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GreeneKing

Lamp/bulb for EBS Fafner

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My Fafner I is proving to be an awesome amp into just one of my two 8ohm Accugroove Tri112’s. On Tuesday the amp started to cut out and the gain control was inconsistent. After about 15 minutes it sorted itself out. I have been storing it in an unheated conservatory and I wondered if the problem may lie in that?
 

I had a spare valve so fitted that in any case. A bit of a fiddle from the front panel due to large fingers and switch wires an inch too short....

It’s now behaving but the orange glow has gone. Does anyone have a link to a replacement lamp/bulb to save me taking it apart again, twice?
 

Peter

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5 hours ago, GreeneKing said:

My Fafner I is proving to be an awesome amp into just one of my two 8ohm Accugroove Tri112’s. On Tuesday the amp started to cut out and the gain control was inconsistent. After about 15 minutes it sorted itself out. I have been storing it in an unheated conservatory and I wondered if the problem may lie in that?
 

I had a spare valve so fitted that in any case. A bit of a fiddle from the front panel due to large fingers and switch wires an inch too short....

It’s now behaving but the orange glow has gone. Does anyone have a link to a replacement lamp/bulb to save me taking it apart again, twice?
 

Peter

Contact EBS and they can ship you a replacement bulb directly. Any lamp of the same type will work though, it just won’t have that red/orange glow. 

In terms of the amp cutting out, the valve and the lamp should not be causing this. The lamp is  purely cosmetic, the valve is only inserted into the drive system so if it blows the rest of the amp should still work.

I kept my Fafner stored in an unheated rehearsal space for nearly three years. It is still working. So I don’t think that the environment you are storing the amp in is hurting it.

It might be worth taking the amp to a tech to have a look. The Fafner I amps are great but they have been discontinued for years. Some parts to the existing amps will eventually start to wear out.

I would agree though that the gain control is finicky. Changing the EQ setting or adding or cutting drive generally has a big impact on the signal so you have to add to reduce the gain to suit. Of course once you change the gain level this again changes the character of the drive signal...

Great amp though!

Edited by thodrik
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Forget the bulb. Replace it with a LED and resistor. It'll never fail (you'd hope) again. You can then have whatever colour glow you want (well, if you can find the appropriate coloured LED).

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On 20/12/2019 at 11:37, EBS_freak said:

Forget the bulb. Replace it with a LED and resistor. It'll never fail (you'd hope) again. You can then have whatever colour glow you want (well, if you can find the appropriate coloured LED).

What kind of LED and what kind of resistor? I think I need to do this mod. Bulb had gone for the umpteenth time at a gig...

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1 hour ago, thodrik said:

What kind of LED and what kind of resistor? I think I need to do this mod. Bulb had gone for the umpteenth time at a gig...

I forgot off the top of my head. Can you tell me what’s written on the bulb? I can give you the required if you give me the spec.

(blue LEDs always look great in a Fafner)

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1 hour ago, EBS_freak said:

I forgot off the top of my head. Can you tell me what’s written on the bulb? I can give you the required if you give me the spec.

(blue LEDs always look great in a Fafner)

I will do! Much appreciated.

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14 hours ago, EBS_freak said:

I forgot off the top of my head. Can you tell me what’s written on the bulb? I can give you the required if you give me the spec.

(blue LEDs always look great in a Fafner)

Hi, just checked the bulb, which is a 42v 2w 45MA bulb. It is about the fifth bulb I have gone through in ten years. Feel free to give me a PM or so with what bits I need. A blue LED would look far better. 

Many thanks again!

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25 minutes ago, thodrik said:

Hi, just checked the bulb, which is a 42v 2w 45MA bulb. It is about the fifth bulb I have gone through in ten years. Feel free to give me a PM or so with what bits I need. A blue LED would look far better. 

Many thanks again!

Ah yes, I remember now. EBS always tend to use weird voltages - same with their fans.

http://led.linear1.org/led.wiz

Using the above, you'll be able to arrange a 6 blue LED array.

(42v, 3.3, 20, 6 as the inputs)

Solution 0: 6 x 1 array uses 6 LEDs exactly

+42V
+ -|>|- -|>|- -|>|- -|>|- -|>|- -|>|- -/\/\/\- + R = 1200 ohms

The wizard says: In solution 0:

  • each 1200 ohm resistor dissipates 480 mW
  • the wizard thinks 1W resistors are needed for your application
  • together, all resistors dissipate 480 mW
  • together, the diodes dissipate 396 mW
  • total power dissipated by the array is 876 mW
  • the array draws current of 20 mA from the source.

To be safe, I'd get a 1.2k Ohm resistor with 1W rating.

