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Courtiestown - Naim Amplifier (Avondale) Upgrade Project

Good afternoon all,

Well I changed out the standard CAP6's for the ones I modified to fit the new AA SMD Schottky FWBR's.

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I have two near identical 'C' cored amplifiers albeit one is 350VA and the other 500VA. I replaced the CAP6's in the 350VA fitted amplifier simply because the change out could be achieved without removing the amplifier boards themselves.

The test system was my M1 MacBook using Tidal out of the headphone socket via 2off Linn Silver RCA cables and feeding a pair of Linn Kan2's via vdH speaker cable. This isn't ideal but the best analogue system I can 'cobble' together.

The two test tracks were Nils Lofgren's 'Keith don't Go' and the Bombay Dub Orchestra 'Egypt in the Air'.

I had to listen to both tracks twice on both amplifiers.

There were 'indications' that there was greater separation and more ringing from the sound of plucked strings on the Nils Lofgren on the 350VA/ modified CAP6 amplifier . TBH it wasn't a 'night and day' thing with this track.

The 'telling track' was the Bombay Dub Orchestra. This is quite bass heavy but also has layers of detail. You would expect the 500VA equipped amplifier might have the edge BUT undeniably the 350VA equipped amplifier was processing the whole track in a much more detailed and revealing way.

Regards

Richard
 
Good afternoon all,

Tea break time here at Courtiestown and another pair of AA SMD FWBR equipped CAP6's ready to go:-

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I will also be fitting/ trialling the new pattern CAP6/ Minicap with integral SMD's shortly.

I'll be dragging the other 'C' core amplifier off its shelf shortly.........

Regards

Richard
 
This will be interest to see ( hear) if it is better.

Nice one Richard , I’m sure you’ll keep us posted….😀
 
Good afternoon all,

OK so both transformer bases show evidence of being dropped. They were very well packaged and no sign of damage to the box so one has to assume this happened at the factory.

One had been 'dropped' (or similar impact) with sufficient force to dislodge the core and retention clamps. I have dismantled the clamps, relocated the core, re-crimped the clamps and re-attached.

The bases have been bent near straight in the vice.

Electrically they give out 45.9, 40.7 and 25.4V with our regular 243V input so no issues there i.e. not a million miles out from the current Canterbury toroids or ETC EI jobbies.

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The one downside is that there is clearly mechanical noise and given both cores are clamped as I believe the manufacturer intended this is a bit disappointing. I intend installing said transformers on cushioning and I'll see what the noise level is like when installed. I can always remove the crimped/ clamp ends and make them less 'tight' and see what effect that has.

I'd give these transformers somewhere near a 5 out of 10 currently BUT the mechanical noise is on a par with the ETC devices I kept and I have yet to install them and listen.

This upgrade will also feature the latest versions of AA CAP6 and Minicap's.

Regards

Richard
 
Just about your cushioning point Richard. I took to adding a couple of thin rubber washers under each of the four mounting points of the transformers in the Radford amps I rebuilt . I also did the same for the mounts of my Paradise PSU's transformers. They are all completely silent and I know a couple of the Radford transformers did hum previously.
 
Good evening all,

Making good progress before Kate comes back from work and equine things take priority!

As it was - the unmarked toroid is an HN15 specification jobbie that Terry built for himself.

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A comparison between the new and old AA PSU's:-

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Rebuilt and almost ready to go back in the case:-

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Next up is soldering M4 ring terminals to the transformers earth leads and securing the connector block and re-attaching the M4 earthing point.

I'm hoping to get this completed tomorrow.

Regards

Richard
 
Good morning all,

I've had a reply to an EM I sent to James Transformers indicating the state that the transformers arrived in along with supporting photographs. This is their reply:-

We are sorry to hear that. That happens. The frames are easily bent during transport. These problems occured before. We definitely don't want to transport a dammaged one to you.

This clearly suggests they know there is a problem. I'm not going to argue with them but given the way these things are packed I wouldn't expect to see any damage let alone the force required to dislodge the core:-

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I'm no expert but the end shows signs of having impacted on something and this photograph shows the core having been dislodged.

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I'll focus on rejigging the wiring and get this amplifier running today.

I'll also be posting the AA PSU's for sale here and on eBay and, hopefully, the transformer after a listening session.

Regards

Richard
 
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