Pls explain the current thing.....

Thompsonuxb

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Feb 19, 2012
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Low wattage high current is better than hi wattage with limited current?

My Rotel 1520 (stereo)60watts per channel using both A and B speaker (bi-wire/bi-amp)to drive a pair of Mission 782se (6ohm/200watt)is not delivering low frequencies like I'd like.
With the recent change of interconnects the sound is better were the mids and tops are concerned. but those low frequencies are just not there.

The Yamaha AX620 90watts (A/B fronts) x5 theoretically can drive 450watts constant into 8ohms (total). This requires more current when things get dramatic. It sounds better in stereo - using A/B fronts as above ( all other channels turned off), making the Missions sing with a fuller dynamic range.

The Rotel go's louder in terms of...er...loudness but its not louder, if you get what I mean, you hear its loudness, but you feel the Yamaha's.

Having read a few of the post I had to ask this, how does it work?
 

Dan Turner

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To put it simply (because to explain it properly in a scientifcally factual way would take ages) the amp kind of tells the speakers "this is what frequency I want you to produce and this is how loud I want you to produce it", and the speaker kind of says "OK, but this is how much current I need" and it just tries to 'suck' that much current from the amp. There are numerous facets of the amp's design which will determine what it's capabilities to deliver a current are, but at some point it may run out of ability and not be able to deliver what the speakers require. Different speakers have differing characteristics in this regard; some are easier to drive than others, but in all cases, for a given consistent volume as frequency drops, the current required to produce that frequency increases.
 

FennerMachine

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If the Mission 782se are the updated version of the 782's I had in about 2003 then you're probably better off putting the jumper bars back on or bi-wireing and just using output A on the Rotel.

As far as I understand using A + B outputs kind of splits the power, its not the same as bi-amping with 2 amps as your Rotel will have a maximum output. Using A + B won't increase this maximum.

Also, I think that the 782's are a 2.5 way design, not a full 3 way.

The inputs separates the treble from the bass + mid driver so the LF channel is much more demanding.

I may be wrong but its worth a try.
 

Sliced Bread

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Jul 28, 2010
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FennerMachine said:
If the Mission 782se are the updated version of the 782's I had in about 2003 then you're probably better off putting the jumper bars back on or bi-wireing and just using output A on the Rotel.

As far as I understand using A + B outputs kind of splits the power, its not the same as bi-amping with 2 amps as your Rotel will have a maximum output. Using A + B won't increase this maximum.

Also, I think that the 782's are a 2.5 way design, not a full 3 way.

The inputs separates the treble from the bass + mid driver so the LF channel is much more demanding.

I may be wrong but its worth a try.
The 782’s are true three way…and very nice they are too J
 

Thompsonuxb

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Feb 19, 2012
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Dan Turner said:
To put it simply (because to explain it properly in a scientifcally factual way would take ages) the amp kind of tells the speakers "this is what frequency I want you to produce and this is how loud I want you to produce it", and the speaker kind of says "OK, but this is how much current I need" and it just tries to 'suck' that much current from the amp. There are numerous facets of the amp's design which will determine what it's capabilities to deliver a current are, but at some point it may run out of ability and not be able to deliver what the speakers require. Different speakers have differing characteristics in this regard; some are easier to drive than others, but in all cases, for a given consistent volume as frequency drops, the current required to produce that frequency increases.
Yes, thats kind of how I figured it worked, the Missions I think are demanding.....like a beautiful woman, the Rotel me thinks is struggling to satisfffffyyyyyyah!....

Question, I'll be checking to see if the amp as an impedence switch, would switching to 4ohm help?
 

Thompsonuxb

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FennerMachine said:
If the Mission 782se are the updated version of the 782's I had in about 2003 then you're probably better off putting the jumper bars back on or bi-wireing and just using output A on the Rotel.

As far as I understand using A + B outputs kind of splits the power, its not the same as bi-amping with 2 amps as your Rotel will have a maximum output. Using A + B won't increase this maximum.

Also, I think that the 782's are a 2.5 way design, not a full 3 way.

The inputs separates the treble from the bass + mid driver so the LF channel is much more demanding.

I may be wrong but its worth a try.
After much tinkering the amp sounds better in this configuration the (speakers definatly do), more seperation in the mids and tops. In terms of delivery there is no difference in 'loudness'. ( these amps are designed to deliver thier power through all channels...I hope) The speakers sounded wonderful on the end of the Yamaha ( but I suspect thats due to its higher current talent).

In fairness, in isolation most would believe the Rotel/Mission sound fine, but knowing there is more...more of everything, all those things you want from hi fi makes it hard to settle . Thanks for the suggestions.
 

Thompsonuxb

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Sliced Bread said:
FennerMachine said:
If the Mission 782se are the updated version of the 782's I had in about 2003 then you're probably better off putting the jumper bars back on or bi-wireing and just using output A on the Rotel.

As far as I understand using A + B outputs kind of splits the power, its not the same as bi-amping with 2 amps as your Rotel will have a maximum output. Using A + B won't increase this maximum.

Also, I think that the 782's are a 2.5 way design, not a full 3 way.

The inputs separates the treble from the bass + mid driver so the LF channel is much more demanding.

I may be wrong but its worth a try.
The 782’s are true three way…and very nice they are too J
Lol....I can't part with them, recent demos make me realise how good they are, I'd have to spend more money than I can afford to spend to get the same results.
 

FennerMachine

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You make me want to hook my 782's up again! Haven't used them for about a year.

