What Audio Research power amps have you owned or admired?

[jadis]

I don't remember whether the SP-10 was dual mono or had a separate power supply. It definitely ate more tube than an Atma-Sphere amp.

If dual mono means 2 separate volume pots for left and right channels, then the SP-10 is not, as it has only 1 volume control. I had an Audible Illusions 2B before and it had 2 volume controls for the L and R channels. That should be dual mono, I think. And yes, the SP-10 had a separate power supply. And there is a power switch for outlets behind it where one can plug a TT or cassette deck.

 

[mep]

I could be wrong (what a surprise), but I don't think the ARC SP-10 was dual mono. It does have a big outboard power supply, but I don't think it has two power transformers. ARC did make some amps that were easy to bias and they made some that are a nightmare. The D-70 and the VT-100 series are just insane when it comes to setting bias and I put both of them in the nightmare catagory.

Mark

 

[MylesBAstor]

I could be wrong (what a surprise), but I don't think the ARC SP-10 was dual mono. It does have a big outboard power supply, but I don't think it has two power transformers. ARC did make some amps that were easy to bias and they made some that are a nightmare. The D-70 and the VT-100 series are just insane when it comes to setting bias and I put both of them in the nightmare catagory.

Mark

I thought it was but so far my internet search of SP10 reviews mention it being dual mono--but of course was two chassis.

 

[Steve Williams]

Here you go

http://www.arcdb.ws/SP10/SP10.html

Anything Audio Research can always be found at arcdb

 

[Sharp 1080]

Preamps/linestages

SP-5 modded to the SP-7 my first AR product
SP-9
SP-14
LS25 MKII

Amps

Classic 60-great sounding amp
Classic 120 monoblocks-hated them, constantly blew tubes running Martin logan Sequel II's
M 300's-forced to try at home by Christopher Hansen

 

[mep]

The SP-10 is not dual mono. It has one power transformer like I thought.

Mark

 

[jadis]

Classic 60-great sounding amp
Classic 120 monoblocks-hated them, constantly blew tubes running Martin logan Sequel II's

There were quite a few Classic Series amps here, most owners reporting break downs, tubes, transformers, and other parts. Boy, these things run very hot.

 

[mullard88]

Preamps and line stage I have owned: SP 3, SP 6, SP 8, SP14, and LS 10. I kept 2 units of the SP 3.

Power amps I have owned: D 76, D 79, D 150, D 70, D 115, and 150.2. I kept 2 units of the D 76 and one unit of the 150.2.

 

[MylesBAstor]

Preamps/linestages

SP-5 modded to the SP-7 my first AR product
SP-9
SP-14
LS25 MKII

Amps

Classic 60-great sounding amp
Classic 120 monoblocks-hated them, constantly blew tubes running Martin logan Sequel II's
M 300's-forced to try at home by Christopher Hansen

Interestingly, the Classic 150s sounded very good on my friend Jack English's ProAcs. He never had a problem til a friend brought over a length of the early vDH ICs. Plugged them in, heard a hum, then a pop and no amp. Took out a circuit board

 

[MylesBAstor]

Preamps and line stage I have owned: SP 3, SP 6, SP 8, SP14, and LS 10. I kept 2 units of the SP 3.

Power amps I have owned: D 76, D 79, D 150, D 70, D 115, and 150.2. I kept 2 units of the D 76 and one unit of the 150.2.

I have to tell you a story about the SP8. A good friend had his SP8 on a equipment stand with a lamp situated maybe 2-4 ft over the unit (at the time, think he was also using the D250s). For some reason, if you waved your hand between the lamp and SP8, one heard a hum in the system

 

[Steve Williams]

That is actually not an uncommon occurrence Youre not implying it was the Audio Research

 

[mullard88]

I have to tell you a story about the SP8. A good friend had his SP8 on a equipment stand with a lamp situated maybe 2-4 ft over the unit (at the time, think he was also using the D250s). For some reason, if you waved your hand between the lamp and SP8, one heard a hum in the system

Interesting. Electromagnetic field voodoo comes to my mind.

 

[MylesBAstor]

That is actually not an uncommon occurrence Youre not implying it was the Audio Research

Nah, perish the thought

 

[microstrip]

The SP10 I think was ARC's only dual mono preamp.

Miles, the SP10 is a dual box, but not dual mono - the tube regulated power supply was shared between channels.

I remember it well - although my first serious hifi was a second hand ARC D70II, later I also owned a SP10. I was lucky, the second owner had trouble several times with it as the technician who serviced it was not able to understand the hybrid tube regulator and sold it almost as rubish! I repaired it myself, and it never gave me any trouble. I should say that this was many years before ARC had a representative in my country, the current distributor has a technician who can service an SP10 with closed eyes...

