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Post by brucew268 on Aug 10, 2021 17:49:47 GMT
XLR's are not my weapon of choice... That 3d imaging we crave is far easier to obtain with RCA connections IMO, but i know that im in the minority there. Oli mentioned this in a PM a while back and I thought I'd ask him and anyone else interested about it...
Do you find that balanced technology in the cables and/or preamp have any effect on 3D imaging either positive or negative? Oli, can you tell more about your own experience of finding 3D imaging easier with RCA connections? Due to connectors or preamp circuit or... ?
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Bigman80
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Post by Bigman80 on Aug 10, 2021 18:04:38 GMT
XLR's are not my weapon of choice... That 3d imaging we crave is far easier to obtain with RCA connections IMO, but i know that im in the minority there. Oli mentioned this in a PM a while back and I thought I'd ask him and anyone else interested about it... Do you find that balanced technology in the cables and/or preamp have any effect on 3D imaging either positive or negative? Oli, can you tell more about your own experience of finding 3D imaging easier with RCA connections? Due to connectors or preamp circuit or... ?
I can't really give a scientific reason for the experience i have had with these two methods, but going balanced seemed to rob the sound of some dimensionality. It's something i have done twice in my hifi journey, and twice i have felt the feeling of "ah, thats better" when i returned to single ended. The 686 really seemed to benefit from removing the XLR connectors. The move to RCA pulled out more image depth. I know Tom designed it for a balanced connection, but like the Speakon connectors...they just don't work for me. I was using the 8x2 preamp too, so that was balanced all through. I used an RCA to XLR cable and felt the imaging extended a bit further back. Then i removed the 8x2, put in the BT2 and was happier still, but thats a new component. Maybe the cable behaved better unbalanced? I just don't know. However, if someone could provide a reason i would be very interested. |
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Post by brucew268 on Aug 10, 2021 20:37:53 GMT
Oli, can you tell more about your own experience of finding 3D imaging easier with RCA connections? Due to connectors or preamp circuit or... ? I can't really give a scientific reason for the experience i have had with these two methods, but going balanced seemed to rob the sound of some dimensionality. It's something i have done twice in my hifi journey, and twice i have felt the feeling of "ah, thats better" when i returned to single ended. The 686 really seemed to benefit from removing the XLR connectors. The move to RCA pulled out more image depth. I know Tom designed it for a balanced connection, but like the Speakon connectors...they just don't work for me. I was using the 8x2 preamp too, so that was balanced all through. I used an RCA to XLR cable and felt the imaging extended a bit further back. Then i removed the 8x2, put in the BT2 and was happier still, but thats a new component. Maybe the cable behaved better unbalanced? I just don't know. However, if someone could provide a reason i would be very interested. If that is the case, I wonder how much is the component and how much is the connector? You said that just changing from XLR to RCA on the 686 amp gave you some back with no other changes at the preamp end, so a single ended output from the preamp before and after? That would imply it's in the XLR connector not the preamp circuit that you experienced a loss. XLR connectors are more metal mass and more dielectric mass and yet XLR's generally considered a better design than RCA's and and balanced cables handle the screening better. I've tended to use balanced years ago and noticed there was a purity that seemed to be a lower noise floor and better space between the notes. At the moment in my new all balanced setup I'm getting that purity and perception of lower noise floor but with a loss of depth & 3D sense. It could well be that it needs some burn in time, and if unsettled teflon connectors are the issue then a couple hundred hours would be needed. But if not, that's a couple hundred hours wasted. Last week I was using the same XLR cables and the same amp sockets but a single ended preamp with RCA sockets at that end. The imaging and depth seemed better but I wasn't focusing on that and it's been many months since I had a single ended amp in the system. I wonder what would happen if I rewired the preamp back to single ended but still used XLR connectors wired for single ended? Of course that's a different focus than your experience. |
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Bigman80
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Post by Bigman80 on Aug 10, 2021 21:25:14 GMT
The 8x2 was balanced. I used XLR from the 8x2 and RCA in the rear of the 686.
As you say, the general consensus is that the XLR is better from all aspects of noise rejection to conductor size, but when I tried it, it never had the depth of soundstage I was used to.....which admittedly wasn't huge with anything.
Interestingly, I've just found some notes I took around the time.
I measured the 1m Spotfire XLR cables with different plugs on. They were all a minimum of 70pf/m higher than the 1m Spotfire RCA cables.
Neutrik being the highest, DHLabs being second and the lowest....elecaudio gold plated copper 😉
Maybe that's where the real difference lies?
The interconnets I use now have very low capacitance.
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Post by sq225917 on Aug 10, 2021 23:56:08 GMT
The difference is the extra noise and distortion from having to run the preamp at twice the level to compensate for the lower signal level on rca vs xlr.
