[Atwood]

I'm considering the purchase of an RM 10. I listen mostly to classic rock, with some newer stuff thrown in as well as bluegrass, jazz and the occasional classical piece (usually not complex orchestral works).

Will the RM 10s work for me or would I be better off looking at an EL34 or KT88-based amp?

Thanks a lot.

[sebrof]

What speakers? How big is your room?

[Atwood]

What speakers? How big is your room?

Speakers are Harbeth Super HL5s. Room is approximately 10'W X 19'L X 7and1/2'H. The room is fairly live--the walls are concrete covered by wall paper but there is furniture, a few wall hangings and throw pillows to damp it a bit. I'm using a passive TVC for a preamp and CD only.

Thanks.

[Clio09]

It will rock and then some. Mine does...

[rbwalt]

the HL5s like solid state and do not require allot of power. 70-75 watt integrated will works well.

r.

[Atwood]

the HL5s like solid state and do not require allot of power. 70-75 watt integrated will works well.

r.

I'm currently using a Linn LK-140--85 watts--but it leaves me wanting a fuller, less flat sound. Plus I usually listen with the volume at 9-10 o'clock, getting up to 12 on some less compressed CDs or when I want it Loud. That's why I'm thinking a tube amp, and lots of Harbeth users have tube amps, and one with less watts. And I'm aware the Harbeths were voiced with SS.

Thanks for the answer.

[Carl V]

I have not used those Harbeths nor am I familiar with them.
I have owned tube amps with el34, el84, 6550 & KT88
all are fine tubes with their own sound...obviously the 84 is the
lowest rated power of the group.  the 84 & 34 tubes will have
a fine mid-range & fuller sound, not the "flat sound" you describe. 
it would of course be nice for you to be able to audition. 
Hi-Fi shop or Audio show perhaps?

[banquo446]

As people have been saying, it depends on the speaker. Evidently, they are capable of rocking out. With my Vandersteen 2ce sigs, I wouldn't say I am rocking out even as I have AC/DC coming through loud and clear. I wish I had Clio's speakers, so I too could, every once in awhile, sample the true sound of Angus Young's guitar.

[phats]

Well, I wouldn't bet on a '84 to rock, unless you got a supersensitive speaker to boot! And, 'imho', rock does need a certain soundpressure to come alive... We are talking about 95+sensitivity or a big muscle-bound amp... Sadly, a '84' is not....

[Roger A. Modjeski]

Speakers are Harbeth Super HL5s. Room is approximately 10'W X 19'L X 7and1/2'H. The room is fairly live--the walls are concrete covered by wall paper but there is furniture, a few wall hangings and throw pillows to damp it a bit. I'm using a passive TVC for a preamp and CD only.

Thanks.

I find that many users over estimate their power requirement by a large amount. If you guess is 10 dB high that's 10 times the power. The other day I returned a Hafler DH-200 to a local customer and measured only 3 volts at his highest listening level. That's 1 watt! 10 dB headroom is sufficient so a 10 watt amplifier is adequate for his needs.

The important questions are:

1. What is the sensitivity of your speaker?

2. What is your listening level (a Radio Shack SPL meter is very useful and accurate for this)

3. How far do you sit from your speakers?

Alternate for 2 and 3.  What SPL do you measure at 1 meter from your speaker?

Alternate for all three questions is to use a peak reading voltmeter connected to your speaker terminals and note the highest reading on a AC scale. This is the best method.

Many meters (most all Fluke Meters) have a bar scale under the number scale so you can see the peaks of the bar easier than the numbers. The range setting gives you the value of the top bar.

[tubegroove]

Sharing my experience, in support of Roger's post on listening levels.  A friend recently discovered a pretty neat SPL meter app for the iphone/ipod which I have used, one made by Logitech and another by JL Audio (the JL Audio also has a real time analyzer).  These apps may not be as accurate as good/professional SPL meters but give you a reasonable sense of listening levels.  I dont listen very loud but was surprised that with the music that I listen (jazz mostly) and at the levels I normally set when I am not alone, I reached a peak of just 76-80db (the logitech app shows dB, avg dB and peak dB) at my listening position.  If my calculations are correct, thats approximately 1W, maybe less!  To get a raw sense of SPL being generated, you may want to try this and work backwards using the 6dB double thumb rule to determine how many watts roughly you will need.  FWIW

[Atwood]

I find that many users over estimate their power requirement by a large amount. If you guess is 10 dB high that's 10 times the power. The other day I returned a Hafler DH-200 to a local customer and measured only 3 volts at his highest listening level. That's 1 watt! 10 dB headroom is sufficient so a 10 watt amplifier is adequate for his needs.