Yesterday I was listening to the classic Paniagua Lafolia with the new Anniversary and was astonished to discover new details and bass nuances in a recording I heard tens of times - I propmise to come back after the mystic 600 hours. But the first time I heard the La Folia with the SP10, Oracle , Sumiko MDC800 and a Kiseki is unforgettable - the energy and the musicality of the SP10 were an whole new experience for me.

 

[DaveyF]

I am currently enjoying an ARC D70 Mk2. I am utilizing SED 6550's in the power stage and NOS GE 6FQ7's along with JJ 6922's in the driver stage. With my SF GH's. this amp is making beautiful music. I do agree with some of the other posters that the biasing procedure is best left to a tech. However, I do not think that once the amp is biased that it tends to drift much... as least mine has been rock solid, which leads me to believe that most likely this isn't an amp that needs too much maintenance once it's dialed in. My a'phile friends and I compared this amp to an ARC VT 100Mk3 and a BAT VK75SE and a 55SE and we all felt that on the whole we liked the ARC the best!
The ARC still has IMHO a midrange that is SOTA. Again IMHO, a KILLER deal on the current used market and deserving of becoming a collector piece.

 

[MylesBAstor]

I am currently enjoying an ARC D70 Mk2. I am utilizing SED 6550's in the power stage and NOS GE 6FQ7's along with JJ 6922's in the driver stage. With my SF GH's. this amp is making beautiful music. I do agree with some of the other posters that the biasing procedure is best left to a tech. However, I do not think that once the amp is biased that it tends to drift much... as least mine has been rock solid, which leads me to believe that most likely this isn't an amp that needs too much maintenance once it's dialed in. My a'phile friends and I compared this amp to an ARC VT 100Mk3 and a BAT VK75SE and a 55SE and we all felt that on the whole we liked the ARC the best!
The ARC still has IMHO a midrange that is SOTA. Again IMHO, a KILLER deal on the current used market and deserving of becoming a collector piece.

Davey:

Have you tried other brands of driver tubes in your ARC eg. 6FQ7s and 6922s?

 

[DaveyF]

Hi Myles, I tried EH 6922's, I didn't like the sound as well as the JJ's. The EH's seemed to add a very small layer of haze to the sound. I have been told that the EH's are more durable and consistent; however, I think they lose too much to the JJ's. I also own GE 6550's, they are magnificent in this amp, BUT mine are getting a little noisy so I run the winged "c"'s most of the time. The winged "c"'s are very smooth and lose very very little to the GE's. Haven't tried any other 6FQ7's. Always open to suggestions. Thanks.

 

[MylesBAstor]

Hi Myles, I tried EH 6922's, I didn't like the sound as well as the JJ's. The EH's seemed to add a very small layer of haze to the sound. I have been told that the EH's are more durable and consistent; however, I think they loose too much to the JJ's. I also own GE 6550's, they are magnificent in this amp, BUT mine are getting
a little noisy so I run the winged "c"'s most of the time. The winged "c"'s are very smooth and loose very very little to the GE's. Haven't tried any other 6FQ7's. Always open to suggestions. Thanks.

The 6FQ7s aren't what they used to be. I think that's why most companies have abandoned this tube.

If I remember correctly, the RCA clear tops 6FQ7s were reprotedly the best. It's been years since I heard them in my cj amps but wasn't all that impressed; the ones I tried weren't the quietest either. The Sylvania 6FQ7s were pleasant but soft, somewhat veiled and the bass was a little thick. The GE 6FQ7s were cleaner but sounded, well like GEs. The best I ever tried, and God knows if there are any around any more, were some Japanese made, Toshiba 6FQ7s. They were to the stock tubes what GEC KT88 or 77s were to the GE or Sylvania 6550s or EL34s.

 

[DaveyF]

I agree that the RCA clear tops have the best rep, BUT i actually liked my GE's better when I heard them in a friends amp. I know which Toshiba's you are referring to, I think they are unobtanium. Like you said these tubes are getting hard to find. I forgot I also tried the Philips 6FQ7's, didn't like those either; seemed to lack high end extension.

 

[mep]

I owned a D70 MKII for awhile and I liked it other than the criminal bias set up. I don't know how ARC can constantly build amps that are damn near impossible to bias when they know better. With the D-76, all you had to worry about was burning your fingers when you plugged in the meter. With the D-76A, ARC installed the bias jacks upside down so now you had to remove the bottom cover from the amp which had some standoffs. Anyway, I sold the D-70 MKII when I had a chance to buy a Quicksilver MS-190 amp. I liked the MS-190 much better.

By the way, I always had good luck with the RCA clear tops.