Maybe the perception of depth is just an artifact that you prefer based on the assumption more depth = mo better?
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Bigman80
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Post by Bigman80 on Aug 11, 2021 7:13:28 GMT
The difference is the extra noise and distortion from having to run the preamp at twice the level to compensate for the lower signal level on rca vs xlr. Maybe the perception of depth is just an artifact that you prefer based on the assumption more depth = mo better? Not sure. I'll look at that and get an expert opinion from the preamp designer...I'll be back. |
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Post by brucew268 on Aug 11, 2021 7:32:03 GMT
Maybe the perception of depth is just an artifact that you prefer based on the assumption more depth = mo better? Admittedly a personal opinion widely shared but... more depth IS more better. It's just not the only measure of 'more better' and can't trump all other measures. |
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Post by brucew268 on Aug 11, 2021 7:45:29 GMT
The difference is the extra noise and distortion from having to run the preamp at twice the level to compensate for the lower signal level on rca vs xlr. Interestingly, now my power supply is probably working harder to drive the preamp ( 4 buffer circuits instead of 2). While it did not appear to be getting warm, it semed to benefit by adding heat sinks to the regulators and am considering a more powerful spec tranformer that delivers more than 1A per rail. |
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Bigman80
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Post by Bigman80 on Aug 11, 2021 8:33:51 GMT
Just having a dig through the notes again and my BT2 preamp (Unbalanced) has the following: 0.00001X% at 1 kHz The closest "rival" in terms of principal, IE being a buffer with no gain, has the following: 0.00025 % at 1 kHz Difference being that one is balanced. I'm not convinced the difference is an artifact of distortion. Considering the the 8x2 was also a buffer type design with no gain, I am more sure that isn't the case. But, I will check with my technical advisor phonomac Also, seeing as all three preamps I am talking about offer no gain, the output would be dictated source? Using the same DAC on 2 of those 3 devices means that they are all working as hard? Not sure if if barking up the wrong tree, but ill find out. |
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Post by misterc on Aug 11, 2021 9:33:40 GMT
Balanced circuitry IF correctly implimented (completely dual differencual discrete set up) will result in a lower noise, greater depth and my dynamics I have found over the years of designing equipment.
Some of the best single ended outputs sound have been from Japanese equipment, possibly the formation of soundstaging in your listening enviroment may be causing your preferance Oli
Can you let me have your secret for poiducing your BT2 pre amplifer which has amazing low distortion please Oli? the Tad C600 is around 0.001% our LM1 is 0.00024% but we are still an order of magnitute off the BT2
That is some achievement fair play sir
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Bigman80
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Post by Bigman80 on Aug 11, 2021 9:46:27 GMT
Balanced circuitry IF correctly implimented (completely dual differencual discrete set up) will result in a lower noise, greater depth and my dynamics I have found over the years of designing equipment. Some of the best single ended outputs sound have been from Japanese equipment, possibly the formation of soundstaging in your listening enviroment may be casuing your preferance Oli Can you let me have your secret for poiducing your BT2 pre amplifer which has amazing low distortion please Oli? the Tad C600 is around 0.001% our LM1 is 0.00024% but we are stil an order of magnitute off the BT2 That is some achievement fair play sir I may have one zero too many there T, but I'll be confirming everything in a few weeks when we've finished measuring everything. |
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Post by macca on Aug 11, 2021 10:59:32 GMT
even if you took out all the zeros it's still not going to be audible.
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Post by brucew268 on Aug 11, 2021 11:06:02 GMT
The difference is the extra noise and distortion from having to run the preamp at twice the level to compensate for the lower signal level on rca vs xlr. Interestingly, now my power supply is probably working harder to drive the preamp ( 4 buffer circuits instead of 2). While it did not appear to be getting warm, it semed to benefit by adding heat sinks to the regulators and am considering a more powerful spec tranformer that delivers more than 1A per rail. Well I had that wrong. When I was 'optimising' the power supply at the same time as I added the 2 other buffer circuits, I took out a resistor that was meant to add to the idle load of the power supply. This PSU design needs 45mA load at idle to perform with best linearity and with the 2nd pair of buffers included I was measuring 44mA load at idle, so left out the 250 Ohm resistor that had been there for load. I decided to add it back in and listen again. Hmmm! My dimensionality/depth is a good bit better, back to my normal range!
Who knew?! Sorry for the misdirection.
