Stereo integrated amplifier into a stereo power amplifier - Possible ? - Pls help

[elangoas]

Plz excuse me if this is a dumb question....

Recently got hold of a Kenwood stereo integrated amplifier (A-3X) which has Pre - in & out connected with jumper, would like to know if there is any modification the can be made so as to use it as a 2 channel power amplifier (Disable the volume control)....

The reason i ask is because, i intend to use this as a 2 ch power amplifier with my AVR... Is this a simple modification (or) complex one ?

If simple can it be done by any local electronics technician ?

If complex, i will drop the idea and use it as it is....

Appreciate your inputs...

 

[Srinath_seshadri]

Its pretty easy. Your AVR has pre outs right, you run that front 2 into the main in with RCA's.
Some avr's if you tap into the signal at any of the pre outs except subwoofer, they will isable the whole power amp section.
If it does that, you're gonna need 3 more channels of power. I know adcom made one that was a 3 channel power amp just for this purpose. You may need to power your 3 other channels if it is like that. However you could also run it into this as a 2 ch setup and disconnect it for the 5.1 out of the avr.
Cool.
Srinath.

 

[venkatcr]

What exactly is your question?

1. Disabling the volume control?
2. Using it as a power amplifier?

The first, I am sure, any decent electronics engineer should be able to do. The second should be possible in any case if you route the FR and FL lines feeds of a 5.1 to the Kenwood and from that to the speakers.

It all depends on how you feed the audio to the AVR.

Cheers

 

[captrajesh]

I guess the jumpers are there between 'pre in' and 'power out' RCA sockets. If so, you remove the jumpers and it becomes a pre amp or power amp as per your requirement.

 

[Danieljohn]

Are you sure its Main in / Pre out pls check again I think "Adapter" is mentioned ther.

 

[elangoas]

Thanks @Srinath_seshadri, venkatcr, captrajesh for your detailed responses..

I should have stated the requirements with more clarity...

My Onkyo TX-NR 818 is a 7.2 AVR which has 9.2 Pre-outs...

Right now the Fronts, center, surrounds & Front wides are powered by AVR... The additional amplifier (Kenwood) is to power the front heights using pre-outs of the AVR...

What i did was, removed the Pre-in & Outs jumper from the stereo amplifier & connected to AVR pre-outs.... But the tricky thing, the kenwood amplifier volume control is still functional....

By removing the jumpers between Pre-in & Outs of Kenwood stereo amplfier, it has become power amplifier, but volume knob is still functional.....This is why i had the query of "How to disable the volume control in Kenwood stereo amplifier"...

Some additional info : The stereo amplifier doesn't have remote control, juz the volume knob....

 

[elangoas]

Are you sure its Main in / Pre out pls check again I think "Adapter" is mentioned ther.

Yes.. Am pretty sure it is, Main-in and Pre-Outs...

Since i have already hooked it to AVR as power amplifier,unable to click pictures.. Hence providing external links from the web.... (Sorry abt that)

http://auction.thumbnail.image.raku...image1/550/11780550/1210/img6430878342691.jpg

http://auction.thumbnail.image.raku...image1/550/11780550/1210/img5810878346968.jpg

 

[captrajesh]

By removing the jumpers between Pre-in & Outs of Kenwood stereo amplfier, it has become power amplifier, but volume knob is still functional.....This is why i had the query of "How to disable the volume control in Kenwood stereo amplifier"

It's not possible to control volume if the preamp is taken out of the circuit. So the jumper could be something else.

Yes.. Am pretty sure it is, Main-in and Pre-Outs.

http://auction.thumbnail.image.raku...image1/550/11780550/1210/img6430878342691.jpg

It's written in Japanese; can't make out whats written.

 

[mpw]

It's written in Japanese; can't make out whats written.

it says do not fiddle..:lol:

 

[Audio_Freek]

Yes.. Am pretty sure it is, Main-in and Pre-Outs...

Since i have already hooked it to AVR as power amplifier,unable to click pictures.. Hence providing external links from the web.... (Sorry abt that)

http://auction.thumbnail.image.raku...image1/550/11780550/1210/img6430878342691.jpg

http://auction.thumbnail.image.raku...image1/550/11780550/1210/img5810878346968.jpg

To be clear, Any Integrated Amp can run as Power Amp by default ,But whether it can be run as pre-amp is again should come by Inbuild.

