On My Bench.

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Dave the bass
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#16 Re: On My Bench.

Post by Dave the bass »

Well a few days later and after a lot of soak-testing the amp still behaves, I now do think the fault was related to the amount of flux on the board.

I needed to replace a nasty corroded/leaky cap on the base PCB in the GP11 pre-amp, cruddy...
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Messy job but lovely and clean now...
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Soak tested again, lid back on and its done. Hooray. I keep playing through this amp (to test it natch...), its lovely.
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Sorted, owner informed, ready for collection.
"The fat bourgeois and his doppelganger"
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andrew Ivimey
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#17 Re: On My Bench.

Post by andrew Ivimey »

Next!👍
Philosophers have only interpreted the world - the point, however, is to change it. No it isn't ... maybe we should leave it alone for a while.
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Dave the bass
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#18 Re: On My Bench.

Post by Dave the bass »

andrew Ivimey wrote: ↑Wed Dec 20, 2023 10:15 pm Next!👍
Well, s'funny you should say that. This time it's a repair for me, I think its summat you've got experiences of.

Refoaming the surrounds on a pair loudspeakers?
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andrew Ivimey
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#19 Re: On My Bench.

Post by andrew Ivimey »

Yep. It's best to practice on a pair of Lowthers - screams with hysteria. Perished felt surrounds yuk - two pairs of HPDs from South Norwood and three ESS 12 Inch brutes success tho' the first pair of Tannoys looked a dogs dinner as I got glue all over my fingers and 'pressed on' regardless. I also did a pair of 41/2 inch rubber surrounds that I wasn't proud of aesthetically but the cones looked straight with no rubbing so...

Remove all debris, down to the metal - be scrupulous. Practice with the surround on place and look how the old cone sits naturally- deep breath and onwards! The PVA looking glue sticks well on a couple of minutes so you can press things home before it gets too stuck. The rubber surrounds had some other glue that reminded me (smell( of evistick dunno, wrong colour, sticks fast - bit of a messy look.

Lock woods sold me an HPD kit of new speaker cones. That was obviously much easier! I survived. Good luck!
Philosophers have only interpreted the world - the point, however, is to change it. No it isn't ... maybe we should leave it alone for a while.
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Dave the bass
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#20 Re: On My Bench.

Post by Dave the bass »

Ta for the words of guidance and experience MrI <thumbs up plus wun etc etc>.

Seeing as the naughty Peavey Amp melted the voice coils in the bass/mid units of my cheap 90's 'Gale' test bench speakers I need to resurrect their predecessors from a long time ago, a pair of RCF Monitor 4. I really liked these a lot, they were nice sounding and fitted awethumnley on the ends of the work bench. However, they developed a weird resonance over the years, seeing as I had the Gales in reserve I just put the RCFs in the loft (the best place of course for storing loudspeakers) which probably hasn't helped the cause.

Yesterday I started investigations, I use them upside down, tweeter at the bottom as that aligns with my ears and I think they sound best that way in this near-field application...
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Aha!
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Erks.
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Meaty but small beasts...
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Needs TLC...
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I've ordered this kit, it seems closest to whats there -> https://www.ebay.co.uk/itm/325245684993 There's a rubber version available too but I thought it best to change like for like perhaps?

Onwards, I hope.
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Mike H
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#21 Re: On My Bench.

Post by Mike H »

Re Trace Elliot -

Oo, rainbow coloured ribbon cable. I've still got some somewhere. And colour band coded polyester caps. And those smaller brown ones that might have once had 'RS' printed on 'em, back when RS put their own logo on things, and you couldn't buy directly from them if you weren't a business. But I'd mail order comps from other businesses, and sometimes they had 'RS' on.

Trivial fun fact of the day.
 
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Dave the bass
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#22 Re: On My Bench.

Post by Dave the bass »

The kit has come to replace the foam surrounds on the RCF speakers.

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Speaker out, the foam is sticky to the touch and crumbling apart, very messy and difficult to clean up but Isopropyl Alcohol dissolves the adhesive and foam muck.

An hour or so later...
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On with the inner lip using the supplied adhesive...
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Whahey, wait for an hour, then do the surround to frame bond...
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I used the speaker baffle to clamp the new surround to the frame...
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Then wait another hour before bolting the cabinet together and testing, then repeat again for the 2nd speaker.

This time some of the foam surround stayed stuck to the inside of the cabinet, yucky and sticky again.
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Results at the end of todays play? Blimey, they both appear to work again 8)
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pre65
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#23 Re: On My Bench.

Post by pre65 »

I doff my cap to you dear boy, well done.

Cq, Cq, Cq, can you hear me ? :lol:
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Mike H
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#24 Re: On My Bench.

Post by Mike H »

Impressive!
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I had rubber surround drivers I bought in 1984, 2 of them were Audax woofers speshly acquired through Mapiln, who'd I'd just joined the ranks of, they were samples that had been 'doing the rounds' of suppliers in the UK, but none of them was interested in. I.e., remained unique (within the UK). :D

Also Peerless midranges, all 4 drivers' surrounds had perished couple of decades later. :(
Last edited by Mike H on Sat Dec 23, 2023 10:19 pm, edited 1 time in total.
 
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Nick
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#25 Re: On My Bench.

Post by Nick »

back when RS put their own logo on things, and you couldn't buy directly from them if you weren't a business.
And if I remember correctly, a entire ecosystem of businesses started to buy parts from RS and make them available to readers of the electronic magazine who wanted to build the projects.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
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Mike H
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#26 Re: On My Bench.

Post by Mike H »

Natch! :D

You might possibly, as a privateer, have created your own 'business' and designed a letter head to prove it, but I didn't try that. :D
 
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Dave the bass
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#27 Re: On My Bench.

Post by Dave the bass »

Afternoon all.

I've got a pair of DC-DC convertors on my bench, they came from an old AV project a chum was involved with. Its been dismantled and scrapped so these were going to be binned, I snaffled them just because I've never used anything like them before.

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One is faulty so I've started fault finding and found a XL4016E shorted between 2 pins....
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Has anyone ever had any joy using somethinkg like this for DHT filament supplies? I'm just wondering if its worth repairing for a future audio project (shock horror!)?

Thoughts, comments, etc etc etc?
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Mike H
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#28 Re: On My Bench.

Post by Mike H »

Has anyone ever had any joy using somethinkg like this for DHT filament supplies?
Joy, not yet, thought about, frequently. :D

Did occur to me you want soft-start or series resistor in case filaments can't take the 'Voltage shock' at switch-on. I've lost Russian (Svetlana) 300B's like that. :(

E.g. one idea is 12V DC converter followed by resistor for 7.5V for 801A.
 
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Mike H
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#29 Re: On My Bench.

Post by Mike H »

What's the background in photos, is it a mat?
 
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Ray P
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#30 Re: On My Bench.

Post by Ray P »

Mike H wrote: ↑Mon Jan 15, 2024 1:52 am What's the background in photos, is it a mat?
Pretty sure it's one of these Mike. I use this sort of mat quite a lot for various DIY activities, th polymer is really grippy but also nice and soft.

https://amzn.eu/d/9Y2AqhF
Sorry, I couldn't resist!
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