Does anyone care to ask an amplifier designer a technical question? My door is open.

Roger addressed this previously in the thread. The short answer is not much if at all. The power cord should be designed such that the ends provide good connections to your outlet receptacle and amp. It should also be of sufficient gauge so as not to cause a safety hazard. I believe the captive power cord on the Music Reference RM-9 was 14 or 16 gauge. Roger used 18 gauge lamp cord for Music Reference preamp and MC head amp captive power cords. I made my own 14 gauge power cords for my components. I bought male and female IEC connectors on Ali Baba and sourced some computer grade three conductor stranded wire. They were not hard to make and parts costs per cable were around $30.

@clio09
In one post Roger says it doesn't make much difference, OTOH in the very same post describes the power cords that he made up special and how anyone can do it. I have to assume that he felt it was worth doing.

@corby2 Hello, I have a budget system I like. It has a 25 watt Will Vincent Balwin tube amp with Coincident Dynamites. I do not have an audiophile power cord. How much do audiophile power cords help with the amp? I was thinking of getting to Anticable stage 3 power cord. Thanks, Cory in Reno

Hi Corby,

Very few amplifier makers wind their own transformers, but I do. When I wind a transformer for a 25 watt amplifier it is about 150 feet of 24 ga wire. After I am done I really dont see how 12 feet of 18 or 16 or 14 ga wire will make any difference.

If you measure the resistance of the primary circuit of your amplifier it is like likely near 5 ohms given that it is 25 watts.

This is easily done by unplugging the amp, turning it on, putting an ohmmeter across the two prongs of the power plug. Now you will know the total resistance of the primary loop. The total resistance of the secondary loop (reflected to the primary) is similar to that so double what you just measured. Now ask yourself how much a power cord of 0.01 or 0.1 ohm or 0.5 ohm is going to make when added to that number.

The claims about RF shielding are absolute bullshit. Along with any other specious claims.

Just get a cord with good connectors.

@tomic601 

  RM - took a hiatus from the book, restarted on page 59....junction temps....had a bad experience with ON Semiconductor thermal tracs.....I know you are a tube guy, can you comment about the diamond topology ?

Not sure what you mean by thermal tracs?  ON semi is making the Motorola parts. I dont know if there is anything new. Do you have a part #.

@atmasphere - this is the power cord he was referring to that does make a difference under certain circumstances:

http://tubeaudiostore.com/pocoyoucanac.html

Otherwise as Roger noted in his last post just get a cord with good connectors.

RM - NJL3281D

not exactly sure which Ayre used but they did not prove hyper reliable...
the Twenty series use a derivative of the Diamond circuit and I believe also switched away from the thermaltrak...

@analogluvr  Over voltage can cause mechanical hum in a transformer

Thanks for pointing that out. The flux (and thus mechanical buzz) of a transformer rises sharply at some voltage. That point is up to the designer. I try to get mine still quiet at 130 Volts but we are getting up to 125 now in our houses so might have to go higher and wind for 125 rather than 120. 

Small amounts of DC on the line make things worse expecially with torroids as they have no gap. 0,5 volts of DC is enough. We make a power cord with a device to block the DC. Ask Clio, or you can make your own. Im not trying to sell anything here or be accused by one who does. 

Power transformers are a pain in the ass. If you make them bigger to reduce the flux they make more noise due to larger size. Ive been around the block several times on this. All our tranformers are silent at 2 feet in a very quiet room. My thought is if you cant hear it at the listening position whats the problem? Who sits next to their power amp? If you want someting lower noise I can make it for you. 

Power transformers can become noisy with age. Spongy feet or a bed of sand helps a lot to decouple from the rack or floor. 

@iamisaf When units are powered on I hear a very mild hum noise from the amplifier unit, if connect amplifier directly to the wall outlet I don't hear any hum noise. If I do the similar setup other side in the basement I don't hear any hum when connected to wall outlet or thru panamax power conditioner.What might be the issue?

The two sides of the basement may be on opposite phases of your 120/240 line. Houses are wired to try to balance the load on each phase. One phase may have DC or slightly higher voltage. Why are you using a power conditioner anyway. I dont.

