Neovibe Questions

[sfx1999]

Does anyone know of a good transformer? The ones I have found seem too expensive. I don't mind having to do AC wiring if need be; I know where to use fuses, etc.

Also, I am not to sure what transistors to use. I was planning on using these; the cross reference lists them as substitutes for the BC108, 2SC828, and 2SC539. I was looking to use the ones with the 200-400 gain range suffix, is this about right? Not to mention they are cheap; I can get 100 of them for like $3. Their data sheet lists them as handling 150 mA, so they should work in the bulb driver.

Can anyone share there experiences with Neovibes transistors (and possibly some clips)?

[Rick Hardslab]

This transformer has R.G.'s seal of approval:

http://www.mouser.com/catalog/specsheets/164124.pdf

[John Lyons]

Everything you need to know is in the Neovibe PDF.
Use 2N3904s or 2N5088s or even 2n5089s and a 2N3904 as the bulb driver.
Go to any decent thrift store that has electronics stuff and get an 14-20vAC or 18-24vDC wall wart transformer.

John

[sfx1999]

My concern is that the stock 'vibe circuit did not use transistors with as much gain as a 2n5088 or a 2n5089. Has anyone successfully used these transistors, preferably with audio clips?

[R.G.]

My concern is that the stock 'vibe circuit did not use transistors with as much gain as a 2n5088 or a 2n5089.

The circuits in the univibe are remarkably insensitive to gain, with the exception of the LFO transistors. Too LITTLE gain there will prevent it from starting. The lamp driver needs decent gain, but also decent (100ma) current rating too.

Yes, the 5088 will work for all of them except the lamp driver.

preferably with audio clips?

And you'd be able to tell the difference in transistors by listening? 

[sfx1999]

Well, after listening to this one Vibe, I plan to use 5088 for the Q1 and 3904s for the others (he used a BC550 I think, but this should work fine). I will throw 5088s in the oscillator circuit to be on the safe side (3904 bulb driver).

Now should I do the unity gain mod, or put a buffer at the end of the circuit? If I were to use a buffer, what would be a good circuit?

Also, has anyone tried to put phaser values in for the caps? I think I might want to make that switchable, but I don't know how it would sound.

[sfx1999]

bump

[R.G.]

I think you should...

build it stock, see if you like it, then modify it if you want to.

An awful lot of people like it as is. A lot of others like it modified. You have no way of knowing which you are until you listen.

[sfx1999]

I just found a great transformer on Jameco -> http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10001&catalogId=10001&productId=163272&pa=163272PS

18VDC @ 500 mA. It's unregulated, so it will give out more than 18V. There was a 250 mA one, also, but it was more expensive.

When I said mod, I didn't mean that I wanted to make it sound better. I was just a little concerned about the volume loss. I was also thinking about putting a switch to change from Vibe to phaser cap values for versatility, but I would like to know how that would sound so I don't wind up with a hole in my case because I took out a switch that I never use.