"Holy rusted metal, Batman!"      Dick Grayson/ Robin, Batman Forever

I'm going through a make and mend exercise... lot's of things breaking all at once!

"You’re about to become compost."       Barbara Gordon/Batgirl, Batman & Robin

Preamp - Audio Note Line M2, 18years in my system and has been a brilliant heart for it. Gone to the Batcave for a bit of TLC. Batman responded with the below.

1) Lots of mice poop inside unfortunately - definitely no-way a rodent could get in there so must have dropped through the top grill - poop not a big issue usually but the likelihood of pee certainly can be. I will de-solder and completely remove both boards and do a thorough scrub to remove any residue and check for any corrosion around component leads etc......
2) Several power supply electro caps are reading well below their intended value - totally normal given the age and the caps used at the time. I recommend doing all 7 in the power supply while the board is on the workbench, none of these are particularly expensive.
3) The BlackGate caps on the audio board test ok but have seen a lot of heat as these are situated very close to the audio tube. If it were me I'd definitely replace these, but with Nichicon Muse variety for sound quality and reliability. Your call here - the BlackGate capacitors have a lot of mystique so you may want to retain them. (these particular ones have not been manufactured for some time).
4) The selector switch is encapsulated in this version of the M2 so very difficult to clean - I'll do my best but might be best to fit a replacement - Last time I checked a suitable replacement can be got in NZ quite easily.
5) Lastly, quite a few solder joints look tired, this may just be dust and dirt and age but I will re-flow the obvious ones to be on the safe-side.

I accepted all of these! However Batman tried the Nichicon Muse caps and reverted back to the BlackGates as they had a better sound - testament to the quality of build and design. So all fixed and working beautifully!

 

"That’s one trouble with dual identities, Robin. Dual responsibilities."        Bruce Wayne/Batman, Batman (TV series)

However the repair highlighted a bit of an issue with that lovely phono stage I got from Beeman. The right-hand channel is failing... So that too will go off to be fixed!

Proof of right channel?

Turn on,
Queue up record
Listen - most signal on left hand side.
Turn off
Switch tone arm leads (+/-) on inputs of phono stage.
Turn on
queue up
sound remains where it is (not the cart, therefore)
Turn off
restore original tone arm leads.
Switch phono stage leads to preamp (+/-)
Turn on
queue up
Sounds move to right hand speaker. (phono stage has the issue)

Check not preamp by switching to alternative source (my Sparky streamer) and no issue

Check not cable (switch cables to Sparky and no issue.

"The bat-signal is not a beeper."       Bruce Wayne/Batman, Batman Forever

My left hand-speakers mid-range unit, an Audax HM130C0, is also failing! Nasty resonance buzzing sounds when in full flight. The voice coil is rubbing against the magnet as you can hear it doing so when turned off and a bit of pressure applied to the cone.

Cost to recone a single driver? Don't care. Cost for a new pair NZ$400 - no brainer and they are winging their way to me, courtesy of Madisound.

Phew!

“For once I’m stuck without a punchline.”       The Joker, Batman: Mask of the Phantasm

Electrolytic caps - if they're not high voltage rated, I'd recommend Elna Silmic - I think a few others here would endorse.
Nichicon Muse are OK, more for SS ccts I feel.

ANote UK used to sell Blk Gates
If you want any (to keep the M2 authentic), I have a small stash, some new, original - let me know values req'd.
I've built ANUK linestage ccts before, I should have the M2 schematic somewhere - I expect you'd need something like 16-50v cathode bypass caps, 47/100/220uF maybe.

DarkLantern blog - darklanternforowen.wordpress.com

That's a lot of excitement !

Will need a cup of cocoa and a lie-down after that lot.

Who is this Batman ?

Id be asking the Q as to why you have mice running about on the top of your preamp ? Maybe time to get a cat ?

OK, Batman is named Brass - maybe I should have called him Count Brass...

I have two cats - both catch rats and mice. I did have the lid off the preamp for a month, so maybe that's where the poop came from.

I've given the cats a good talking to, however they pointed out that they do not want to be that Cat on a Hot Tin Roof!

The experience of a pal of mine. who (once) had his HT floor-shaker amp under the floor, was that mouse pee is the problem, not mouse poop

I'd still light a fire under those cats

DarkLantern blog - darklanternforowen.wordpress.com

Fire lit - although with the number of valves and the heat they generate!

Denon phonostage into the batcave this weekend.

My replacement speaker driver should arrive next week

Sigh - I am blind! The phono stage has two inputs depending on the cartridge (MC or MM) and... AND a pair of switches as well to switch between them. Righto, this is the blind bit. I broke it down to take to the Batcave and it was only then I realised that the switches were not facing in the same direction.

Click! Problem solved.

You can also get Black Gates from Hifi Collective.
www.hificollective.co.uk/search/site?title=black%20gate

Not cheap but its probably worth replacing like for like to preserve the original sound profile.

Hahaha Jon that is a happy ending story. Hows the Audio Note sounding

Singing fabulously

My replacement hm130c0 are due tomorrow...

I forgot...

Thanks to you all for the blackgate offers. I will be following up sooooon! First step take the M2 apart and check the values.

And in. It's the midrange unit... wonderful.

Just in time for SWMBO's birthday party.

I'm making pastrami and bagels...

HM130CO is a great driver, I used them in the 90s after hearing them in some Gershman Acousitcs speakers at the Las Vegas CES.

AMR-iFi R&D

The WAD KLS3 puts it into it's own closed box and I think Noel Keywood was very clever in doing so.

Right so now I'm thinking I might replace the old and aging Audax HM210C0 with a new pair.

Available here: www.nonsolospeakers.com/8-20cm/3521-audax-hm210c0-210mm-midwoofer-hda-8-ohm.html