NeoVibe Questions

blester · May 05, 2009, 12:22:37 AM

I'm on the home stretch of my first NeoVibe Build and have a few questions.

1. I adjusted the RS bulb to an orange glow with the depth pot all the way down. When the Drive pot is almost all the way up the bulb is almost as bright as a flash bulb. The Drive pot is smooth until the top of it's range and then it just jumps way up. Is this normal or should I try replacing the 2N3904 LD transistor?

2. I am using an 18V DC transformer (Dunlop ECB004) so I removed the diode bridge so that I would have >17 VDC at the input to the 7815 (17.75 VDC on my meter). The two 1000uF caps seem like overkill, would different cap values be better to filter any ripple off of the DC?

With the speed and drive pots in the middle of their ranges this thing is sweet. I don't see my CE-2 clone getting much use in the future.

Thanks,

bl

gwtekman · May 11, 2009, 10:17:41 AM

On the depth control did you use the 50K Audio (log) taper called out in the parts list or did you the Linear taper as shown on both the schematic and the layout? (just wondering...I have both and have just started my build...its going to take me a while because of limited time to work on it but eventually I will get mine done.

R.G. · May 11, 2009, 11:11:16 AM

Quote from: blester on May 05, 2009, 12:22:37 AM
I'm on the home stretch of my first NeoVibe Build and have a few questions.

1. I adjusted the RS bulb to an orange glow with the depth pot all the way down. When the Drive pot is almost all the way up the bulb is almost as bright as a flash bulb. The Drive pot is smooth until the top of it's range and then it just jumps way up. Is this normal or should I try replacing the 2N3904 LD transistor?

As noted before, it's probably a pot taper problem. Try audio taper.

Quote2. I am using an 18V DC transformer (Dunlop ECB004) so I removed the diode bridge so that I would have >17 VDC at the input to the 7815 (17.75 VDC on my meter). The two 1000uF caps seem like overkill, would different cap values be better to filter any ripple off of the DC?

They're not overkill unless your transformer is already incredibly well filtered for an unregulated version. In fact, given that you have a DC level so close to the 17V the 7815 needs, they may be marginal. Put them in.

Quote
With the speed and drive pots in the middle of their ranges this thing is sweet. I don't see my CE-2 clone getting much use in the future.

Then it passes the most important test!

slideman82 · May 11, 2009, 11:14:49 AM

Quote from: blester on May 05, 2009, 12:22:37 AM
The two 1000uF caps seem like overkill, would different cap values be better to filter any ripple off of the DC?

I think filtering is almost never overkill... unless your circuit has an excellent NMRR (was it for series signals?)

blester · May 12, 2009, 06:52:24 PM

I used the following Pots:
313-2420F-100K - 100K dual reverse log taper control
31VJ501-F - 100k log
31VJ405-F - 50k log

bl

R.G. · May 12, 2009, 10:52:13 PM

Quote from: slideman82 on May 11, 2009, 11:14:49 AM
I think filtering is almost never overkill... unless your circuit has an excellent NMRR (was it for series signals?)

Neutron Magneto-Restrictive Resonance??

slideman82 · May 13, 2009, 06:40:04 PM

Right!

blester · May 17, 2009, 05:14:39 PM

NeoVibe is fixed. I had a bad lamp driver transistor (2N3904). I used a socket for just the lamp driver and it was an easy fix. All of the pots work as they should now, the Depth pot is smooth and gradual from start to stop. I used a 200K trim pot fro R35 & R36 as suggested on the GGG site and it really helps to dial the Vibe in. What a great project I highly recommend it. I have a box to put it in but haven't had time to drill the holes, too busy playing through the Vibe.

Thanks R.G.,

bl

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