Haes 4 X 40W Amplifier Functions

[CJordan]

Searched but could not find definitive discussion of this amplifier's functions. My 2001 with M490 (dash and door speakers, no rear speakers) has the "four-channel" Haes amp, but the stock setup has no controllable "rear" channel. All speakers currently operate on the "front" setting only. What (if any) function is active on the second (rear?) channel for this amp (and which pin numbers identify this channel?) I understand that the door speakers are fed only low frequency signals from the amp, but are they on the second "channel" - not controlled separately from the head unit? Are there any unused output pins from this amplifier that may be used to drive the door speakers independently of the filtered signal now being supplied by the amp's current wiring? Several wiring diagrams suggest that a second (rear) channel may be available from the amp to drive any additional rear speakers, or a set of full-range door speakers. Any help is most appreciated.

[KevinH90]

When I installed my rear speakers (in the storage box behind the seat) I replaced the 4-channel amp with a 6-channel amp from a 996 Cabriolet.  Is it possible that the wiring diagrams you reference in your statement that, "Several wiring diagrams suggest that a second (rear) channel may be available from the amp to drive any additional rear speakers, or a set of full-range door speakers," are 996 wiring diagrams?  Please note that you can power rear speakers from the CDR 220 head unit.  This article explains how to do it: Rear speaker install

 

Since I completed my rear speaker installation, I've done audio upgrade work on other family vehicles.  If I were to do this project today, I would purchase an after market amp rather than use the HAES equipment.  A good after market amp has controls that allow you to adjust gain and bypass settings to achieve better sound quality.  I used the HAES 6-channel amp because it was easy to install and wiring it only required a minor adjustment to the amp harness connector.

[CJordan]

Thanks, Kevin. The previous owner had installed a set of full-range speakers in the doors as well as replacements in the dash. The door speakers are barely audible. Since the Haes amplifier is supposed to have four-channels, I was hoping to find the "second" set of channels (rear, left and right shown on some wiring diagrams for an M490 system) to bring the door speakers up as a fully-functional rear channel. I have since learned that the "second" set of two channels on this amp are the low pass filtered circuits to the door speakers. These circuits do not respond to the fader function, so are therefore not part of a secondary channel in the typical sense. Attached is the M490 system diagram showing the additional rear channels. Although the actual amp is not identified, my pin configuration is identical. If there is output at pins B16, B6, B15, B5, then I might have the rear channel. More testing is in the works. If there's nothing there, your suggestion of a new amplifier is probably the way to go. Thanks again.

[KevinH90]

I think you are right about the function of the 4 channel Haes amplifier.  It would probably work well if you want to retain it to power the dash speakers (I hope the previous owner replaced those too) but I suggest you assess the pros and cons of an additional amp for the door and rear storage box speakers.

 

I added a subwoofer and  pair of rear-deck speakers to my 2005 Mercedes C230.  I bought a "scratch and dent" 4-channel Kicker amplifier from Crutchfield for around $100 to power the speakers.  I bridged two channels for the sub and the other two channels power the rear-deck speakers.  I think that the amp I bought would fit in the space on the passenger side of the spar tire where the OEM 6-CD changer would be installed in a 986.  I saw pictures on an installation that used the OEM CD-changer bracket to support the amp.

 

The Boxster is not the best environment for music, but I found that installing speakers in the storage box makes a noticeable improvement in the sound quality when I drive with the top down.

 

 

[lkchris]

No, recall that Porsche sells as an option rear shelf speakers that would perform the function of fader rear.  There is of course no directional presence for low frequencies ... and 2 of the four amp outputs are post crossover separation of low frequencies for the door woofers.  It makes no sense to control them as fader rear and imho little sense to convert them to full range speakers ... again the rear shelf speakers are a better solution.  See Suncoast Porsche for the kit.
 

Search here will reveal a “pin out for 6x40” thread that will detail how to get rear outputs for full range rear shelf speakers. FWIW there are unused direct to speaker outputs on the Oe radio and those can be used to connect rear speakers as well.  Nicer obviously to power them from auxiliary amp.

 

its pretty easy to find a 6x40 amp from a 996/911 on eBay.  They come in both coupe and cabrio versions and I’d recommend the cabrio version.  Note that the wiring between radio and amp already includes rear speaker wires, so the only work is to accomplish amp to rear speaker wiring.  As an aside, I’d venture the 4x40 circuit for the door woofers is limited ... when I installed the 6x40 amp, the door woofers really came alive ... it’s all around a better amp.  Finally, note also that option 490 dash speakers are mid range plus tweeter, the crossover  being at the speaker.  And 6x40 means 2 dash, 2 rear, and 2 door woofers.

 

 

 

 

Edited May 8, 2020 by lkchris

[lkchris]

FYI

 

1999-2005 Porsche 996 911 Cabriolet Amplifier Amp 6x40 99664532300 M490 Haes

WWW.EBAY.COM

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Porsche 996 Convertible Cabriolet radio stereo amplifier. HAES 6x40. In excellent condition.

 

[CJordan]

Thanks, all. I'll continue to research options with the four-channel amp and pass on anything new that I discover.