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PostPosted: 12 Oct 2010, 10:53 
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Joined: 22 Jun 2010, 13:30
Posts: 66
they dont need to glow up all the parts
the 4 dots you see are the fillaments inside the annode (if i am corect)
there job is to heat the tube so electrons get flowing (and that makes the amplivication)
a computer power supply works

santik wrote:
How to know if it is a regulated supply?

Are computer power supplies ok for this?

About the gel battery and sealed lead acid battey, I am afraid with the charging...

My tube is glowing, there is sound but the glowing is just 4 red-Orange dots; 2 on top, 2 at the bottom. They are just glowing dots, and not bright enough to light up the other components even in a dark room.


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PostPosted: 12 Oct 2010, 11:20 
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Joined: 18 Sep 2010, 12:48
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The heater is to heat up the cathode, so that electrons will flow across to the plate(anode), but I don't know how much glow it should have, though the sound is reasonably good, I just want the amp to perform at it's best. :D


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PostPosted: 12 Oct 2010, 12:02 
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Joined: 22 Jun 2010, 13:30
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if the glow is barly seen you have enough power

mine alway's opens with a flash and the glows bright red (fillament 2 points top and bottem)


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PostPosted: 12 Oct 2010, 12:17 
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Joined: 28 May 2008, 21:53
Posts: 4592
Location: Winnipeg, CANADA
robot797 wrote:
an old ecc85 wit worn down filaments does also works great

How did you hook up the heaters? ECC85 is a 6.3V heater.
Cheers

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PostPosted: 12 Oct 2010, 12:28 
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Joined: 28 May 2008, 21:53
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Location: Winnipeg, CANADA
santik wrote:
So, the 'thunk'... will it damage the headphones?

The turn-on thump occurs as the output capacitors charge up on application of power. I've used this output stage with Grado SR80 for some time and there was no damage. I didn't like the loud turn-on thump so I eventually install a "mute" switch on the output.

Of course there are many delay circuits one can use. In addition to the e12 there are a couple more simple delay circuits you can consider in the Simple Turn On Delay Circuit (Relay) Amplifiers & Speakers thread.

santik wrote:
Besides the batteries, what other sources of power can I use? Laptop adapter? Router adapter?

Those will work. But unless they are regulated you will get unwanted noise. An option is to use a laptop adapter (16V+) and a regulator circuit set to about 12.5V. Here is an example of a suitable regulator circuit for this head amp: Voltage Regulator for NP-100v12 - 12AU7 / IRF510 Headphone Amplifier.
Cheers

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PostPosted: 12 Oct 2010, 13:16 
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Joined: 18 Sep 2010, 12:48
Posts: 81
What about occasional clicks and pops while listening to songs?

What could possibly cause it?


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PostPosted: 12 Oct 2010, 13:31 
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Joined: 13 Apr 2010, 10:39
Posts: 37
Location: Dallas, Texas, USA
santik wrote:
What about occasional clicks and pops while listening to songs?

On mine, I've noticed some 'warm up' crackling, which I've traced down to the new-old-stock CINCH socket I used.
I even replaced the first one (with another CINCH, but from the same batch - all I had on hand I'm sorry to say), but occasionally it still 'crinkles' during warm-up. I can only guess this is some looseness in the socket's contact with the tube-pins. As it warms, I guess there's a tiny bit of sliding around there.

Once it's warmed up - maybe 10 minutes - it's fine.

Check for any loose wires or bad solder joints.
Sometimes you can hold the whole enclosure stable and wiggle the input plug, power plug, or headphone plug or even tap on it with just a finger to get an idea where a weakness might be.

Rarely, a tube might have in internal defect where the grid very nearly touch or something. You can try a different tube to test this.

Here's my lil' project; built entirely from 'stuff found on-hand'. Except I did have to buy upgraded (slightly larger) heat-sinks - both the amp and the lil' regulated power supply I built produce a prodigious amount of heat.

Image

Mike Y
Dallas, Texas


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PostPosted: 14 Oct 2010, 03:24 
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Joined: 18 Sep 2010, 12:48
Posts: 81
Mind to show us the how-to on building your power supply?


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PostPosted: 14 Oct 2010, 08:50 
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Joined: 13 Apr 2010, 10:39
Posts: 37
Location: Dallas, Texas, USA
santik wrote:
Mind to show us the how-to on building your power supply?

Not much to say, I suppose. I didn't use Mains transformer, so there's no shock risk. Plus no transformer, so no rectifier bridge. I skipped all that and used a scrapped laptop power supply.

These are typically 15 VDC to around 19.5 VDC, and usually supply plenty of current (2 to 3 amps) AND, they're regulated. But in this case, it was noisy and the voltage was a bit high. So I supplied a few components to filter and lower the voltage to approximately 12.6 volts. Again, my audio experience is the Millet Max, so I stole just the filtering and regulating portion of their power supply.

Basically, from their schematic, I'm using everything from CR1A to the right to CR5.

Image

I found that only 3 of the 4 CR1's were necessary (and more importantly, fit in the enclosure!). Then there's your basic LM317T setup, almost straight from the datasheet, with a trimpot on the ADJ pin so you can load it up and make an accurate final voltage setting. DR3 is there, I believe, to protect the LM317 from any stored voltage upstream; upon power-off, voltage MIGHT flow into the output of the LM317 - not such a big risk since the CR1A,C,D behind it will be holding quite a charge. CR4 and DR2 act to stabilize the ADJ setting. And the final CR5 (tantalum) just to assure output stability and I suppose to send any stray RF to ground. I think a small valued electrolytic might work if no tantalum was available.

And you'll need a small-ish heatsink. Depending on the voltage drop from the input, the LM317 will dissipate P=I*V, or 400ma x (voltage drop) in pure heat output.

This makes an extremely quiet, simple, regulated supply, and you can use any sort of wall-wart, laptop supply, whatever you have on hand for input voltage. However the input voltage will need to be at least 14 VDC or so, to provide headroom for the LM317 to regulate.

Mike Y


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PostPosted: 14 Oct 2010, 14:13 
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Joined: 17 Apr 2010, 16:07
Posts: 39
Location: Huddersfield ,West Yorkshire,UK
Hey Guys

i showed my updated 555 delay in Kramme's excellent delay timer thread for his Np-100v12 and i thought it would be usefull to mention it in here also as it was designed directly for this amp

i still have not started my own amp yet but will be in the next week of so but i have made a turn on delay (0-55 secs) pcb which incorporates audio in header and a pcb mount headphone jack with the intention of including this and a regulated PSU into the headamp design on one board .

All the details for the delay can be found in Krammes thread http://diyaudioprojects.com/Forum/viewtopic.php?p=19338#p19338 inc a link to the Eagle board files ,schematic,etch pdf etc

but heres the board layout ( 100mm x 40mm ).

Image


Thanks
Koog

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