Insides of the venerable 1000/1 showing the main cap bank, the 8 shiny topped black bits. These are ‘SamYoung’ branded parts and after 5 plus years they are well past their best. Symptom is cutting out whenever the amp is cranked.

Original cap (black), bulging out the top like a Shoebury girl. New higher grade Cornell Dubilier part (blue) has better specs and shouldn’t need replacing again.

New parts fitted and bonded to the board. Typical power on one of these with the high grade cap bank is around 1150 – 1170 watts into 4, 3, 2 or 1.5 ohms at a current draw of 140 or so amps. We provide a 1 year fully comp warranty on these amps as the build quality is high.

Very tidy and well loved DM200 arrived this week. We’ve replaced the relays and caps, now it’s good for another 21 years faithful service. The front panel scratches are reflections of the worksurface, case has come up a treat with buffing, just like new.

Amp had a dead output, on these they are soldered 4 at a time onto a heat spreader. It’s possible to heat the spreader up and replace the outputs, as I’ve done on 30001′s before.

But it’s a lot easier to replace the old bank with a new factory fresh one. Bought a big box of Rockford parts from the previous service company and in there were several of the correct strips.

 Old strip removed and holes are in the process of being sucked clean of solder and leads. Main rail cap has a bulge like a teenagers shorts so will be replaced.

Mounting surface cleaned up, new thermal compound spread on it ready to fit the new module.

Module in place along with a brand new CDE cap, and another module replaced the same way. 1000w amp makes 1479 watts at 1 ohm. That’s the difference in buying a decent brand versus a cheap one. This amp will get a 12 month warranty as I know it will go the distance.

I’ve grown to really like working on these amps. They are well designed and reliable when repaired properly. There are a few common faults that come up as shown below, but overall I feel it’s a well designed product.

Fried output coil, one of 7 strands has shorted and got hot enough to fry the insulation. This needs to be unwound and completely rewound with new wire. It’s a bit of a tedious job but satisfying when the amp works again.

Thermal pads on bottom plate, vibration has caused the coil from the previous pic to short onto the base. We add Kapton tape and new pads so it won’t short out in future.

Pic of a cap that’s been vibrated off the board. Yellow marking is from arcing where the broken lead was making then not making contact and arcing and is vapourised metal.

New caps vs old, we can even uprate them with new EPCOS parts.

Input socket vibrated to death, missing 5 of it’s 8 connections. 4 Shiny Neutrik sockets fastened to the front plate and wired with flexible leads sorts this out very nicely.

This endplate is from an SPLD D5 but you get the idea. I believe D5000 amps are definitely worth repairing so much so that we are happy to offer a 3 month fully comprehensive warranty on any we sort out.

Bias mods to a Continuum, absolutely necessary if the bias is to be set into Class A. The sensor now measures the output device temperature, not the heatsink, and therefore responds around 200 x faster to changes. Without this mod the outputs overheat.

Pile of switches from two 705′s and a Continuum. These were very low quality and I change them as a matter of course as they will fail at some point, it’s just a matter of when. Shafts get replaced with metal parts that fit properly.

Crappy OE switch on the left, quality branded part on the right. Price differential is around 8 times which is probably why SS went for the el cheapo option.

Main board now has new switches, uprated rail caps, upgraded preamp chips, bias adjusters, new control shafts, gain mods so it can be used with horns. More to follow next week.

The casing has a sheet of Polyamide / kapton to insulate the power devices but let the heat into the heatsink. When we increase the bias on the front channels we need a thermally better interface, so the Kapton sheet is removed where the 4 channel outputs go.

Board is now ready to fit into the chassis. Special Boron Nitride filled insulators are fitted to the 4ch outputs, and thermal compound to all the other parts.

Channels 3&4 set up for the horns. Sensitivity has been dropped so they don’t play too loud, and distortion is very low. With horns being so efficient 1 watt will be very loud, typically 105dB.

Distortion residual is clean.

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As promised, this is a standard Continuum straight out of the box, just as it arrived. Distortion is ball park for a SS reference series amp. Compare with the modified result though reduced by approx 92%

This shows the jagged distortion residual caused by underbiased outputs in the stock amp. The output stage biasing modifications detailed above all need to be done so this can be virtually eliminated. Picture taken at the same settings as above.

 Our first P15 service

After replacing the red/blue LED’s under the tubes, new thermal gap filler was applied to the preamp board. This like many things in Essex is slightly tacky, and will stick to the baseplate when the board is back in position

NOS preamp tubes were fitted in place of the Russian parts fitted originally. These are tested for low noise and microphonics. These are pre-1971 production as the price on the box was in Shillings…

The high voltage supply in one channel was low, so some components were replaced to bring it back up to spec of 300 volts +/- 1 volt. All the other voltages were checked and were well within spec as was power and other specs.

Moody ‘night shot’ of the illumination on the laser etched top logo. These mostly get seen at brightly lit shows however look their best in adarkened boot. As well as sounding gorgeously smooth and detailed. Not that I’m biased you understand.