Starfire tinkering continued

[mellowgerman]

My 1970 Starfire is my forever #1 player. I've never enjoyed an instrument more. It has gone through several stages of evolution, but has not been on the work bench for quite some time now.
When I managed to get My hands on a NOS ACG EQ-01, I knew it was time for the Starfire to undergo a new phase in evolution. The EQ-01 is an active filter-based preamp inspired by classic Alembic designs. It has separate low-pass filters for each pickup and a blendable high-pass filter. About 5 years back I tried the EQ-02 (same idea but only one master low-pass filter) in my Warwick Starbass. At the time however, I was gigging every week, often under wild circumstances (we'll leave it at that), and the Starbass was my main player then, so I didn't want to have to worry about batteries and super powerful but sensitive electronics on stage. I ended up going back to more familiar passive electronics, though admittedly still unconventional and overcomplicated in their passive homebrew design, with loads on switches and knobs.
Anyway, nowadays I'm spending my music time working on original music for/with my current band, mostly at home and in the studio, rarely playing out, so I'm going to give the remarkable ACG filters another go.
So far I've only pulled the former controls from the bass, which were master volume, Noll no-load blend, master tone, and passive high-pass control for the bridge pickup. Next I'm carefully plotting the creation of a cavity cover, which will be necessary since the preamp uses a 9volt battery and has internal trim pots to tweak pickup input levels and the blend of the high-pass filter. I have debated doing a top-loaded control plate kind of like Jack Casady's first modified Starfire had, but will most likely go with the back-door design instead. Either way, stopping by my local Rockler wood shop today to pick up the 1/8" wood sheet I'll be crafting the cover out of. What type of wood will depend on the grain and shades of what they have in stock.I
Once this is all done I'll post a demo of some sort, but for now, here's a teaser shot

 

[gilded]

Wowzers!

 

[twocorgis]

Looks very cool Ingo! Keep us posted on your progress.

 

[Happy Face]

That's the filter set I have in my red JS-II.

One word of caution- the slide on clips love to work loose from the posts and slide off. Try pinching them a little to help keep them attached. Did you ever encounter that with the 02?

Otherwise a fine upgrade.

Being a lazy sort, I've ended up setting the filters on both pickups and just relying on the pickup sweep knob and the master tone control. But I'm sure that you will dive in much deeper!!!

 

[Nuuska]

Great - we get another interesting process to follow. The other being that F50? project by Koustask?

 

[mellowgerman]

Thanks for the interest, fellas!

That's the filter set I have in my red JS-II.

One word of caution- the slide on clips love to work loose from the posts and slide off. Try pinching them a little to help keep them attached. Did you ever encounter that with the 02?

Happy, I DID actually experience that with the 02! It was probably the deciding factor in ultimately letting the preamp go and reverting back to passive tweakers. As the story goes, we were playing an outdoor gig on an unseasonably cold late-spring day in Buffalo, 2016. Granted, I wasn't as gentle with the Warwick as I have always been with this Starfire, so the ground wire slipping out of the terminal was probably in part my fault, bumping the bass around in its gig bag on the way to the gig. My fingers were already numb from the cold, so once I realized there was a wiring issue, I didn't even bother to try pulling it all apart. There was not enough time before our set, so I just borrowed a buddy's bass. Problem was that it was a Fender Precision bass with light roundwound strings, tuned to standard. We always tuned a 1/2 step down at the time, so me taking tension off the neck by loosening the already loose strings, in addition to the cold outside air, made the neck go completely flat. The bass was already set up with very low action for a light touch, so it was fret-buzz city! To make matters worse, I'd been playing with nothing but high tension flatwounds on my 32"scale Warwick for months at that point, so the 34" Precision with zingy, grippy roundwounds only made my numb fingers feel even more incapable. Needless to say, as far as 2016 gigs went, that was not my among my favorites! Rather than bounce around the fretboard a bit and improvise around the roots, I just played super simple and hated the tone I was getting... of course, people in the audience said "it was a great set!"
Anyway, I'll tighten the terminals properly this time and perhaps I'll add a little electrical tape to make sure the wires stay put.

 

[Happy Face]

Thanks for the interest, fellas!
Happy, I DID actually experience that with the 02, Of course, people in the audience said "it was a great set!"
Anyway, I'll tighten the terminals properly this time and perhaps I'll add a little electrical tape to make sure the wires stay put.

I pondered dropping on some rubber cement sorta of stuff after a third episode. But a better tech than I warmed me right off of that. One good protocol would be to check connections each time we change a battery. Probably good for all active basses.

But what we should BOTH do it photograph how the connections should be made. As I recall, the company is incredibly non-helpful about this stuff. In fact, when the 01 rig came out, I chatted with the designer on TalkBass about the issue. He claimed I was the only one to have encountered the problem. Not "thanks" for pointing out a quality control issue.

