Will Changing my 100 Watt Tube Amp to a 200 Watt SS Amp Solve My Problem?


Hello All,  I have a 100 watt Audio Research VT100 mk II amp, with an Audio Research LS-25 preamp.  My speakers are relatively low in sensitivity, and I find that I must turn the volume up to 3 o'clock on the preamp to get enough volume for a loud listening experience.  When I do that, I am introducing more background noise.

I would like to achieve a quieter noise floor.  I am also curious about the limits of the 100 wpc amp with the Mira Monitors.  Would an older Krell 200 watt class A amp "control" the speakers better?  If so, what are the benefits of this?  There are a few amps on this site that caught my eye, all about the same value as my amp, so I can potentially make a move with very little cost.  Is this a good idea? How much wattage increase is necessary to get a significant enough difference?  Would a jump to 150 watt solid state be sufficient?


here are the 3 amps that caught my eye:

Ayre: https://www.audiogon.com/listings/solid-state-ayre-acoustics-v-5xe-amplifier-2016-02-05-amplifiers-h...

Krell: https://www.audiogon.com/listings/solid-state-krell-ksa-250-2016-02-14-amplifiers-91754-monterey-par...

BAT:
https://www.audiogon.com/listings/solid-state-balanced-audio-technology-bat-vk-250se-bat-pak-2channe...



You can see my complete system here if you want to know more about the other components:  https://systems.audiogon.com/systems/5421



Thanks!
Mark
marktomaras
I am a SS man.  I have the Devialet 200 (and the nuPrime IDA-8 and IDA-16) and it is really the quietest amps I have owned.  The devialet has a very nice phonostage.  The Devialet is my exit amp.
Hi Mark,

I have had a similar problem with an Audio Note Tube Preamp I introduced into system to audition. I heard noise and with the volume cranked diminished volume compared and contrasted to the Intergrated Amp I was previously using just as a preamp sending signal to 2 250watt amplifiers, (Acurus A250 and Rotel RB1572). Noise increased when volume turned up. For me it came down to gain issue. Did not purchase the Audio Note and put in a restored vintage Superphon CD Maxx dual mono volume control and separate power supply. No noise and great volume. simple design.
Post removed 
The Job 225 amp has an input sensitivity of .75v and gain of 35db.
Problem solved?
I owned an LS-25 and the 200w version of the amp, but also heard the VT100 with it....should have a gain boost on the preamp...should give you plenty of gain unless something is wrong?
A good high current amplifier ,a 250 Pass labs is a nice choice Plinius,
Even better Vitus,Gryphon ,depending on your budget,son of Ampzilla great buy
Good luck let us know what uou do.there are many good products out there.
When your system is struggling for lack of power nothing will scratch that itch better than a Krell KSA amp! 
So, does this experiment show that the preamp is quiet and the phono stage is noisy?  Or, is it still the preamp somehow, and the higher gain of the phono stage is bringing out the inherent noise in the preamp somehow?
That's what I was saying earlier...

BTW a bit of hum on the DCP input is likely coming from the CDP itself.
Great thread, marktomaras...typically reliable advice from both Al and 'newbee'!  ;-)

-Sam

Hi Mark,

For the record, the "JC" who designed the JC3 and the "JC" who designed the Delos are different people.  John Curl (a distinguished electronics designer) and Jonathan Carr (a distinguished cartridge designer), respectively.

I have no specific knowledge, though, of how the performance of the JC3 may compare with that of your Whest.

Best regards,
-- Al
 
Any thoughts on the Parasound Halo JC 3 phono preamplifier?  It has the balanced outputs that I want to keep and 68db of gain, which would allow me to avoid being at the top of the volume control.  I believe it is designed by the same designer as my cartridge, so that may be a plus.  Do you think it may be quieter than the Whest?
Thank you Newbee & Almarg.  I really value your input and time.  If you find yourself in south Florida, you are invited for a listen and a drink!

I sent a note to Whest to see if they can help me to determine if my unit is working as it should.

To be fair, I am nitpicking a bit here.  In truth, at normal listening levels of anything under 90db, the analog sounds perfect.  It's only when I am rockin out at levels of 93db and higher that I can allow myself to be slightly annoyed by the noise, and that is only during quiet passages or between tracks.

