View Full Version : Can anyone source one of these for me please?
(the LED not the metal housing)
http://i434.photobucket.com/albums/qq61/gazjamster/20150416_1350392.jpg (http://s434.photobucket.com/user/gazjamster/media/20150416_1350392.jpg.html)
Densen Preamp on its way back from service/recapping from factory in Denmark, dropped the LED on my kitchen floor and there's a chance it could be broke.
Might not be, just shoring up a Plan B.
Its a 3mm LED easy to get, but is there an example you can get with the 6mm plastic surround?
This is what makes it fit properly into the metal housing, which in turn locks into the acrylic front panel.
Can always build up heatshrink to suit, but its the varying diameter of the plastic surround that locks it in place.
Could be a bespoke Densen item (which they don't do any more) and I'll just need to work around it if I have to, but wanted to ask here too.
Thanks Guys. :)
You may be able to reuse the surround if the worst has happened. chances are its ok. what voltage is it?
The Barbarian
16-04-2015, 21:29
Looks like it serves no special purpose apart from a snug fit in the brass insert & that it covers the LED Pins that are soldered on the wires.There might even be the resistor in there wired in line with the LED's anode leg.
Audio Advent
16-04-2015, 23:43
Drop it from the Empire State building and I'd wager nothing would go wrong with it, if you could find it afterwards.
LEDs are available everywhere in all sorts of sizes and voltage requirements. Don't bother going to any effort finding a replacement until you make the unlikely discovery it doesn't work.
EDIT: I didn't read the O/P fully... but even if you had to replace the LED, can't you just remove the actual LED from the housing and slide a new one in with wires attached, so it would still only be the LED to replace?
Firebottle
17-04-2015, 06:37
Wot Sam said.
If there is a resistor within the black housing you could test the LED with a battery, minimum 3V to make it light up.
If you can't see if there is a resistor temporarily connect one of a few hundred ohms then connect to the battery. The LED will light one way around only.
:cool: Alan
Thanks all,
Just figured it was very fragile and assumed the worst.
Good to know these things aren't that breakable.
The plastic surround seems to be moulded around the LED.
Worse case, I can get a 3mm LED and build up around it with heat shrink to suit.
Just wondered if you could get them with the plastic surround as a standard part.
Wait and see what happens when the amp gets here.
Cheers.
Light Dependant Resistor
17-04-2015, 07:40
LED's are a light emitting diode, they have two terminals one called the anode, the anode can be recognized looking into the red plastic as
the smaller section and the cathode as the larger. legs then lead out for each. if brand new the anode is the longer leg, and in doubt trace back
to find the smaller section anode.
The LED following the dropping current resistor that arranges current delivery, being red and of this early style design will have a forward voltage of approx 1.8 volts
( the very early LED's from the 1970's the first I saw being in the Quad 405 has a forward voltage of 1.6v ) The one you have here
is a very common part. The modern ones now have clear plastic and are much brighter and their forward voltage has crept up to about 2.1v
Hidden inside the black rubber is a resistor to drop current, A typical arrangement would be to have 1200 ohms supplied by 12 volts = 10ma
LED's do not like going over 20ma so 600 ohms with 12 volts is about the maximum resistance ( although they exhibit less noise when biased on like this )
so you can test your LED connecting it to a 12 volt source - if it has a red wire and a black wire red is positive and black is ground connect these appropriately it should light up.
10ma is a good value to work with. Modern clear LED's have gone somewhat silly with brightness and require much larger dropping resistors, and 15-20k
is common.
http://en.wikipedia.org/wiki/LED_circuit
LED's in audio circuitry require added care as they are noise generators, one of the best circuits to use them with is a fixed voltage regulator
where the regulator supplies its reference voltage, the ground pin of the regulator being connected to the LED anode, the output of the
regulator has resistance calculated by in the case of a 7805, 5v so 5/500R = 10ma, placed between the output and the ground leg.
If using a Vref circuit like this try not to exceed more than 20v as the input voltage as the regulator is being tasked and asked to drop approx 17.9v with modern LED's
One of the best LED's to use is a Infra Red ( non visible light ) if placed and used as a voltage reference, they exhibit the least noise.
http://www.diyaudio.com/forums/parts/35821-some-noise-measurements-leds-zener-diodes.html
Cheers / Chris
Great info Chris, thanks very much.
