Hi, I just spoke with a buddy who uses a pair of Krell MDA-300s to drive the woofer towers of his modified RS-1Bs. He uses a Dahlquist active crossover in lieu of the Infinity crossover for a couple of reasons, one that the latter is out of commission and the other that it won't work with the MDA-300s which are quasi-bridged. He said he had tried both the KRS-250 and the Eagle 7A and found the MDA-300s to be better than either. I can't say how the others would do. You want something with generous output current capabilities and ample heat sinks.
Brian |
It's been a long time since I owned the RS-1Bs, but I remember the crossover having a servo control function. This may be creating a feedback problem with the Perreaux. Have you tried floating the A/C ground on the Perreaux?
The Eagle 7A is a great bass amp, but who's going to fix it
if it breaks? Nothing beats a Bryston for performance and reliability.
Another amp to check out is the CarverPro digital ZR1600. 300 watt/channels for $1k.
Finally, those tall woofer columns in RS 1-Bs can be improved with some Blackhole 5 applied to the inside long
walls. |
Rick: I apologize for not getting back to you after last time we spoke. Too many things going on and not enough brain cells to keep track of them.
Here's the thread that i made mention of: [url=http://forum.audiogon.com/cgi-bin/fr.pl?htech&1014011751&read&keyw&zzac=polarity]AC noise, polarity & hum[/url]
If you can verify that everything checks out fine with your AC system and you don't have any ground related problems, it is possible that the "servo control" that Kana mentions could be playing games. I'm not directly familiar with this design, so i have no idea what it does.
As to Kana's comments about the Eagle's breaking and who will fix them, there is someone ( can't remember who ) that used to work at Electron Kinetics that repairs / updates these amps. Besides that, a good tech can repair anything that you hand them. It all boils down to whether or not one wants to pay the money to do so.
The Carver Pro ZR1600 as tested by John Curl via Brian Cheney at VMPS showed the amp to produce less than 200 wpc cleanly. Carver Pro ( nothing to do with Bob Carver other than someone using his name to market their products ) can say anything that they want, but when an amp goes into self-oscillation at or below 66% of rated power, it obviously doesn't meet spec. Then again for that matter and a WHOLE lot more money, the Pass XA 160's are a miserable failure also. Sean
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John Iverson, designed the Eagle 2 and later the 7A. His work was ahead of its time, as was he. He commented to me that designers did not understand the difference between voltage and current, and how manipulating them differently was the secret; I frankly didn't understand, and may have misplaced the words somewhat, and these are distant memories at best. However, his amps, and their sound are not distant memories to me. They were excellent! I put several Eagle 2's at $595.00 with the Conrad Johnson, Premier 3, a financially imbalanced system, but sonically spectacular.
I remember them sounding, generally, much more like a Bryston, though much more refined by comparison, than any of the others you mention. The Krell, for example, is much too hashy in the higher frequencies to have similarites in anything but the bass.
For its day the 7A was as remarkable as John, ahead of its time, just like him. With the difference in technologies, over the past 20 years, even at its level, I would doubt, but not emperically, that it could compare. Transistors are faster now, and more linear; circuits, and knowledge of proper placement of items on the boards, have evolved so much, unlike tubes. It is odd that a 1930's design may actually sound wonderful, even by today's standard; there have simply been too many advancements in the internals of solid state.
Plus, as someone mentioned, repair potential is not great.
Where is John? I would like to hear if anyone knows. He supposedly disappeared quite mysteriously. Someone told me that he was working on, 'Eyes only', Government weaponry systems, and one day, just vanished. This is all true. Stange, I admit, but true.
If any audiophiles familiar with John have any information I would like to know. He was a remarkable and brilliant man. If he were around today, working in audio, he would shame the lot of them out there. |
Sean- I don't understand why you want to put down an amp you haven't heard. Yes, it didn't test well, but even Mr.Cheney feels it sounds really good. For those who are interested, here's part of his comments(the rest can be found on Audiocircle.com):
Brian Cheney-subject: ZR 1600 comparitive listening tests:
"I'm not going to keep you in suspense: this amplifier has a sensational sound and is all the web buzz cracks it up to be, and more."
Carver Professional is a division of Phoenix Gold International, they have never claimed to have anything do with Bob Carver. They bought the name just like Superscope did when they bought the Marantz name in 1964, and just like Philips did in 1980, when Superscope sold them its shares of Marantz Japan.
Rick- when I owned the RS-1 B, I had a ARC D79B on the panels and Electron Kinetic Eagle 7A on the bass towers and there was no hum.
After reading your post again, I suggest that with the power off, you gently push on the center each woofer in the right tower and see if you hear any scrapping noise. You may have a woofer(s) with the voice coil out of aliment, which could be making the "sneakers of a gym floor" noise when the servo control powers up. Aloha, Kana. |
Kana: My comments are not only based on the technical measurements that John Curl obtained when testing this unit, but the suitability of this product for Rick's specific intended use.
From my past experience with the Perreaux 2150's, these amps typically clip in excess of 250 wpc @ 8 ohms and 400+ wpc @ 4 ohms. The 3150 is a far beefier amp with much greater bottom end authority, as Rick will confirm. While i can't explain the specific problems that he's having, my guess is that the Carver Pro might not solve the problem and would probably be a step backwards in terms of bass output and control.
The fact that the ZR 1600 was breaking up / oscillating at less than 200 wpc @ 8 ohms ( John measured 180 wpc into a dummy load ) would mean that it would probably perform even worse with a more reactive, far lower impedance load. Comparing that to the "real" 500+ wpc that the 3150 is capable of into 4 ohm loads or even the 400 wpc that the 2150 was offering should demonstrate why i have the thoughts that i do.