Sorry to say this is a horrible product. Anytime they bring all you phone, cable, power, God whatever into one box its a horrible idea. If you can send it back please do. Modern devices generally do not need surge protectors and they tend to catch on fire!!

 https://www.crutchfield.com/p_299M5300PM/Panamax-M5300-PM.html?awkw=75647650225&awat=pla&awn...

Hi there would appreciate some help, I am shipping my Macintosh intergrated amp 200watt plus my def tech bp7000 sc to Thailand to live with me ? Very dodgy mains power !!! I am toying with the idea of ups or stabilizer or whatever , for some protection ? Against voltage drop . The def techs have 1800 watt driven subwoofers x2 of course ? I know that the equipment will never be driven at capacity, as house would fall in , your thoughts on a possible soloution,,, thank you : skiramp

@ramtubes

I could really use some help betting a better grasp of amplifier/speaker interaction. Specifically, in what sense a speaker is "easy to drive" for an amplifier.

This seems to generally relate to two parameters:

1. Speaker sensitivity
2. Speaker impedance (and phase angles etc).

I’ve seen speakers with higher sensitivity but lower or wilder impedance termed "easy to drive" and speakers with lowish sensitivity but higher and smoother impedance being "easy to drive." So I’m trying to get a grasp on what it means...in practical and possibly sonic terms...when a speaker is "easy to drive"for an amplifier and what you get when trading off sensitivity vs smooth impedance.

To turn it in to a practical example:

I owned the Thiel 3.7 speakers. Here are the Stereophile measurements:

https://www.stereophile.com/content/thiel-cs37-loudspeaker-measurements

Note the 90.7dB sensitivity, but with it seems a fairly challenging impedance.

Then take the Joseph Audio Perspective speakers (a speaker I’m considering):

https://www.stereophile.com/content/joseph-audio-perspective-loudspeaker-measurements

JA measured a low 84dB sensitivity but with a higher/smoother impedance he deemed them "a very easy load for the partnering amplifier to drive."

So I’m trying to understand the practical/sonic consequences - higher sensitivity, vs lower sensitivity but an easier impedance load. What does this mean for the power requirements, or type of power for each?

I have Conrad Johnson 140Wside tube monoblocks


https://www.stereophile.com/content/conrad-johnson-premier-twelve-monoblock-amplifier-measurements


And I’m wondering which of those speakers would be "easier to drive" with the CJ amps, why, and in what sense.

(FWIW: the CJ amps seemed to drive my Thiel 3.7s great: tight, non-flabby base, etc).

Thanks for any wisdom you can impart!

ramtubes - So, you don't believe power cables make a difference other than connectors and isolation transformers are worthless?  Is that correct?

It’s doesn’t really matter what he believes, that’s the way it is. 

For the OP what are the pros and cons in relation to damping for amplifiers; eg Hegel store great reliance for damping in relation to driving difficult speakers.

@ramtubes, how do you make a power cord that blocks DC?

ramtubes - So, you don’t believe power cables make a difference other than connectors and isolation transformers are worthless? Is that correct?

I don’t think he is saying connectors make a difference sound wise as some people might lead you to believe. In other words a Furutech connector won’t sound any better than an Oyaide connector. He is saying just use good ones. For me that means the ability to get a snug fit with the outlet (I use Hubbell hospital grade) and a means to make a good connection with the wire (I use off the shelf "Oyaide" connectors I buy on Ali Baba).

Hello
 How can I use a Plinius SA 250 amp setup for 230v in the USA, thanks John 

Sorry to say this is a horrible product.

Ouch!
Power in Los Angeles could be very problematic.
I added a 5300 in about 2003 and it was a significant improvement even though my amp had an internal LC power filter. At the time, I auditioned 2 Panamax, 2 Monster and 1 Furman. The Furman was best, followed by the 5300, then the Monsters and Panamax. Each added it's own coloration.

15 years later in Oregon with different electronics, it still works and I like what it does. Cable and other jacks remain unused.