Preamp-Just boost the signal
Add power to the signal so that it could be used connect the Speakers.

In your case you looking for the Kenwood to be used as Power amp, So the speakers are connected to Kenwood. So the Preamp work is done in AVR. When i connected my Sansui (Power Amp) to Yamaha ( Pre amp) mode, I could notice that the volume in the Yamaha was not working but i could adjust the tone\bass at same time i could increase the volume in sansui.



As per the standard the Pre-out should be in Left and Mains are on right side. I have noticed that the inputs are in vertically aligned (White on the top and red below.

So the cable from the AVR (Pre-out) Should be connected to the right side (Main input) of Kenwood to act as Pre- Power Combination.

So Modified signal( adding some color) job is done by the AVR but, it will bot boost the volume though and Kenwood shall act as power amp to sing yout speakers enabling the volume.

Sorry in case i have mistook your actual requirements.



Just share your input.

 

[Fantastic]

That is out / in in Japanese on that jumper. That would mean pre out and power in.
The volume is usually at the input to the preamp and so 'out' here would be controlled by the volume control. Power amp in should not be affected by the volume control. Unless there is no active stage in the preamp (passive- no gain stage) which doesn't appear to be the case.

 

[elangoas]

Are you sure its Main in / Pre out pls check again I think "Adapter" is mentioned ther.

Am sorry buddy.. My bad... You are right... It is indeed mentioned "Adaptor"...

It's not possible to control volume if the preamp is taken out of the circuit. So the jumper could be something else. It's written in Japanese; can't make out whats written.

But i have connected my AVR Front Heights "Pre-out" to "IN" of the stereo amplifier... Have connected speakers to Kenwood amplifiers speaker terminals... When i check the level calibration in my AVR, the speaker makes the sound....

it says do not fiddle..:lol:

hyeah:

To be clear, Any Integrated Amp can run as Power Amp by default ,But whether it can be run as pre-amp is again should come by Inbuild.

Preamp-Just boost the signal Add power to the signal so that it could be used connect the Speakers.

In your case you looking for the Kenwood to be used as Power amp, So the speakers are connected to Kenwood. So the Preamp work is done in AVR. When i connected my Sansui (Power Amp) to Yamaha ( Pre amp) mode, I could notice that the volume in the Yamaha was not working but i could adjust the tone\bass at same time i could increase the volume in sansui.



As per the standard the Pre-out should be in Left and Mains are on right side. I have noticed that the inputs are in vertically aligned (White on the top and red below.

So the cable from the AVR (Pre-out) Should be connected to the right side (Main input) of Kenwood to act as Pre- Power Combination.

So Modified signal( adding some color) job is done by the AVR but, it will bot boost the volume though and Kenwood shall act as power amp to sing yout speakers enabling the volume.

Sorry in case i have mistook your actual requirements. Just share your input.

Perfect buddy.. I had it connected the way you juz said.... I don't know for some reason the volume control knob is functional.....

Attaching some more actual pics....

 

[Fantastic]

There are people using it by just connecting the 'in' section of the jumpered sockets. Do a Google you will find someone selling this amp. He has the input connected to the 'in' terminals. The 'out' as usual is left open. He has a red coned woofer in the pictures !
one of a kind Trio Kenwood Midi A-3X Hi-Fi Integrated Amp - 202652

If the volume control is functional ( but does not have gain ) just leave it wide open ( max clockwise)! Even if it has gain you can turn it to suit it for the level you want. Why worry .
What speaker cables are you using ?

 

[elangoas]

There are people using it by just connecting the 'in' section of the jumpered sockets. Do a Google you will find someone selling this amp. He has the input connected to the 'in' terminals. The 'out' as usual is left open. He has a red coned woofer in the pictures !

If the volume control is functional ( but does not have gain ) just leave it wide open ( max clockwise)! Even if it has gain you can turn it to suit it for the level you want. Why worry .
What speaker cables are you using ?

Yup.. Saw this picture, before i went to purchase this amp....

