Keeping Pre Amp and Power as far apart as possible.

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Pure_Carbon

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I've been running my S-1EX speakers with a Plinius SA100 Mk 3 , but decided it didn't quite have the grip on the bass I needed , so started a search for something more grunty.

I had couriers forming an orderly queue to drop Power amps off to try, quite a smorgesbord of different Solid State, Valve and Hybrids.

Eventually I settled on a Vitus RS 100.

Sounds great.

I then thought , lets try Bi amping, as my Pass Labs XP30 Pre lets me tweak the balance between the Master and Slave outputs , can dial the "slave" in an out, which for me if the HFs , so tried the Plinius on HF and Vitus on LFs.

I had the Plinius on the left of the system , on the floor, and the Vitus on the RHS on the floor.

It sounded good, but felt it was a tad muddled , and wasn't as fast or imaging as well as I'd hoped.

Then purely by chance, I moved the Vitus about 6 inches away from the gain stages on the pre, and wow , what a difference, it all began to get more focussed.

I've now got the both the Vitus and Plinius as far away from the pre as my cables will allow, and it has made a huge difference.

I'm guessing the transformers on the power amps were throwing some noise into the system?

Not noise like buzz or hum, but something that was interacting badly somehow.

Pass Labs did say that if possible , keep the control box away from the 2 gain stages . 

Worth a try if you can do it. 

 

pmcuk

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It's true that large power transformers and also chokes can produce a field around them so moving other more sensitive parts of the circuitry out of this field can be beneficial. But we are only talking something like 6 to 9 inches here, maybe a foot at most, not "as far away as possible". 

The other question is how you divide the cables between the preamp and the speakers. If you have a low output impedance in the preamp you may find it sounds better with longer interconnects and shorter speaker cables, if you move the amp closer to the speakers. 

 

Pure_Carbon

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In this case, as far away as possible, is about a foot at the most.

I'm using all balanced , roughly 1.5m interconnect cables, then 3.5m speaker cables.

Guess I could try longer balanced interconnects , and shorter speaker cables, but as you said, about 1 foot between the pre and powers seems the magic distance !

 

uzzy

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The ideal is to have speaker cables as short as possible so if it is possible to site the amp between your speakers (or for mono blocks one by each speaker) then that is in my books the best course of action.  However, if your amps do not have balanced connections it can be disadvantageous to have a long signal cable run from preamp to the power amps.  

I do not have balanced connectors and I am also a lazy git (the thought of having to walk to each end of the room to turn on the power amps and then back to the preamp is exhausting) so I have long speaker leads and my amp situated at the bottom of my hifi rack and the preamp at the top.   It seems the 20 inch gap from top of amp to bottom of preamp is sufficient to be totally quiet and my decca (prone to picking up hum) being only 6 inches or so from the top of the preamp is fine too (I would suspect the Decca is more susceptible to induced hum so I would also suspect I could shorten the distance between pre and power with acceptable results) 

As electricity is just shy of the speed of light one has to point out that with balanced cables you would be hard pushed to be able to tell the difference between a 2 foot and a 20 foot cable (if at all) and it is worth remembering that nearly every band you go to see live has a massive cable run between mixing desk and microphones (and before some smart arse says radio mics they do not use those to mic up the drums and amps through the PA system) and in a lot of cases long runs from the mixing desks to the power amps driving the pa loudspeakers.

I think we all get a bit caught up in this in our younger days but when you get to be a doddery old git like me you accept compromises and as long as the system sounds great to your ears then job done.   Could my system sound better with a lot more care and room treatment and a host of tweaks, the answer is very probably .. can I be arsed ?  definitely not.  All I can say is @Bokke was round this week and had a listen (not a long enough listen as he was on a long journey from work to home) but perhaps he can tell us all what he thought of my system with all its compromises.

 

 

MF 1000

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My main power amps ... 2x750 watt Behringer KM750 units for bass and the MF A370 beast for mid bass duties plus a Behringer A500 for tweeters are all housed in a hybrid Hifi/19" rack mount tower that's 6ft away from my preamp ......but then again my 845 mono locks sit either side of the preamp without any ill effects it would seem - and given the type 26 valves are very microphonic etc I'm sure it would be vv obvious if there was an issue.

 
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Non-Smoking Man

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My RH man, Martin Ware and myself were rejigging the 5 way horn system yesterday in an attempt to solve a noise problem. This is just the sort of system where you find out about juxtaposition issues, though they are now much lessened in general since the system went 'top-to-toe' balanced several years ago.

What we found this time around was that the First Watt F5 clone (toroidal tranny)(Joe Henry build) did not like to be close to the Ashly analogue crossover. With space at a premium for all the equipment in a medium sized room (if you've seen the system you would know what I mean!) we are constrained into having the electronics quite close. (We already were aware the Ayre P-5xe and K-5xe, phono and pre respectively need to be apart (1 foot and intervening item) to prevent hum.)

We dropped the F5 to the bottom shelf and all was well. The system is pretty quiet now considering the widespread use of valves and in 2 of the 5 levels115 db/w driver sensitivity.

Jack NSM

 
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Bokke

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The ideal is to have speaker cables as short as possible so if it is possible to site the amp between your speakers (or for mono blocks one by each speaker) then that is in my books the best course of action.  However, if your amps do not have balanced connections it can be disadvantageous to have a long signal cable run from preamp to the power amps.  