JA measured a low 84dB sensitivity but with a higher/smoother impedance he deemed them "a very easy load for the partnering amplifier to drive."

@prof
Tube amplifier power has traditionally been expensive. Inefficient loudspeakers as mentioned above only became possible in the era of solid state since that power is so much cheaper. Unless you are in a very small room, I'd consider a different speaker as 140 watts isn't a lot of power when dealing with a sensitivity that low, regardless of the 'difficulty' of the speaker.

@clio09

this is the power cord he was referring to that does make a difference under certain circumstances:

http://tubeaudiostore.com/pocoyoucanac.html

Otherwise as Roger noted in his last post just get a cord with good connectors.

Apparently though Roger sees or saw fit to build his own power cord setup using some pretty heavy gauge wire (see page 12); this suggests (if actions speak louder) that he does think they make a difference, else why go through the bother?

(FWIW a power cord with light gauge but good connectors will not bring home the bacon, generally speaking. I've seen power cords, not just the connectors, heat up.)


I first heard how dramatic a power cord can be at the 1990 CES in George Cardas' room. The impact and nature of the bass was easily heard by all present to be quite different and with more impact when stock power cords were replaced by a pair that George offered. I found it disturbing; at the time I just didn't understand what was happening (and it clearly was not snake oil as it was repeatable) but I also knew enough to not buy the explanations that were offered (which clearly **were** snake oil).


But in time I found out that all you have to do is to simply measure the effects a power cord has on an amplifier. Generally speaking, the more power the amplifier draws, the more you will hear differences between power cables. 

Thanks atmosphere. 


(I'm still interested in ramtube's view as well).

My room is on the smaller side: 15' x 13' wide and I listen at modest volume - typically 70 db to maybe 75, probably 90 at the most if I crank it more to listen from down the hall.

I also wonder how the introduction of a subwoofer alters the load to an amplifier.  So say if you have a powered sub and you crossover to the sub from the mains at maybe 80 or 60 Hz.  Once one has off-loaded much of the low frequencies to the sub, I wonder how much the main amp "sees" and if that, in effect, is like adding a more powerful amp in to the equation. 

@testpilot  Take a look at the Isotek Synchro EVO3.

@atmasphere - I can't seem to find the reference you referred to on page 12. What I did find was this which Roger wrote:

I would have had the electrician put in several duplex outlets so no power strip is needed. Power strips vary in cost and quality but the expensive ones with big claims are just marketing. You have nice 10 Ga wire in the wall and then what?

Heres something Ive done. Get a bunch of reasonable power cords, like $20 each of various lengths. Cut off all the male plugs strip and hardwire the cut end directly to the 10 GA wire with a bussbar. Solder good solder lugs to the wires and screw them with a star washer to the bussbar. THe star washers are important. Now you have direct power cords and have eliminated one connection. Make some extras of course. The ones you arent using just coil them up.

I had custom power cords made that are 8 ft long, very flexible, supple, drape nicely and wont pull your smaller devices off the shelf. We have them if you need some.

Bottom line here. Its not the wire that matters. You have hundreds of feet of ordinary magnet wire in every transformer. What you gonna do bout that? :). All this power cord and power strip is just foolishness. Why do we need powercords that are a pain to run?

The custom power cords he is referencing in the quote above I believe to be 14 or 16 gauge, I'll have to check. I don't disbelieve your statement on connectors or power cords heating up, but I have never experienced it on any of my components including yours and Roger's amplifiers. As for the reference to light gauge cords not bringing home the bacon, what gauges are we talking about?

@skiramp Hi there would appreciate some help, I am shipping my Macintosh intergrated amp 200watt plus my def tech bp7000 sc to Thailand to live with me ? Very dodgy mains power !!! I am toying with the idea of ups or stabilizer or whatever , for some protection ? Against voltage drop . The def techs have 1800 watt driven subwoofers x2 of course ? I know that the equipment will never be driven at capacity, as house would fall in , your thoughts on a possible soloution,,, thank you : skiramp

I dont know the specifics of  your equipment as to low voltage. Solid state amps I have designed work fine down to half line voltage. Some do not. Well designed switching supplies are low voltage protected but if not they smoke and burn up. 