As a side note judging by what Rick and i discussed on the phone, i don't think that he's unhappy with the performance of the 3150. From what i gathered, i think that his main problem is the hum and other "odd" noise being generated with it in the system. If he could solve this problem, i think that he would prefer to run what he already has. I could be wrong, but that's what i was led to believe. Sean
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I had several of John Iverson's amps including the Electro Research and the Eagle 7s. This was a long time ago, however, and regardless of how good I found them then, they are probably surpassed today. For example I use a Citation 7.1 four channel amp on my subwoofers. I bridge the left and right two channels. I had actually looked for my old Eagles when I needed a subwoofer amp, but could not find them.
John's amps are rather straight-forward so I think someone competent in circuits could repair them. |
Hi all....just an update and again.....Thank you all for chiming in.
Sean you are correct with regard to my admiration for the Perreaux 3150B. If I can fix the two problems...this is the amp form my bass columns. It has the weights and control to offer a concert hall realism to music.
Now to some of your questions and some comments.
Yes, I do float the ground. I also tried direct into the wall and unfloating the groung.....still the problems.
As to the woofer columns and Kana's suggestion about pressing the woofer's to see if the noise appears.....that I will try. However, this "sneaker to gym floor noise", sort of a squeak, happens intermittently with or with any music playing. It also appears, for a second, when I turn on the amp. Then it goes away.
My biggest concern is that this does not happen whether 2150B is installed. So if it was a problem with the servo control on the Infinity, wouldn't it be doing the same problem with the 2150B???
Again, thanks all and Sean I will read up on your thread. I still would love to offer you a great Italian dinner to coax you over for a visit and "repair".......???? |
Hi all....just an update and again.....Thank you, all for chiming in.
Sean you are correct with regard to my admiration for the Perreaux 3150B. If I can fix the two problems...this is the amp form my bass columns. It has the weights and control to offer a concert hall realism to music.
Now to some of your questions and some comments.
Yes, I do float the ground. I also tried direct into the wall and unfloating the groung.....still the problems.
As to the woofer columns and Kana's suggestion about pressing the woofer's to see if the noise appears.....that I will try. However, this "sneaker to gym floor noise", sort of a squeak, happens intermittently with or with any music playing. It also appears, for a second, when I turn on the amp. Then it goes away.
My biggest concern is that this does not happen whether 2150B is installed. So if it was a problem with the servo control on the Infinity, wouldn't it be doing the same problem with the 2150B???
Again, thanks all and Sean I will read up on your thread. I still would love to offer you a great Italian dinner to coax you over for a visit and "repair".......???? |
Rick- one final thought- if you have a multimeter, check the DC offset in the right channel of the 3150, If it's off(should be as close to 0 vdc as possible) or not stable(compare it to the left channel), it could be interacting with servo crossover to cause the your problem.
Sean- I haven't heard the Perreaux 2150B/3150, I'm sure
they are excellent amps. |
Kana: That's a good suggestion about measuring the DC leakage. My brother did this after having problems with some speakers. What he found was that one amp was passing 3 volts of DC on one channel and 2.5 volts on the other. Luckily, this problem arose while he was running some junk speakers. Needless to say, that amp is out of the system until we can get it straightened out. 500 millivolts ( 1/2 a volt of DC ) is considered to be "acceptable" by most, but that is way high in my opinion. The amp that i gave my Brother to use measured less than .02 volts of DC on either channel.
As to the Perreaux's, the 2150's and 3150's are very similar amps ( cosmetically and in terms of basic circuitry ) that have very different sounds to them. I don't know anyone that has ever chosen a 2150 over a 3150 after hearing them side by side. Having said that, i run my 3150's strictly for woofers, as that is what they do best. Sean
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Thanks Sean and Kana about the suggestion regarding DC leakage. However, don't you think the people that checked out the amp where I brought it would have checked it? Maybe not?!@?@!!!!
Anyway, I am a total incompitent when it comes to anything technical. Sean....my offer still holds!!!! (LOL) |
I am sorry for hogging this thread but I must report to you all that...as of today....the hum and funny noises are GONE!! No, I have not done anything to the system or cables. It's just so weird?
SEAN, can you add any suggestions as to why it's gone (I hope for good). Do you think the amp has finally settled in??? I know it is still a week away from Halloween, but there many be spirits playing with my system. |
Rwd: Hogging this thread ? It's YOUR thread !!! : )
As to your problem fixing itself, that is simple. Your 3150 overheard you discussing it being replaced, so it decided to straighten up and fly right. This is common practice for electronics when they are about about to be replaced or go in for service. I run into it all the time.
Quite honestly, i have NO idea why this stuff happens. It is possible that something else in your system or outside of your system was aggravating the situation. Something as simple as moving a cable, altering the quality of connections, etc... could have solved your problem. All i can say is that you should enjoy this while it lasts. It could be forever or you could be back to tracking it down tomorrow. Sean
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RWD,
All the great things mentioned about the Eagle 7A are true. If you are lucky enough to find and purchase one, you can get it modified to the latest upgrade standards by John Iverson's right hand man, Russell Sherwood at Electron Kinetic Service Center (EKSC). Not only does the power get boosted 440 X 2 into 8 ohms, but the sonic signature is one of accuracy, precision, PRAT, dynamics to die for and extreme clarity and control. It's an amplifier, after upgrads, that you will happily live forever with and never let go of. Email me if you want further info or just call Russell at EKSC. Here is the company's URL:
http://eagle-audio.com/
Eagle amps are alive and well, thank you!!!!!
Best Regards,
Steve |
Do you how much they go for today? |
