Hi everybody. I am trying to replace the pots on a guitar with a single coil lipstick pick up and a humbucker. It had a blend pot (only 3 poles) and a volume and tone control. All the pots are 250K. Would it be better to go to 500K and a two tier blend pot? As I understand it, you need a dedicated blend pot. Thank you.
↧
Mixing Single Coi & Hummbucker with Blend Pot?
↧
Birch-Stolec AC30
I'm looking for the schematic for an early '70s PCB based Birch-Stolec AC30 with reverb, if anyone can help. It's not the same as the later '78 reverb model.
↧
↧
Right to Repair movement
Interesting movement. It looks like right to repair legislation is gaining traction 8 States Have Introduced Right to Repair Legislation, Apple to Oppose | iFixit
Thoughts?
Thoughts?
↧
Mesa V-Twin pedal schematic request
I know there's one out there somewhere as I've seen snippets posted on the web. What I'm after is a factory-issue schematic. All I can locate is a redrawn version intended to construct a pedal, but the component references and ICs don't represent the actual unit.
↧
Vox T15 Bass Combo Amp
Please upload schematics or service manual
Thanks in advance
vk
Thanks in advance
vk
↧
↧
Gibson GA50T frequency pot
Hi All,
I have one of these that is having a problem with the tremolo. The frequency pot turns 360 degrees so I was thinking of changing it . But it is a dual gang pot. I have a feeling this might be a reverse taper style pot. I tried a linear and the trem works but the speed is fast at the minimal setting and nothing at the fastest.
Is this meant to be a reverse taper?
If so where can one be found?
Thanks
pete
I have one of these that is having a problem with the tremolo. The frequency pot turns 360 degrees so I was thinking of changing it . But it is a dual gang pot. I have a feeling this might be a reverse taper style pot. I tried a linear and the trem works but the speed is fast at the minimal setting and nothing at the fastest.
Is this meant to be a reverse taper?
If so where can one be found?
Thanks
pete
↧
Crybaby EW-95 wah
Customer swears the boost is randomly happening and that the pedal will suddenly sound distorted. I've poked and prodded and tried to emulate the symptoms, nothing. Curious to see the circuit, with its 6 14-pin ICs to investigate further. :surprised:
↧
Marshall 8080 - clean and boost channel sound distorted
Hi, folks, last year I bought a 90's 8080 amp, and it worked fine, but last months it had a intermitent fail, suddenly went low volume and sounded distorted. I kept using it because the amp started sounding well again, and failure wasn't that often, but now it sounds distorted all the time, in both channels.
I've been reading posts about issues with this amps and I started measuring some things, but I'm getting a little lost with this.
Today I tried all +15 and -15 V lines and readings were really close to 15, but never exact. Positive line changes a little when I plug the guitar, increases some, but sometimes is below 15, I don't know if I'm measuring wrong, the tester is bad or if this is normal, really.
I've also checked that transistors are getting around +42 and -42 at the center leg, but I don't know if they are working well. All three of them must be isolated from the heatsink, right?
How you'd start repairing it?
I've been reading posts about issues with this amps and I started measuring some things, but I'm getting a little lost with this.
Today I tried all +15 and -15 V lines and readings were really close to 15, but never exact. Positive line changes a little when I plug the guitar, increases some, but sometimes is below 15, I don't know if I'm measuring wrong, the tester is bad or if this is normal, really.
I've also checked that transistors are getting around +42 and -42 at the center leg, but I don't know if they are working well. All three of them must be isolated from the heatsink, right?
How you'd start repairing it?
↧
Fender Princeton Reverb starts humming loudly after 15 min.
This Princeton sounds great for about 15 minutes and starts humming insanely. I changed the tubes, unplugged the reverb and checked all resistors and caps. I think it's the big power supply can but I'm not sure.
↧
↧
boss geb-7 schematic
hi , anyone have the service manual for boss geb-7/ theres two versions one being the easiest to find on line. the one i have has a serial for the pwb , and it is... G292711 7RO.
I believe it might be a nwer version than the one that is common online. if needed ill post a pic of the board assy. thanks ahead of time.
I believe it might be a nwer version than the one that is common online. if needed ill post a pic of the board assy. thanks ahead of time.