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6 minutes ago, EBS_freak said:

Ah yes, I remember now. EBS always tend to use weird voltages - same with their fans.

http://led.linear1.org/led.wiz

Using the above, you'll be able to arrange a 6 blue LED array.

(42v, 3.3, 20, 6 as the inputs)

Solution 0: 6 x 1 array uses 6 LEDs exactly

+42V
+ -|>|- -|>|- -|>|- -|>|- -|>|- -|>|- -/\/\/\- + R = 1200 ohms

The wizard says: In solution 0:

  • each 1200 ohm resistor dissipates 480 mW
  • the wizard thinks 1W resistors are needed for your application
  • together, all resistors dissipate 480 mW
  • together, the diodes dissipate 396 mW
  • total power dissipated by the array is 876 mW
  • the array draws current of 20 mA from the source.

To be safe, I'd get a 1.2k Ohm resistor with 1W rating.

Many thanks. I will try and get my head around the maths and electronics (not my strong suit) but I’m definitely going to do it! 
 

Cheers!

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Here you go -

https://www.ebay.co.uk/itm/50-100pcs-3mm-5mm-LED-Diode-Clear-White-Red-Blue-RGB-Light-Emitting-Diodes-Lamp/202717758478?var=502845008360&hash=item2f32eb840e:m:miGcURJ96LGXGEFlCh0UjOQ

Using the specs in the listing - 

Color
Lens Type

Dominant W avelength

(Unit:nm,IF=20mA)

Forward Votage

(Unit:V,IF=20mA)

Luminous

(Mcd)

Viewing

Angle 2θ 1/2

Typical
Typial Max
Red
Water Clear
620
2.0
2.2
10000
30
Orange
Water Clear
600
2.0
2.2
6000
30
Yellow
Water Clear
585
2.0
2.2
6000
30
Green
Water Clear
520
3.0
3.2
8000
30
Blue
Water Clear
468
3.0
3.2
8000
30
Purple
Water Clear
395
3.0
3.2
400
30
White
Water Clear
6000-6500k
3.0
3.2
12000
30
Warm White
Water Clear
3000-3500k
3.0
3.2
14000
30
Pink
Water Clear
x=0.38,y=0.18
3.0
3.2
8000
30

I've highlighted the line in question so the figures are in red. Using the array calculator (inputs 42v, 3.2, 20, 6)... you'll still get the same result. So these LEDs are good. As I say, make sure you get the right resistor though.

Is not too hard - for chaining LEDs, solder the shorter leg, the cathode (negative), to the longer leg, the anode (positive) of the next LED. Make sure you heatshrink to prevent shorts.

-|>|- -|>|- -|>|- -|>|- -|>|- -|>|- -/\/\/\- + R

 

 

Edited by EBS_freak
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I've bought some blue LED bulbs on eBay, less than £4 for 5 all the way from China. They are 36v so may prove unsuitable.

I'll update..

 

DSCF0009.jpg

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Don't use those unless you want to release some magic smoke.

Also, if you take the lid off, you may want to give the pots and valve bass a sprinkling of servisol.

Edited by EBS_freak
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If you live anywhere near Brighton, take it into Bernie Goodfellow who'll do the LED mod for you at a reasonable price - he did it for my old Fafner, you can pick the colour too😀

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An update;

I took the top off and the amp is very clean. The guy I bought it from told me that it had recently been serviced but shipping always carried potential for damage. I checked all connections that I could get to and used Servisol on the pots (from the front with knobs and nuts removed) and the valve base.

I've had it on for over 4 hours now with the blue LED lamp fitted and all is good. The blown incandescent lamp that I removed was a red 'painted' 48v. I've sourced a UK made red 48v LED at RS Components and it arrived today. £7.25 with free delivery. However with the blue one working so well I may just leave it in.

Practice tonight but fingers crossed.

 

DSCF0010.jpg

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Looks great. I always thought the Fafner looks better with blue lights on the right anyway... but each to their own!

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Also @GreeneKing - the blue LED in there to which you refer - are those the ones from the post further above. If so, it would seem that the voltage on the Fafner light is not 42v... or 48v otherwise those LEDs would have been toasted. In reality, I am guessing that the stock bulbs are mismatched on the voltage front - maybe intentionally, to give a more valve like glow as opposed to a bright light?

May be worth getting a meter in there next time somebody has one open so we know what the actual voltage being delivered is.

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The amp was faultless tonight. I love it. Just using one of my Accugroove Tri112L 8 ohm cabs and it copes with ease. Okay it's a heavy old lump but weight or size isn't an issue for me. I've mainly used 500 watt class D amps before but the Fafner seems to have more headroom. 

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