Vintage Gretsch Guitars

Please school me on “treble boost”

1

Ok... it was added to the mid- '67 Corvette, Rally(s), and Jets. Any other models? What was it's intension? Did it need a battery (extra cavity on back)? Was it controlled by a switch or knob? Anybody think it worked? Any perspective is appreciated!

3

Wow!! That's so cool. I never knew. Thanks, Ed and Rob!

4

Fortunately, the link is a pdf document which can be saved, should anybody want to repair or replicate the circuit.

5

I had one in my Rally.

With the battery connected and turned on, it yielded the most annoying shrieking feedback on the planet.

I wound up tearing everything out of that Rally and replacing it with a '56 Dynasonic.

6

Ran across one in a black '67 6117 Catseye. Battery hatch for a 9V on the back. Electronics were shot so I never got a chance to hear it. Think I've seen them on AstroJets and Corvettes.

7

Wow, "Masterclass" Thanks

8

Wow, "Masterclass" Thanks

– 949Norm

The author of the article has some extremely esoteric electronics projects... some of them quite fascinating from a technical point of view. Here's his home page:

http://worldphaco.com/

9

It was controlled by a switch and a knob. This will pull back the curtain and reveal all on the Gretsch "Sonic Boom" treble boost circuit:

http://worldphaco.com/uploa...

– Tartan Phantom

Thanks so much Rob!

10

Pretty advanced for the time... 9v Saw one on a Jet Firebird. Not sure how many are working now -- and like HiLo Trons even need a treble boost.

Now a lot of the goofy Gretsch stuff is attributed to Jimmie Webster --- but what about this?

HiLo Trons on Treble Boost-- the sound of the 22nd centruy.

A " boom" implies a big deep sound... so a boom it was not (?)

11

Ran across one in a black '67 6117 Catseye. Battery hatch for a 9V on the back. Electronics were shot so I never got a chance to hear it. Think I've seen them on AstroJets and Corvettes.

– lx

Thank lx... I've documented examples of Rally, Corvette and Jet with either a dedicated cavity on the back or a modified one to accommodate the 9v battery. The Astro Jets from '67 have the additional knob and are easy to spot, but lack any "new" compartment, so I guess you had to get under the main pickguard to get at it? Likewise I can't find a 6117 Cat's Eye with anything on the back... but you say you've seen one? I'm on the quest!

It is interesting to me that this was applied to both Hilo'Trons and Super'Trons.

12

It was controlled by a switch and a knob. This will pull back the curtain and reveal all on the Gretsch "Sonic Boom" treble boost circuit:

http://worldphaco.com/uploa...

– Tartan Phantom

The author displays hi Jet Firebird but doesn't give us the actual serial # (or model year)... clearly it's '67/68 when the treble boost was in-play. Here's an August of '67 example... but it lacks any "switch"???

13

The author displays hi Jet Firebird but doesn't give us the actual serial # (or model year)... clearly it's '67/68 when the treble boost was in-play. Here's an August of '67 example... but it lacks any "switch"???

– kc_eddie_b

The reverb listing mentions that a previous owner did some modding to the pots & switches.

14

The reverb listing mentions that a previous owner did some modding to the pots & switches.

– lx

I didn’t catch that... but there should still be evidence of a switch (short of a refin)... no??

15

IIRC there was always an extra knob, not sure if there was an extra switch. Perhaps the cut-off switch was ditched for the treble-boost versions?

16

Thank lx... I've documented examples of Rally, Corvette and Jet with either a dedicated cavity on the back or a modified one to accommodate the 9v battery. The Astro Jets from '67 have the additional knob and are easy to spot, but lack any "new" compartment, so I guess you had to get under the main pickguard to get at it? Likewise I can't find a 6117 Cat's Eye with anything on the back... but you say you've seen one? I'm on the quest!

It is interesting to me that this was applied to both Hilo'Trons and Super'Trons.