They are nice speakers, especially when driven properly.

Your Yamaha AX620 is probably doing that and if you prefer the sound that way...
 

Thompsonuxb

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FennerMachine said:
You make me want to hook my 782's up again! Haven't used them for about a year.

They are nice speakers, especially when driven properly.

Your Yamaha AX620 is probably doing that and if you prefer the sound that way...
I know, I know....but I just spent 600 pound+ on this amp, it may still be breaking in I have to keep believing that or I'll never stop crying myself to sleep. The Ax620 is now doing surround sound duty's under the telly driving a set of kef kht1000... ( been sitting around for about 5yrears waiting for their time....)the small eggs and it turns out its a better stereo amp than a surround sound amp......

But I wouldn't know how to go about selling this amp without losing way too much on it.
 

FennerMachine

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Checked the manual for the Rotel 1520.

It is affected by using A + B.

It says in the manual that if using two pairs of speakers you need 8 ohm or higher speakers, with one set of speakers it can go down to 4 ohm speakers. The Missions are 6 ohm, so may be too difficult a load for the Rotel using A + B to sound at its best even though technically its only 1 pair of speakers. It could be that the Rotel is running out of steam.

I remember using a Cyrus Smart Power, 60W per channel, to drive my 782's.

I bought the speakers and the Cyrus amp with the idea of Bi-amping when I could afford a second amp. When I ran two Smart Power's bi-amping the one driving the LF got very hot and cut out a few times! I then changed the Smart Power's to mono mode giving 105W per channel. Never had an amp cut out after that!
 

jiggyjoe

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Aug 21, 2010
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I think you'll find the Rotel has more than enough current to drive your speakers with much more grip than the Yamaha.

Rotel Amps are very conservatively rated, in fact the 1052 can produce around 90w per channel into 8 ohms and is more than comfortable driving low impedance speakers.

I suspect its this lean tight bass character from the Rotel that your not so keen on prefering the looser, fuller bass from the yamaha.

Have you tried moving your speakers around a bit? closer/further from walls or bass drivers facing inwards/outwards?
 

Thompsonuxb

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FennerMachine said:
Checked the manual for the Rotel 1520.

It is affected by using A + B.

It says in the manual that if using two pairs of speakers you need 8 ohm or higher speakers, with one set of speakers it can go down to 4 ohm speakers. The Missions are 6 ohm, so may be too difficult a load for the Rotel using A + B to sound at its best even though technically its only 1 pair of speakers. It could be that the Rotel is running out of steam.

I remember using a Cyrus Smart Power, 60W per channel, to drive my 782's.

I bought the speakers and the Cyrus amp with the idea of Bi-amping when I could afford a second amp. When I ran two Smart Power's bi-amping the one driving the LF got very hot and cut out a few times! I then changed the Smart Power's to mono mode giving 105W per channel. Never had an amp cut out after that!
The amp as never cut out and it does go loud - loses quality though, soundstage flattens out.

And I did read the manual, honest I did. But speaker terminal A drives the bass/mid while B drives the tweeters the tweeters are not a difficult load and there is little to no difference when single wired. It even runs pretty cool too when played at normal levels (volume dial at 9 o'clockish) which suggest its playing within itself.

It does not distort etheir (apart from when pushed pass 10 o clock on the volume dial)....but maybe the running out of steam thing is the problem. The thing is the mids and tops are very good.
 

Thompsonuxb

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jiggyjoe said:
I think you'll find the Rotel has more than enough current to drive your speakers with much more grip than the Yamaha.

Rotel Amps are very conservatively rated, in fact the 1052 can produce around 90w per channel into 8 ohms and is more than comfortable driving low impedance speakers.

I suspect its this lean tight bass character from the Rotel that your not so keen on prefering the looser, fuller bass from the yamaha.

Have you tried moving your speakers around a bit? closer/further from walls or bass drivers facing inwards/outwards?
I'd love for you to hear them side by side in a blind test.....the speakers have bass the drivers facing in and I have wasted a rabbits life time moving and adjusting my speakers...an old rabbit at that.

The difference in bass performance between the the two, the Yamaha has tight bass thats textured, you can differentiate between the various bass tones in the music, accoustic bass to electric bass. It also makes the voices sound more human with the lower registers clearly defined. Its that the Rotel is missing.

its like certain tracks when a singer is really close to a mic you can pic up the pah on p's as their breath hits the mic (Toni Braxton - Libre - track 10), hear flem gargling in the back of a singers throat (Antony Hamilton - Superman pt2) with some intamacy.

At -40db The Yamaha produces a real 3d sound, detail, frequencies.......you guys are making me wanna go put it back on the CD player.

The Rotel does do edges though - but my fear is the rose tinted glasses thing, its about 2months now since the Yamaha played with the Missions
 

jiggyjoe

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Aug 21, 2010
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Have you tried just single wiring the missions using the Rotel?

choose just one set of outputs on your amp lets say A. and use a single run of cable to the missions lower binding posts and install the bridging links that came with your speakers to connect lower and upper binding posts. make sure all connections are nice and tight.

Sorry if this sounds bleedin obvious but I cant think of anything else to explain why the bass on the Rotel should be weak other than maybe something not connected up right.

Worth a try anyways.
 

Overdose

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Feb 8, 2008
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jiggyjoe said:
Sorry if this sounds bleedin obvious but I cant think of anything else to explain why the bass on the Rotel should be weak other than maybe something not connected up right.
Maybe the Yamaha is a better amplifier?
 

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