Tube Monoblock location? - Rack or near speakers?

Isolating the tube amp on the floor or the shelf from vibrations is what matters more than where it is.

If the speakers and amps are sitting on a suspended floor,work on the underside floor joists and stiffen them up.

If the speakers are on a solid concrete basement carpeted floor,I think the amps placed beside them will perform better than on a less solid stand.
Of course there are costly equipment racks that will prove me wrong.

Short speaker wires and longer balanced IC are the way to go for me.

Atmasphere,

You mentioned that a preamp having 600 ohm output impedance doesn’t necessarily mean it could drive a 600 ohm load. So, not being an engineer, hence cannot read the schematics, is there a way to tell whether a preamp can drive a 600 ohm load by reading the specification general given by the manufacturers?

I am using an Aesthetix Callisto Signature, which has an output impedance of 600 ohm, and I wonder whether it supports the balanced standard that you mentioned.

Thanks

Thanks very much, Atmasphere.

I thought as much as well, still, much appreciated.

5 meters is a long way to run single-ended cables.

FWIW your dealer must not know what balanced lines can do. His statement is preposturous.

But since the CAT has a single-ended input, and because the ARC does not support the balanced standard (which includes the ability to drive 600 ohms- you'll find it looses bass and output when trying to drive such a load) you are probably better off running the long single-ended cables. I know that the preamp has a 600 ohm output impedance but that is not the same as saying it can **drive** 600 ohms, and for balanced operation, that is important.

If the ARC did support the standard, you could run balanced lines to a set of transformers that could convert balanced to single ended right at the input of the amps. That way the length of the cable would not be a source of degradation. Jensen makes a nice set of transformers for that purpose that are 600 ohm to 600 ohm- now you see why I mentioned that part of the balanced line standard.

I am in the same boat set-up wise.

However my question is a little equipment specific, sorry OP for hijacking the thread.

I am running the ARC Ref5 preamp to CAT's JL3 Mk.2 monoblocs. My dealer says single-ended sounds better but I am concerned that the 5meter length of ICs will degrade the sound. (I will use Nordost Freys)

What do you guys think?

Thanks for the question Cooljazzcat (great name). There really isn't a quick and dirty answer or correct or wrong answer to your question about maximum cable length. it depends on 1) how well the electronics were designed and built, 2) quality of the cables, 3) impedance and phase interaction between cables and equipment. However, if you can, check out the specifications of your equipment, eg, input impedance, output impedance, loading that the equipment can handle over frequency, etc. Also, look at the specs of the cables, particularly, the capacitance, resistance and inductance per unit lenght, and if they list it (probably wont), the capacitance and inductance impedance variations over frequency for the cable. That will tell you volumes. But, here is the best way. Have a good relationship with a Stereo store and ask them if you can take sample cables home for a week to audition them with your equipment. They don't have to be the perfect length for your equipment, but that will tell you what you want to know. Also, and this is important. Purchase the equipment that you are auditioning from that store. If you show them that you are serious and will buy from them, they will let you audition the equipment. Especially in this market today. Give them a credit card and they won't charge to it until you either don't return the equipment or when you purchase it. My favorite store is far from me, in San Diego, CA (Stereo Design). I have purchased most of my equipment from them over the years. They allow me to take equipment home (to Los Angeles) and listen for a week or so. Cables and electronic both. I trust my ears first, but their recommendations are valuable to me also.

So, ask to audition equipment (leave the credit card info.) and see for yourself. If your store won't do that, go to one that will. As you know, equipment sounds much different in the store than in your home and purchasing blind doesn't work for me. But, once I use their expertise and consideration, I buy from them, not elsewhere. I want to keep this Dealer in business. So, if I am going to purchase, I typically go to them first.

Enjoy.

Minorl, thanks for your reply. So what is the maximum length of speaker cable before you start to have issues? I was told 10ft is typical.