Nitpicking or not, this has been an educational experience thus far. I learned my amp and preamp are just fine!  I love the sound from them, and I am pleased that switching to solid state is off the table.

It would be interesting to audition an ARC PH6 or a similarly priced alternative to the Whest, just for the sake of comparison, but we will see what Whest says first.


Mark, I forgot to mention, be careful thinking about the wonders of a tube phono stage, ARC or not. The sonics are quite often great but noise, not so much. When I think about tubed phone stages I always think of high output MC cartridges. Low output MC's can be a real challenge. I used to have a love affair with Benz cartridges but that was quite a few years ago.
Newbee,
I think it’s time to change your handle to old pro!
+1. Excellent suggestions by Newbee!
Interestingly, but probably inconsequential, is that the unused CD input has a little hum to it at full volume, whereas the other inputs do not. This is just a little side note.
That sounds like normal behavior. It can be expected, especially with high impedance inputs such as those provided by your preamp, that small amounts of noise and/or hum will be picked up by unconnected inputs. Although it is essentially a non-issue, if you wanted to get rid of this hum you could purchase RCA shorting plugs from one of several eBay sellers who offer such things, and insert two of them into the RCA jacks for that input while setting the input mode to single-ended for that input. Or you could insert those shorting plugs as stated, and also jumper pins 1 and 3 together on the corresponding XLR connectors. Doing that would eliminate the hum regardless of whether the input mode is selected to be single-ended or balanced.

Regarding the more significant issue, I understand that noise is clearly audible at the listening position in phono mode when the volume control is set at max. But based on what has been said I’m somewhat uncertain as to how loud and how objectionable the noise is at the listening position, with no music playing, when the volume control is set to the highest position you would normally set it to when listening to music. That is really what matters.

In that regard, these two statements in update 2 appear to conflict:
I lowered the gain on the phono stage from 55 to 50db. The theory is that I can turn the volume high without much issue on the preamp. I did this, and indeed, with the lower gain on the Whest, I had to raise the volume quite high to get a loud experience, but I was not maxed out.
50db is working, though I am still at the top of the volume control.
As I say, what matters is the noise level, as perceived from the listening position, when the volume control is at the highest setting you would normally use.

Also, to be sure it's clear, keep in mind that phono sources are inherently much more susceptible to noise issues than both digital sources and non-phono analog sources (e.g. tuners), due to the vastly lower signal levels that phono cartridges put out, compared to other sources, and the vastly higher gains those signals are subjected to compared to the outputs of other sources. Any noise introduced to or generated by the circuitry at or near the input of a phono stage, and/or subsequent amplification circuitry within the phono stage, will be much greater in relation to the magnitude of the signal at those points than the same amount of noise would be in relation to the magnitude of a signal provided by other sources.

But if this noise does in fact occur to an objectionable degree at the listening position at normally used settings of the volume control, and you have not been able to reduce it to acceptable levels after trying various phono stage gains, it would seem that you’ve probably isolated the issue to the phono stage. Which is surprising, given its reputation for quiet performance and given the not particularly low 0.6 mv rating of your cartridge.

Although I’d feel more confident in that conclusion if shorting plugs were placed on the inputs of the phono stage when the turntable is disconnected, rather than leaving its inputs unconnected. Assuming you don’t have any shorting plugs on hand, though, what might be worthwhile would be re-assessing the noise with the turntable disconnected and with the phono stage’s input loading set to its lowest possible value, which I’ve seen indicated as being 50 ohms. And for that matter, let us know what loading choice you’ve been using with the Delos.
Any suggestions on a super quiet phono stage?
The Herron VTPH-2 ($3650) which I purchased not long ago is incredibly/totally/absolutely silent in my setup with the 0.5 mv cartridge I am using, as well as being wonderful sonically (see the many comments that have appeared here about it in past threads), as well as providing much more versatility than the single gain setting of the ARC phono stage you mentioned. And Keith Herron is an absolute treasure to deal with.