Get a power regenerator with wide voltage tollerance and let it deal with it. I do mean regenerator like PS audio makes. IF it fails you can send it back. 

I would also question what you are doing with those big subs. Are you watching Das Bot.

I wish you well in Thailand. Its a lovely and exotic place I visited many years ago.

@testpilot  How do you block DC.

Connect two diodes back to back in parallel and insert in hot lead of power cord. 

@stargazer3 For the OP what are the pros and cons in relation to damping for amplifiers; eg Hegel store great reliance for damping in relation to driving difficult speakers.

There is no con to high damping if done properly. However more than 20 will have little effect and may cause the designer to do some bad things to achieve it.  When a designer goes to maximize his favorite parameter he can go too far and other things will suffer. In this case stability from oscillation.  There are many amplifiers out there waiting for the wrong load and their own destruction.

I have seen many amps with very high damping oscillate into a 0.1 uF load which is typical of some speaker cables. Smoke and shorted output transistors was the result. The cause is too much feedback and assuming that if the amp is ok with the standard 2 uF test load it will be stable with smaller capacitive loads. Many well known amps are not. I tested an early ADCOM that took of with 0.1 uF. I did it for one second. A few more seconds would have been the smoke test.

Do you have a link to Hegel, I would like to read it?

As for the reference to light gauge cords not bringing home the bacon, what gauges are we talking about?

18ga for sure- not suitable for larger current draws. The wire gets warm along its entire length with a big enough amp- that suggests its limiting current, and certainly the voltage at the amp will not be that of the wall.

Connect two diodes back to back in parallel and insert in hot lead of power cord.

The diodes are bypassed by electrolytic capacitors, which conduct only when neither diode is conducting.

@testpilot.

You can purchase this DC blocking board (link below)and populate it or buy one completed at the link below. Great double thick circuit board that is very high quality. The in and out pads accept 12gauge solid core wire which is also nice. Instructions and part lists also on the site. The board is a two layer design in parallel (70um thickness of each) so yes - it can handle current of 20A. The capacitance needed for 1kVA is 22000uf, but since the difference in the price is not big I’d prefer 33000uF. I think the board cost me something like $15-$18 shipped. The parts were only another $20 or so.

I use them in my isolation balanced power conditioners. I just built them right into the chassis. They quieted down the toroidal perfectly. Quiet as a mouse now and used to buzzzzz.....

Yes, I love my balanced power conditioners and will never take them out as the music simply sounds so much better with them in place. I find them to work wonderfully in many systems.

https://www.atlhifi.com/shop/bare-pcb/pcb-for-dc-trap-blocker-filter-for-toroidal-transformers-toroi...

Can changing the power cord to the amp changes the musicality of sound at the speakers.

@khiak  Can changing the power cord to the amp changes the musicality of sound at the speakers.

Some think so.

@prof1   I also wonder how the introduction of a subwoofer alters the load to an amplifier. So say if you have a powered sub and you crossover to the sub from the mains at maybe 80 or 60 Hz. Once one has off-loaded much of the low frequencies to the sub, I wonder how much the main amp "sees" and if that, in effect, is like adding a more powerful amp in to the equation

.  

I assume you are using some crossover to rolloff the main speakers. Is that via and electronic crossover or the series caps found on some subs?  Makes a difference as to voltage the main amp still has to produce and thus clipping and IM distortion. The correct way is to rolloff the main amp at its input so it never sees the bass voltage. 

@fleschler  ramtubes - So, you don't believe power cables make a difference other than connectors and isolation transformers are worthless? Is that correct?

Do I detect a little nudge there?  I think isolation transformers are great when needed. I like balanced power which also isolates. These things have a good chance of reducing noise if one has noise.

My stand on power cords is entierly intellectual from an amplifier designer and transformer makers point of view. I know what is inside a transformer and how it works. When you know about transformers, house wiring etc. we can further discuss this interesting topic. 

