Speaker replacement Technics PR Series

Info for those who may have speakers that are buzzing or distorted

I have a Technics SX-PR305 which I purchased last summer from Ebay for a bargain. When I started playing, I noticed that the speakers in the speaker box were distorted and buzzing when playing the lower end of the piano. After searching on-line for possible causes, I narrowed it down to either a faulty amplifier in the piano or disintegrated speaker foam around the cones.
As recommended, I disconnected the speaker box from the piano to avoid possible damage to the amplifier circuit and carried on playing using headphones or the built in monitor speakers (which sound tinny and not very nice).

Last week, I finally got around to removing the speaker box and taking the back cover off. This revealed what I had hoped - that the foam around that connects the speaker cone to the speaker chassis had disintegrated and was lying in the bottom of the speaker cabinet.

I removed the damaged speakers to try and find a replacement. The information on the back of it was very limited and googling the Technics part number turned up no information. All I had was the size(165mm or 6.5") and the impedance (8ohm).

I looked in all the usual big stores for a suitable replacement; Maplin, RS Conmponents, Farnells but couldn't find anything to match. I wanted exactly the same size so I didn't have to modify mounting holes.

I visited a couple of small shops in London that specialised in electronic instrument and amp repairs and they couldn't help much either. One shop had a perfect match but only had one and I needed a pair. It was also a discontinued speaker so they couldn't get another one.

With the information I had gathered, I reluctantly turned to Ebay to have a look for a replacement. I found a speaker that looked the right size, impedance and freq response and ordered 2.

When they turned up, I was delighted that they were exactly the same size as the old speakers, and even the mounting holes lined up so no need to modify.
The only change I had to make was to change one of the spade terminals on the original wiring to fit onto the new speaker.

Once back together, the piano now sounds great again with no distortion or buzzing.

Total cost - Less than 20 GBP.

If anyone has a similar problem and wants details of the speaker then comment on here and I'll let you know.

Hope this is useful to people as the tech specs in the manuals don't give much info on speaker specs. I think these are the same for seversal of the PR Series Pianos

I have some pictures of the old speakers and new which I will post on here once I can upoad them.