Suggestion for Tube based Power amplifier

[joeling]

Hi all,

While my solid state curiosity is piqued, my main system is having some issues. I have become disillusioned with my ARC ref250s after one of the monoblocks developed a mechanical buzz after 1000hrs of use. Other issues were documented elsewhere on this forum.

Anyway, enough about that. I am looking for suitable tube power amplifier to replace the ref250. For the moment, I am pretty happy with my linestage - ARC ref40 so I may not change it out.


I listen to a lot of vocals so my preference in descending order of importance :

1) mid range - vocals must sound nice
2) soundstage
3) bass - bass would be nice

My speakers & associated equipment are listed in my signature.


Any suggestions on what to audition ?

Regards,
Joe Ling

[jdandy]

Joe.......I can easily recommend a pair of McIntosh MC2301 power amplifiers. I love mine. Glorious sound from bottom to top.

[cmalak]

Joe...if you go with the MC2301s, get a McIntosh preamp. The lowish input impedance on McIntosh amps does not play nice with the slightly higher output impedance of ARC pres. Check out commentary of Ryan Coleman about the mismatch between a Ref 5Se and a MC501 in his review of the Ref 5SE at Soundstage.com: SoundStage! Hi-Fi | SoundStageHiFi.com | Audio Research Reference 5 SE Preamplifier

The Ref 5 SE sounded like its specs: a big, bold, powerful single-ended-triode (SET) tube amplifier, but without a SET’s stereotypical flaws of limited dynamics and truncated frequency extremes, and this character was clearly on display no matter what power amps I plugged it into, provided the amp’s input impedance was greater than 20k ohms, balanced. Otherwise, the bass was ill-defined, recessed, and woolly -- as I found when I partnered the Ref 5 SE with the McIntosh Labs MC501 monoblocks, which have an input impedance of 20k ohms, balanced.

The Mc501 and Mc2301s have similar input impedance. I also remember a shootout that Bob did a few years back between an ARC Ref 3 and a McIntosh C500T pre both driving a McIntosh power amp (I think it was MC1.2KWs but I may be wrong) and again the C500T beat out the Ref 3 in his shoot out and I remember suggesting back then that the issue could have been the potential impedance mismatch. You can actually search the thread for Audio Research Ref 3 and McIntosh C500 shootout and I am sure you can pull it up. So if you go down the route of keeping your Ref 40 pre, then I would look at tube amps with at least 40Kohms input impedance to make sure there are no potential issues with impedance matching. If you decide to give the Mc2301s a whirl then they should match perfectly with the C1000 series preamps.

As for known positive matching with ARC pres, here's a suggestion that does not exactly fit your request but may be something to consider. ARC pres and Lamm amps have been known to gel well (ARC known for open, transparent, 3 dimensional sound, whereas Lamm excels at adding tonally rich hues to timbre while still being very resolving and detailed which complements ARC). Two possibilities here to match the output rating of the ARC Ref 250s and both are Class A SS with a single tube used in the input stage of the amplifier:

The M1.2 monos: 110wpc into 8/4 ohms and 220wpc into 2ohms and 400wpc into 1ohm of Class A power and 41Kohms input impedance

Here's a link: M1.2 description

The M2.2 monos: 220wpc into 8/4 ohms and 440wpc into 2ohms and 600wpc into 1ohm of Class AB but highliy biased into Class A (I think the first 50wpc is in Class A I believe) and 41Kohms input impedance.

Here's a link: M2.2 description

To stick with tube amps that offer big power (>100wpc), then the names are the usual: VTL, Atmasphere, Convergent Audio Technologies, BAT, McIntosh (see above), Manley, Rogue Audio, and Octave Audio (Germany). The first 7 are US-based and I suspect you will have similar issue of having to deal with long service-time if an issue arises with one of these amps as well (i.e., unlikely to have local certified techs able to deal with a major issue from any of these amplifier brands in Malaysia) as the units will have to be shipped back to the US, serviced and then returned.

I would just make sure again you look at options with at least 40Kohm input impedance. If you look at all of ARC's power amps (SS and tubes) they all have a minimum of 100Kohm impedance (this makes sure that they present an easy load to whatever preamp is driving them).

One last tangent, another SS options to consider that are known good matches with ARC pres are D'Agostino Momentum stereo or mono amps (Dan used to demo his amps at audio shows with ARC pres before he developed his own pre and they always got rave reviews for the combo).