Best regards,
-- Al

Mark, I don't know how assessible the folks at Whest are but my next move would be to contact their service department or technician and set out the issues to them and see what response you draw, if any. 
Well, I wonder if the Whest is a fine unit, but just doesn't fit well with my system?  Or if it is a fine sounding unit that happens to have a noise floor that I just don't care for.

Any suggestions on a super quiet phono stage?

The Audio Research PH 6 has the same price tag, so conceivably I can sell my Whest and purchase a used PH 6 for about the same price.  58db of gain seems about perfect, as long as it's quiet.  Plus it is a tube model, which should be a nice thing to fit in with the 2 other ARC tube amps in my system.  But is it quieter than the Whest, that is the question.  


Mark, What this says to me is that your issue is with the noise floor of your phono stage. With the cartridge (TT) disconnected from the phono stage the noise you are hearing is inherrent with the design or the mechanical condition of the phono stage.

 This really has nothing to do with, in an absolute sense, the gain issues. You can lower or raise the gain but this will not remove the noise issue. If you lower the gain from the phono stage but compensate by increasing the signal level with the volume control you have a net zero change. If the noise is a substantial issue for you after you have adjusted all of the gain possibilities you need to reconsider your use of this phono stage. 

BTW, FWIW, I really appreciate those folks who can rise above the obvious implications of my 'handle'. Says much more about them than me
I think. 


Newbee,

I think it's time to change your handle to old pro!
Ok, so I tried a quick test, I listened as I did before, to the phono stage with the volume all the way up, and then I muted the preamp, removed the IC from the table to the phono stage, and unmated the amp.  The noise was the same.  Changing the gain means pulling the phono stage from the rack, unscrewing a panel, flipping some dip switches, and reassembling, so I cannot do it on the fly.  If the noise is the same at 50db gain setting, with or without the turntable connected, is that conclusive enough?  What is my next step? 
Hi Mark, It appears that you have sourced your problem correctly to your phono stage and/or cartridge. To determine whether its is the phono stage or the cartridge or both in combination, disconnect the IC from your TT to the phono stage and just listen to the phono stage at various gain levels and with your pre-amp VC . If there is no noise (as I suspect there will not be) then you have either a mismatch with the cartridge due to the inherent noise floor of the cartridge, something mechanically deficient in the cartridge or its set up. I'm not familiar with your phono stage or cartridge so I can't help you on this issue.

I'll save your eyes a bit by not amplifying on these comments but I would be happy to explain my conclusions if you ask.
1) There is nothing wrong with your pre-amp.
 2) There is nothing wrong mechanically speaking with its tubes.
 3) There is nothing wrong with having to listen with your volume control at 3 o'clock or even wide open if that is the position that meets your needs. Remember, all a volume control does in your pre-amp is lower the strength of the signal from the source before it reaches your volume control.. That's all. It does not lower the strength of the output from the pre-amp's tube section which is seen at a constant level by your amp.To some degree its function is redundant to the other options your have to reduce source output strength.

BTW, re the hum on the unconnected CD input selection. Small hums can be very difficult to trace. But before you conclude that this is a problem try connecting your dac to this input and see if the hum goes away.

Hope this helps a bit. Perhaps others can comment on your phono stage/cartridge/set up issues. 
Update 2.

After the above experiment, I followed the idea that the preamp is actually quiet and that the phono stage is causing the noise.  I lowered the gain on the phono stage from 55 to 50db.  The theory is that I can turn the volume high without much issue on the preamp.  I did this, and indeed, with the lower gain on the Whest, I had to raise the volume quite high to get a lout experience, but I was not maxed out.  Before I played the music, I listened to the noise at full volume, with the newly lowered gain on the phono stage.  The noise was lower, as expected, but not by a huge amount.

I played Miles Davis Kind Of Blue.  I listened to the noise at full volume with nothing playing to familiarize my mind and ears, then I lowered the volume and played the record.  As the needle began to play, I immediately heard a fairly considerable amount of noise.  But this I felt was in the recording, not due to my amplifiers.

The sound was excellent by the way, but that noise is still there a bit.