I was actually confused why the volume knob is functional when am using this amplifier as "power amplifier".... Yes...I had set the volume control to "Maximum" on the amplifier and using it...

Am using Belden 14 AWG....

 

[theironhorse]

Thanks @Srinath_seshadri, venkatcr, captrajesh for your detailed responses..

I should have stated the requirements with more clarity...

My Onkyo TX-NR 818 is a 7.2 AVR which has 9.2 Pre-outs...

Right now the Fronts, center, surrounds & Front wides are powered by AVR... The additional amplifier (Kenwood) is to power the front heights using pre-outs of the AVR...

What i did was, removed the Pre-in & Outs jumper from the stereo amplifier & connected to AVR pre-outs.... But the tricky thing, the kenwood amplifier volume control is still functional....

By removing the jumpers between Pre-in & Outs of Kenwood stereo amplfier, it has become power amplifier, but volume knob is still functional.....This is why i had the query of "How to disable the volume control in Kenwood stereo amplifier"...

Some additional info : The stereo amplifier doesn't have remote control, juz the volume knob....

connect pre out of avr to power in of stereo amp and put volume to full.
thats bout it.. pretty simple.. volume knob cannot be disabled but to use it as power amp rotate the knob to full volume and the avr will do the volume control will pre-outs

 

[Audio_Freek]

:-( I think you still in some confusion.

Preamp is only for Coloring the Signal+add Gain to the Signal ,So Pre-amp dont have or should have Volume Knob since it doesnt add power to the Signal for feeding the Speaker.

Conclusion = Preamp Volume would be Bypassed and Power Amp would have volume Knob.

If am Not wrong The Volume in the AVR for the Front speaker should be Non-functional \by passed and you could control the volume of the Front speakers only in Kenwood,which is used a power Amp.

For me your set-up is working fine .The Power amp only function adding Power to the signal so the Volume Knob should work for sure.


If you like test then, do something. Run AVR as pure Pre-amp by Just disconnect all the speaker from the AVR Center,Rear and Sub,Since the front is connected to Kenwood)


If you try playing the music from your source via AVR and Kenwood, I Bet you cannot control the volume from AVR since its Preamp,Either the volume from the Source or the Kenwood only can control the speakers.

Just give a try

 

[Danieljohn]

Buddy I have kenwood KRX-69 its adapter sockets wont work anything like a Pre out/Main in's.

Actually they are just monitor outputs with Loop in's so forget abt it ask FM's what to go for now.

If you would have asked FM's before purchasing Kenwood I'm sure they could have helped you get the perfect Amp for your requirements.:sad:

 

[elangoas]

connect pre out of avr to power in of stereo amp and put volume to full.
thats bout it.. pretty simple.. volume knob cannot be disabled but to use it as power amp rotate the knob to full volume and the avr will do the volume control will pre-outs

Cool.. Thanx...Hope setting the volume knob will not do any harm to speakers...

:-( I think you still in some confusion.

Preamp is only for Coloring the Signal+add Gain to the Signal ,So Pre-amp dont have or should have Volume Knob since it doesnt add power to the Signal for feeding the Speaker.

Conclusion = Preamp Volume would be Bypassed and Power Amp would have volume Knob.

I got it now.. Thanx for enlightening me... :thumbsup:

Buddy I have kenwood KRX-69 its adapter sockets wont work anything like a Pre out/Main in's.

Actually they are just monitor outputs with Loop in's so forget abt it ask FM's what to go for now.

If you would have asked FM's before purchasing Kenwood I'm sure they could have helped you get the perfect Amp for your requirements.:sad:

FM have suggested to use as it is..... I got this amp along with Sony Hi-Fi BS speaker for 4.5K... I had earlier used a proper stereo power amplifier + AVR, so thought if i remove the jumpers, it would become power amplifier.... But anyways, i can live with this hyeah: until i find a suitable replacement....

 

[Fantastic]

Belden 14 AWG....

Right, it looked something like that !
Thanks.

 

[jls001]

Preamp is only for Coloring the Signal+add Gain to the Signal ,So Pre-amp dont have or should have Volume Knob since it doesnt add power to the Signal for feeding the Speaker.

The above is most likely misleading information.
Volume control is usually implemented at preamp stage.

Also if it has gain it adds power.