"Musicality" is one of those oh-so-subjective terms with no agreed-upon meaning. But the same can be said about the incomplete sentence by khiak above ;-) . The "can" implies it is a question, but the "changes" negates that. Should the sentence read "Can changing the power cord to the amp change the musicality of the sound at the speakers?" (a question), or "Changing the power cord to the amp changes the musicality of the sound at the speakers." (a statement) ?

@ atmasphere
In one post Roger says it doesn’t make much difference, OTOH in the very same post describes the power cords that he made up special and how anyone can do it. I have to assume that he felt it was worth doing

.
Ralph, what is OTOH mean? Im a newbee.The cords with diodes make a difference when needed. I think I have been clear and consistant here.

Your amp draws heaps of current when played hard. Something heavy ga might help a little at full power. At idle Im not so sure. I note the current draw of the M-60 goes up quite a lot at full power testing.

How long can I run an M-60 sinewave at 60 watts into 8 ohms before the tubes get unhappy?

@prof 

I could really use some help betting a better grasp of amplifier/speaker interaction. Specifically, in what sense a speaker is "easy to drive" for an amplifier.

This seems to generally relate to two parameters:

1. Speaker sensitivity
2. Speaker impedance (and phase angles etc).

I’ve seen speakers with higher sensitivity but lower or wilder impedance termed "easy to drive" and speakers with lowish sensitivity but higher and smoother impedance being "easy to drive." So I’m trying to get a grasp on what it means...in practical and possibly sonic terms...when a speaker is "easy to drive"for an amplifier and what you get when trading off sensitivity vs smooth impedance.

To turn it in to a practical example:

I owned the Thiel 3.7 speakers. Here are the Stereophile measurements:

https://www.stereophile.com/content/thiel-cs37-loudspeaker-measurements

Note the 90.7dB sensitivity, but with it seems a fairly challenging impedance.

***********GREAT QUESTION, EVERYONE READ THIS**************

Ill take this one speaker at a time. The 3.7 is THE speaker that birthed the RM9-SE and RM-200 designs. Those are AB2 designs that use positive grid voltage to extend the output current range of an AB1 amplifier. We had a MK1 RM-9 customer who was going through output tubes at an alarming rate. The speaker and his love of Miles was driving the tubes hard.

First, JA did not point out, as he now does that 2.83 volts is NOT the proper voltage for a 4 ohm speaker. Its 3 dB too high so the 4 ohm sensitivity of the 3.7 is 87 db. Its even worse because this it a 2.5 ohm speaker so take off another 2 and make it 85 dB. So its really not a very efficient speaker.

I made the RM-200 with taps down to 1 ohm for speakers like this to preserve the damping, reduce the tube stress and lower distortion. The 2 ohm tap on the RM-200 is ideal for this speaker. Mismatching the load on a tube amp makes it work really hard. This is a 2.5 ohm speaker so good luck. Many SS amps will not play this speaker well.

Thats your the gist of question #1. 

#2. Phase angle..

As the phase approaches 90 degrees the output devices have both full voltage and full current across them. The dissipation in SS or tube amps goes wildly high. SS amps are sure to current limit, tube amps just take it. This is why tube amps have a reputation for driving such loads at the 3.7 and ESLs.

Thats all for now. This great question deserves several parts. Anyone please feel free to ask as we go for clairfication.

"Musicality" term used to express a fatigue free listen . Still as resolving as anything but probably not boosting any frequencies . Hence fatigue free . No distortion as well .

Hi Ramtubes,
In response to my query about damping you asked for a link to Hegel
which is:
 https://www.hegel.com/

You will see they describe what they put into their components,  also when looking up integrated amps, the damping factor is specified eg their starter amp H90 is only 2 x 60 watt in 8ohms but the damping factor is over 2000 therefore capable of handling above average difficult speakers (but not mammoth difficult speakers!) As they quote " The grip, or damping factor as it is called, is up to 20 times higher than the industry average. Ensuring a dynamic and powerful bass response, even on larger floor standing loudspeakers."  

i’m late to thread but have a perplexing question. 
i own an expensive ss amp and leave it on 24/7.
i could turn it off when i’m not going to use it for a few hours as well as overnight. for amp longevity what is best? thanks

Are you familiar with Primare's UFPD power technology? Is it pure Class D or something else?

