Audiolab and monitor audio biamping

[Tackleberry1]

Hello, I was hoping for some biamping feedback.

I currently have an audiolab 8200a (60w per channel) integrated amp and 8200p (100W per channel) power amp biamping a set of Monitor audio GX100. Common sense has be using the power amp driving the bass drivers and the integrated driving the tweeters. I find that the treble isn't as sparkly and defined as expected. I actually get a more balanced sound when connecting the speakers to the 8200a only

Has anyone ever reversed the a biamped speaker to have the power amp with more power driving the tweeters instead? Or is this idea idiotic?

Or is ther another combination that I could do with the equipment I've got?

With all the experieince out there, I thought one of you may have some feedback. Thanks

 

[Frank Harvey]

Back in the 'original' Audiolab days, they frequently recommended driving the HF units with the power amp and the bass drivers with the integrated amplifier. So no, it isn't idiotic, and worth a try!

 

[Tackleberry1]

Thanks David. I'll give it a go over the weekend and see if it's of any benefit.

 

[Tackleberry1]

Just thinking about this scenario before I try it, and wondering if thjios could damage the tweeters due to it being overpowered? Thoughts?

 

[sonic21]

for bi-amping you need both amps to be the same currrent(wattage) or not it will be unbalance between your HF,mid and LF.

 

[cstanwhf]

The 8200A and 8200P output may not be the same in watts, but the gain are the same. So the sound will be balance.

The GX100 is rated at 60 to 120W. The 8200P 100W will not cause any issue unless the volume is set too high.

 

[davedotco]

The 8200A and 8200P output may not be the same in watts, but the gain are the same. So the sound will be balance.

The GX100 is rated at 60 to 120W. The 8200P 100W will not cause any issue unless the volume is set too high.

Not absolutely sure about this........ :?

Surely input sensitivity needs to be the same to maintain 'balance', not sure about the gain. Given identical sensitivities, the more powerful amplifier will have more gain or am I misreading that...... :doh:

To be honest, I think passive biamping to be largely a waste of money in terms of the performance gain but it sure raises some interesting questions.

 

[cstanwhf]

http://www.audiolab.co.uk/ProductDetail.aspx?lang=En&Tab2=8200M

"Like all Audiolab amplifiers, the 8200Ms are gain-matched, ensuring perfect integration with other Audiolab amp components – so you can start at the level that suits you best, and build up your system over time"

 

[davedotco]

http://www.audiolab.co.uk/ProductDetail.aspx?lang=En&Tab2=8200M

"Like all Audiolab amplifiers, the 8200Ms are gain-matched, ensuring perfect integration with other Audiolab amp components – so you can start at the level that suits you best, and build up your system over time"

Interesting....... :?

The mono and stereo power amplifiers claim to be gain matched yet have different input sensitivities.

Driven by the same source (pre-amp) the more sensitive (stereo) amplifier should be louder in direct comparison but with a lower maximum output capability, in this case gain matching is not the issue, input sensitivity is.

 

[Tackleberry1]

Thanks for all the feedback and suggestions. My stereo equipment and cabling is quite difficult to get to, and with it being frantic over christmas, I've had no time to try anything out. In the meantime, I've had a response from IAG (Audiolab distributors) and they had said that the 8200P and 8200A are gain matched, so that's good, but he's saying that there is an imbalance between the power going to the tweeters and the bass drivers so the two amps don't work properly with the speakers that way. My retailer and additonal web surfing suggests otherwise, that what I'm currently doing (baiamping the two) is fairly basic standard pratice - especially being gain matched and the best way to go about it. My ipmression of the right thing to do was that tweeters require less power so use a gruntier power amp for the bass drivers - Why bother having gain matched amps if you can't use them together.

IAG are saying use the 8200A as a preamp only and biwire of the 8200P to the speakers. I'm a bit dissapointed that I've forked out money for the two components when I'm not getting the benefit of the extra power from the two combined. Am I better to keep the current Biamp scenario, or use the 8200a as preamp, and 8200P as single amp? Anyone has experience with this or something similar? This purchase was a long time coming and quite expensive for me and I'd hate to have been sold a configuration that was never intended on being used in it's current set-up

Am I missing something, Am I wrong, Is he wrong????

Thanks

 

[davedotco]

I assume Audiolab are saying that the gain of the power amp section of the integrated is the same as the power amplifier.