Nor will they provide you with a schematic for the rig.

 

[mellowgerman]

I did it! Found a beautiful 1/8" thick piece of Walnut at Rockler yesterday which had a perfect little bit of curve to it (just like the Starfire top) and was large enough for at least 4 attempts at fashioning a control plate, if need be. My woodworking skills are lacking and my tool stash isn't huge, so I was stoked about how well it came out! The walnut nicely matched the rosewood bridge saddles and it was pretty enough for me to opt to top-mount. In retrospect I'm glad I did it this way, because it's very convenient to just undo 3 screws, pop it out, and have it all neatly in-hand. I had to do this 3 times before all connections were finally tight and not slipping out. Also, I love how comfy my Starfire feels on a strap and I worried that making a back door would ruin the perfect smooth contour of the back and that I would feel it when playing standing up.
The only real mishap in the whole process was while fashioning the control plate. I cut out the rough shape, trimmed tiny bits here and there until it looked like what I had in mind, sanded it meticulously... keeping my novice woodworking skills in mind, I did this very slowly and carefully so it took a couple of hours until I had it looking nice. Then it was time to plot out the holes for the pots. This was also a challenge, since, as you can see in photo #3, there are 3 separate filter boards which are attached to the pots, so squeezing them onto a relatively small control plate was not easy. Once marked, I got out the drill. 1, beautiful. 2, perfect. 3, sehr schön. Almost there! 4, SPLIT! Literally the last step of this multiple-hour process and the darn plate splits into 2 pieces! Luckily, it glued back together super well with some run of the mill super glue and is barely noticeable. The hole was only half drilled though and the split was right across the center of this half drilled hole. Would it hold up? Yes! Lucky. So there it is!
I still plan to stain the control plate to protect it a bit and emphasize the beautiful grain, but I was too excited to try out the new filter setup. I'm not too worried about it drying out either since we use our AC sparingly and we've got plenty of humidity here in FL, so the house maintains a comfy level.
In any case, demo coming eventually, but I want to familiarize myself with these filters first. I have plenty of experience with the rack-mount Alembic SF-2, but it's a little different when you have a low-pass filter for each pickup, combined with a master high-pass. The Alembic SF-2 only lets you run 2 master filters at once, though it does allow you to select whether you want low-pass, band-pass, or high-pass respectively. So I do speak the language, this is just a completely new-to-me dialect.
One final thought, I love how the fact that my Starfire started out as a SFB-I, actually worked out in terms of aesthetics. I think having the single plate and no extra holes on the rest of the bass looks nice a clean!

 

[gilded]

pretty cool!

 

[Happy Face]

I hate to quibble with gilded, but I don't think it is cool. I think it is awesomely cool! Or maybe Wicked Cool, as folks up in Maine night say ....

 

[gilded]

Happy, I was saving the highest accolades for the audio results!!

 

[mellowgerman]

Update and a little snippet.
Maybe about a month back I was lucky enough to find two sets of NOS Maxima flatwound strings on eBay. Through a good amount of research I'm 99% certain that these are the exact same German-made flats that were re-branded and sold by Framus in the 60s, which were the flats that Casady used back then; even the long silks down by the ball-ends match just about every photo and video where Jack's bridge was visible. If I recall correctly, there's still a stash of the Framus branded strings at Rick Turner's shop, from which the original modified Starfire got a fresh set when it was returned to Jack a few years ago.
The Maximas are pretty low tension, similar to Thomastiks, but the tonal difference comes from the materials they're made from. Had a convo with the seller and he mentioned that a key factor of their unique tone and long sustain comes from the soft, brittle bell metal cores they are wound on. "Brittle" makes sense considering that Jack broke a string at both Woodstock and Altamont! That said, I'm sure that they were frequently removing them back then and tinkering with the bass's setup and electronics, so I'm hopeful that if I just keep them installed on the bass, they'll last a long time before I have to break out the second backup set.
Anyway, yesterday while getting set up for rehearsal, I was fiddling a bit with the filter controls and tapped into some of that glassy old Casady tone -- blending lows and mids from both pickups via the dual low-pass filters, tipped slightly more toward the neck pickup, and separately sourcing all highs from the bridge pickup via the high pass filter. I had just enough time to record a quick video with the ol' cell phone camera before Jerry arrived (not Garcia but the band's guitarist none the less). He's the guy knocking at the end of the video.
This recording's audio is not ideal, with a noticeable amount of lows missing since it was just my very non-fancy phone's microphone, but I think it still does a great job capturing the essence of that throaty tone, with all those rich overtones.
Also, the amp I'm playing through here is my Ampeg PF-350 with my 1x12 Eminence-loaded cab. Eventually I'll get a good recording of this bass through the AGC Bonham amp for the full Casady effect.

