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DIY Stingray 3EQ Preamp
- Thread starter Dominic D
- Start date
If you have 250k or 500k pots, you can try that. It might not make sense, but when I put my amp together I did not have 50k pots and just put 250k pots from strat. When eventually I replaced them with 50k I had an impression that I was getting more hiss from fully cranked 250k on the hi filter before the swap, but I never tried to put those back as the preamp works great as is for me. But if you have a 250k pot, you can wire that in and check... Let us know if it does anything.
Switching cap or resistor in RC section will change the middle frequency of the filter and your 3 band EQ will have a hole. You can wire in a pot I stead of the fixed resistor that there is currently and see what works. It will not be more boost, but it will make the filter work different and perhaps the way you want. There are calculators on line that can calculate RC filters mid frequency. You can play with that, compare to the current values and perhaps find what you want this way as well.
For my needs this Guitar FX Layouts: Sadowsky Preamp has much more oomph!!! I cannnot seem to get the bass boosted on this 3 band eq. it's a nice preamp but just lacking bass for me even after using 100n caps.
Thanks so much for the wealth of information. I'm planning on replacing the C4 and C6 caps with 100n caps, as I play in drop A or even drop G a lot of the time, and the stock HPF just nukes my fundamentals. My old fenders don't have this, and they sound so much fuller. I don't use them for this band though.
Should I be after a particular type of cap? Tantalum, poly, electrolytic?
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I just wanted to verify that it's the caps pointed out below? It's a few $ worth of parts for me, so can't wait!!! I have a HPF set up on my HX Stop at around 26hz to prevent overexcursion down that low for all my downtuned basses, so there is some semblance of control.
Should I be after a particular type of cap? Tantalum, poly, electrolytic?
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I just wanted to verify that it's the caps pointed out below? It's a few $ worth of parts for me, so can't wait!!! I have a HPF set up on my HX Stop at around 26hz to prevent overexcursion down that low for all my downtuned basses, so there is some semblance of control.
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These are basically wrong caps as these are polarized capacitors. You need regular non-polarized film or ceramic.
Also this might not be a preamp for you as it is based on a bandpass filters, you probably need an amp that is based on shelf filters. Like Peavey Cirrus or basically any 2-band eq
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Thanks for that. So one of these guys then?
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Ye
I used the monolithic and polyester, but either of the 3 will do and there is no difference as far as the sound goes.
I used the monolithic and polyester, but either of the 3 will do and there is no difference as far as the sound goes.
Ok, I'm hopelessly lost. Pulled my pre today in preparation of swapping the 2x 8.2uf caps on the input to 100uf caps to kill the hpf, and I can trace the input to the first adjacent cap, which is C1 on the original wiring diagram, but C4 on Dominic's diagram. On the circuit board, this connects directly to a 1uf electrolytic cap, which doesn't correspond to anything on Dominic's diagram.
Please Help!!!
This is not the same schematic. The EQ discussed in this thread is 1988 design I think. This one you have is from earlier 2000. Which is an improved version with polarity reversal protection and perhaps a couple of other design improvements including adjusted EQ voicing. So while it is likely that there are 2 caps that you can also replace, they are not labeled C4 and C6. Without an actual schematic it is hard to say which ones.
I gathered as such. Thanks for the clarification. Schematics seem to be hard to find.
According to musicmanbass.global it's the same circuit, same values, different pots. Mine's a 2009 HH.
October 2006-July 2018 (3 band).
The circuit remains the same and continues to use the TL062 chip. Although pot resistance values remain the same, the previous larger pots are replaced by smaller "Noble" pots.
The preamp is not the same. Yours has diode for example and the 1988 model does not. The diode is most likely for battery polarity protection. Without it, if you plug or touch the battery wrong while bass is connected, the op-amp is fried. I have done that in my bass. The diode being one way conductor, simply does not conduct the power from the backwards connected battery, hence keeps the op-amp safe.
If the schematic otherwise is the same but parts labeling is changes, the caps you are after are probably c1 and probably c4. Basically the input(pickup hot) is connected to one leg of the 8.2.nf cap, the other leg of the same cap is connected to the second 8.2nf cap. These are the caps you need to replace. They should be marked as "822".
From your phone, I think one of them is c1 and another if I would guess is C4. The C12 is probably the 2.2nf (marked as 222) cap for resonant pick offset. This cap is connected just parallel to the pickup. It colors the pickup tone, and can make it sound more mid-rangy (I would say). For 2HH at full it is probably does not do much, maybe boosts high end a little. You can desolder one leg of it out and see if you like the tone more. I personally replaced it with 560pf which sounds a lot better with my cheap single humbucker setup.
