Another vibrato unit

[tubeswell]

Saw Steve Luckey's one a few months back and liked the sounds of that so I decided to try it for myself. This one has a bypass switch that makes the unit function as a tube booster when the vibrato is not on (I need to tame down the booster at this stage). Also has a CF bypass to get a plain ole 'uneffected' sound and 4 x 'sigma' (pitch/phase/harmonic) controls (one on each of the 12AU7 triodes) and a feedback control.

(Willabe sent me a couple of Hammond SR units a few months back in return for a favour).

Found a nice bit of scandinavian pine for the front of the box from an old draw end at the local recycling centre/tip.

Managed to cram it into an old 2nd-hand head chassis I had lying around. (Wouldn't want it to be any bigger ;-)

I had it going last night with only one minor trouble shoot (wired the CF bypass plate and cathode the wrong way - those CF get me every time dammit). Otherwise it seems to be working fine.

Only delved into the tip of sounds so far but got several variations ranging from chorus to phase to vibrato to tremolo by tweaking the 4 sigma controls, and many variations in between. There are a few settings that sound quite magnatone-ish. I need to get a few .mp3s done.

[HotBluePlates]

That's not one of Hoffman's old aluminum chasses, is it? His was the only other one I've seen with the thick aluminum block capping the ends.

[tubeswell]

Its a steel chassis I got 2nd-hand a wee while back in a pile of stuff I bought off Simcha Delft (a local tech here in Wellington). Where Simcha got it, I don't know.

[HotBluePlates]

So tell some more about this "sigma" control. It might have been described somewhere else, but I must have missed it.

What is the net effect of using those controls?

I ask because I've got one of the Hammond vibrato units waiting to be turned into this same project, and I'm interested in working out the details.

[tubeswell]

Schematic attached. The 'sigma' controls are level controls that blend in the mojo that is happening in each of the 12AU7 stages.

[Willabe]

Man, you do very good work, looks great tubeswell, cab too!

Are you going to take it down to one of the jam nights in town? I bet the guys will love it.


           Brad       

[tubeswell]

Jam night? you bet, this is just the stuff for jam nights.

[Willabe]

If you get a guy who wants buy one (that you would build for him), I could probly get you another 1 or 2 SR units. I still see them on e-bay every month or so.


           Brad         

[tubeswell]

Thanks Brad. I appreciate that very much. I'll let you know. Mind you, whoever it is might have to wait a while for me to knock off another one of these. It takes a fair few hours to cram all that stuff in.

[Willabe]

Mind you, whoever it is might have to wait a while for me to knock off another one of these. It takes a fair few hours to cram all that stuff in.

Yeah but, now you have this 1'st one to copy for your lead dress and chassis drilling. That should knock off some time.

What are the chassis dimensions? And how about a pic of the the PT side of the chassis?

My wife Pam says hi and to tell you it looks real nice.

(Hey Pete, did you ever get a chance to measure the voltages on the little bottles of your reverb unit?)  


                  Brad    

[HotBluePlates]

Yes, you definitely do good work!

I like your variant. I think you might have talked that stuff over in the warbler thread, but I haven't gone back to look.

I am strongly considering a "variant #8" which includes a simple trem option as well as the vibrato.

The story in a nutshell: I'm working up an amp build with a separate preamp and power amp chassis. Since there is an umbilical between them anyway, it seems like a good place for an effects loop. The umbilical also carries power supply voltages and ground, so there's an option presented of creating add-on effects units to plug between the chasses, in "the loop" (even though it's just in between preamp and power amp).

I've been interested in building up a warbler, but I also really like some tremolo!

[tubeswell]

Did some very rough sounds earlier this avo into garbageband not properly mic'd (mac built-in mic) and didn't get time to run through all the sounds, will try and find time later in the week. Guitar is a strat. Other amp is my PR clone. Please excuse the shoddy playing

Links follow:

http://music-electronics-forum.com/attachments/16501d1324188712-vibe-buggy.mp3

http://music-electronics-forum.com/attachments/16502d1324188749-viberator-sky.mp3

http://music-electronics-forum.com/attachments/16503d1324188799-black-sand-vibe.mp3

http://music-electronics-forum.com/attachments/16504d1324188888-stray-vibe.mp3