Then I fired up the PS Audio Perfectwave DAC mkII and played the same track.  I use the balanced connections on the DAC and I also turn the volume to full as I was instructed by some of the aficionados of this product.  The result is that the output is much higher than that of the phono stage, so my volume control on the ARC preamp is far lower, dropping the noise floor even lower.

To finish the comparison of Miles Davis, the noise in the recording that I heard on the vinyl was also there on the digital.

I am looking forward to hearing your thoughts on these new tests.  Please let me know if I am drawing the proper conclusions.  Perhaps I need a quieter phono stage.  Maybe I do not need a ton of gain.  50db is working, though I am still at the top of the volume control.  If I could have a dead quiet, phono pre with 55 db of gain, that may be the perfect accompaniment to this system, that is, if I am interpreting the experiment properly.
Update,

I tried listening to the noise of the preamp on its own.  I powered on the phono pre, the preamp, and the power amp.  I then put the volume at maximum, with no source playing.  I began with the phono selector on the preamp.  At full volume, the hiss+subtle hum is fully audible at the listening position.  Then I tried the other inputs on the preamp, beginning with the input for the DAC, powered on, no music playing.  Followed by all of the other inputs.  Even at full volume, only the input connected to the phono stage produces the noise.  The other inputs, including the connected DAC input are extremely quiet, even at full volume with my head near the speaker.  I can hear noise, but it is subtle, and my head is near the speaker at full volume!

I tried moving the phono stage to another input, to see if there was a problem in the input circuitry.  This is not the case.  The same noise simply moved over to an aux input, and the phono input went quiet.

Interestingly, but probably inconsequential, is that the unused CD input has a little hum to it at full volume, whereas the other inputs do not.  This is just a little side note.  

So, does this experiment show that the preamp is quiet and the phono stage is noisy?  Or, is it still the preamp somehow, and the higher gain of the phono stage is bringing out the inherent noise in the preamp somehow?

Lastly, I found some tubes that I bought years ago, and never used.  They are NOS 6H23P-EB (Premium) tubes.  http://www.thetubestore.com/Tubes/6922-E88CC-Tube-Types/6H23n-EB-6922

I was thinking to try them out to see if there is lower noise, but after this experiment, I don't think it will do much, it seems that the culprit is the phono stage.  

What do you think?
1 more thing. Even running with the 4 ohm, the 100+ watts wasn't controlling the low end enough for me, and in some cases I had to get the volume setting to around 2 o'clock for the output I wanted. I ended up buying a 250 watt Hegel integrated and night and day difference IMO. Never go above 50 out of 99 for volume and the speakers don't sound as wholly. i liked the rogue very much but I would have had to get a larger tube amp but even then I'm not sure it would have helped to control the bass. the best of both worlds could be using a tube pre with a ss amp.

I have had the following problems in the past. 1st: I had a classe preamp driving a mcintosh amp and I had to turn the volume up almost all the way to get the volume I wanted. It was a mis match between the preamp and amp voltages and classe told me they could modify the preamp to make it compatible with the mcintosh, so I ended up with a classe amp and I was driving the same setup at around 10-11 o'clock on the preamp.
2nd issue: I had a rogue magnum integrated tube amp with the it-120 tubes and it didn't control the speakers very well. I changed the wiring inside for 4 ohm tap and it was much better. 
I have had the following problems in the past. 1st: I had a classe preamp driving a mcintosh amp and I had to turn the volume up almost all the way to get the volume I wanted. It was a mis match between the preamp and amp voltages and classe told me they could modify the preamp to make it compatible with the mcintosh, so I ended up with a classe amp and I was driving the same setup at around 10-11 o'clock on the preamp.
2nd issue: I had a rogue magnum integrated tube amp with the it-120 tubes and it didn't control the speakers very well. I changed the wiring inside for 4 ohm tap and it was much better. 
If you do decide on the Krell amp, I have a much nicer specimen and it has also been upgraded to a 250S.
Thank you all.  There are a lot of good info and ideas here.  I am interested in what sdcampbell said about the poor signal to noise ratio.  Perhaps that is worth investigating.  Newbee, I have tried what you suggested, but I think I need to refresh my memory by doing it again.  Saturday Morning is listening time for me, so I'll tackle that in the morning.  By the way, I just listened to some Ella Fitzgerald on vinyl at low volume and it is excellent.  No hiss, no problem.  But that was at a volume level one could have a conversation over...
I'm coming late to this discussion, so I'll try to be succinct. One of your problems has already been identified: the preamp, for whatever reason, has a poor signal-to-noise ratio. This could be due to mediocre original design, but it could also be due to deterioration of some of the internal electronic components. It would make sense to get a good technician to diagnose the preamp and make any indicated repairs.