If the schematic otherwise is the same but parts labeling is changes, the caps you are after are probably c1 and probably c4. Basically the input(pickup hot) is connected to one leg of the 8.2.nf cap, the other leg of the same cap is connected to the second 8.2nf cap. These are the caps you need to replace. They should be marked as "822".
From your phone, I think one of them is c1 and another if I would guess is C4. The C12 is probably the 2.2nf (marked as 222) cap for resonant pick offset. This cap is connected just parallel to the pickup. It colors the pickup tone, and can make it sound more mid-rangy (I would say). For 2HH at full it is probably does not do much, maybe boosts high end a little. You can desolder one leg of it out and see if you like the tone more. I personally replaced it with 560pf which sounds a lot better with my cheap single humbucker setup.
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That's amazing advice. Thank you. I can confirm C1 is connected directly to the hot pickup wire, it then connects to C10 (big blue 1uF) and to ground. That's as far as I got with a multimeter before I stopped being able to trace a circuit. C4 seems to connect directly to the middle pole of the treble pot, which is 2.2uF C8 in Dominic's layout. I can't seem to find a second 8.2uF hanging off the leg of C1, only that C10.
I probably need a little more quiet time without the Mrs and the dog in my face to get things done to try and nut it out.
You're correct, the 8.2uF's are marked as "822".
I probably need a little more quiet time without the Mrs and the dog in my face to get things done to try and nut it out.
You're correct, the 8.2uF's are marked as "822".
Thanks once again for the information, it's absolutely invaluable and I really appreciate your time. I'm at work with some nice big screens to look at these photos, and will confirm later tonight when I can get a multimeter onto my bass.
I suspect I either have to replace C2 and C3, OR, C1 and C2. C1 makes less sense as it's other leg connects to a 1uF electrolytic (C10) and then to ground. I've drawn the trace I can visually see in the photos of the bottom of the board to demonstrate where the pickup hot wire (W) comes in and where it goes.
Oops, I may have this trace all wrong, curse my eyes.
It looks as if C1 (from W) goes to C12 (2.2uF?), this in turn traces around C2 and C3 to R1 and the + from the battery, which kgbeast informs me is a protection method to only allow 9v one way through the circuit. That same leg of C1 goes straight to ground. This seems to be C4 in Dominic's layout.
It looks as if C1 (from W) goes to C12 (2.2uF?), this in turn traces around C2 and C3 to R1 and the + from the battery, which kgbeast informs me is a protection method to only allow 9v one way through the circuit. That same leg of C1 goes straight to ground. This seems to be C4 in Dominic's layout.
Continuing...
C1 (MM diagram) leads into to C12 (MM diagram) 2.2nF? I think is C12 is C5 in the DIY diagram. This then bridges to ground.
C4 on the MM diagram equates to C8 (2.2nF?) on the DIY diagram running from the middle pin of VR2 (Treble). I can disregard this cap.
C5 (MM diagram) is C9 (DIY diagram). 4.7nF. Again, I can also disregard this cap.
I think C3 (MM diagram, 8.2nF) equates to C6 (DIY diagram) due to the resistors hanging off each end. I think the same 150k on the front leg of C3 (mm diagram) is connected to the back leg of C2 (MM diagram).
This leads me to believe that C2 and C3 in the MM diagram are C4 and C6 in the DIY diagram. They're both labelled "8FO 822J", which are 8.2nF caps.
I'll get a meter out and test, and also visually verify values once I'm home later, then confirm. If it seems completely wrong, please chime in
C1 (MM diagram) leads into to C12 (MM diagram) 2.2nF? I think is C12 is C5 in the DIY diagram. This then bridges to ground.
C4 on the MM diagram equates to C8 (2.2nF?) on the DIY diagram running from the middle pin of VR2 (Treble). I can disregard this cap.
C5 (MM diagram) is C9 (DIY diagram). 4.7nF. Again, I can also disregard this cap.
I think C3 (MM diagram, 8.2nF) equates to C6 (DIY diagram) due to the resistors hanging off each end. I think the same 150k on the front leg of C3 (mm diagram) is connected to the back leg of C2 (MM diagram).
This leads me to believe that C2 and C3 in the MM diagram are C4 and C6 in the DIY diagram. They're both labelled "8FO 822J", which are 8.2nF caps.
I'll get a meter out and test, and also visually verify values once I'm home later, then confirm. If it seems completely wrong, please chime in
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