Thanks for the question Cooljazzcat (nice name). The general rule in electronics is to minimize the cable length if you are concerned about losses (power) and phase shifts due to the reactive impedence caused by the inductance and capacitance of the cables. The inductance caused reactive impedance is 1/jwl and the capacitance caused impedance is jwc. where c=capacitance of the cable, w=2(phi)f and f is frequency and phi is 3.14157...... for inductance l=inductance. These values change depending on the length of the cable and the frequency of the signal. As you can see, the simple impedence is R+1/jwl+jwc. Basically, real+reactive impedance. One is fixed (resistance) and the other varies over frequency. A nightmare if your equipment is not really designed to handle variations in impedance. They are designed for a particular imput impedance that it will see and for a particular output impedence that it will see. But a good designer must account for real and reactive impedance variations. So, the shorter the cables, the better. The rediculously expensive cables with internal networks are built to try to reach a point of resonance where the inductive reactance and the capacitive reactance over a certain frequency range basically cancel themselves out and you are left with only resistive load on the wires. That resistive load causes losses in the form of real power (IxIxR) losses. Current squared times resistance of the wire. This is why electrical transmission lines are of much higer voltages, 230kV, 500kV, etc. The higher the voltages, the less the impact of the losses on the line will be. I hope I didn't put you all to sleep. But, this is not magic. It is science and everything else is basically creative nonsense. But, if the equipment isn't designed very well, then yes, you have to play with the cables to get good sound. Not really because the cables are better, but because the equipment was designed poorly. It is really hard to design an amp or pre-amp that will handle all the really desired design characteristics with load over frequency and impedance, voltage, current, phase, and power ratings and not oscillate like crazy. Really? this is why the best equipment cost a lot of money. But, a one foot pair of Mogami 10 gauge speaker cable would really sound the same or better than a five foot $2,000 cable if the equipment was designed property.

enjoy

Hifitime, true, if the noise is in the signal. False, if the noise is common-mode (for example, impinged on the cable itself). Of course, you need a balanced input at the amp to take advantage of that.

Atmasphere,Balanced lines reduce not block noise.

For 4 ohms, 1 meter, for 8 ohms, 2 meters and 4 meters if 16 ohms. Hifitime, I have never heard what you are saying about balanced lines and it is simply untrue. You might tell whoever told you that that they are full of beans. I have yet to see RF problems in a balanced cable- the assertion is absurd!

Balanced lines were developed originally by the phone company decades ago and made trans-continental phone calls possible. A few years later they were in common use in the recording industry- most of your records and CDs were recorded with them, in some cases the cables were over 150 feet long.

In the home they solve the issue of speaker cable length quite elegantly. **If** the preamp supports the balanced line standard, then the length and the cost of the cable is not important in the overall sound. I have seen my 30 foot $85 pair of Mogami Neglex be indistinguishable from a $24,000 set of balanced cables 24 feet long. (The system was mbl101e speakers, with mbl power amps driven balanced by our MP-1)

I've done numerous PA setups over the years. One might interest you. It was in a concert hall- we needed a PA for the singers. The speakers were mounted in the ceiling so we set up amps and ran 40 feet of speaker cable to the speakers. You could not make out the words they were singing! Then we moved the amps to the speakers and ran the same cable, shortened to 1 meter long. We set up a transformer system that allowed us to run a balanced line between the mixer and the amps- the instant increase in clarity was startling!

I've done the same thing in my home, and BTW have a set of SRA stands for our amps as well. They do help (they are some of the best), but by far the bigger difference is seen in keeping the speaker cables short as possible. Since we can run a balanced line of any length with our preamps this is a very easy test to perform.

Minorl, what would you consider as an acceptable run of speaker cable (length?) thanks

this may have been addressed earlier but here goes. It comes down to real and reactive power and IxIxR (I squared R, or power) losses on the cables. The current running on speaker cables is higher than on interconnect cables. Consequently the power losses on the speaker cables by using the equation above can make a drastic difference. It is typically better to have short interconnect and short speaker cables, but if you can't have it your way, then short speaker cables and long interconnect cables. This is simple electical engineering. There are less power losses on the long interconnect cables than there will be on long speaker cables. Also, there are reactive losses that increase/decrease the reactive impedance of the cables depending on the frequency of the signal. So, the general rule. Use cables as short as possible. But, if you can't then short speaker cables and longer interconnect cables. But, that means that the interconnect cables must be really good, properly shielded, etc. No matter what people say, it comes down to the ampacity of the cables and the impedance of the cables. That is why changing cables makes sometimes such a huge difference in sound. The manufacturer is playing with the impedance characteristics of the cables to alter the music signal and hence the interaction with your equipment and ultimately, the sound. This is not rocket science, but it is science.

