Rotel RA-12 not as powerfull as RA971 why?

[ciaranb]

I bought a Rotel RA-630 that looks just like the RA-12 but only has 1 set of speaker outputs it says it is 60 watts just pluged it in to replace my Rotel RA971 also 60 watts. Turning up the volume the new amp is only half as powerful why?

 

[ID.]

I bought a Rotel RA-630 that looks just like the RA-12 but only has 1 set of speaker outputs it says it is 60 watts just pluged it in to replace my Rotel RA971 also 60 watts. Turning up the volume the new amp is only half as powerful why?

Because it's a fake? Can't find anything online about a Rotel RA-630.

Otherwise the most likely answer is, that it isn't less powerful. Just how far you have to turn the volume pot to reach the same power output differs. Perhaps the RA971 reached max volume very early on (like 10, 11, or 12 on the dial) while the RA-630 lets you adjust the volume more finely and doesn't hit max power output until your turn it further around.

Here, let me Google that for you

"I just spoke to the shop I purchased from who've said the volume control is an exponential type, which would be a good thing as it gives more control at lower volumes."

 

[rainsoothe]

I bought a Rotel RA-630 that looks just like the RA-12 but only has 1 set of speaker outputs it says it is 60 watts just pluged it in to replace my Rotel RA971 also 60 watts. Turning up the volume the new amp is only half as powerful why?

Because it's a fake? Can't find anything online about a Rotel RA-630.

Otherwise the most likely answer is, that it isn't less powerful. Just how far you have to turn the volume pot to reach the same power output differs. Perhaps the RA971 reached max volume very early on (like 10, 11, or 12 on the dial) while the RA-630 lets you adjust the volume more finely and doesn't hit max power output until your turn it further around.

Here, let me Google that for you

"I just spoke to the shop I purchased from who've said the volume control is an exponential type, which would be a good thing as it gives more control at lower volumes."

Hi. I'm affraid ID is right, and that is a fake. The only report I could find of a 630 led me to a .co.nz store. Googling it further, brought up an article of said store having to retreat fake PlayStation 3 from their store. However, clicking the article made Google say the page was not available, despite the page clearly loading for half a second before the message. Weird stuff. But try to take the amp back. You're way better off getting a used RA1520 or Arcam A19 for that money.

 

[ciaranb]

I took it back to the shop with my RA917 tested it in store found the new rotels use a exponential volume where as my RA917 is mechanical and linear. My question now is how high would you turn up the amp before you are going to get distortion?

 

[davedotco]

Until some part of the circuit overloads, most likely but not necessarily the output stages.

The physical setting of the volume control is largely irrelevent, it is in the hands of the designers and marketing guys who know that an amplifier that 'gets loud' at lower settings of the volume control impresses the average punter and sells better than one with a 'sensible' wide ranging control.

 

[MajorFubar]

My question now is how high would you turn up the amp before you are going to get distortion?

I don't want to sound rude but how can anyone realistically answer that for you, it's going to vary from album to album, also depends on your speakers and what your room's like. I have some albums mastered very loud where the wallpaper would peel off the walls with the volume at 11 o'clock or higher, but other albums from years ago, notably classical recordings of eg solo piano, where I need to head towards 12 o'clock to get a decent level.

 

[ciaranb]

I tested both the ra-630 and the ra-1570 with exponential volume it is hard to see the volume difference as both need to be at about 50 before you really hear anything. If I am running it at 85 would you be concerned that I would be pushing the amp too hard?
I have B&W 602 s2 speakers.

 

[davedotco]

All modern amplifiers use 'exponential' (more corectly logarithmic) volume controls, this simply replicates the way the ear/brain interprets loudness. Ie twice as loud requires ten times the power (in hi-fi terms).

Different manufacturers/designers have their own ways of designing volume controls so they all vary. The first thing to understand is that the setting on the volume control is in no way related to the power output of the amplifier, as long as you can get the amplifier to go loud enough and deliver full output, the position of the volume control does not matter.

Generally speaking, a design that, for 'proper' listening requires the volume to be set around half way, or a little above, is the best, it makes precise settings of the playback volume (very important to some listeners) much easier and avoids the lowest settings on a rotary control which are often unbalanced.

Amplifiers that are deliberately designed to go loud very quickly are produced to impress the uninformed, which given how well these amplifiers sell, is the bulk of hi-fi buyers.

 

[ciaranb]

Just had a listen to the Arcam FMJ A19 today and it had a linear volume increase much easier to use I think.

 

[davedotco]

Just had a listen to the Arcam FMJ A19 today and it had a linear volume increase much easier to use I think.

It isn't linear, it is still logarithmic but the designer has chosen different 'values'.

Also, the A19 has an input sensitivity of 1 volt, the RA12 just 150 mv. Ie the A19 requires more than six times the input level of the RA12 to reach full power. Same power, different gain.

So, what are the typical volume settings on the amplifiers you have been trying?

 

[ciaranb]

With the A19 I am about 45 and the RA12 about 60 to reach the same volume though this is rough as they are in different shops,speakers...

 

[ID.]

With the A19 I am about 45 and the RA12 about 60 to reach the same volume though this is rough as they are in different shops,speakers...

and the relevance of this is?

 

[ciaranb]

If I run it up to 80-90 on the RA12 listening to rock music is this OK or should I be looking at a bigger amp?
At what level does the RA12 produce unwanted distortion?

 

[davedotco]

If I run it up to 80-90 on the RA12 listening to rock music is this OK or should I be looking at a bigger amp? At what level does the RA12 produce unwanted distortion?

We keep trying to explain but obviously we are not doing it very well as you seem to be missing the point.

There are so many factors that go into the design of an integrated amplifier that, in reality, the setting of the volume control on any given amplifier is in no way representative of the power being used (hence the cryptic 'so what' comments).

If your amplifier requires you to play at 80-90 (out of 100 I presume), that is entirely fine, providing that is as loud as you will play in normal situations. As I said earlier, the way the volume control works is the choice of the designer, many budget amplifiers of lower power than the RA12 have controls deliberately set so that they get very loud at around 30-40 (about 9-10 o'clock on a conventional knob). This impresses the unwary and the fact that the amplifier can not be pushed beyond half way without producing horrendous distortion only becomes apparent later.

In fact it seems to me that, despite their differences, the Arcam and the Rotel have very usable ranges on their volume control in this instance and either should be fine in normal use.

 

[rainsoothe]

Again, I don't think that's a genuine RA12. Rotels sound more powerful then their listed specs. I say get rid of it and try to get a used Naim Supernait. If you want new, look at Naim Nait 5si or Exposure 3020s2 or 2020s2 (and if you also need dac, Arcam iRdac for any of these two). Maybe also check Cambridge Audio CXA80 or CXA60, or Hegel H80.

 

[celestion]

http://www.harveynorman.co.nz/tv-and-audio/blu-ray-and-home-theatre/av-receivers-and-audio-components/rotel-integrated-amplifier-en.html