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Marvin's picture
Last seen: 3 years 3 months ago
Joined: Oct 19 2012 - 8:20pm

Hi,  I am wondering if I will have a problem if I connect my 4 ohm electrostactic speakers to my 500amp 8 ohm receiver?   Are they incompatable?

   I know that this may sound like a dumb question but I just don't know much about ohms.

   I really enjoy my speakers and would like to someday put a tube amp behind each one, but for now I will have to settle on the solid state amp.


Kal Rubinson
Kal Rubinson's picture
Last seen: 4 hours 56 min ago
Joined: Sep 1 2005 - 9:34am
First, I think you mean

First, I think you mean 500watt, not 500amp.

Second, it is unclear what the receiver's amp is capable of from that one number.  What is the output per channel?  Is there a 4 ohm output spec?  What receiver is it?

Third, which electrostatic speakers do you have?  What is their sensitivity and, if you can tell us, what is the impedance curve like?  

jackfish's picture
Last seen: 2 years 4 months ago
Joined: Dec 19 2005 - 2:42pm
Make and model of all equipment


alanca3's picture
Last seen: 1 year 2 months ago
Joined: Oct 28 2012 - 7:03pm
It really depends.

Usually driving a 4 ohm load will heat up an amp pretty quick, and probably void the warranty.

jackfish's picture
Last seen: 2 years 4 months ago
Joined: Dec 19 2005 - 2:42pm
Useless generalization.
alanca3 wrote:

Usually driving a 4 ohm load will heat up an amp pretty quick, and probably void the warranty.

I'm driving a pretty consistent 4 Ohm load with Emotiva UPA-1 monoblock amplifiers and they are barely warm to the touch. There are many amplifiers and receivers on the market which are rated for 4 Ohms.

alanca3's picture
Last seen: 1 year 2 months ago
Joined: Oct 28 2012 - 7:03pm

You are certainly right. Lower end 8 ohm amps sometimes get hot though. 

Good luck with your system!

KenBurak's picture
Last seen: 3 years 2 months ago
Joined: Oct 31 2012 - 10:15pm
Regarding a tube amp and electrostatic speakers

My interest is in learing more about how tube amps and electrostatic speakers pair up, which is how I happened to come across these comments.  I wrote the following in a reply to some comments on another forum about Chinese equipment (that was being both trashed and lauded). It might be of interest, and maybe it will promote some feedback that I can learn from. So here goes...

Some of those comments and opinions I have read on the other Stereophile forum appear to have been made by informed, intelligent persons, while others appear to be emotional, irrational and ill-informed.  I’m not sure which category I’ll fall into, but for anyone who may be interested, I’ll share an experience that I have had with Grant Fidelity and one of the Chinese-manufactured items of equipment that they import, promote and distribute throughout North America.


After doing his research and due diligence, a hi-fi friend of mine purchased a Canadian manufactured 225 wpc, high-current integrated amplifier, the Magnum Dynalab model MD309 at $8,900. The company introduces this product as follows: “From our pedigree in pure analog circuitry, we're proud to introduce our most uncompromising 2-channel Integrated Amplifier. Using ...Hybrid-Acoustic CircuitryTM found in our MD-209 Audio Receiver, JJ 6922 Cryovalve tubes, and stocked with Magnum Dynalab's unrelenting build quality and audio engineering, the new MD 309 is a future-ready anchor for your high-performance home audio system. We believe it is the best Integrated Amplifier on the market.” For more about the validity of that statement, there are many reviews online about this and other products from this Canadian company, world renowned for making perhaps the best FM tuners in the world, and now applying their resources towards additional hi-fi components.


So, my friend brought over the Dynalab unit and we compared it head-to-head with my not-too-long-ago-acquired Grant Fidelity “reference integrated tube amplifier”, a “RITA-880S”, manufactured in China. The RITA-880S is a class A ultra linear design, utilizing a pair of Psvane  A CV181-T (6SN7); a pair of 1960's Chinese NOS military grade 6SL7 tubes and 4 Psvane KT88-T output stage tubes, capable of 45 watts per channel from its  8 or 4 ohms taps. It weighs in at 115 pounds! (I have always been a believer that, in audio, “HEAVIER IS BETTER”. I once said something to that effect in front of 3 rather large women that I shared office space with at one time, and they immediately took me out for drinks and a VERY expensive lunch!)


Back to the story…We were set up in a terrific room, rather on the larger volume side, about 14 feet wide by 31 long and extending further to about 52 feet in total length, with vaulted ceilings in multiple directions up to 14 feet high and plenty of sound absorption contents. There is plenty of “room volume” here for big energy emissions. We listened to numerous good quality CD’s on a well-regarded/well-reviewed player. The reasonably good quality speaker connect cabling was moved from one amplifier to the other so that there was absolutely nothing different in our evaluation other than the 2  amps. The speakers were however, going to be a good test for the amps…a newer pair of Martin Logan Vistas, extremely well matched to the room in that they were positioned about 13 feet forward from the rear wall (which has a 14 foot ceiling and what I believe to be an ideal mix of reflective/non-reflective surface areas). The Logans have a very low impedance in the upper end and for that reason, as well as others, they are considered by some to be a speaker that will easily demonstrate weaknesses in amplification stability and generally, weaknesses in any other system components as well.


