[PaulFolbrecht]

Anybody out there running RM30Cs full-range with something like 25-30W 845 or 805 SETs?

Am considering these speakers and if I buy will be trying this.  Consonance 845 SET monoblocks (heavenly mids and highs).  Worst-case, I'll bi-amp with the powered-bass amps but I'd rather not if it works well without it.  Just wondering if anyone is doing this.  Thanks.

[shokunin]

Roger Gordon of Positive Feedback is using RM30's with a deHavilland Aries 845 amplifer.  I briefly used the Aries G 845 amplifier to power the top end of my RM/x's for a little while.  I couldn't get the integration with the solid state woofer amp so I sold the dehavilland.

[PaulFolbrecht]

That's true; I'd noted that.  He's one guy, though, so I was looking for more feedback, and somebody who could talk about the bass performance. 

He did used the M model too with the 10" woofers.  Yeah, most likely this should work out well full-range.

If that's true, though, it makes me wonder why so few are doing such things.  From what I read, it seems most people throw a lot of solid-state power at these things.  Perhaps that's just because high-power SS amps are just much more common. 

[mjosef]

That's true; I'd noted that.  He's one guy, though, so I was looking for more feedback, and somebody who could talk about the bass performance. 

He did used the M model too with the 10" woofers.  Yeah, most likely this should work out well full-range.

If that's true, though, it makes me wonder why so few are doing such things.  From what I read, it seems most people throw a lot of solid-state power at these things. Perhaps that's just because high-power SS amps are just much more common. 

I have noticed that too, seems like a lot of people feel that VMPS speakers needs gobs of power. I don't have the RM30, but the guy I bought my RM1s from felt that they (RM1s)needed lots of power. I ran my speakers with a Jolida 20W EL84 tube amp and got mid 90's dB easy in my 11x15 room. I have tried solid state amps ranging from 60W. to 350W. and they all fared well. Currently I am using Response Audio Signature 3205 (40W. EL34s) and can easily hit over 105dB.
I don't buy that you need hundreds and hundreds of watts to drive speakers of 90dB efficiency, unless maybe its a huge space and you like it loud. For normal listening levels which is around 85-95dB for me, 40 tube watts is more than enough for my space. But maybe I am getting old...

[warnerwh]

You're right that most people use SS amps in this hobby. However with VMPS speakers I believe alot of people are missing alot of the potential of the speakers planar/ribbon drivers. This is my opinion. Once Jim Romeyn (spelling) told me that if you haven't heard VMPS speakers with tubes you haven't heard them. Boy was he right.

Both amps I've tried on this set of RM 40's are hybrids. The first was a Blue Circle BC 24 and the sound now was exceptional but not enough power. Presently I'm using an AVA Fetvalve 550 with Mullards. This has sound similar to the Blue Circle without the low power issue.

I am biamping with an SS amp on bottom as I love powerful and accurate bass. I also tend to listen to peaks in the mid 90's most of the time so power is a necessity and I certainly don't have enough money for a powerful tube amp , not to mention I don't believe in ever pushing an amp anywhere near clipping.

My point is that with the bit of tube sound added to the planar/ribbon section of my speakers much more body and wholeness has been added to the sound that a pure ss amp just can't do, at least none I've heard. Tubes adds more realism to the midrange and treble regions.

I may try a pure tube amp one of these days but it will have to be not too tubey. I've had that and it sounded slow and mushy to me. There were qualities that I really liked though and it was then I knew I was on the right track.

Being as SET amps are something I've never heard I really can't comment on them. Being tubes and reading that the midrange is gloriously good I'd tend to believe that at least using them on the midrange/treble would be a good idea. I suspect bass would not be as good as an SS amp, at least to me, but I know of at least one person on this board who I believe uses tube Kora amps on his RM 40's full range and has been happy with his setup for at least a few years now.

If you're willing to forego taught bass then you'll have outstanding sound. Being as you listen to what I consider moderate levels you should have enough power also. I don't know your taste for bass but a subwoofer integrated into the system may be a decent idea. In either case best of luck to you.

[shokunin]

If you augment your RM30's with a subwoofer say a VMPS Larger powered by a solid state amp or the built it amp then you could have the best of both worlds, the SET amp on the RM30's and a powered sub to cover everything below 50hz. 

[BobRex]

Once I receive my RM30Ms (should be shipping any day now) I'll be reporting on driving the mids and highs with a 2A3 SET.  The bass power will be provided by the PBS.  Given 93db and a linear 8 ohms, I have high expectations.

