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Hello
I just transformed my hifi into tri-amping using Tannoy D700 with tweeter and super tweeter, middle driver and bass driver driven each by mono tube amps, needing in sum 6 tube mono power amps (3 for each speaker) at all.
I played a lot around with cables. And came to the conclusion that it sounds best to use only one mass cable shortcutting all the 6 mass outlets of the individual drivers and connect them straight away to the earth pole of the main earth outlet (that is connected to the internal masses of the pre- and power amps anyway).
This means I use from each power amp individual "+"-cables to the speakers (3 for each speaker - tweeter, middle, bass), but only one mass speaker cable. I save the money on 2 cables for each speaker. And to my ears the sound is more homogenious, too.
Does anybody know? Is there on clear physical (and not esoterical) reason why someome should use individual mass speaker cables for each driver, and not connect them alltogether to mass?
Follow Ups:
Why do you insist on making your system so complex? You only bring in integration issues and added expense. Six mono amplifiers, each one with it's own sonic signature driving six individual drivers, each with albeit slight different sonic signatures. Again, why?
In pro audio we tri-amp and use active-crossover systems to maximize efficiency. We need all the clean, undistorted volume to serve large crowds. We are willing to trade off some quality for quantity. How many people are you serving in your listening space ?
I'm not quite sure I understand your use of some terms in your post. It seems that you have three individual wires for + on the speakers but just one ground wire that all three amps share. Is that right? 4 individual wires? Or is it two pairs of two? Either way......I find loading an amp with a part of the frequency spectrum AND one DCR/impedance level with that part of the driver/x-over's impedance peak is a lot easier on an amp. I went from single wire to bi-wire with improvement and and another level of improvement by adding bi-amp. My amps are the same brand,input impedance,gain and sensitivity. Great for passive biamp. I had to get the better (LF) amp repaired and connected just the lower powered, older amp full range. It wasn't worth listening to, to my ears after having the biamp scenario for a few years now.
I also recently lifted all my earth grounds with great results. It was like a veil was lifted.
ET
Question "Authority", the mainstream media sucks - I need music to help forget the reality of today
Edits: 01/12/09
yes, you are right. I use 3 + cables and one ground cable (but consisting of 3 cables of the same sort bundled together) for every speaker. And this sounds better to me than connecting all 3 ground cables seperately.
And I fully agree with you. The difference of tri-amping compared to using one amp only for one speaker is tremendous. I use 4 Pye HF91 mono blocs and one stereo Naim Nait 2 now. The performance, impedance and power rating of the solid state Naim Nait is most similar to the Pyes, and gives the benefit of better control of the bass drivers compared to the tubed Pyes. One Pye is used to play the tweeter and the super tweeter. One Pye is used for the midtone driver. As these are Tannoy speakers they have an dual-concentric driver with the tweeter horn in the middle and the midtone driver around it. The bass driver sits under the dual-concentric in the D700, that is a really fantastic speaker on the day you get everything right. Otherwise the treble is easily to dominant, especially with digital sources.
The tweeter horn goes up to 30000 Hz. But it is incredible how the super tweeters (up to 100000 Hz) improve the impression of being real in the room with a singer. Without the super tweeters the setup sounds much more "electronical".
Wonderful treble now, and perfect 3-dimensionality and immense musical.
And, most surprisingly to me: the difference with analog sources is a real upgrade. But with digital, it is the first time that digital sources play fine. I was already convinced that digital is always worse than analog. In my earlier setup even own-recorded 24/196 material sounded hissy, but analog material was okay. Now 24/196 plays - to be honest - as good as reel-to-reel or vinyl. Does digital treble has some artefacts that worsens the sound as long as the drivers are not seperated electronically. If I listen to my system now I get the impression that the whole digital-analog debatte could miss a point here...
In general it is not a good idea to connect audio 'ground' to AC safety-earth at any more than a single point. It is also not a good idea to connect the audio grounds of separate amps together. With heterogeneous amps, you could experience a spectacular failure and destruction of the equipment.
Assuming your setup uses identical amps, they already share a common audio ground at their inputs (at least, one for each channel). They may or may not include internal connections of their audio grounds to their AC grounds, if they have grounded AC inputs. They also may or may not have their output return terminals connected to audio or AC ground.
Multiple connection points between AC ground and audio ground create physical conduction loops, that can inject noise from external induction into the audio signal path. By connecting your speaker returns together and to AC ground, you may be shunting ground loops with lower-resistance wire. While this may improve performance, it would mask a larger problem.
Thank you!
I use identical tubed mono power amps. And as I can see from the internal circuits of the amps the input ground is connected to the output ground as well as all grounded caps and resistors and the earth pole of the mains power supply.
The sound is for sure better with the ground of all drivers connected to a central ground post at the earth pole of the main plug. The sound is then "one sound". By connecting the grounds individually onto all 6 power amps the sound does not come together to one picture. It overemphatises the different instruments as stand alone and all in front. With connecting all grounds together the soundpicture becomes one picture with width and depth and more musicality, like everything plays "in phase".
Do you think my installation can be dangerous if for some other reason a shortcut happens? That the main fuse or fuses in the amps might not blow?
Thanks a lot,
Peter
if another person were to try it with heterogeneous amps. There may be some offset between the audio ground potentials of the amps, or, if the amps are switching types, there will be a large DC offset between the speaker terminals and the power supply ground.
Ground loops are ways for RF noise to enter audio systems, even if they are silent with respect to power frequency hum. Your sonic description fits my experience with RF noise. You've found a way to reduce the effects of this entry path.
I would not use a single ground (if that is what you are proposing), it sounds bad.
Why?
In an unbalanced system everything is connected to mass anyway.
For the same reason that bi-wire sounds better than one wire, less intermodulation distortion.
Read Jon Risch on the subject.
As a practical matter, I have heard it both ways, one ground sounds distorted (in a direct compare).
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