enjoy

Atmasphere,I would never want 35'long interconnects in my home like you have.I have tried numerous combination's with interconnects and speaker cables.My friends and myself all agree and all have longer speaker cables instead.Lower level signals pose more of a problem with longer cables.In theory balanced cables may work,but they are even more prone to RF noise than speaker output levels,and this isn't news to you.All brands.The vibrations from the speakers causing abnormal microphonic music is a nightmare.I can't imagine anyone liking this effect.Microphonics have been a known and proven problem with tubes,and even capacitors too.Wilson Audio and other high end speaker builders even use vibration isolated crossovers to help keep vibration noises from affecting the sound.Tubes and speaker vibrations have never got along,and I've never seen any other solution to the problem other than locating them in the least vibration prone areas of the room.Every room in my home has different areas that work best for keeping tube and vinyl feedback down.Distance itself works good for starters.

Ralph I always wanted to ask you if you are a fan of tube dampers for pre and power amps?

Hifitime, if you think about it, a tube amp sitting beside a speaker is not going to get any more vibration than one far away. But really, if you try the difference between long speaker cables and short interconnects as opposed to short speaker cables with the amps near the speakers and long interconnects, the across-the-band improvement is instantly audible. IOW, apparently the vibration issue does not seem to play a role.

Cooljazzcat , As with everything in this hobby you must try it yourself and then decide.Because a dealer or even a manufacturer tell you that one way is better then the other does not make it so.Only you can decide what you think sounds best.

I guess the governments,industry,and tube builders all wasted their time building tubes more resistant to vibration problems and failures.

This is one advantage of balanced cables. The shorter you can keep the speaker cables, the better (more resolution, more impact). Preamps that have a low output impedance can drive longer cables, so some single ended preamps will allow up to 20 feet (although that is rare). For the most part, running longer cables than that is best done with balanced lines. My cables at home are 35 feet.

Vibration in the tubes is generally **not** a problem!

I figured there would be a split in opinions here.

Blue Jeans cable for instance admit that if you are using speaker runs of less than 10 ft, just use decent oxygen free copper because there is no measured difference compared to very short cable. I think you would need better rca cables at that length which are more susceptible to interference and noise.

Don't forget,it is a show.Less than ideal conditions for setting up,transporting,etc.Dealers don't have the best options either.Plus audiophiles like to look at what they're buying.Those big amps are heavy too.Dealers I know keep their amps away from their speakers at home.Just another of my 2¢

 
Wrt the Sanders and Walker observations - these are not mutually exclusive.

Put each monoblock near its speaker and cable accordingly. Generally, shorter speaker cables are preferred assuming your preamp has enough output voltage to drive the needed length of IC.

You'll get different opinions here, but just take a look at pictures from CES or most dealer showrooms if you doubt placing amps near speakers. Or ask a few amp manufacturers - you'll be hard pressed to find many (any?) who advocate long speaker cables.

Of course the cables themselves have an impact. Cable geometries influence capacitance and inductance. A cable with, for example, high capacitance will smear a signal more over a long run. Keep overall reactance on the low side without disproportionate weighting of one over the other.
 

It seems odd that they would want the tubes vibrating.All tubes are microphonic.They(the tubes) might even get more microphonic with all the vibration rattling their insides possibly causing a premature failure. Then a longer run of interconnects too.Longer speaker cables have always been preferred over longer IC's.Its a new one to me.

I have my mid-monos sitting close to my speakers and I have 3ft speaker cables and 6ft ICs. Sounds perfect to me, Mike really knows his stuff...

Marakanetz, you mean follow Mike's or Lloyd's advice?

thanks guys.

in case with quickies that have a very high input sensitivity and low output power the advice is correct.

Opinions vary, but I've had good success following Quicksilver's advice: longer interconnects and shorter speaker cables, when talking about one or the other being greater than 8 feet.

FWIW, I follow Lloyd Walker's advice of keeping speaker cables consistently at 8 feet rather than using the shortest length possible. He claims to have tested this multiple times and consistently found the 8 foot length superior to shorter lengths of the same cable. I trust his ears. He says it has to do with back wave EMF from the drivers. Clearly, YMMV.
.