I have shown pictures of vintage Pioneer HPM-700 refurbishment , now I would like to show you full picture gallery with comments.
Is I said previously, major improvents are:
- new caps in crossover
- new internal wires
- extra sound dumping inside
- new vinyl
- new stands – it was quite obvious, that tweeters need to be lifted in to height of ears upon listening.
Speakers were bought from eBay, they look great on the pictures but in I was horrified when they arrived. Absolutely filthy, scratched vinyl, corners gone. Well I wanted to refurbish them anyway. In the end I got a big fat partial refund from the seller.
I didn’t have original grill, so I thought to remove the plastick insterts. I wouldn’t use grills with them anyway.
First of all woofers were and crossover were taken out. I have planned to exchange caps, internal cabling and banana connectors. Problem with the old ones is, that they are only screwed and having clips for the wire. Retro is cool, but in this case absolutely useless.
Everything is being taken appart.
In crossover were the cheapest possible caps. We find out, that crossover is absolutely identical with crossover from 12″ model Pioneer HPM-900 (HPM 900 has got potentiometers at the front of the speaker). Also internal speaker cables were like the cheapest bell wire shit. Connectors was falling off the woofers.
The viewer can with the sharp eye, that all caps and wires are gone be now. Speaker connectors are attached in very peculiar way, with screw and piece of metal which creating connection with other side of PCB. All holes for internal wiring need to be enlarged. All caps were glued to PCB. All that mud is taken away.
I have chose new banana plugs. Lovely looking English style vintage banana / spade plugs. Very rigid and nice quality. Bet the made in china 🙂
Original connectors are taken away and plastic drilled away. New plastic washers (supplied with banana plugs) were glued to base board with super glue and just in case also with hot glue gun.
Caps are very good quality from Jantzen Audio Denmark – Cross caps. Bet they are better than most of the caps used in hifi speakers. On DIY forums I’ve seen caps attached horizontally. It was lucky and have space to attach them vertically.
Finally all finished. I’ve used Supra cable 1.6mm2 – tin plated copper, recommend as a great cable for internal wiring. As I said higher, holes in PCB needed to be enlarged. Banana plugs are crewed with nut and washes, contact was created with short wire through PCB. All components were re-soldered again, just in case. You never know, because speakers are more than 30 years old. All is soldered. Potentiometers cleaned with contactol, no cracking sounds anymore my dear comrades!
Of course I was playing with crossovers and other toys when I was waiting to wood filler dry out. I used dark wood filler in color of wallnut. It took me three days to fill it, sand it and again repeat it few times. I sand out entire vinyl. Plastic inserts went out in proper layer of wood filler insted. Oh dear, you don’t know how many scratches and holes was in the vinyl. The worse job was to do corners nicely. I was using sand paper in density 60 – 80 – 120 and 160 on some places. The yellow bricks are made of glass fiber and suppose to be inserted in mid-range speaker chamber..
I decide to repaint even back side of speakers. I do it properly if fiddle with something. Dark brown is same like original. I don’t have any garage, so gotta be done on the mini roof between houses. No excuses!
Boxes were drying out on the middle platform in stairs area. Entire house was smelly like acrylic paint. Neighbours must hate me now! Back side brown, and front cornes black, just in case I mess up vinyl laying.
So everything has dried out now. Every lover of National geographic will notice, that there’s no vinyl covered yet. I have used vinyl from D-C-FIX – MATT BLACK SELF-ADHESIVE VINYL 450mm roll /m front side and D-C-FIX WALNUT NATURAL SELF-ADHESIVE VINYL 450mm sides and top. Bought on eBay, search it there. Great quality vinyl.
I was quite scared to do any work with vinyl, because I’ve never done it before. It end up over all expectations. First walnut vinyl, from bottom, over side, then top, side and bottom again. All from one piece. I’ve ironed in the vinyl with wet cloth. All edges got sharp shape. Than matt black front side. After application of vinyl, I have cut edges with razor. Imperfection were masked with pencil.
Firs enclosure done. Now do the second and than put it all in.
I have stuffed top of the enclosuer with Monacor MDM-3 High-End Speaker Dampening, as I said before, it smells like kennel. The wool went in the top of enclosure, I’ve made sure not to suff bass port. Attached with staple gun. Speakers are benefiting from this, less and tighter bass. It was like cheapest sub from genius before tweek.
Crossovers waiting to pop in…
First went in crossover, attached with original screws. Maybe you wondering why marker pen? well… with my kind of OCD I can’t leave heads scratched, can I?