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SHIRK 19th July 2005 11:32 PM

Pendulum MDP1 Lights keep burning out?
I've owned and loved my Pendulum Audio MDP-1 since I bought it back in 2001. Since then I've had a consistant problem with the stupid light bulbs (behind the VU meters) burning out. I have the preamp in a rack with vents in the spaces above and below it. It gets good ventilation and it never leaves the rack...except for light bulb replacement. I've had Greg send me replacement bulbs two seperate times. In addition, I've used replacement car dome light bulbs purchased from an auto parts store that were a close put not perfect match. All eventually burn out in about 6 months.
I've had this unit plugged into power conditioners since I first started using it. Greg mentioned that some studios run their AC voltage higher than normal (126V-130V) which results in excess heat produced by the units. My Furman power strips, as well as the Furman balanced isolation transformer which feeds my whole studio, never show voltages of higher than 118V. I'm normally running between 110V and 114V. This seems OK to me.

I've contacted Greg a few times over the past few years and he's always been cool and sent me a few replacement bulbs. However, I'm sure he's growing tired of this. I use the unit regulary and am not too psyched about having ot send it back for service.

Anyone have this probelm with Pendulum or other gear? Any idea of what might me going on here? Something I can fix? A good source for replacement bulbs, etc.

I love this peice.


joeq 19th July 2005 11:52 PM

I have the MDP-1 and my vu meters went dark as well. In fact, both seemed to go out at once. ? I haven't even gotten around to ordering the new bulbs, since it works fine anyway and once the tubes warm up I can tell the unit is 'on' by the blue light. I never realized I wasn't alone- but now thanks to Gearslutz I can connect with others in my same boat. we could form a Pendulum/VU meter support group.

It IS annoying, but I too love my Pendulum kfhkh - it gets used all over the place. I too would be interested in any long-term fixes.

ZEUSS 20th July 2005 01:44 AM

Mine burn out quick as well. Same thing with my MC76.

tmarra 20th July 2005 04:07 AM

Having not see the inside of a Pendulum unit I'm not sure if this will work, but we sell this great upgrade for Drawmer 1960's. It's made by Drawmer and is basically a bunch of yellow LED's on PCB that slide on the back of their VU meters. It runs on 12V. The old 1960's used to use the same "festoon" bulb I believe you guys are talking about.

If you go to my new parts website: and do a "Quick Find" for a SO18 you can take a look at it. If this even seems close I'd be happy to give you some more dimensions to help you out.

Although pricy as compared to a replacement lamp, you would NEVER have to replace the lamps again.

I don't know about you guys but I hate when you see VU meters where the lamps have burnt out. How about all those pics you see in mags of SSL's and NEVE's with burnt out meter lamps? grrr


aevan 20th July 2005 05:47 AM

Hey Tony,
is anybody planning to make those led pcb's with some different colored leds? Like all red or all blue , so you can make your vu's match your mood?

David R. 20th July 2005 06:24 PM

Call or email Greg at Pendulum. Very nice guy and very helpful. I had a problem with mine (it was my fault) and he figured it out in a jiff.

vince @ speck 20th July 2005 06:55 PM

Incadesent lamps don't last forever. The festoon type lamp is good for about 1000 hours max. The cheap ones made in China are more like 500-600 hours. You can do the math on how long that lamp will last given your own circumstances. The short period when the lamp is turned off is when the filament will break from vibration.

I think the Pendulum gear uses Sifam meters with a "light box". The light box is available in two flavors; one that uses the festoon lamp and the other that uses (2) midget-flange lamps. A good Midget-flange 12V lamp can last for 10,000 hours. I've seen the innards of that gear but can't remember which style is used. The Sifam festoon sytle can be upgrade to the MF style.

Also... if the meter requires a 12V lamp, you might want to consider a 14V lamp. a bit less light, but will last much longer.

84K 20th July 2005 11:47 PM

We have (7) of them! No lights have burned out in over 6 years.

brianroth 21st July 2005 08:28 AM

Several options....

1. Select a lamp that is mechanically the same, but with a longer life. Typically, these will be somewhat dimmer.

2. Use a lamp rated for a higher voltage.

3. Add a dropping resistor in series with the lamp to drop the voltage.

On the Pendulum bulbs, see if there are any markings to give bulb info. Typically, it will be a 2, 3 or 4 digit number somewhere, and we can see if there are alternatives.


brianroth 21st July 2005 09:39 AM

And another "keep the VU bulbs running" story comes to mind...

Time Machine: 1980. The desk was an MCI JH-636 which ate VU bulbs regularly. Since the power distro to the meter bulbs was accessable, I ended up wiring a string of silicon diodes in series with the meter-lamp supply rail. Each diode added approx 1 Volt drop, and I vaguely recall adding 4 or 5 diodes in series with the VU lamp line.

Incandescent lamps have an odd, exponential curve of voltage vs. life. I'm making this up, but it's something like "go 10% over-voltage, life drops to 50%...go 10% under-voltage, lamp life doubles". I know the numbers are probably incorrect, but you get the drift....Chicago Miniature has plenty of interesting info on their website.


larry zip 21st July 2005 02:54 PM

we just let all the bulbs burn out then everythig looks the same. on a few things like the 24 track machine we just took out the bulbes because they didnt burn out at the same tiem

T_R_S 21st July 2005 04:41 PM

Use a higher voltage rated bulb it will be dimmer but it will last also make sure you have good filtered power. I have a filter on my 220 supply plus I use filtered power distro bars as well.

Dan-O 22nd July 2005 01:22 PM

I spoke to Greg about this at Tape Op 2004. My OCL-2 was doing it (not my MDP-1A though). If I recall his explanation was the difference in alloys between the bulb and the socket that were problematic. Sometimes just opening the case and playing around with it dose the trick (did with mine). I use to be able to lightly tap the meter sometimes and this would also work. Now I think their dead. I'm having the same problem with my TG-1 as well.

1484 22nd July 2005 02:19 PM

Oh just sell it and get a Manley. (Just kidding)

Sergievsky 22nd January 2006 07:17 AM

Well, the lamp in my Quartet just went out. Did you folks use 14v lamps or other replacement ones? How are those coming along?

Fletcher 22nd January 2006 05:24 PM

If that's the biggest criticism of the product line I'd have to say Greg's doing something really right.

FWIW I usually keep the meter on my MDP-1 switched to the "off" position and twiddle the knobs until I like the sound... then add the next piece of the chain and get the level to where ever it might need to be.

Tim L 22nd January 2006 05:34 PM

Hmm... I've had my MDP-1a for 4 or 5 years and haven't blown a bulb yet. It's certainly not on 24/7 but it get's used alot...

... I shouldn't have said anything, when I fire it up in a little while I'll proly pop one... gooof