[Brad]

I tried a 2a3 tube amp on the top end of my RM2s way back when.
Glorious sound, but alas, not enough of it.  Definitely ran out of gas when things were really getting interesting in the music.

I hope you have better results.  The extra mid of the RM30 and the higher efficiency of the FST may swing things in your favor.

[woodsyi]

8 watts from 300B amp ran out of juice on my 40s (ribbons only) when "pushed" to 80 dB output.  Sounded good at low level.  The ribbons still sound the best with my push pull over the top 120 tiode watter with full octal tubes for voltage gain and driving.  The sound is not loose or bloomy -- just full.    Good luck with 2A3 on the '30s. 

[PaulFolbrecht]

Hey, the thread took off!  Cool. 

Couple points to make.  First is that desired listening level is a very important part of the "how much power is enough?" question.  I like peaks around 90dB - no more is necessary for me.  I listen to 90% jazz and world music and this does it for me.  If I wanted 100dB peaks, that's *ten times* more power required, as we all know.  Now you're in another league.

#2 - bass control and tube amps, especially zero-feedback tube amps with low damping factors.  It all depends on the speaker/woofer(s).  Some, in fact, work best with lower DF amps.  The "tightest" bass is *not* always best, or most realistic.  This is one reason I much prefer my SET amps running full-range on my Hyperion 938s rather than bi-amped with SS on the bottom.  Tried it - the bass is fuller and more natural with the tubes.  This is no doubt because these speakers were designed to work with low DF amps; the woofers are very light and the suspension compliant.  That said, it sounds to me that the VMPS woofers might be another story (which is fine).  Then again, as we know, at least one reviewer liked the 30s, even with those 10" woofers, on 25W of low-DF, zero-feedback SET power.

For me, 93dB is not nearly high enough sensitivity for the 3W or so that 2A3s give.  I would not even consider trying that...

Regarding power, current delivery capability is another part of the equation that is obviously not really considered when quoting wattage. 

And then there's clipping.  My experience is that SS amps sound like crap when pushed into clipping *at all*.  Since dynamic music can require 100x the power on transients, this does mean you generally need a lot of SS power to avoid that nastiness.  Tubes overload so gracefully that honestly you probably cannot even tell when even 10x their power is pulled (thus clipping) for a ms here or there.  The dynamics won't be quite as nice as if the amp were really delivering that juice, but at least there is not a hint of that utterly nasty upper-harmonic nastiness that sand amps put out.  (Not a knock on sand amps -- as I said, I just think you want to have lots and lots of headroom to make sand sound good.)

Paul

[BobRex]

For me, 93dB is not nearly high enough sensitivity for the 3W or so that 2A3s give.  I would not even consider trying that...

Then you're really gonna love this one.  Before the surrounds wasted away, I was driving a pair of Acoustic Energy AE1s, early vintage, with the 2A3s.  It worked much better than expected.  At my listening levels of roughly 75dB average, I only had issues on really dense music.  Otherwise the combo was scary good.

Given that I'm picking up 10dB just in sensitivity and I'm restricting the signal to above 100Hz, I'm pretty confident that this will work well.  Let's see... 93dB sensitivity, 6dB of gain for a total of 99dB before clipping, plus 3dB for stereo contribution means I should easily see 95dB peaks at my listening position.   It won't part my hair, but I've brushes for that job.

[duggie]

8 watts from 300B amp ran out of juice on my 40s (ribbons only) when "pushed" to 80 dB output.  Sounded good at low level.  The ribbons still sound the best with my push pull over the top 120 tiode watter with full octal tubes for voltage gain and driving.  The sound is not loose or bloomy -- just full.    Good luck with 2A3 on the '30s. 

woodsyi, if you remember, 40w of set power from 6c33c monoblocks did just fine driving your ribbons.     these amps are a fantastic value, imo, even when purchased brand new.  used, they are even a better deal.  aa  mine don't have the latest capacitors, vlad of audio mirror is sending me them for install...

http://cls.audiogon.com/cgi-bin/cls.pl?ampstube&1167344305

[Brad]

I thought the RM30's cut over to the mid at 280hz?

I remember it taking quite a bit of current to drive through the x-over on the RM2's I had.
280hz should be easier on the 2a3 amp......

[BobRex]

Yep, the mid crossover is at 280.  But it's a first order crossover so it's only going to be about 8db down at 100Hz.  B also has a second leg added around there to limit the power going into the panels.

[PaulFolbrecht]

woodsyi, if you remember, 40w of set power from 6c33c monoblocks did just fine driving your ribbons.     these amps are a fantastic value, imo, even when purchased brand new.  used, they are even a better deal.  aa  mine don't have the latest capacitors, vlad of audio mirror is sending me them for install...

http://cls.audiogon.com/cgi-bin/cls.pl?ampstube&1167344305

Those are beautiful amps! I considered them at one time but passed because I didn't know anything about them and the deal seemed much too good to be true.