The important questions are:

1. What is the sensitivity of your speaker?

2. What is your listening level (a Radio Shack SPL meter is very useful and accurate for this)

3. How far do you sit from your speakers?

Alternate for 2 and 3.  What SPL do you measure at 1 meter from your speaker?

Alternate for all three questions is to use a peak reading voltmeter connected to your speaker terminals and note the highest reading on a AC scale. This is the best method.

Many meters (most all Fluke Meters) have a bar scale under the number scale so you can see the peaks of the bar easier than the numbers. The range setting gives you the value of the top bar.

1. The speaker's sensitivity, per the manufacturer, is 86db at 6 ohms nominal. This may be very conservative since one review magazine said, after testing the speaker that it was 91db sensitive and someone mentioned another magazine which tested them and got 89db but that well could have been the 91db review and the person's memory wasn't so hot.
2. I don't have a spl meter.
3. I do have a cheap multi-meter. I'm getting a high reading of .9 ACV at medium volume. That, however, doesn't sound right to me. Am I using the meter incorrectly?

Thanks!

[Roger A. Modjeski]

Nice to hear there's an ap for SPL measurement on the i phone. I hope someone will check it against a real SPL meter. Given what people spend on other tweaks for their system a $50 SPL meter from Radio Shack would be a wise investment.

Before you buy your next power amp you really should know how much power you need. Big amps DO NOT NECESSARILY sound better, in fact they usually don't.

Don't be surprised if you measure something around 1 volt at moderate levels, it's probably right. It certainly is more useful information than people guessing how much power they are using.

I have sold a lot of 2.5 watt/channel amps to moderate listeners. The reason I am so adamant on this topic is that I am on the brink of making some OTL amps. It takes eight output tubes to get 100 watts while two will give you 10 watts. It takes a big power transformer and a lot of electricity to light up eight tubes.

[Atwood]

Thanks for the reply, Roger. Yesterday afternoon I had a chance to really turn it up and got some peaks of 3 volts but things were mostly in the 2 volt range. I live in an apartment, and I rarely listen at that high a volume so as not to overly disturb my neighbors.

If that's only one watt or less, then your 35 watt EL-84 amp should be plenty, unless I'm missing something.  What do you think?

[Roger A. Modjeski]

Thanks for the reply, Roger. Yesterday afternoon I had a chance to really turn it up and got some peaks of 3 volts but things were mostly in the 2 volt range. I live in an apartment, and I rarely listen at that high a volume so as not to overly disturb my neighbors.

If that's only one watt or less, then your 35 watt EL-84 amp should be plenty, unless I'm missing something.  What do you think?

You are correct, that's only a watt. The RM-10 will give you plenty of headroom. Thanks for taking the measurement, this is precisely what I am talking about.

[jtwrace]

I find that many users over estimate their power requirement by a large amount. If you guess is 10 dB high that's 10 times the power. The other day I returned a Hafler DH-200 to a local customer and measured only 3 volts at his highest listening level. That's 1 watt! 10 dB headroom is sufficient so a 10 watt amplifier is adequate for his needs.

The important questions are:

1. What is the sensitivity of your speaker?

2. What is your listening level (a Radio Shack SPL meter is very useful and accurate for this)

3. How far do you sit from your speakers?

Alternate for 2 and 3.  What SPL do you measure at 1 meter from your speaker?

Alternate for all three questions is to use a peak reading voltmeter connected to your speaker terminals and note the highest reading on a AC scale. This is the best method.

Many meters (most all Fluke Meters) have a bar scale under the number scale so you can see the peaks of the bar easier than the numbers. The range setting gives you the value of the top bar.

My speaker specs are Sensitivity: 95 dB / 2.83 volt / 1 m

At 90dB at the listening position which is just under 3 m I got 5.39V

[Roger A. Modjeski]

My speaker specs are Sensitivity: 95 dB / 2.83 volt / 1 m

At 90dB at the listening position which is just under 3 m I got 5.39V

For the same settings could you measure the SPL at one meter?

[jtwrace]

For the same settings could you measure the SPL at one meter?

~96dB

[Roger A. Modjeski]

~96dB

That sounds right. You have lots of headroom.

[jtwrace]

That sounds right. You have lots of headroom.

With 300w Class A mono blocks I'd say so.