's very useful information! It would seem that the floating nature of it raises the stakes for controlling the loop more. I suspect DartZheel's amps compensate for that.

Thank you!

I guess so. I wonder how many others use the Dartzeel preamp with other brand amps and get black backgrounds. There is something to be said for system matching i guess.

 

[asiufy]

Are you still using the Analog Domain amp?
Do you get the hiss even with the Analog Domain set for +26dB gain? +41dB gain is clearly excessive.
Do you still get the hiss if you use RCA?
Also, if you have your source hooked up to the XLR inout (VI), I'd play with the two switches below the connector on that input. The first one, I'd switch it to the left, to lower gain by +6dB. The bottom one is grounding, with 3 different settings.
Straight from the manual:
"For input VI (Chapter 3.2. pos. 4), the upper tog- gle default position is center. Right position offers 600-ohm input impedance for professional gear. Left position lowers the gain by 6 dB; this attenua- tion only works when true floating source is used (transformer output source).
Lower toggle switch allows for various ground path schemes regarding the XLR chassis jack. Default position is right. Center position is floating, useful in certain circumstances for cancelling ground loops. Left position is with XLR chassis connected to ground via a 100-ohm resistor, for same purpose as described for center position."

 

[dandylinpsst]

Dartzeel connected: Hiss from 12 inches sometimes further. It is audible as you walk past.

Dartzeel on mute: same as above.

Dartzeel with PSU turned off: same as above.

Dartzeel with PSU disconnected: same as above.

Dartzeel disconnected: Hiss only audible if you put ear to tweeter.

Trinity Golden Reference Preamp: Hiss only audible if you put ear to tweeter.

My sysem(drartzeel pre+boulder 2060 balanced wire with transparent cable)

Dartzeel connected: Hiss from 12 inches sometimes further. It is audible as you walk past.

Dartzeel on mute: Hiss only audible if you put ear to tweeter.

Dartzeel with PSU turned off: same as above.(Hiss only audible if you put ear to tweeter.)

Dartzeel with PSU disconnected: same as above.

Dartzeel disconnected: Hiss only audible if you put ear to tweeter.

Boulder Preamp: Hiss only audible if you put ear to tweeter

PS: When PSU turned off(battery is full charged) , How much time can dartzeel work?

 

[howiebrou]

Are you still using the Analog Domain amp?
Do you get the hiss even with the Analog Domain set for +26dB gain? +41dB gain is clearly excessive.
Do you still get the hiss if you use RCA?
Also, if you have your source hooked up to the XLR inout (VI), I'd play with the two switches below the connector on that input. The first one, I'd switch it to the left, to lower gain by +6dB. The bottom one is grounding, with 3 different settings.
Straight from the manual:
"For input VI (Chapter 3.2. pos. 4), the upper tog- gle default position is center. Right position offers 600-ohm input impedance for professional gear. Left position lowers the gain by 6 dB; this attenua- tion only works when true floating source is used (transformer output source).
Lower toggle switch allows for various ground path schemes regarding the XLR chassis jack. Default position is right. Center position is floating, useful in certain circumstances for cancelling ground loops. Left position is with XLR chassis connected to ground via a 100-ohm resistor, for same purpose as described for center position."

Thanks for the info. I tried the toggles. Hiss is the same whether the upper toggle is in the middle or -6dB. Same for the lower toggle. It doesn’t make any difference. And yes the Analog Domain Apollos are still here. With the power amp at 26dB gain it is MUCH quieter than 41dB but i can often still hear it from my listening position (just). May be i just need to get the 468s in for a demo. Seems like Dandylinpsst also has the same issue or should i say characteristic?

 

[howiebrou]

My sysem(drartzeel pre+boulder 2060 balanced wire with transparent cable)

Dartzeel connected: Hiss from 12 inches sometimes further. It is audible as you walk past.

Dartzeel on mute: Hiss only audible if you put ear to tweeter.

Dartzeel with PSU turned off: same as above.(Hiss only audible if you put ear to tweeter.)

Dartzeel with PSU disconnected: same as above.

Dartzeel disconnected: Hiss only audible if you put ear to tweeter.

Boulder Preamp: Hiss only audible if you put ear to tweeter

PS: When PSU turned off(battery is full charged) , How much time can dartzeel work?

I am guessing the Dart is a much sweeter presentation than the Boulder preamp. Funnily my psu to the Dart doesn’t seem to affect the hiss much, unlike yours.

 

[Alrainbow]

Does the hiss stop if you select an unused input on the preamp ?