For this to be correct the input sensitivity would have to be different, leading to an output level mismatch, perhaps why Audiolab do not recommend the bi-amp configuration you wish to implement.

Point of information, passive bi-amping does not significantly effect to power being delivered to you speakers. The only power increase you get is the difference between the output of the integrated and the power amp, bi-amped or not.

 

[cstanwhf]

Does your 8200CD comes with the digital volume control (think the earlier version does not).

If yes, activate it and connect an interconnect from the output of the 8200CD to the input of the 8200P.

Ensure the vol of the 8200CD is set to lowest.

Bi-wire your GX100 with only the 8200P.

You can adjust the vol on the 8200CD.

If you wish to bi-amp to try.

Connect another interconnect from the "load" of the 8200P to the power input of the 8200A (set to pre-power AV mode).

Use the 8200A (in pre-power AV mode) to drive the bass, while the 8200P to drive the tweeter.

Or vice versa.

See if there is any improvement over using the 8200A as the pre-amp.

The pre-amp section of the 8200A is said to be it's weakest point.

 

[Thompsonuxb]

Not a bi-amping man myself but I'm curious.

using the 8200a as a pre-amp only gives you gain - i.e you increase the source level being sent to the power amp, hence less volume required to drive your speakers to your normal listening levels. This may give you more control over your speakers as the amp is operating well within its window providing the source signal is not distorted. it theoretically increases your power amps output (louder source, less volume).

or does the 8200A control volume on both amps?

How many sets of speaker terminals on the back of the power amp?

if there are 2sets then bi-wire/amp your speakers as suggested, using the 8200A purely as (a rather expensive one I might add) pre amp.

driving one set of speaker with one amp - i.e tweeters with the power amp will gain you very little as you'll end up trying to balance/match the weaker amp with no real gain in 'power'....oh you'll need better speakers too, the power handling on those GSX100 cannot handle what you want to throw at them and are the limiting factor in your set.

I had a 8200a for a while it is a beautiful looking amp and at low levels sounded lovely, superb earphone amp on it too but its attinuated pretty poorly though and is maxed out at 9 o'clock on the volume dial before distortion but its loud enough not to need a power amp.

But try using it as a gain amp up to 9 o'clock into your power amp, let us know how it goes.

 

[Thompsonuxb]

how do you set the 8200p up - is it controlled from the 8200a.

can you set the output level on the line out on the 8200a - (never got that far into it) - as a young man I would just use one amp as a gain into another. How do you utalise the power of the 8200p?

 

[Tackleberry1]

Thanks Everyone,

Davedotco, I beleive the input sensitivities of the amps are different in order to gain match them

Cstanwhf, I've read in other forums to do a similar setup going through the CD player, but I have other multiple components currently connected to the amp, so this would wouldn't work. With regards to the pre-power configuration of biamping, that is what I'm doing currently.

Thompsonuxb, The 8200a in it's current biamped set up does control the volume of both amps, both amps and speakers have terminals for biamping / biwiring, I also have Chord oddessy4 speaker cables so I'm set up to do this. I'm surpised that you think the GX100 can't handle the power, I thought they would be pretty aqccomodating speakers. Eitherway I initlally liked the sound of the speakers and considering what they cost me, I'm in no postion, nor want to repurchase items.

I gather that from what you're all pointing me towards is that it may be best using the 8200a as a sole preamp and just run both speakers off the 8200P (biwire configuration, beacuse I can). My biggest dissapointment is that Audiolab make a note about how you can purchase an amp and add more of them as neccessay - "gain-matched, ensuring perfect integration with other Audiolab amp components - so you can start at the level that suits you best, and build up your system over time"

It seems to defeat the purpose a bit......You'd think that products from the same range of series should work together in this fairly basic configuration.

 

[davedotco]

The gain of a power amplfier is fixed, it is the ratio between the input and output voltage.

Input sensitivity is what matters in this case. If the sensitivity is higher on one amp than the other then the more sensitive amplifier will be at a higher output level than the less sensitive one if they are fed the same signal. Basic electronics.

What I hope Audiolab are saying is that, with the pre-out on the integrated feeding the power amp and the integrated power section then the output level is the same. Simply using 'gain matched' amplifiers does not ensure that this is the case.