[Jerome W]

Originally Posted by cmalak

Joe...if you go with the MC2301s, get a McIntosh preamp. The lowish input impedance on McIntosh amps does not play nice with the slightly higher output impedance of ARC pres. Check out commentary of Ryan Coleman about the mismatch between a Ref 5Se and a MC501 in his review of the Ref 5SE at Soundstage.com: SoundStage! Hi-Fi | SoundStageHiFi.com | Audio Research Reference 5 SE Preamplifier

The Mc501 and Mc2301s have similar input impedance. I also remember a shootout that Bob did a few years back between an ARC Ref 3 and a McIntosh C500T pre both driving a McIntosh power amp (I think it was MC1.2KWs but I may be wrong) and again the C500T beat out the Ref 3 in his shoot out and I remember suggesting back then that the issue could have been the potential impedance mismatch. You can actually search the thread for Audio Research Ref 3 and McIntosh C500 shootout and I am sure you can pull it up. So if you go down the route of keeping your Ref 40 pre, then I would look at tube amps with at least 40Kohms input impedance to make sure there are no potential issues with impedance matching. If you decide to give the Mc2301s a whirl then they should match perfectly with the C1000 series preamps.

As for known positive matching with ARC pres, here's a suggestion that does not exactly fit your request but may be something to consider. ARC pres and Lamm amps have been known to gel well (ARC known for open, transparent, 3 dimensional sound, whereas Lamm excels at adding tonally rich hues to timbre while still being very resolving and detailed which complements ARC). Two possibilities here to match the output rating of the ARC Ref 250s and both are Class A SS with a single tube used in the input stage of the amplifier:

The M1.2 monos: 110wpc into 8/4 ohms and 220wpc into 2ohms and 400wpc into 1ohm of Class A power and 41Kohms input impedance

Here's a link: M1.2 description

The M2.2 monos: 220wpc into 8/4 ohms and 440wpc into 2ohms and 600wpc into 1ohm of Class AB but highliy biased into Class A (I think the first 50wpc is in Class A I believe) and 41Kohms input impedance.

Here's a link: M2.2 description

To stick with tube amps that offer big power (>100wpc), then the names are the usual: VTL, Atmasphere, Convergent Audio Technologies, BAT, McIntosh (see above), Manley, Rogue Audio, and Octave Audio (Germany). The first 5 are US-based and I suspect you will have similar issue of having to deal with long service-time if an issue arises with one of these amps as well (i.e., unlikely to have local certified techs able to deal with a major issue from any of these amplifier brands in Malaysia) as the units will have to be shipped back to the US, serviced and then returned.

I would just make sure again you look at options with at least 40Kohm input impedance. If you look at all of ARC's power amps (SS and tubes) they all have a minimum of 100Kohm impedance (this makes sure that they present an easy load to whatever preamp is driving them).

One last tangent, another SS options to consider that are known good matches with ARC pres are D'Agostino Momentum stereo or mono amps (Dan used to demo his amps at audio shows with ARC pres before he developed his own pre and they always got rave reviews for the combo).

Cyril,

x100000
Your added value to AA is really priceless !
We are lucky to have you MON AMI !

[cmalak]

Originally Posted by Jerome W

Cyril,

x100000
Your added value to AA is really priceless !
We are lucky to have you MON AMI !

Jerome...thank you . I hope it's helpful to Joe

PS: Jerome...did you order the O96 or Silverbacks in the end? (Sorry for the tangent Joe).

[Jerome W]

Originally Posted by cmalak

Jerome...thank you . I hope it's helpful to Joe

PS: Jerome...did you order the O96 or Silverbacks in the end? (Sorry for the tangent Joe).

Thanks to you and John Devore advices, I am ordering a pair of Silverback.

[cmalak]

Originally Posted by Jerome W

Thanks to you and John Devore advices, I am ordering a pair of Silverback.

Jerome...I think you are going to really enjoy them I'll be looking forward to seeing your comments on them when they get to you. Congrats

[Jerome W]

Originally Posted by cmalak

Jerome...I think you are going to really enjoy them I'll be looking forward to seeing your comments on them when they get to you. Congrats

Thank you Cyril !

[joeling]

Thanks guys. I will look into it.

Regards,
Joe Ling

[AudioGremlin]

Joe,
I'm a retired electronics engineer. When I replaced my high end equipment I looked more towards reliability in tubed equipment. I went for Manley because their circuits are well proven not complex, easily repaired & have superb factory backup if required. Although I previously used ARC I thought some of their circuits overly complex (especially when I used the old SP11, although for me it was reliable there were some solid state components that were not easily identifiable except by ARC!)
For tubed gear I now adhere to the Kiss method (keep it simple stupid).
Cheers Mike