The other relevant point is that increasing the amplifier power from 100 watts to 200 watts will not have much effect. Doubling the output power of the power amp will only increase the maximum audio signal level by 3db, which is discernable only as a slight volume increase. Your AR VR100 amp is a fine unit, but it needs to be paired with more sensitive speakers if you want to listen at high decibel levels. As a rough rule of thumb, I like to pair low to moderate power tube amps with speakers rated for 90-92db sensitivity or higher.

Just my 2 cents, FWIW.
AL, What speaker manufacturer does not say this..?? ROFL.
(please dont answer that)

All I was saying is that Mark should try a SS amp (of course one that will drive the speakers) .
And all I was saying is that:
... before going to a more powerful amplifier it would be prudent to research how much power the particular speakers can handle without their sonics degrading, or worse. The only relevant spec I can readily find for the Rockport Mira Monitors is a minimum amplifier power recommendation of 50 watts.
My comment being inspired in part by someone else's mention of 400 watt monoblocks, in the post just above the post you made yesterday.

Glad my comment provided you with some amusement.

Regards,
-- Al
I just mounted a new Dynavector 20X2 on my Xtension 10 and I have noise too! :-( I really dont think its the cartridge...or my Chinook phono pre...or my Manley Jumbo shrimp linestage, nor is it my amplifier. I think noise is getting in from the house electrical system. All I know is that it sux major *(&^. otherwise my system would be awesome sounding. Now im looking at power conditioners (yuk).

Matt M
I personally love anything Ayre makes...all my electrical components are Ayre ....extremely pleased.  However....It seems to me that your problem is not with your amp.
"minimum amplifier power recommendation of 50 watts."

AL, What speaker manufacturer does not say this..?? ROFL.
(please dont answer that)


All I was saying is that Mark should try a SS amp (of course one that will drive the speakers) .

Matt

^^ bigger amps won't cure this problem as it is not caused by amplifier power or the lack thereof.

I have seen problems with cartridges where the magnet structure was damaged and has caused low output in both channels. The Whest, while not my favorite phono section, is not known for noise, so right now I am suspicious that the cartridge might have taken a hit somehow and is not making the proper output voltage- hence the noise.

I would try a different cartridge to test this theory.
I still really think you need to either borrow gear from a dealer or friend.  You have 2 issues:  Noise and lack of volume.  A pair of 400 watt monoblocks will cure that.  Curing the noise issue might be trickier unless excess power solves all.  And yes, the Devialet might do it. However, it's going to be cheaper to buy new speakers...
Are you running a low output MM or MC? It sounds like you need a head amp or a SUT to improve the gain. I think your ARC tube amp is fine.
Sorry, another question.Have you disconnected all of your sources from your pre-amp, in fact unplugging them is best, and then rotate your volume control to its 3 o'clockposition and see if you still have the noise? Rotate to max, any noise then? If the answer happens to be 'no noise' then add your sources back, one at a time until you find the one which starts the noise as previously described.

 If the answer is there was no change from your fully connected system then you have either found the noise floor of you pre-amp or that you have something in the circuitry in the pre-amp prior to the amplification stage which is causing it. You might then contact ARC and ask their service department techie.
Mark, Maybe a dumb question, but exactly where are you when you can first hear the noise? When you are in your listening chair? 6' from your speakers? 6" from your speakers? I know some folks, of the anal sort, like me perhaps, who put their ear right up to the tweeter and judge by this. Does this noise really intrude on the allusion of a black background when music is playing? Is the background noise a hiss or a hum?
I don't know the answer to that question, Mark.  In part because I have no experience with integrateds in recent times, and never in that kind of price range.  And in part because we haven't been able to arrive at an understanding of what is presently causing the noise issue.