Tested it using the diode setting on my (cheap) multimeter and it didn't light up, hence wondering if its knackered.
Read about though, all meters don't provide enough juice to do the test properly, so discounted that.
Just need to wait and see when the amp comes. :)
The Barbarian
17-04-2015, 12:37
LED's are a light emitting diode, they have two terminals one called the anode, the anode can be recognized looking into the red plastic as
the smaller section and the cathode as the larger. legs then lead out for each. if brand new the anode is the longer leg, and in doubt trace back
to find the smaller section anode.
Hidden inside the black rubber is a resist
Cheers / Chris
Cheers Chris for not reading my post :rolleyes:
Cheers Chris for not reading my post :rolleyes:
Sorry, what did you say? :D
Audio Advent
18-04-2015, 15:00
Cheers Chris for not reading my post :rolleyes:
His post was completely different and went into tech details of LEDs and how Denson may be connecting them. Without repeating some bits you said, his post wouldn't make sense and cross-referencing to yours would have been equally nonsensical :scratch:
Audio Advent
18-04-2015, 15:02
[QUOTE=Gazjam;640116Good to know these things aren't that breakable.
The plastic surround seems to be moulded around the LED.
[/QUOTE]
I'd doubt it was - would be too bespoke to be worth the bother. I'd say it's just a tight fit or there's a one-way clip which holds the standard LED in place.
The Barbarian
18-04-2015, 15:08
What eva :rolleyes:
Well, I've good news and good news.
Preamp came back from hospital in Denmark and I tried the LED.
Its fine, survived the rapid descent to my kitchen floor.
All good. :)
337alant
20-04-2015, 16:58
Well thats a relief :rolleyes:
Plenty of LED bezels here if you fancy a change
Alan
Well, I've good news and good news.
Preamp came back from hospital in Denmark and I tried the LED.
Its fine, survived the rapid descent to my kitchen floor.
All good. :)
:worthless::D
Audio Advent
20-04-2015, 19:15
What eva :rolleyes:
Ever the drama queen.
Audio Advent
20-04-2015, 19:17
Well, I've good news and good news.
Preamp came back from hospital in Denmark and I tried the LED.
Its fine, survived the rapid descent to my kitchen floor.
All good. :)
Hope they appreciated your polishing!
Amp rebuilt and about to plumb her in...so glad I went to the effort of losing 3 days and 30% mobility in my right wrist to polish the frontplate up.
Looks SO much better than it did last time it was assembled.
Some pics for now:
http://i434.photobucket.com/albums/qq61/gazjamster/Kit%20pics/Densen%20polish/20150420_192159.jpg (http://s434.photobucket.com/user/gazjamster/media/Kit%20pics/Densen%20polish/20150420_192159.jpg.html)
http://i434.photobucket.com/albums/qq61/gazjamster/Kit%20pics/Densen%20polish/20150420_192319.jpg (http://s434.photobucket.com/user/gazjamster/media/Kit%20pics/Densen%20polish/20150420_192319.jpg.html)20pics/Densen%20polish/20150420_194836.jpg[/IMG][/URL]
http://i434.photobucket.com/albums/qq61/gazjamster/Kit%20pics/Densen%20polish/20150420_194731.jpg (http://s434.photobucket.com/user/gazjamster/media/Kit%20pics/Densen%20polish/20150420_194731.jpg.html)
Well thats a relief :rolleyes:
Plenty of LED bezels here if you fancy a change
Alan
It is to me..phew!
Major pain in the arse if it was broke.
Amp rebuilt and about to plumb her in...so glad I went to the effort of losing 3 days and 30% mobility in my right wrist to polish the frontplate up.
Looks SO much better than it did last time it was assembled.
Some pics for now:
http://i434.photobucket.com/albums/qq61/gazjamster/Kit%20pics/Densen%20polish/20150420_192159.jpg (http://s434.photobucket.com/user/gazjamster/media/Kit%20pics/Densen%20polish/20150420_192159.jpg.html)
http://i434.photobucket.com/albums/qq61/gazjamster/Kit%20pics/Densen%20polish/20150420_192319.jpg (http://s434.photobucket.com/user/gazjamster/media/Kit%20pics/Densen%20polish/20150420_192319.jpg.html)20pics/Densen%20polish/20150420_194836.jpg[/IMG][/URL]
http://i434.photobucket.com/albums/qq61/gazjamster/Kit%20pics/Densen%20polish/20150420_194731.jpg (http://s434.photobucket.com/user/gazjamster/media/Kit%20pics/Densen%20polish/20150420_194731.jpg.html)
Lots of Caps in there Gary. Looking good. :)
Canetoad
21-04-2015, 03:32
What big knobs you have there Gary! :stalks:
Seriously though, great job! It now looks brand new! :)
Lots of Caps in there Gary. Looking good. :)
Yeah, Densens own too. Dual mono design which I hadn't realised before.