– kc_eddie_b

Initially, Astro Jets did not have the treble booster. It had a standard 3-knob pickup switch/tone switch/standby switch circuit. Later, the standby switch was eliminated and replaced with the Treble Boost circuit. An extra knob was added, and the standby switch was replaced with the on/off switch for the Treble Boost. There was an additional "hatch" added on the front for the battery. Here are two examples:

Early Astro Jet, circa 1965 (no treble boost):

Later Astro Jet, circa 1967 (with treble boost and battery "hatch"):

17

I didn’t catch that... but there should still be evidence of a switch (short of a refin)... no??

– kc_eddie_b

The switch should be in the last position, where the 4th knob is on that particular example. Remember... a standard version of that guitar would have a total of 3 knobs (all volume knobs), and the ONE additional knob for the boost level.

Looks like the boost was either removed and replaced with a V/T knob for each pickup, or the boost is intact and a rotary switch was installed in place of the toggle... I'm betting on the former, not the latter.

This is what it SHOULD look like for a Firebird with factory treble boost:

compared with your example:

And finally, a NON-treble boost Firebird, -- the wiring harness for this is the same as the original early Astro Jet, only the Astro Jet has all the controls lined up on the pickguard, instead of in the traditional locations.

18

Geez Rob... I've been working on this all day and STILL missed the additional hatch on the Astro Jet! Now I can't NOT see it! Thanks so much guys... this has been a big help!

19

Ok... so now let's talk Rally model. The earliest I've documented is June of '67 and that guitar has the treble boost upon its introduction. Interestingly, it seemed to have evolved a bit through that model year. This comparison of the control plate arrangement is (left-to-right) June '67, August '67, and October '67. I have documented additional examples of each.

20

Ok... so now let's talk Rally model. The earliest I've documented is June of '67 and that guitar has the treble boost upon its introduction. Interestingly, it seemed to have evolved a bit through that model year. This comparison of the control plate arrangement is (left-to-right) June '67, August '67, and October '67. I have documented additional examples of each.

– kc_eddie_b

The one in the middle was obviously built on a Friday, and the one on the right was built during a labor strike.

21

I wonder how long the average 9 volt battery lasted?

22

Back in the day I guess the battery would need to be changed fairly frequently, but these days a good battery would last ages because of the low current draw. It's interesting that Gretsch chose to use a "hi-fi" transistor because Ge trannies are not known for being particularly quiet. And they're also not known for their high-end response. So although a Rangemaster was called a Treble Booster it was more of a high-mids booster, giving a pleasing honk to the tone. In effect it was almost like a Tubescreamer, where it reduced low end and added a strong mid-hump to help leads cut through.

It looks like the Gretsch version was boosting at a higher frequency than the Rangemaster. It wouldn't be difficult to build one to hear what it sounded like. I might build an NPN version so it could be negative ground - I have a stash of NPN Russian Ge transistors to use. The Russian transistors are excellent and relatively quiet compared with some NOS European trannies I have used.

One of my favourite boosts is based on the Red Rooster which in turn is based on a Rangemaster. The key difference is a knob which allows you to dial in low end as you want it and it makes for a very authentic sounding '60s sounding booster but with some extra punch should you want it.

BTW these tend not to be a very clean sounding boost. Part of the reason they were popular is that they added a fair bit of gain and dirt. So don't think of them as being a pristine, hi-fi clear treble boost.

24

I remember those. They were quite highly regarded as I recall. It's a classic sound.

25

If anyone wants to try building a Gretsch Sonic Boom boost I drew up a strip-board layout. It doesn't really have much to it and I have drawn it with regular modern parts. You could use mojo parts if you want but I doubt it would sound much different. I would suggest finding a decent NPN Ge transistor - I like Russian MP38s. No idea what hfe or leakage you would want - as long as it's not too leaky it probably doesn't matter too much.

If you want to use a NOS PNP transistor all you would need to do is reverse the polarity of the 22µF cap and use -9VDC instead of +9VDC. I added an anti-pop 1M resistor onto the input and wired the volume pot slightly differently but it should sound much the same. Built as an NPN pedal you can use your regular pedal board power supply.

I also used a 5K bias trimmer to help dial in the bias on the transistor. It should save some hassle!


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