 

[Nuuska]

I listened with my Sennheiser headphones - and then via my ReVox sound system - and as FOH-engineer I would warmly welcome that sound. Well done.

 

[Happy Face]

Now ain't that something!

Out of curiosity, please send me a more complete description of the filter settings since I hv the same rig on my red JS-2.

 

[mellowgerman]

Now ain't that something!

Out of curiosity, please send me a more complete description of the filter settings since I hv the same rig on my red JS-2.

Howdy! Sorry I forgot about this comment. I've tweaked them a bit since this video but will do my best to draw up a diagram or something. It's a little tricky because my knobs don't have pointers with numbers or any way to mark and communicate exact settings. If I don't send you something within a few days here, feel free to send me a private message to remind me. I've been all over the place lately, having just moved into our new-to-us house and a seemingly endless to-do list, so things have been slipping through the cracks here and there

 

[Happy Face]

Howdy! Sorry I forgot about this comment. I've tweaked them a bit since this video but will do my best to draw up a diagram or something. It's a little tricky because my knobs don't have pointers with numbers or any way to mark and communicate exact settings. If I don't send you something within a few days here, feel free to send me a private message to remind me. I've been all over the place lately, having just moved into our new-to-us house and a seemingly endless to-do list, so things have been slipping through the cracks here and there

Zero.zero rush. I barely touch the filters once I find a sound that's OK. Or after someone picks up the bass to "try it out" and starts turning the knobs like a toddler.

But I know that you would never be so cursory, so I am curious what you have come up with.

 

[mellowgerman]

Zero.zero rush. I barely touch the filters once I find a sound that's OK. Or after someone picks up the bass to "try it out" and starts turning the knobs like a toddler.

But I know that you would never be so cursory, so I am curious what you have come up with.

Finally! Here is a somewhat vague approximation of where my settings fall.

High pass filter's internal phillips head pan control is set fully to the bridge pickup, with the frequency band at about 2 out of 10. Boost set a tiny hair past 5 out of 10.

Low pass filter frequency for the bridge pickup is set at about 5 out of 10. Boost set at 6 out of 10

Low pass filter frequency for the neck pickup is set at about 3.5 out of 10. Boost set at 6 out of 10.

Let me know if that makes sense or not!

 

[Happy Face]

Thanks.

It all makes sense, except for the internal hp control. I'd totally forgotten about it. What was your thinking on That?

 

[mellowgerman]

Thanks.

It all makes sense, except for the internal hp control. I'd totally forgotten about it. What was your thinking on That?

Just a quick prologue: I feel like I have a good practical grasp of these filter preamps (ACG, Alembic, etc.) from experience, but I'm no sound engineer or electrician, so I know my watered-down, layman's explanations may not be the best. These thoughts and pointers all come from what I hear with my ears, corresponding with what my fingers did to get there, typically based on my general interpretation of complicated write-ups I've studied, penned by people who fully comprehend these things in a scholarly sense. So if anybody spots any questionable statements or potential misunderstanding on my end, please feel free to set me straight!

Anyway, since the internal phillips head mini pot is essentially just a pan control, allowing you to blend from which pickup(s) you're sourcing your high frequencies, there's a lot to explore. To get the more Casady-ish sound like in the video, I set the HPF 100% on the bridge pickup, using only lows and low mids from the neck pickup.
That said, at first I really enjoyed sourcing and boosting the highs from the neck pickup (not boosting anything on the neck LPF) and pushing only nice, tight lows from the bridge pickup. It's a unique punchy sound that retained a lot of the tonal character of the neck pickup, but boosted the nice even lows and low mids coming from the bridge.
As for feeding the HPF from a blend of both pickups, I found that a lot less useful, since any kind of blending between two pickups inevitably results in some frequency cancellation and a corresponding scoop. When wired passively, blending two Bisonics results in a bit of a scoop, but it's still a very useable sound. However, since the ACG preamp doesn't have a "band pass" stack (like an Alembic SF-2 unit does), which would translate to a kind of mid-boosting tool, the mids already need to be compensated for in dialing in the ACG preamp. That's not to say that you can't get mids out of your bass once you install an ACG filter preamp, just that you want to avoid creating a mid-scoop by boosting both highs and lows. Of course, I'm not saying these are just your run of the mill, active boost preamps. There's a whole universe of tones to explore since you can dial in your resonant peak frequency. The smallest adjustment of these knobs can make a big difference, which is another reason why communicating these settings in words is tricky. Again, hope that makes sense!

 

[Happy Face]

Thanks again, Mellow One.

I think I swept the internal mini pot over to 3/4 treble pickup but I'm not sure. It was a long time ago. Next time I have to change the battery I will check it.

Sincerely,
Mr. SetitAndLeaveit