http://i434.photobucket.com/albums/qq61/gazjamster/Kit%20pics/Densen%20polish/20150420_162137.jpg (http://s434.photobucket.com/user/gazjamster/media/Kit%20pics/Densen%20polish/20150420_162137.jpg.html)
New caps, volume pot and input selector. New transformers as well. Noticed quite a lot of the resistors have been swapped out too.
So pretty much new inside and out, I'm a happy bunny.
Just the new power amp to slot in and that's my journey complete, apart from a tonearm upgrade later on.
Playing some music this morning...Good gawd :eek: .
http://i434.photobucket.com/albums/qq61/gazjamster/Kit%20pics/Densen%20polish/20150421_091359.jpg (http://s434.photobucket.com/user/gazjamster/media/Kit%20pics/Densen%20polish/20150421_091359.jpg.html)
What big knobs you have there Gary! :stalks:
Seriously though, great job! It now looks brand new! :)
Cheers Bernie, sounding pretty good as well.
The music will keep me warm in the cold Scottish evenings :)
The Black Adder
21-04-2015, 09:39
Ooooooh-ho!
Very nice... I had the DM-10 MKII back in 09/10 - A beautiful integrated... Love the design too. Wouldn't mind another one to be honest.
I feel that these older Densen's have something over the new types... Great sound.
An it's looking smashing!!!
orbscure
21-04-2015, 09:52
Cheers Bernie, sounding pretty good as well.
What was the ball part figure spent in the end Gaz and what was their turn around? My DM20 is sat on my rack and once the JBL4311's are back from Paul/RFC, as you know from our PM discussions, I plan to send mine across the North Sea for an "overhaul" too...
Yeah, Densens own too. Dual mono design which I hadn't realised before.
http://i434.photobucket.com/albums/qq61/gazjamster/Kit%20pics/Densen%20polish/20150420_162137.jpg (http://s434.photobucket.com/user/gazjamster/media/Kit%20pics/Densen%20polish/20150420_162137.jpg.html)
New caps, volume pot and input selector. New transformers as well. Noticed quite a lot of the resistors have been swapped out too.
So pretty much new inside and out, I'm a happy bunny.
Just the new power amp to slot in and that's my journey complete, apart from a tonearm upgrade later on.
Playing some music this morning...Good gawd :eek: .
http://i434.photobucket.com/albums/qq61/gazjamster/Kit%20pics/Densen%20polish/20150421_091359.jpg (http://s434.photobucket.com/user/gazjamster/media/Kit%20pics/Densen%20polish/20150421_091359.jpg.html)
great stuff mate...your system will soon sound as good as mine :rfl::rfl::rfl:
have a dance on me :dance:
Audio Advent
21-04-2015, 15:24
It does look fantastic! Love the gold and black acrylic look.
There is one problem with that though... having to employ this guy to turn the knobs..
http://www.jurgengruson.com/assets/elementen/snooker_ref.jpg
But hope you don't come home to find this!
http://operachic.typepad.com/photos/uncategorized/cass3s.jpg
Firebottle
21-04-2015, 15:51
Looks absolutely stunning Gaz, almost goes without saying that the sound will match.
Well done that man :youtheman:
:) Alan
337alant
22-04-2015, 06:26
Yes a beautiful looking Pre amp Gaz :eyebrows:
Looks like your Selecta switch needs to be reconnected in the photo
cant see anything in the way of a pre amplification components in there? just a nice DM power supply, is there a lot of SMT stuff under the board?
Alan
Fine looking system my friend.
Bet it's doing the job.
Ali Tait
22-04-2015, 08:35
Yes a beautiful looking Pre amp Gaz :eyebrows:
Looks like your Selecta switch needs to be reconnected in the photo
cant see anything in the way of a pre amplification components in there? just a nice DM power supply, is there a lot of SMT stuff under the board?
Alan
My thought too. Looks good mate, fancy bringing it over sometime?
