Using a Bulb lamp on the EQD The Depths?

[Atodovax]

Hi everyone. Is it possible to use a Bulb lamp on this pedal? I tried and while the LFO is working, the Lamp glows super dimed... Is there a way to improve the current on the LFO? I used this schematic.

[Ripthorn]

The problems will be three-fold:

1. That LFO does not provide a high enough voltage for (what I assume to be) a 12V lamp
2. The LFO also is not meant for supplying lots of current
3. The bulb might not work as well with the LDR called for the in BOM.

Is there any reason you want to go for the more expensive, more power hungry option? Mojo?

[Atodovax]

The problems will be three-fold:

1. That LFO does not provide a high enough voltage for (what I assume to be) a 12V lamp
2. The LFO also is not meant for supplying lots of current
3. The bulb might not work as well with the LDR called for the in BOM.

Is there any reason you want to go for the more expensive, more power hungry option? Mojo?

Hi! Its exactly MOJO hehe. I was actually thinking of using this instead of the usual Univibe LFO. Do you think is there an easy qay to adapt it to use a 12v 60ma lamp? I want ti use the same PCB if possible...

[anotherjim]

Might be possible to replace the 100R emitter resistor in the LED driver with the lamp? Then the collector runs off a wire-wound 1k pot from +9v

[Atodovax]

Might be possible to replace the 100R emitter resistor in the LED driver with the lamp? Then the collector runs off a wire-wound 1k pot from +9v

Thanks, i will try that. I though the current demand was similar to the original Univibe's LFO. Can i hook the colector straight to +9?

[antonis]

By hooking the Collector straight to 9V, Emitter is set at about 5.5V (feedback bias configuration turns into voltage divider one..) so, even if bulb lights (it should need about 130mA) Q2 wouldn't be happy..  

[mac]

I used a 4.5-6v small lamp with the MXR P90 LFO. I direct coupled a BD139 with a screw & nut as heatsink, bulb at the emitter IIRC.
I guess that if you feed the output of the LFO into an opamp buffer and a direct coupled BDxxx it might work. BUt you have to add those parts...
Another option would be using and opamp instead of Q1 and a BDxxx as Q2...

mac

[antonis]

IMHO, by wiring bulb at Q2 Emitter, you might overcome No. 2 of what Brian said but it still remains No. 1 issue..
(and, of course, INTENSITY pot makes things even worse for any setting other than FCW..)

[Atodovax]

IMHO, by wiring bulb at Q2 Emitter, you might overcome No. 2 of what Brian said but it still remains No. 1 issue..
(and, of course, INTENSITY pot makes things even worse for any setting other than FCW..)

Do you think a 6volt bulb lamp mugh work there?

[Atodovax]

I used a 4.5-6v small lamp with the MXR P90 LFO. I direct coupled a BD139 with a screw & nut as heatsink, bulb at the emitter IIRC.
I guess that if you feed the output of the LFO into an opamp buffer and a direct coupled BDxxx it might work. BUt you have to add those parts...
Another option would be using and opamp instead of Q1 and a BDxxx as Q2...

mac

Thanks Mac! I was hoping to keep it as simply as just replacing some components or soldering the least amount of them floating around.

[antonis]

Do you think a 6volt bulb lamp mugh work there?

In theory, yes,,,

But you have to consider another beast called "brightness"..

[Atodovax]

Do you think a 6volt bulb lamp mugh work there?

In theory, yes,,,

But you have to consider another beast called "brightness"..

I was so sure that the LFO section was the same as the Univibe that i didnt even check... . I was hoping to use a light bulb in my build...

[Atodovax]

Do you think a 6volt bulb lamp mugh work there?

In theory, yes,,,

But you have to consider another beast called "brightness"..

What if i use darlingtons like Mpsa13 for both transistors and i power it up with 18volts? Would that be enought to replace the LED with a 12v Bulb Lamp?. I really want a lamp there. Or do i still have to move things around? The schematic looks pretty similar to the LFO in the Univibe. I dont mind soldering things in the air. I just dont want to throw away this board..

[antonis]

Could you plz post a schematic of the way you conceive of the lamp driver..??
(anything after C14..)

P.S.
Take into account Q1 output amplitude, also..
(it's more than crucial in case of lamp driver is configured as Emitter follower..)

[Atodovax]

Could you plz post a schematic of the way you conceive of the lamp driver..??
(anything after C14..)

P.S.
Take into account Q1 output amplitude, also..
(it's more than crucial in case of lamp driver is configured as Emitter follower..)

Im using the schematic i posted in my first poist. I though it had the same LFO as the original Univibe but now that i have seen them both, i realize they do differ in the transistor configuration... Im thinking about the emitetr follower configuration. Do you think i could hook up Q1's colector to +9 and get the ouput from the emiter and tweak a few values? Im trying to use the same board but i dont care if i have to solder some comp'onents in floating on the air.

I guess i could redraw Q1's configuration but i will have to stick with the double potentiometers layout because i have it soldered to the pcb

[antonis]

Im thinking about the emitetr follower configuration. Do you think i could hook up Q1's colector to +9 and get the ouput from the emiter and tweak a few values?

IMHO, no..!!

Q1 is the amplifier part of LFO so better leave it as it is..

P.S.
You realize that you need current togheter with voltage to drive the bulb, don't you..??
As circuit is, you can't do anything..

[Atodovax]

Im thinking about the emitetr follower configuration. Do you think i could hook up Q1's colector to +9 and get the ouput from the emiter and tweak a few values?

IMHO, no..!!

Q1 is the amplifier part of LFO so better leave it as it is..

P.S.
You realize that you need current togheter with voltage to drive the bulb, don't you..??
As circuit is, you can't do anything..

Ok ... I give up hehe..... unless... is there such thing as a bulb that light up at LED current?

[antonis]

is there such thing as a bulb that light up at LED current?

AND voltage..

[Atodovax]

is there such thing as a bulb that light up at LED current?

AND voltage..

Well.. I have found 3 and 6volt lamps . What do you think? Do you think they'd light up with low curent? I dont even know how much current is flowing through Q2 with the LED

[pacealot]

And we're not examining the actual Univibe LFO (or another pre-existing LFO that uses an incandescent bulb) because...?