Ralph, what is OTOH mean? Im a newbee.The cords with diodes make a difference when needed. I think I have been clear and consistant here.

OTOH: On The Other Hand; other slang acronyms you may find handy:
IMO: In My Opinion
IME: In My Experience
IIRC: If I Recall Correctly
YMMV: Your Mileage May Vary
If there are only diodes in the cord, there will be no conduction near the AC crossover point. Electrolytics are thus used as I mentioned prior so that the AC waveform is undistorted. However, it appears you are conflating two different subjects in your comment above.

Your amp draws heaps of current when played hard. Something heavy ga might help a little at full power. At idle Im not so sure. I note the current draw of the M-60 goes up quite a lot at full power testing.

How long can I run an M-60 sinewave at 60 watts into 8 ohms before the tubes get unhappy?

Not very long, but long enough so that organ pedal tones and the like can be reproduced without damage. The tube is linear with grid current.

Is it pure Class D or something else?

It is a good example of class D.

Would very much like your advice on what occurred to me a few days ago with my ss stereo amp.
I own a large stereo ss amp and speakers that both allow for bi-wiring. Four connectors per side and therefore I utilize two separate connectors per speaker cable per side ( four in total on each speaker and amp side). i normally connect two positive and two negative to each respective amp terminal and speaker terminal...left and right. A few days ago, I was re-inserting the amp back into the system and was NOT thinking! This time, I connected the amp correctly, BUT I connected the speakers as positive and negative connectors onto wrong terminals! So, what I ended up with was a positive connection and a negative connection X 2 ( per side) at the amp side ( correct) and a positive and negative connection for each terminal at the speaker end...one positive cable on positive, one negative cable on positive, one negative cable on negative, one positive cable on negative. This was done on both speakers!!! I powered up and noticed that I was getting signal only through ONE speaker, the right hand speaker, with no signal from the left hand speaker! What was going on??? Why signal at only one speaker with this bad connection scheme?
Luckily after much head scratching, I realized my mistake and corrected the hook up...and then both speakers were playing fine. Again, any idea as to why i had sound from one channel...and not both or any? Could I have done damage with this bad connection error?
Thanks for the reply.

No damage, and from what I can surmise, due to luck- one of your connections was apparently loose, otherwise neither speaker would have played. Essentially on the non-playing side, it sounds like the output of the amp was shorted. Fortunately you caught it and sorted it out, so no damage to the amp.

This is assuming that the biwire connection on the loudspeaker employs a common connection between the woofer and HF section.

Thanks. The speakers are bi-wirable at the input, so I am assuming that without a connection at the terminal, which I have removed, that there is no common connection between the woofer and the tweeter. ( it’s a two way). Nonetheless, the right speaker did play, just not the left? I also have a REL sub hooked up to the amp, it is left, right and ground at the amp, as both the amp and the REL are balanced designs. I guess I got lucky and didn’t blow one channel at the amp...or worse that and both speakers! 

I've found over the years that its not wise to make too many assumptions. If you have a Digital Voltmeter, check the continuity between the woofer and HF sections (with nothing connected to it) and see if they really are completely isolated.

Ok, what would be the difference if they are isolated vs not isolated...would this have changed the way the amp behaved...or I guess the right side speaker? 

@Daveyf, what model are the speakers and what model is the sub? Also...

I also have a REL sub hooked up to the amp, it is left, right and ground at the amp, as both the amp and the REL are balanced designs.

I presume you are using a three-wire cable to connect the sub’s Speakon connector to the outputs of the amp. Does "ground at the amp" mean that the ground (black) wire in the cable is connected to the amp’s chassis, or to a terminal that may be provided on the amp as a means of connecting to its circuit ground, or does it mean that the ground wire is connected to one of the negative output terminals of the balanced amp? And if the latter, is the ground wire connected to the negative terminal of the channel that produced sound when you misconnected the wires, or to the negative terminal of the channel that didn’t produce sound?