:lol:
It does look fantastic! Love the gold and black acrylic look.
There is one problem with that though... having to employ this guy to turn the knobs..
http://www.jurgengruson.com/assets/elementen/snooker_ref.jpg
But hope you don't come home to find this!
http://operachic.typepad.com/photos/uncategorized/cass3s.jpg
Thanks Alan,
Systems getting there, almost done.
Could you expand a bit on the selector switch thing and the lack of components?
Interested as selector is working perfect.
Maybe just an unusual design...wonder if Densen did things differently design wise from other companies back in the day?
As far as I can see there's no SM components under the board, just what's on the top.
Densen talk about their "zero feedback" design, so there's no feedback loop circuitry in there.
Is that the kind of thing you'd be looking for?
There's not an awful lot to it internally, but knowing next to nowt about amp design I put it down to it just being the circuit!
Thanks. :)
Yes a beautiful looking Pre amp Gaz :eyebrows:
Looks like your Selecta switch needs to be reconnected in the photo
cant see anything in the way of a pre amplification components in there? just a nice DM power supply, is there a lot of SMT stuff under the board?
Alan
Thanks guys for that,
Yup she's a bit of a looker now its all polished up.
No problem bringing it over Ali, but I'm without the car for a while.
When I get the 300B Set power amp in and settled I'll be having the troops over for another board meeting. :)
wiicrackpot
22-04-2015, 11:35
Thats gorgeous, it's got that sumptuous look about it which Scandinavian manufacturers do well,
is that Blu Tac i see on the IEC socket and under the circuit board?. :scratch:
Thats gorgeous, it's got that sumptuous look about it which Scandinavian manufacturers do well,
is that Blu Tac i see on the IEC socket and under the circuit board?. :scratch:
No mate,
Its my audiophile grade resonance dampening compound. :lol:
Been messing about with different builds for my servers and found I could get a slight improvment dampening the PCB board, mad I know but its there to be heard.
The IEC socket had a bit of movement so dampened it with blutack.
Also thought I'd do the same with the pcb on the amp, it sits on plastic risers and there was a bit of movement with the board sitting on the pegs.
Blutak took care of that.
A bit Heath Robinson I know, but its inside the case and every little helps.
337alant
22-04-2015, 18:59
Thanks Alan,
Systems getting there, almost done.
Could you expand a bit on the selector switch thing and the lack of components?
Interested as selector is working perfect.
Maybe just an unusual design...wonder if Densen did things differently design wise from other companies back in the day?
As far as I can see there's no SM components under the board, just what's on the top.
Densen talk about their "zero feedback" design, so there's no feedback loop circuitry in there.
Is that the kind of thing you'd be looking for?
There's not an awful lot to it internally, but knowing next to nowt about amp design I put it down to it just being the circuit!
Thanks. :)
Hi Gaz
On the selector switch the box at the end of the remote cable needs to be connected to a sliding switch on the circuit board but I cant see where it goes just looks unusual at an angle like that and so close to those resistors
When you operate the switch is it actually changing the source?
In a Pre amp there is normally a buffer stage and an amplification stage in the form of discrete components op amps or a chip but I dont see any of them so just curious what the power supply is feeding?.
Im sure Ali will sus it out when he gets her top off :D
Alan
Ali Tait
22-04-2015, 19:17
Always like getting her top off.. :-)
Source changes no problem Alan, all working perfect.
I suspect some clever out of the box design from Densen, defo no SM components under the board.
Just a guess though!
Hi Gaz
On the selector switch the box at the end of the remote cable needs to be connected to a sliding switch on the circuit board but I cant see where it goes just looks unusual at an angle like that and so close to those resistors
When you operate the switch is it actually changing the source?
In a Pre amp there is normally a buffer stage and an amplification stage in the form of discrete components op amps or a chip but I dont see any of them so just curious what the power supply is feeding?.
Im sure Ali will sus it out when he gets her top off :D
Alan
Firebottle
23-04-2015, 06:42
Gaz, does the Denson have any gain? From what I can see it looks like a v. high quality FET buffer stage.
:) Alan
No idea Alan, All I know is about the
zero feedback circuit and it gets louder when you turn it up!
Subjectivly,
It goes a LOT louder than the Beresford Capella as preamp I had on loan before.
Powered by vBulletin® Version 4.2.3 Copyright © 2024 vBulletin Solutions, Inc. All rights reserved.