Best regards,
-- Al
 
Al,

Indeed I evaluated the system with digital components off completely.  Just curious as this may not be the way I will go, but how would you expect a high end integrated unit to work in this regard?  Something like a $13k Jadis tube integrated with phono stage or a similarly priced Deviate with phono stage?  Would the lack of cabling and assumed synergy between the internal components in such a unit provide a quieter, higher performing system? 
Hi Mark,

I have no experience with the Whest phono stage, but based on all that I’ve read about it I too would expect it to be very quiet with a Lyra Delos, which is rated at 0.6 mv output under the standard test conditions. And since the phono stage is solid state, noisy tubes are not an issue with it.

Also, the circuitry in the front end of your ARC LS25 preamp, up to and including both the gain select circuitry and the volume control circuitry, is all solid state (as can be seen in the schematic at arcdb.ws). So noisy tubes are not an issue there as well.

And you’ve already done significant re-shuffling of how your components and cables are physically positioned, to minimize any noise coupling that may be occurring as a result of how everything is positioned.

So regarding the noise issue I’m pretty much out of ideas at this point. Other than to suggest that if you already haven’t you try unplugging all of the digital stuff from AC power, to verify that digital noise is not radiating or otherwise coupling into the analog front end.

Regards,
-- Al

Ha!  Newbie, I love the tube devotion.  I am wondering if I am a fool for considering it.
Does it have a quiet phono stage? Or you could buy a gun. Personally, I I had to go solid state I think I'd choose the latter! :-)
Do you think my Whest PS .30R is the culprit here?  I can definitely say that my PS Audio DAC does sound quieter than the analog, both driven through the ARC preamp.  I was under the impression that the Whest is quite a capable phono stage, with ample gain and balanced circuitry.  It is definitely a confusing process to determine how components play well together!
Mark, your ARC LS25 is a  selectable gain line stage. It looks like you can set the gain anywhere between 0 dB and 18 dB. What do you currently have the LS25 gain set at?
The line stage gain will not make any difference. The volume control won't affect the noise of the line section. The only thing it can affect is how much noise is present from sources, like the phono section. Its my opinion that this is where the problem lies. It might simply be noisy tubes and it could also be that the phono cartridge has output slightly too low for the phono section to work with gracefully.


John, Is the adjustibility of gain is the LS25 applied after the source but before the volume control and line stage amplification (tubes).  It did on my ARC Pre (a different model). The blurb I read on this pre-amp talked about the ability to reduce source gain in the context of matching gain of multiple sources. I didn't see anything about reducing pre-amp output gain. Typically you can only change pre-amp output gain either by internal implementation of a resistor or by adding an aftermarket fixed attenuator.

 If so, then any tube noise (or any other noise for that matter) would be passed on to the amp full strength. Since Mark's noise increases as he rotates his volume attenuator, the cause of the noise  increase must originate in the pre-amps circuitry before the amplification stage or in the source, which IMHO would more likely be the phono stage which are notoriously noisy. With a phono stage the noise could originate with the design itself, of if it uses tubes, then the tubes might not be low noise enough. It could also be the phono cartridge itself. 

Mark, I haven't read the preceding posts.  I'm sure Al or someone else have already mentioned this to you. But, I would point out that the difference between 100wts and 200 wts is only 3db, i.e. not very noticible. Now if your speakers require an amp with high(er) current (i.e. they have a impedence curve dropping to 4ohms or less) this could be an exception. But even if your amp could produce 800wts at  2 ohms you still would not be solving any noise issues caused by your pre-amp's amplifications stage.

FWIW. Forgive any redundancy created by existence of preceding posts.
John, I have it set to 18db. I was told that setting is the native setting, and the lower gain settings were attenuated.

matt, I have toyed with this idea. If I were to sell my amp and preamp, and look for a similar quality / age / price solid state pair, I wonder if I would get a better performer? But then again, the ARC tube gear does sound excellent...

Mark
Mark, your ARC LS25 is a  selectable gain line stage. It looks like you can set the gain anywhere between 0 dB and 18 dB. What do you currently have the LS25 gain set at?

Cheers,
John