Anyway, with some anticipation, we embarked on our little mission to discover the audible differences between the MD 309 and the RITA 880S…which we had both listened to previously… and away we went. Going in, I think we both fully expected the Dynalab, costing more than double that of the RITA, to be clearly superior in several areas. We expected to now find out just how much superior.


So,... here is the essence of our experience. The Dynalab played louder. On some, but ONLY ON SOME musical material, it had a perceptible advantage in reproducing a greater dynamic range of the music …but ONLY IF there was a lot of program content on the recording and if that content built up to a crescendo of one sort or another. The Grant Fidelity amplifier drove the Vistas (with the electrostatic panels that have very low impedance in the upper end, and which DO NOT have built-in amplification for the conventional cone speaker in the low frequency cabinet) to “normal”, “reasonable”  and “adequate” listening levels for the various music we listened to…with more than ample volumes for what either of us would typically utilize. In all other respects - transparency, sound stage definition both side-to-side and front-to-back, low frequency performance and control (we did not use the sub that was on hand), background silence, nuance and detail… to our ears and perceptions… and with careful assessment and judgment,  BOTH of us came to the conclusion that the 2 amplifiers sounded…IDENTICAL !


I would expect (?) that a professional audio industry reviewer with vastly more experience than the 2 of us, supported by sophisticated laboratory technical analysis of the 2 amplifiers, would be likely identify more subtle differences in the amplifiers than eluded us. HOWEVER, for us, in the real life environment in which our assessment took place, unless we were going to play music SO loud as to scare the hell out of our friends or family, the Grant Fidelity RITA 880S impressed us with its same ability as the Magnum Dynalab MD 309 to provide equally magnificent sound in every other sense. We clearly liked both of these amplifiers better than the excellent Canadian made Bryston or American made MacIntosh brands that each of us are familiar with (…aren’t we all?) Personal taste? Perhaps so. My son prefers the more analytical, brighter Bryston sound and I respect that preference.


My hi-fi friend and I are both very happy with what we bought. He simply prioritizes more money for this purpose than I, and for that, he got something more that I didn’t. But we are both going to be listening to virtually the same high fidelity sound. (With his bigger budget, he’ll have the new Martin Logan Montis, which, for now, I will only dream of.)


If you’ve stuck it out this far, would you please hang in a minute  longer to allow me to make a point please?. It’s about how this whole thing started. It’s that, if given an “apples-to-apples” choice at essentially the same cost, I would RATHER support a Canadian or American manufacturing corporation and their employees and shareholders than a company in China. While Grant Fidelity is a Canadian importer, promoter and distributor of numerous brands of Chinese-manufactured audio equipment, as far as I can discern, they do not employ very many people in this country and therefore do not augment the Canadian economy very significantly in that respect.  But with the service that they do provide, they have augmented MY economy by allowing me to get superb sound performance AND in doing so, in terms of the Dynalab amp, retain over $4,000.00 to allocate to other priorities in life, whether they relate to the enjoyment of music or otherwise. Consequently, that money I did not spend on some other amplifier that I felt I needed to satisfy my expectations...that money saved may ultimately benefit some other domestic or American manufacturer of audio equipment, or otherwise. So, thank you, Grant Fidelity, and China.


Footnote: My amp and speakers have only 158 hours on them at the time I am writing this..which is about double the hours when we did the testing. The sound seems to keep improving (as the “break-in” period continues). I could have bought Bryston, MacIntosh, NAD Master series, or any number of other amplifiers, and my hi-fi friend could have done the same…we listened to all of those and then some. They all sounded great. But I’m especially  pleased with my choice  and he with his. All I wished to do here by writing this is to share with those who may be interested, what a great experience I have had and continue to have thus far with my Grant Fidelity/Chinese amplifier, and how pleased I am with the sound quality that I’m enjoying for my hard earned dollars spent. (I feel just as good about the Martin Logan Vistas as well, but I do hope to someday up-grade to the new Montis model. I believe that those, paired up with the RITA 880S will be awesome!  - Ken




Magnum Dynalab MD309 Hi-Fi Plus Issue 69 Review:


Grant Fidelity RITA 880 (Predecessor to RITA 880S) Reviewed by Colin Smith Soundstage


Grant Fidelity RITA 880 (Predecessor to RITA 880S) Customer Review


Grant Fidelity RITA 880 (Predecessor to RITA 880S) Reviewed by Richard Austen of Constantine Soo’s  Dagogo


JungSon DA88Ti Integrated Valve Amplifier

JoeE SP9
JoeE SP9's picture
Last seen: 3 months 1 week ago
Joined: Oct 31 2005 - 6:02pm

That's a very interesting and informative post. Unfortunately it doesn't answer Marvin's question.

Marvin, we need to know the specifics about your question.

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