 

[Tackleberry1]

I've looked up my 8200a user manual and it even has instructions on how to connect the 8200p to a 8200a (in the pre-power setting) - so it must be a suitable way of doing things.

 

[Tackleberry1]

I've looked up my 8200a user manual and it even has instructions on how to connect the 8200p to a 8200a (in the pre-power setting) - so it must be a suitable way of doing things.

 

[Tackleberry1]

I've looked up my 8200a user manual and it even has instructions on how to connect the 8200p to a 8200a (in the pre-power setting) - so it must be a suitable way of doing things.

 

[adamrobertshaw]

I used to bi-wire my GX50 from an 8200A.

After reading reviews I decided to revert to single wired, positive to HF and negative to mid/LF.

I know the GX100 have a larger driver and I appreciate you have bought an 8200P for the opportunity to bi-amp, but I'd suggest using the "pre" mode from the 8200A and single wire the speakers from the 8200P ... positive to HF and negative to mid/LF. (Hopefully you still have the jumper cables)

Potentially this will put less tax on the 8200A while only in pre mode, your GX100 drivers get a crisper current from the 8200P, and if the GX100 are similar to the GX50 ... a more coherent sound using single wires.

 

[Thompsonuxb]

So are the levels of the pre-outs on the 8200a fixed or are they variable. Can the level being presented to the 8200p be increased?

(always thought thats what pre amps did - amplify the signal being presented to the power amp)

Tackleberry1 - googled your speakers the power handling is 120watts they would suit the 8200a at 60watts per channel - but the 100watts of the 8200p would maybe improve their sound it would bring no gain in terms of volume or slam the speakers are limited by the travel on their 'coil'.

I owned some 8ohm 100watt speakers which sounded fine on the end of a 90watt per channel amp, but could only handle so much before 'pucking', they were budget but played at what I thought was a reasonable level they were limited.

the 200watt into 6ohms (about 150 to 175 into 8ohm) speakers I own now can handle everything the same amp can throw at them without distortion and they have smaller cones). I take it you like your music loud and thumping ..... those speakers won't deliver.

Actually how would you discribe the sound of you current configuration compared with the sound of the 8200a on its own - oh, stick with the biwire it does sound better, appreciated more with complex music and volume.

 

[Tackleberry1]

Thanks I don't play my music at overly high volumes,more of a comfortablelstening volume. The current sound is fine - bass really good and punchy, I just find that on certain tracks that things like hi hats, ride cymbals, etc are quite recessive. The systemi it;s current form overall sounds really good, it's not like there's an obvious problem or fault, it just doesan;'t seem to have that crystalline / sparkly qualkity that I have heard this system do (albeit with just the 8200A on its own) in demos at my retailer.

I'm aware that room acoustics, sizes, surfaces, etc, make a difference, but my room is all fairly standard. I wouldn't have though adding the poweramp would have made it worse.

 

[Tackleberry1]

Adamrobertshaw, for your setup in the den, how were you speakers placed? Is the room a smaller sized room? Did you use port bungs or not? I'd love some feedback on any findings you experienced with setting up your speakers in this room.

Thanks

 

[Tackleberry1]

Well I finally got the chance to play around a bit and thought I'd let you know how I went. I now have the speakers biwired going through the 8200p and am using the 8200a as a preamp only. It was a pretty noticeable difference that even my wife could pick up on it. That clarity and crisp was is back. There also seems to be more instrument separation. I'm absolutely stoked at the marked differene and also highly relieved. It's as I expected it would sound based on my original successful in store demos.

I've also decided to run the sub through the 8200p as well (instead of the 8200a in a pre-power mode) figuring it's probably best all speakers are fed the same signal through the same source.

Thanks for all your suggestions guys!

 

[adamrobertshaw]

The speakers are 36cm from the wall.

They point in at an angle of about 5 degrees or so.

The cabinet sides are 54 inches apart

I leave the grilles on as it make no difference.

My stands are heavy, sand filled and have some decent rubber pads to add some isolation under the speakers.

I've never used the bungs for proper listening, although I have tried them and noticed how much they tone down bass (not to my liking).

Although I have them in my den, the den is actually at the back of a 24 foot long room with flat walls and loads of room to breathe.

I rarely turn the 8200A volume past 10 O'clock. Most of the time it is at 9 O'clock

I keep the DAC in optimal transient as optimum spectrum (to my ears) make the highs too sharp which gets tiresome.