Regards,
-- Al

Al, the ground wire(black) of the sub is connected to the ground lug on the amp chassis. Rel T5i sub and Sonus Faber Guarneri Homage speakers. The sub is connected with a three wire connection. Left, right and ground. 

@Daveyf, thanks for providing the additional info.

Sounds good re the connections of the REL sub. You have NOT made the mistake I’ve seen more than a few members here describe having made, in which the ground wires of REL subs have been connected to a negative output terminal of an amp having balanced or bridged outputs. Which depending on the internal grounding configuration of the sub and the amp may often work ok, but depending on those factors risks the possibility of hum, sonic degradation, or even damage to the sub or the amp.

Given that, I think we can rule out the presence of the sub as contributing to the consequences of the miswire at the speaker terminals.

Also, while I couldn’t find a manual for the Sonus Faber Guarneri Homage speakers, I found a couple of indications that they are suitable for biamping, including this statement by no less than Martin Colloms in a 1994 review in Stereophile:

The filters are nominally 6dB/octave over the crossover range, augmented by additional components to shape the acoustic output. The treble high-pass section thus has three elements: two film capacitors and an air-core shunt inductor. For the woofer’s low-pass section, the primary element is a large series air-core inductor with an RC Zobel network and an additional film capacitor. The multi-way binding posts allow for normal and bi-wiring, or even bi-amping.

I would conclude from this and from user comments I found elsewhere that it is a near certainty that the high and low frequency sections of the speaker are not interconnected in any way.

Given that, I don’t see how the miswire you described could have resulted in damage to anything. I would have expected the result to be that both speakers would have played, but with poor sonics as a result of the high and low frequency sections being driven with opposite polarity signals. I can’t explain at this point why one speaker would have produced no sound, assuming there weren’t any loose connections. But perhaps Ralph or Roger will have some further thoughts as a result of the additional information.

In saying this, btw, I’m interpreting your statement that the misconnection at the speakers that involved "one positive cable on positive, one negative cable on positive, one negative cable on negative, one positive cable on negative" did NOT mean that the positive amp output was connected to both + and - of the SAME section of the speaker, and did NOT mean that the negative amp output was connected to both + and - of the SAME section of the speaker. In that situation no sound would have been heard at all, from any speaker or speakers that would have been connected that way. Although again, even in that case no damage would have resulted to anything.

Best regards,
-- Al

Thanks, Al. I think that given that I had the cables crossed only at the speaker end...the amp end was wired correctly, that it is unlikely that the amp was connected as in your last paragraph. What I don’t understand, is why the right channel was playing and not the left.No signal to the left whatsoever! Only once i corrected the cabling connection error did the sound return to the left speaker...and all seemed fine.
OTOH, perhaps I hadn’t noticed if one speaker ( the left) was hooked up the way you describe in the last paragraph, Hmm.

I realize I'm only on pg 7 of this wonderful blog, but I must chime in.

Dear Mr. Modjeski,

Thank you so much for taking all of this time to provide such great information for all of us.  Your honesty and humility is so refreshing and the graceful way you handled the adversity of some of these comments has been truly amazing.  I have owned a couple of your products in the past and I can only mirror the other comments mentioned here.   

From michaelgreenaudio on 11-29   

"Sigh, in the best way possible. The RM-5, one of my favorite components of all time regardless of price.

Speaking of Harry, I was tuning up two of his systems, one with the CAT and one with the Classe. I had my RM-5 with me and me and Harry listened to it for about two hours.

Man did I ever love that preamp! You could mate the RM-5 with anything and it would transform that amp and speaker combo. When Kenny started dampening his Pre-amp it was all over for me, I kept the RM-5 close by. It tuned better than all of them. I think I toured with the RM-5 for about 3 years.

mg

I too owned the RM-5 (serial #0023) for about 5 years (89-94) and yes - Man, did I ever love that preamp too!  It sounded absolutely amazing with everything I threw at it, all except for one amplifier.   First off, aestethically, in silver with the older graphics, I thought it was beautiful to look at, with a great fit n finish.  It sounded absolutely wonderful with a B&K ST140, McIntosh MC225, B&K EX442 Sonata, Paoli M70 monoblocks and Music Reference RM-9; unfortunately, it didn't seem to mate up at all well with the cj MV50?  I don't know why because I really wanted to like the MV50.  At one point, there was a little problem with the mute circuit, so I sent it back to you in VA and you updated it the current RM-5 MkII.

