Vintage Yamaha BB1500A Bass Guitar Preamp Repair
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- čas přidán 9. 09. 2023
- In this video I repair the onboard preamp from a Yamaha BB1500A bass guitar. It needed a new blend pot, and had some other damage. I also tested and plotted the frequency responses of the various filters. It was a challenging and fun project.
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Can't help but imagine the face on the next guy in there to look... "Clearly someone's been in here before but what the heck was he up to?!?" Very neatly done!
And the fact that he had that weird dual taper pot just lying around! This guy's got proper experience!
Yeah I'm a bit of a bass pickup blending control nerd. It's good when the pickups balance well and the blend pot works nicely. I think it's more effective than a mid filter TBH.
I accuired an old HH 100 watt amp. A module of preamp died off and was swapped to custom one that controlling mids and presence. Decided to build original module and did it. It has bobbin filters which I never seen or heard before it works well also has two mosfets. Nevertheles it was fun to build old 70's circuit and get it working. I have build couple overdrive pedals but never seen a circuit like this, it pinpoints the tone. Like an eq.
Beautiful investigation and work!
Thanks mate. This was a fun challenge. A very nice bass.
incredible patience & ingenuity!
Thanks mate.
Genius. ❤❤❤
Ha ha. I'm not sure about that... but I'll take it!
That's awesome! I really really enjoyed this one. I love these circuit board mods. I would have loved to see what you would've done work all of that empty circuit board space if it was your bass. Love the channel!
Thanks mate. I didn't actually trace that part of the board, but I'm quite sure the missing parts were a pair of buffers. The IC was a dual opamp and the pickup inputs appeared to go to each of the non-inverting opamp inputs. IOW, an active pickup blend. Pretty much the same set up as I did with Project Berocca.
Loved the video. Just worth mentioning it's the same electronics as on the original TRB series. IMHO had they stuck to eq2 alone plus some front mounted stacked pots instead of hidding them inside the cavity would have made this preamp a selling point. Actually, that would be a nice mod!
Ha ha, yes, if this was my bass, I'd think seriously about bringing some of those internal controls to the front. It would make for a very versatile instrument for sure!
Can you tell me a bridge that would fit that bass if I need a replacement? Color doesn't matter to me.
I'm afraid I don't know. And this isn't my bass so I can't measure anything as it's not on hand.
Hello. Can you share the shematics with me pls?