How to connect a 901 VI speakers to a Yamaha A-S500 amp

[marard]

Bose product name

Bose 901 Series VI speakers (2), with Active EQ Series VI and a Yamaha A-S500 amp.

How do I connect the above systems? Are they compatible?

I connected, the Active EQ to the Amp as described below:

On the Active EQ, Amplifier Output and Input ports are connected to the Yamaha ports, PB2.

On the Yamaha Amp, Speakers are connected to speaker set A, and impedance selector is set to High.

Audio source is CD.

Amp info:

https://sg.yamaha.com/en/products/audio_visual/hifi_components/a-s500/index.html#product-tabs

Amp backplane pic:

https://usa.yamaha.com/products/audio_visual/hifi_components/r-s500/features.html

Now when I fire up everything and play music, it sounds dull and flat. And nothing changes when I move the sliders on the EQ. In fact absolutely nothing changes when I completely power down the active EQ.

Have I cabled this incorrectly, or is this Amp unsuitable for these speakers?

I found the below on Amazon in response to a query, is the below information correct?

The Bose 901 speakers use an equalizer as part of their operating design. They need to be used where the equalizer has to be connected between the preamp and amplifier. Some amplifiers have a preamp out and main in that allows this connection. The AS500 does not have this. The alternative is to connect the equalizer to a tape out and tape in and use a "tape monitor" switch to hear the recording , on a three head machine, as it was made. The AS500 has the Tape in and out connections, but does not have the tape monitor switch. Sorry, the AS500 is not a good choice for the Bose 901 speaker system. 

Please help.

Thanks.

[Vicky_W]

Hello Marard, 

Welcome to the community! 

I would love to help. The manual here on page 9 and 10 explains how to set up an equalizer with your system. Can I please confirm if it is the Bose equalizer you have or a third party?

I look forward to your reply. 

[marard · Accepted solution]

I have a Bose Active Equalizer.

Anyway, I resolved the problem. I was misled by an improper dial selection on the AMP from my side and also due to incorrect posts and reports on the internet about the Yamaha AS500 being an unsuitable AMP for speakers with Active EQs.

Basically as I connected my music source to the "CD" input ports at the back of the AMP, I selected, "CD" on the Input selector dial on the front of the AMP.

This was incorrect as we first want the Bose Active EQ to process the input signal from the "CD" port(or any other input), and then have the EQ send the processed signal back to the AMP via the PB "IN" port on the AMP.

When I selected the correct Input source(Line 2) on the selector dial, everything was fine.

Here are my detailed steps:

1. On the Bose Active EQ, connect the "Amplifier Connections->Input->(From AMP "Tape OUT") to, PB2 (or PB3)* "REC" ports on the Yamaha AS500.
2. On the Bose Active EQ, connect the "Amplifier Connections->Output->(To AMP "Tape IN") to, PB2 (or PB3)* ports immediately above the "REC" ports on the Yamaha AS500.
3. Connect the speakers to either port group A or B on the Yamaha AS500.
4. Connect Audio source to the Yamaha AS500 to CD ports.
Please remember to match polarity for all the above connections.( + and - for the speakers and R and L for the connections from the Bose Active EQ)
Your connections are now complete.
Now, the audio signals from your device connected to the CD ports on the AMP are sent to the Bose Active EQ via the PB REC ports, they are then processed by the Active EQ unit and sent back via the (To AMP "Tape IN") ports into the PB ports on the AMP.
The AMP now amplifies and processes this signal for Bass, Treble, Loudness etc., and sends it to the speaker.

Be sure to set the below dials/settings on the AMP before you play or test the setup.
On the Yamaha AS500 AMP, set...
-INPUT Selector to Line 2(PB2) or Line 3(PB3)
-REC OUT Selector to CD
-SPEAKERS Selector to A or B depending on where you connected the speakers.

You now ought to be able to hear the speakers.

You can also verify the above setup by following the "Testing the speakers and equalizer" section of the 901 owners manual.

Rest assured the Yamaha AS500 will work with a pair of Bose 901s and Active EQ.