Here's the part that gets interesting and has become the basis for my theory on our aural memory.  When the RM5 was with you getting repaired and updated, the dealer loaned me a Dyna PAS2 preamp to go along with my B&K ST140 and ProAc Studio 1 speakers.  After a short time, I really started enjoying the PAS2 preamp and it sounded wonderful and lush.  After a couple of months the RM5 mkII was returned.  You had mentioned the changes weren't very drastic but when I got it back, my ear had become so accustomed to the PAS2, that I really hated to see it leave and actually thought it sounded better in my set up than the RM5.  I understand its all about system synergy so perhaps the PAS2 added that extra lushness to the ST140; whereas with the MC225, the RM5 balanced out its lushness.  And if I had the opportunity to try the PAS2 with the MC225, it would have probably been like putting too much sugar on top of your already sweet grapefruit.  

Unfortunately, while I do not possess the electrical knowledge to be able to repair or build gear, I have learned an awful lot from reading literally 100's of issues of TAS, Stereophile, HiFi Heretic, HFH & RR, Listener and others over the years.  And what I've realized over the 35+ years of being an audiophile and changing gear sometimes seasonally, sometimes less often (whenever I have solid state gear, I'm wanting to change gear a lot more often, and when I own tube gear I make a lot less changes) is that I believe there is an aural memory that we all have that you get accustomed to.  Whenever I make a change in gear, even if its an upgrade, my mind needs time to get used to that new change in sound.  Sometimes, it takes a week or two, sometimes longer for my ear to adapt to the new change in my system to where I can really enjoy the new piece in my system.

I'm grappling with this very issue now as I've recently sold some classic gear for a friend and in a short term have switched from a McIntosh MC225/MX110/Rauna Tyr II combo to a B&K ST140/Technics SU9070 preamp/Rauna combo to a moded GemTune EL34 SE int/Rauna combo and the differences have been pretty profound, but I'm loving the journey.  These little concrete speakers from Sweden were the first speakers I ever heard when I went into my first real high end store in the mid 80's and my jaw dropped & now I own a rare pair.

I apologize for my very long-winded response here, but if you have a chance, perhaps you can shed some light and your thoughts on this non-technical subject. 

Sincerely,

Louis  

      

   

   

Well ramtubes, we have 100% opposite opinions concerning the necessity for well designed power cords.  I am a beta tester for a boutique manufacturer.  I've sampled at least 50 designs and tested them against all types of high end cables.  When substituted at audio shows, they were the equal of or blew away the comparable high end and expensive cables.  The worst power cables were from High Fidelity with their patented magnet design.  (I've have 8 friends and two high end homeowners who did testing on their equipment as well and the latter two dumped their HF cables).  Two posters have thought HF cables are supreme.  We (10 of us), have found them to be hard, bright, forward sounding and harmonically thin on a wide range of tube Class A, A/B SE and SS amps, pre-amps and phono pre-amps.  

I don't have any electrical engineering degree or knowledge concerning transformer design or household current.  Basically, after auditioning so many PCs on so many high end systems, it appears that you could conclude that all the auditioned equipment was faulty do to poor transformer or power supply designs or implementation.    I disagree.  My own various custom made Class A/B tube equipment are greatly altered based on the power cables and I do not believe they are poorly designed.  They sound magnificent.  The chassis and transformers remain cool to the touch (maybe 80 degrees) after hours of use at sound levels averaging 90 db with challenging impedance speakers (Legacy Focus) with 6 - 12" woofers in a 5,000 cuft room.  The EAR 890 amps Class A chassis and transformers are burning up trying to drive those speakers (no problem with the Signature IIIs at 1 ohm higher impedance and 6-10" woofers).