Author Topic: My Vintage Collection: Time for some Housekeeping - or not?  (Read 48818 times)

Offline Kent Kassler

Re: My Vintage Collection: Time for some Housekeeping - or not?
« Reply #270 on: July 10, 2017, 09:08:24 PM »
Those marvellous outputs in the 5-20's.....I have one and I search forever for another....
Audiophile Sound Sommelier Extraordinaire....aka Manic Depressive Temporary Void Filler Deluxe.

Offline Family_Dog

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Re: My Vintage Collection: Time for some Housekeeping - or not?
« Reply #271 on: July 11, 2017, 08:08:28 AM »
Kent, they do pop up for sale now and then. I built one for use as a PA system for a local brick company many, many, many years ago. They are no longer using it but no-one knows what happened to it and my efforts to locate it have been fruitless. It looked the same as the others in my collection and it could have made its way to you with pleasure had I located it.


-F_D



-Eric

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Offline Raj Nair

Re: My Vintage Collection: Time for some Housekeeping - or not?
« Reply #272 on: December 11, 2017, 07:08:39 AM »
painful to let go of such lovely equipment

Offline Chingy

Re: My Vintage Collection: Time for some Housekeeping - or not?
« Reply #273 on: December 11, 2017, 02:29:54 PM »
painful to let go of such lovely equipment
i can see something going to zero very soon.  :facepalm: :banned:
VA BW Pre, Tannoy Chevoits,Linn Kann, on Linn Stands,
Power trio (guitar, bass, and drums)

Offline Family_Dog

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Re: My Vintage Collection: Time for some Housekeeping - or not?
« Reply #274 on: January 01, 2018, 06:16:07 PM »
So this bad boy started misbehaving again - playing perfectly when set to the low-power position, but cutting out and going into protection when switched to high-power. In order to preserve the meter lights (expensive and snotty to replace), I normally run it in the 30w low-power mode which switches the lights off when running. The other day I wanted to show off the luvverly illuminated VU meters to someone and switched to high-power mode, and the lights came on displaying the true beauty of this magnificent beast. Five seconds later the amp went into protection mode. Back to low-power mode, runs perfectly. High-power mode - protection.



Opened it up and took bias measurements - all was fine. Unsoldered the 10k resistor which I had fitted to the input of the protection IC and the amp worked perfectly, all measurements were still in line. Left it on for four hours or so and took measurements again. Immediately noticeable was the left channel heatsink which was running hot, not too hot to touch, but much warmer than the right channel. Measured the voltage of the Bias settings control pot that controls the quiescent collector current of the output transistors and it was running very high at 65mV (should have been 15mV), resulting in the over-heating. So it had drifted. Resetting this to 12mV seems to have cured the problem. Not sure why it ran away like that, I guess one of the biasing trannies might be going wonky but it played fine at the high-power setting for something like 30 hours without going into protection mode again.

This is a magnificent amplifier but most certainly not the easiest one to work on.

Original restoration story here:
https://www.avforums.co.za/index.php/topic,38005.msg520223.html#msg520223


-F_D



-Eric

That Guy in South Africa...
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Online charles

Re: My Vintage Collection: Time for some Housekeeping - or not?
« Reply #275 on: January 01, 2018, 07:32:16 PM »
Congratulations finding the fault.

This is a magnificent power amplifier.

Offline Family_Dog

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Re: My Vintage Collection: Time for some Housekeeping - or not?
« Reply #276 on: January 01, 2018, 08:08:04 PM »
Thank you Charles, I *hope* I have found the fault this time! An intermittent fault is not easy to sort out but I am confident enough to close this up once more and find a place for it somewhere, not too much room left in my house for the various systems I am currently running, most of them vintage equipment.


-F_D



-Eric

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Offline Family_Dog

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Re: My Vintage Collection: Time for some Housekeeping - or not?
« Reply #277 on: January 08, 2018, 12:34:44 PM »
So this has been playing for about a week now, so far so good! I did find that it takes a good 30 minutes or so for the collector currents to stabilise, apparently quite normal for this amp and it is running cool with no problems (yet!).



The speakers are probably around 50 years old and all original including the crossovers. They are probably only rated at 20w or so - if! I have a pair of KEF Concertos which I was keen to try with the SE-A5 but as can be seen, space is at a premium. The B&O speakers would probably be better off standing on a pair of stands but the pointy ones I have will not do the woodwork any good at all.


-F_D



-Eric

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Offline El Sid

Re: My Vintage Collection: Time for some Housekeeping - or not?
« Reply #278 on: January 08, 2018, 01:42:57 PM »
FD - are those B&Os Beovox 2400/2600 or something else?

Offline Family_Dog

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Re: My Vintage Collection: Time for some Housekeeping - or not?
« Reply #279 on: January 08, 2018, 04:50:35 PM »
El Sid, these are Beovox 2600, I meant to mention this but forgot. I have various B&O speakers at hand and just grabbed these because I had already fitted wire pigtails on them, the others I have all require the 2p DIN plug connectors. I am keen to test them also with the Beovox S45 speakers I got from Andre a few years ago but I need to make up a DIN lead for them first. Think this will also make a nice combo.


-F_D



-Eric

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Offline HBAutomation

Re: My Vintage Collection: Time for some Housekeeping - or not?
« Reply #280 on: January 08, 2018, 05:35:02 PM »
@F_D-  your lounge resembles my lounge, office, bothe spare bedrooms and the master. Not to mention "our" rather convoluted "man cave".  :facepalm:
When You Come to a Fork in the Road, Take It!            [Yogi Berra]

Offline El Sid

Re: My Vintage Collection: Time for some Housekeeping - or not?
« Reply #281 on: January 08, 2018, 06:12:39 PM »
El Sid, these are Beovox 2600, I meant to mention this but forgot. I have various B&O speakers at hand and just grabbed these because I had already fitted wire pigtails on them, the others I have all require the 2p DIN plug connectors. I am keen to test them also with the Beovox S45 speakers I got from Andre a few years ago but I need to make up a DIN lead for them first. Think this will also make a nice combo.


-F_D

Ok then make sure you use the 30W mode when driving those!  ;D

Offline Family_Dog

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Re: My Vintage Collection: Time for some Housekeeping - or not?
« Reply #282 on: January 08, 2018, 07:39:54 PM »
@F_D-  your lounge resembles my lounge, office, bothe spare bedrooms and the master. Not to mention "our" rather convoluted "man cave".  :facepalm:

Yep. It's a crying shame that Architects have no clue on designing suitable lounges for us Vintage Audio lovers, there should be little nooks and crannies everywhere for us in which we can mount equipment. I have five systems running in that lounge, three in the other lounge, and we'll leave the HT room out of it - all the excess equipment is lovingly packed there.

I need a place like Nkandla, heard it may be on the market soon as the current owner might relocate to Dubai.


-F_D



-Eric

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Offline Family_Dog

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Re: My Vintage Collection: Time for some Housekeeping - or not?
« Reply #283 on: January 08, 2018, 07:41:50 PM »
Ok then make sure you use the 30W mode when driving those!  ;D

I do, but more to preserve the meter lamps than protect the speakers ;)

Fortunately 2-3 watts makes quite a good sound, no need to drive the amp more than this.


-F_D



-Eric

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Offline HBAutomation

Re: My Vintage Collection: Time for some Housekeeping - or not?
« Reply #284 on: January 08, 2018, 07:44:15 PM »
He he he...
When You Come to a Fork in the Road, Take It!            [Yogi Berra]