Researching the service manuals and inspecting the DIN socket on the 303 reveal the following pin configuration.
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| Front view with DIN pin numbering |
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| From the manual |
There are two popular bi-amping configurations - standard bi-amping (or horizontal bi-amping) and vertical bi-amping. Borrowed the handy illustrations below from the internet.
I decided to proceed with vertical bi-amping. Vertical bi-amping requires two amplifier of similar configuration (as close as possible). I cable the interconnect with output from the Quad 33 LEFT channel to the LEFT&RIGHT for one of my Quad 303. Likewise for the RIGHT channel using my other Quad 303.
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| Overview of bi-amp setup |
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| View from top of the cabling |
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| Side view |
Cost of the experiment was about $20 with the Deltron plugs accounted for most of the cost.
There's definately improvement in the presentation - the soundstage presence, vocals and instruments are much much better defined and realistic; so much so took some getting used to??? At low volumes, the sweet spot sounded like using a single 303 in stereo mode. When the volume was turned up, the sweet spot "grew". At the usual listening position, it was as if I was seated much closer to the speakers. Guess the 303's were having an easy time driving my Meridian A500 speakers (89dB)?
Actually sounds quite divine!!!
Highly recommended for Quad 303 enthusists who want more from their old faithful.
I used my 1st Quad 33 to drive the 303's.
FYI: One of my recent visitors actually inspected the 303's to make sure there were no valves in them!!!
FYI - My friend (who bought my Philips CD460 and Sansui AU-4400) drop by to hear the bi-amp 303's and was extremely impressed by it's ability to sound musical while delivering details with precision, in a transparent manner - well balance tonally throughout the bass, mid and highs!
ReplyDeleteI have to agree that bi-amping with a pair of 303's is a very good step up. I use mine in vertical bi-amp mode to drive a pair of B&W P6's and the sound stage is very wide, and the sense of 'air' around the individual notes seems better than the single amp set up.
ReplyDeleteNot sure if this is still active, but I am bi-amping the same setup youäve done above. The difference is, my speakers are not biwired (meaning, I only have 1 + connection and 1 - connection. Not 2 & 2 as above). Is there any risk or issue in connecting both + wires from amp to + pole in speaker, and the same for the . wires? Thanks in advance! Brad
ReplyDeleteI would not advise doing anything else which does not adhere to the wiring illustrated by the pix(s) or the link below.
DeletePlease refer to https://www.audioholics.com/frequent-questions/the-difference-between-biamping-vs-biwiring
hi, I've inherited my dads Quad 303 speakers, quad 303 amp, and FM 3 tuner, quad 33 amp (it has all the options buttons like tape, disc, radio on the front.) I have a number of the original cables, wires. I need help because I dont want to blow it up by connecting it all wrong. I have the original mains leads for the speakers, please the leads from 303 amp to speakers. Can you tell me what plugs in where etc? i could send a photo of what I have? I would appreciate any help! Francesca Black
ReplyDeleteSomeone has already done it on youtube - https://www.youtube.com/watch?v=GqyhQj9Lvf4
DeleteIm thinking about doing the same thing
ReplyDeleteIt's will be quite a revelation vs just using a single 303!
DeleteHey WCK,
ReplyDeleteWanting to follow in your footsteps on this project! The phone cables used as signal cables, are they shielded? Please also "spill the beans" on the speaker cables - are they LAN cables? Any chance you could be specific on the cables used for both signal and speakers?
Thanks:)
Replied on the other thread. Apologies for the belated reply as had to cleanup the backup mess after a HDD died - was using the theory of multiple backups BUT forgot about the hassels of multiple versions and dates for same folder!!
DeleteHi! Old thread I know, but I have a question. I have a similar setup, Quad 33 + 2 303's. The 303s are close in serial number <1000apart.
ReplyDeleteIt seems to me the "standard" setup would account better for any differences between the 303s. Have you tried connecting them this way? Did you notice any differences to the presentation? Did one setup sound "better" than the other in your opinion? Curious to get your thoughts...
Discovered a dedicated 303 to a speaker produced better results for my setup, as some of my speakers are a little power hungry types. If your speakers are easy to drive types, doubt you will hear much differences.
ReplyDelete