New tube-driven stand-alone Vibrato unit build

[tubeswell]

Just finished wiring it 10 minutes ago. Haven't fired it up yet (so excited I had to blog first 8-)

Its a 'pitch-shifting' vibrato unit that utilises a hammond saturable reactor (one of my state-side buddies sent me a couple a while back) and 2 x 12AU7, 2 x 12AX7 and a 12DW7. Designed to be plugged in front of a geetar amp (like a stand alone reverb). Its got 4 phase/pitch/harmonic controls, a feedback control output level/CF bypass and the trem oscillator controls. There is a switch on the front stage that bypasses the vibrato section to make the unit function as a tube booster. The output level is a dual-gang pot that turns up the recovery stage whilst mixing out the CF bypass or vice-versa. See schematic (pdf file)

Found a nice bit of scandinavian pine for the front of the box.

Hopefully there isn't too much troubleshooting ahead and I can get some soundbytes up soon

I used a spare 2nd-hand chassis I had lying around otherwise everything is hand-made (incl the PT)

[Steve Conner]

That's pretty cool I've seen the Hammond preamp unit with the saturable reactors on EBay, and wondered whether it might make a good guitar vibrato. Now we're going to find out!

Hammond had an extraordinary approach to design, they would never use any other component if they could make a transformer do the job.

BTW, your rendition of the Shadows' "Man Of Mystery" appeared on my iTunes shuffle the other day. Now you must record it again with the vibrato.

[mooreamps]

I am officially impressed.... "very nice job"........

-g

[tubeswell]

a few soundbytes

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

[Chuck H]

Posting just to keep this thread in my "settings" file I want to follow along.

P.S. It would be cool if we could tag threads just to follow them without the need to have a post involved... Tboy? I know this is more about the host than the administrator, but they sure wouldn't listen to me!?!

[Diablo]

Nice job Tubeswell! Are these Hammond reactors available for a reasonable price, or are they unobtanium? Like I need another project....

[tubeswell]

Try searching for 'Hammond AO-47' every so often

[Tom Phillips]

... It would be cool if we could tag threads just to follow them without the need to have a post involved...

That feature is available Chuck. Look for "Thread Tools" in the bar just above the first post in a given thread, select "Subscribe to this thread..." from the drop down menu & follow the instructions.
Cheers,
Tom

[jpfamps]

Marvellous!!

A very cool project.

I love vib/trem, and also eccentric valve-based designs, and this fulfils both criterion.

[tubeswell]

Finally took the time to do a few 'proper' tracks with the 'viberater'

All recorded through this (scratch-built) rig




(Main amp is a PP 6V6 ~22Wer with Merlin's EF86 morph control idea/feature in the pre, and Weber sig 12S and a Greenback G12M in the extn cab, and a 6G15 clone (covered in gingham) and the vibrato unit (stained pine).

Recorded with both cabs mic'd with SM57s through my desk and into garbageband. Me accompanying myself on my JM.

[deci belle]

More Tubeswell tunes on my iPod!!

[tubeswell]

Ha ha! Nice one.

[tubeswell]

As a wee follow-up to this, I have found that it works even better if the input stage is reaaaalllly low gain (like 5 or so). This seems to stop any stray oscillation (which I was getting before) and the knobs work all the way around the dial too. (And the vibrato is therefore able to be tuned to be richer and fuller too.) FWIW

[mort]

Can't listen here at work but will be in the morning!

Looks nice, which is always important


I remember you Tubeswell. You were always very polite and helpful with the greenhorns like me Thanks for that!

[jbennett]

Sounds really nice. That tremolo is really cool sounding.