They are single-ended?  What have you compared them to?

[duggie]

hin paul,

i can understand your trepidation.  i was swayed by the good price i got mine for!     also, the seller had a lot of experience w/tube amps, bi-tri-quad-amping of hi-efficency systems, etc.  he said the a-m amps actually did better running his system full-range than any multi-amp configuration.  he was unloading a lot of gear, having been hit hard by the recession in rust-belt ohio.  he was also one of the audio-mirror early adapters - his amps were one of the first, they had transformers too small for the power draw of the 6c33c tubes, & they blew up on him.  he sent them back to vlad of audio mirror, who installed bigger, much better transformers, & they have been fine ever since.  vlad actually upgraded all future amps, based upon the early experience, & the power rating went up as well - they were initially rated at 30w, mine is rated at 40w, the latest, according to vlad's ads on agon, are now 45w.  i actually sent mine back to vlad for a once-over, & to have him install bias pots on the outside  of the chassis, so they could be biased on the fly, w/o opening up the amp.  now, they are all like that, mine had internal bias pots.

as far as other amps, well, i compared them to the asl extreme hurricanes (retail ~$10,100), & a blue circle bc202 (retail $5,800) 125wpc stereo amp in woodsyi's system.  imo it was a toss-up between the asl's & the audio-mirror's, tho others present would tell you that the asl's had an edge.  at one point, it seemed the midrange & treble was a bit lacking w/the audio mirrors; it turns out it *was* - a loose interconnect on the right channel meant we were listening to the rm40's ribbons thru only one speaker!  it definitely improved when the connection was fixed.     i suspect if the rm40's were being driven full range, instead of only from 280hz on up, that the asl's would have done better in the bass - even tho the 6c33c tube is quite robust, twelve kt-88's per channel in push-pull operation should do better than a pair of s.e.t.-confgured paralleled 6c33c!      and, even in triode mode, the asl hurricanes are still pushing 100w per side; if you are running rm40's full range, 40w of tube power might run out of steam when the going gets heavy.  but, imo, 40 tube watts is plenty to drive the ribbons of the rm40s, at least in a medium-sized room.  both amps were better than the blue circle, but the blue circle's gain sensitivity was much lower than the other amps, which we all didn't know at the time, so it wasn't a good match w/the settings woodsyi had on his outboard x-over & rm40 pots.  so, i am not sure how fair the blue circle evaluation was.

in my own system, they have been compared only to low power amps - 5wpc or less.  (my speakers, coincident victory's, are 97db-efficient.  amps included the decware zen taboo, asl wave-8's w/auricap & holco resistor upgrade, almarro a205a mkll w/hovland musicap upgrade, a pair of el84 set amps taken from an old akai m8 r-t-r tapedeck, and two home-brew set amps - one w/6v6 tubes, & the other w/el84's.  all amps except the taboo work extremely well.  oh yeah, i also used a sharp digital amp, the sd-ex111 that everyone went nuts about a while back; it too was very good.  i suspect the taboo didn't work well because it has 6 ohm output transformers & my speakers are 14 ohms - that, combined w/the fact that the taboo is quite insensitive w/2.3v needed for full gain, made it a mismatch w/my speakers.

recently, i have moved, so i have a better room, which has allowed me to retire my yamaha yst sw305 powered subs & go back to my vmps largers.  in both cases i was actively crossing over w/a marchand x-over.  so, bass capability of none of these amps was ever tested.  and, since i have moved, i have only used the taboo & the almarro.  my system in this room has never sounded better, so until i get around to trying my other amps, i really feel that i am not qualified to make any further judgments as to one vs the other for ultimate sonics.  and, really, 40wpc is way more than needed w/my speakers.  before i got the victory's, i was using proac tablette reference 8 signatures (86db-efficient); they also sounded great being driven by the audio mirrors.

and yes, the a-m amps are single-ended, in a parallel configuration; go to the a-m website to get more details.  they also have a slightly less expensive, less powerful parallel-single ended amp w/the same layout as the 6c33c amp, but using the 6as7g output tube...

http://www.audiomirror.com/

the pics on the website show the older style amps (like mine), that used an eye tube which, afaik is not in the audio circuit...

Those are beautiful amps! I considered them at one time but passed because I didn't know anything about them and the deal seemed much too good to be true.

They are single-ended?  What have you compared them to?

[PaulFolbrecht]

 

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