2 Pre Amps To 1 Power Amp

[alcarmichael]

I'd like to connect a home cinema processor to my stereo system with the one and same power amp used for my main speakers.

Croft 25R
Audiolab 8200 AP

I'm thinking I can use the main L/R pre outs from the Audiolab to one of the line inputs on the Croft and have the volume pots at full (making sure I remember to turn back down before using the Croft for stereo duties!!). The only other option I can think of is to introduce a Switch Box in to the system.

Any other/better suggestions?

[Stryder5]

If I understand you correctly, then what you propose will work, BUT, you do not need your Croft at full volume.

Interconnects from Audiolab to an input on Croft, front speakers connected to Croft. Turn volume to zero on Croft

Switch on.

Audiolab is now master volume, so you now have all speakers except fronts. Turn Audiolab volume to reasonable listening volume. Turn Croft volume to match and leave there.

The Audiolab is now in control of all speakers.

This is my setup, all other devices, cd etc direct to Croft.

Hope this makes sense



I'd like to connect a home cinema processor to my stereo system with the one and same power amp used for my main speakers.

Croft 25R
Audiolab 8200 AP

I'm thinking I can use the main L/R pre outs from the Audiolab to one of the line inputs on the Croft and have the volume pots at full (making sure I remember to turn back down before using the Croft for stereo duties!!). The only other option I can think of is to introduce a Switch Box in to the system.

Any other/better suggestions?

[alcarmichael]

Interesting (and a bonus) that I don't require the Croft to be switched on.

I thought it might be better to have the Croft volume pots at the same position each time the Audiolab is in use, I suppose it doesn't have to be full volume but at this position it guarantees the volume pots will be exactly the same position every time. The Audiolab will then adjust the volume output to suit.

[Stryder5]

Interesting (and a bonus) that I don't require the Croft to be switched on.

I thought it might be better to have the Croft volume pots at the same position each time the Audiolab is in use, I suppose it doesn't have to be full volume but at this position it guarantees the volume pots will be exactly the same position every time. The Audiolab will then adjust the volume output to suit.


The Croft will need to be on otherwise there is no power to the front speakers.

[alcarmichael]

Sorry, I thought the Croft Pre would have to be on, I think I must have misinterpreted your unedited post!

[alcarmichael]

With the volume set as you have it, won't I need to adjust the volume on the Croft whenever I turn the volume up or down on the Audiolab?

[Simon_LDT]

Yep, which is why ideally you need to set the Croft at unity gain (full volume I presume like most pre-amps). For me, I use a passive pre but still require volume to be on full for no attenuation. Then just set the trim levels for all speakers in the processor or player (depending on which if you're using for settings). That way whenever you're using the multichannel setup just turn volume to full on the stereo pre and levels will be set and only the processor will alter the volume, along with all other speaker connected. Best way to do it unless your pre has HT bypass.

[Stryder5]

With the volume set as you have it, won't I need to adjust the volume on the Croft whenever I turn the volume up or down on the Audiolab?

No, the master volume on the Audiolab will control the overall output from all the speakers, it's just another source.

[Stryder5]

This is just not correct, and has the associated issue of forgetting your at full volume as in the OP, when you change sources.

Not going to argue, try it my way.

I reiterate connect IC's from Audiolab to Croft line input of choice, speaker cable from Croft to speakers turn on Audiolab and set a reasonable volume, turn Croft on set volume on Croft to zero, increase volume on Croft to match other speakers using the tone output from the Audiolab (or your ears). Now when you increase or decrease volume on Audiolab the Croft volume will follow.....period.

Assumptions.....you are using a pre-out for front speakers from Audiolab.
Any line input you choose on Croft



Yep, which is why ideally you need to set the Croft at unity gain (full volume I presume like most pre-amps). For me, I use a passive pre but still require volume to be on full for no attenuation. Then just set the trim levels for all speakers in the processor or player (depending on which if you're using for settings). That way whenever you're using the multichannel setup just turn volume to full on the stereo pre and levels will be set and only the processor will alter the volume, along with all other speaker connected. Best way to do it unless your pre has HT bypass.













Yep, which is why ideally you need to set the Croft at unity gain (full volume I presume like most pre-amps). For me, I use a passive pre but still require volume to be on full for no attenuation. Then just set the trim levels for all speakers in the processor or player (depending on which if you're using for settings). That way whenever you're using the multichannel setup just turn volume to full on the stereo pre and levels will be set and only the processor will alter the volume, along with all other speaker connected. Best way to do it unless your pre has HT bypass.

[Simon_LDT]

Well, technically both ways are correct, it just depends on what the user prefers. For me, I don't want to be faffing with volume matching and prefer to go unity gain and in my turn off procedure I always turn the volume on the pre down to zero and haven't had any problem ever. The best way to do it if not using unity gain is to set the Croft at a set volume (say 12 o clock) and then set all other speakers to that. That way each time you want to use the Croft pre for cinema you set to 12 o clock and it'll click into place.

[Stryder5]

I agree with the proviso that the A/V amp volume is master and the volume of the slave amp once set will follow without adjustment.

Think of it this way, if you are using a pre-amp and a power amp, the power amp will follow the pre amp volume, the gain of the power amp is irrelevant. The Croft in this case is a power amp with variable gain.