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Bigman80
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Post by Bigman80 on Aug 11, 2021 12:04:55 GMT
Interestingly, now my power supply is probably working harder to drive the preamp ( 4 buffer circuits instead of 2). While it did not appear to be getting warm, it semed to benefit by adding heat sinks to the regulators and am considering a more powerful spec tranformer that delivers more than 1A per rail. Well I had that wrong. When I was 'optimising' the power supply at the same time as I added the 2 other buffer circuits, I took out a resistor that was meant to add to the idle load of the power supply. This PSU design needs 45mA load at idle to perform with best linearity and with the 2nd pair of buffers included I was measuring 44mA load at idle, so left out the 250 Ohm resistor that had been there for load. I decided to add it back in and listen again. Hmmm! My dimensionality/depth is a good bit better, back to my normal range!
Who knew?! Sorry for the misdirection.
Well at least youve gotten to the bottom of it. That's all that matters. |
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Bigman80
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Post by Bigman80 on Aug 11, 2021 16:38:02 GMT
even if you took out all the zeros it's still not going to be audible. Well, ok....but if the preamp has say 1% THD+N, it's adding that 1% to everything. So will the amplifier and speakers, so keeping those devices as low distortion as possible can only be a good move. |
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Post by sq225917 on Aug 11, 2021 18:57:58 GMT
A pre amp doesn't have a spot noise measure at one frequency, it has a range of distortion depending on impedance of the next devices input and the position of the preamp volume control.
0.0001% thd @1khz at 2v out into a 2k load would be a very good figure, that would require very good layout shielding and regulation of the pcb and input/ output sockets and wiring.
0.00001% would be world class, only a handful of active pre amps currently manage this.
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Bigman80
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Post by Bigman80 on Aug 11, 2021 19:45:47 GMT
A pre amp doesn't have a spot noise measure at one frequency, it has a range of distortion depending on impedance of the next devices input and the position of the preamp volume control. 0.0001% thd @1khz at 2v out into a 2k load would be a very good figure, that would require very good layout shielding and regulation of the pcb and input/ output sockets and wiring. 0.00001% would be world class, only a handful of active pre amps currently manage this. Well, when the figures land, we'll see if it's very good, or World class, or somewhere in between.... But I do expect it to achieve similar/better numbers than the Neurochrome buffer, which advertises 0.00025% at 1hHz..... However measurements aren't really my bag, so I'll let an independent party do them. |
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Post by macca on Aug 11, 2021 20:24:58 GMT
sixty-odd years ago Harold Leak reckoned if you were below 0.1% you were golden. I don't think any research done since has showed that to be wrong. I think the absolute threshold is 0.02% but in the real world listening to music you're never going to hear that or anything close.
On the other hand I totally agree with the approach of aiming for perfection to achieve excellence.
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Bigman80
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Post by Bigman80 on Aug 11, 2021 20:27:24 GMT
sixty-odd years ago Harold Leak reckoned if you were below 0.1% you were golden. I don't think any research done since has showed that to be wrong. I think the absolute threshold is 0.02% but in the real world listening to music you're never going to hear that or anything close. On the other hand I totally agree with the approach of aiming for perfection to achieve excellence. Might as well do it right If you're gonna do it, ay! |
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Post by sq225917 on Aug 11, 2021 21:34:57 GMT
May as well swing for the doors
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Bigman80
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Post by Bigman80 on Aug 13, 2021 8:58:10 GMT
A pre amp doesn't have a spot noise measure at one frequency, it has a range of distortion depending on impedance of the next devices input and the position of the preamp volume control.
0.0001% thd @1khz at 2v out into a 2k load would be a very good figure, that would require very good layout shielding and regulation of the pcb and input/ output sockets and wiring. 0.00001% would be world class, only a handful of active pre amps currently manage this. Finally got a minute to chat with Angus about this, and that is not the case with the BT2. The double buffer design specifically isolates the volume control from both source and load impedances. Also, the BT2 already beats 0.001% THD+N with absolutely no attention to layout, shielding or even using a particularly good PSU. It's currently running with a generic Walt Jung PCB from China in a case that's too small and with wires floating around in the air. Suffice to say that when I finally make mine properly with the Avalon PSU (same power requirements and designed with both units in mind) i will have another little upgrade on my hands. |
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Post by jandl100 on Aug 13, 2021 20:18:21 GMT
I've always found XLR connected cables to be a bit boring compared to RCAs.
Tried and tested quite a few times in different systems. I just don't like XLRs
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Post by antonio on Aug 13, 2021 23:07:58 GMT
Well said Jerry, with everyone ranting and raving these days about balanced interconnects, it is good to hear a remark like yours. Never actually done a side by side comparison, but pretty close to, and really I could not tell the difference.
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Post by sq225917 on Aug 14, 2021 15:54:55 GMT
You could triple buffer it, the last device still sees the load, look at a few opamp spec sheets, they give thd at a range of voltages and loads specifically for this reason.
Yes, the volume CAN be done in such a way so that level doesn't affect thd etc.
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