I do not have balanced connectors and I am also a lazy git (the thought of having to walk to each end of the room to turn on the power amps and then back to the preamp is exhausting) so I have long speaker leads and my amp situated at the bottom of my hifi rack and the preamp at the top.   It seems the 20 inch gap from top of amp to bottom of preamp is sufficient to be totally quiet and my decca (prone to picking up hum) being only 6 inches or so from the top of the preamp is fine too (I would suspect the Decca is more susceptible to induced hum so I would also suspect I could shorten the distance between pre and power with acceptable results) 

As electricity is just shy of the speed of light one has to point out that with balanced cables you would be hard pushed to be able to tell the difference between a 2 foot and a 20 foot cable (if at all) and it is worth remembering that nearly every band you go to see live has a massive cable run between mixing desk and microphones (and before some smart arse says radio mics they do not use those to mic up the drums and amps through the PA system) and in a lot of cases long runs from the mixing desks to the power amps driving the pa loudspeakers.

I think we all get a bit caught up in this in our younger days but when you get to be a doddery old git like me you accept compromises and as long as the system sounds great to your ears then job done.   Could my system sound better with a lot more care and room treatment and a host of tweaks, the answer is very probably .. can I be arsed ?  definitely not.  All I can say is @Bokke was round this week and had a listen (not a long enough listen as he was on a long journey from work to home) but perhaps he can tell us all what he thought of my system with all its compromises.

 
Hi 

I'm sitting at the airport, catching up on here 

Uzzy's sound system is awesome. For most on here would be an end game.

It has everything I like.

Raw power, musical but detailed, layered, full of texture, organic - you name it.

If you listen to this loud for a month you may go deaf 😅😅 it's  capable of sounding like a concert in your living room. 

In my very short stay I could easily hear the difference between DACs, sources.

Even the industrial look of the speakers is right up my alley.

Awesome @uzzy

 
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uzzy

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Hi 

I'm sitting at the airport, catching up on here 

Uzzy's sound system is awesome. For most on here would be an end game.

It has everything I like.

Raw power, musical but detailed, layered, full of texture, organic - you name it.

If you listen to this loud for a month you may go deaf 😅😅 it's  capable of sounding like a concert in your living room. 

In my very short stay I could easily hear the difference between DACs, sources.

Even the industrial look of the speakers is right up my alley.

Awesome @uzzy
Thanks Andrew .. amazing comments.   

Of course the great thing now is, if you say something sounds awesome I know your feelings and ears are similar to mine, so I will take note and go listen.  Similarly you know you can ask me for my views on how something sounds, that you have not heard, and get a good idea of what it will sound like to you too. 

These types of relationships are invaluable and it takes me back to my days in Guildford HiFi when the owner Bob Eubanks would say, "you have to listen to this" and I knew before I did it was going to sound great.

Hope that next time you can spend more time as we only touched the tip of the iceberg of my music collection.
Take care and stay safe

Uzzy

 
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hifinutt

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My RH man, Martin Ware and myself were rejigging the 5 way horn system yesterday in an attempt to solve a noise problem. This is just the sort of system where you find out about juxtaposition issues, though they are now much lessened in general since the system went 'top-to-toe' balanced several years ago.

What we found this time around was that the First Watt F5 clone (toroidal tranny)(Joe Henry build) did not like to be close to the Ashly analogue crossover. With space at a premium for all the equipment in a medium sized room (if you've seen the system you would know what I mean!) we are constrained into having the electronics quite close. (We already were aware the Ayre P-5xe and K-5xe, phono and pre respectively need to be apart (1 foot and intervening item) to prevent hum.)

We dropped the F5 to the bottom shelf and all was well. The system is pretty quiet now considering the widespread use of valves and in 2 of the 5 levels115 db/w driver sensitivity.

Jack NSM
Using joe henry f5 right next to pre and sounds extremely good !!
 

John (big)

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I remember an article in the late 1970's where a number of respected HiFi writers/designers shortened speaker cables & likewise shortened/lengthened phono leads using several mono block amplifiers & pre-amps and different speakers.
The consensus of opinion was that the shorter the speaker cable the better, whereas lengthening phono leads to compensate was the way to go. It was contended an audible improvement could be discerned for each foot removed from a speaker cable I do not remember practicality being an issue.
 

2010*zuma

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A nice idea if possible would be to integrate the pre and power into one simple unit thus having less cabling and using less power points that help bring more noise and interference into the system…
 

rabski

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Depends on the system. If your preamp is relatively high output impedance, longer interconnects will be detrimental. If you use very high power amplifiers and low sensitivity speakers, longer speaker cables may be problematic.

Large transformers do have a reasonably sizeable 'field' around them, as pmcuk notes above. Any effect from that will of course also depend on the shielding and layout inside other components, as well as the relevant signal levels. My moving coil step-up is very well screened, but has to handle an extremely low signal level and it's horribly sensitive to positioning. Stick it anywhere near a power supply, and it's hum city. My power amp, on the other hand, has massive transformers and the HT voltage is horrendous, but I've done all the internal signal wiring in unscreened point-to-point and it's effectively silent.