↧
Convert Marshall 100watt1959 superlead EL34 to KT88
I'm sure this must have been covered here at some point but I just need some confirmation.
I have 12000 series super lead that I build way back based on Metro Amps dual tap PT which can deliver either 530VDC or 480VDC to the plates depending on the position of the standby switch. It has the traditional 27K bias range resistor and 220k bias feed resistors as spec'd for EL34.
My question is: can I just swap out the 27k bias range resistor to accommodate the KT88s or do I need to also swap out the 220k bias feed resistors for 150k?
The JJ KT88 data sheet says I could use 220k http://www.thetubestore.com/lib/thet...re/JJ-KT88.pdf
Can anyone comment if the 220k would work?
Thanks
I have 12000 series super lead that I build way back based on Metro Amps dual tap PT which can deliver either 530VDC or 480VDC to the plates depending on the position of the standby switch. It has the traditional 27K bias range resistor and 220k bias feed resistors as spec'd for EL34.
My question is: can I just swap out the 27k bias range resistor to accommodate the KT88s or do I need to also swap out the 220k bias feed resistors for 150k?
The JJ KT88 data sheet says I could use 220k http://www.thetubestore.com/lib/thet...re/JJ-KT88.pdf
Can anyone comment if the 220k would work?
Thanks
↧
IC adapters SMT to DIP
A few times there has been mentioned a need to use modern SMT IC's on boards equipped with DIP's. One of the adapter sources had dried up from what I recall.
I came across this company, who has pretty much any IC adapter you might need, the link is for simple 8-pin, like op-amps, but they have a lot of different types.
Proto Advantage - SOIC-8 to DIP-8 SMT Adapter (1.27 mm pitch, 150/200 mil body)
I came across this company, who has pretty much any IC adapter you might need, the link is for simple 8-pin, like op-amps, but they have a lot of different types.
Proto Advantage - SOIC-8 to DIP-8 SMT Adapter (1.27 mm pitch, 150/200 mil body)
↧
Alto TS115W powered speaker
Good morning .
I'm looking for a schematic for a Alto TS115w. I know they don't give them out and this is going to be a long shot.
It's a pre amp fault so a pre amp map for any of the range might help
BBB
I'm looking for a schematic for a Alto TS115w. I know they don't give them out and this is going to be a long shot.
It's a pre amp fault so a pre amp map for any of the range might help
BBB
↧
↧
Blackfacing a Fender Dual Showman reverb
HI Guys.
Decided to blackface a SF dual showman reverb for a customer.
Now I have done a couple of similar conversions, but never one with a Trem circuit such as this.
My question. Where does the 2,2M for the trem "jump start" need to go?
Does it go to the diode side to the 3k3 or to the pot side as in the original SF circuit diagram?
I have attached the original SF circuit.
Thank you!
Decided to blackface a SF dual showman reverb for a customer.
Now I have done a couple of similar conversions, but never one with a Trem circuit such as this.
My question. Where does the 2,2M for the trem "jump start" need to go?
Does it go to the diode side to the 3k3 or to the pot side as in the original SF circuit diagram?
I have attached the original SF circuit.
Thank you!
↧
Mark bass s450 schematics needed
Hello everybody,
I have a mark bass s450 "club series" on the bench right now with a weird problem: the gain knob is crackling and the more you turn it up, the lower goes the amp's volume; when gain is maxed the amp is dead silent.
I tried to trace the board but it looks like a 4 layers board with lots of points going nowhere, so i'm here asking if anybody has a schematics for this beast.
I have a mark bass s450 "club series" on the bench right now with a weird problem: the gain knob is crackling and the more you turn it up, the lower goes the amp's volume; when gain is maxed the amp is dead silent.
I tried to trace the board but it looks like a 4 layers board with lots of points going nowhere, so i'm here asking if anybody has a schematics for this beast.
↧
DeArmond Bassist 2
I have a DeArmond Bassist 2 bass guitar combo with a blown power transformer. There is very limited information out there on the web and was wondering if anyone had a schematic or knows where to find a PT?
I have attached a picture of the inside of the chassis.
![Click image for larger version.
Name: DeArmond chassis.jpg
Views: 4
Size: 242.5 KB
ID: 43929]()
Thanks,
Dan
I have attached a picture of the inside of the chassis.
Thanks,
Dan
↧
I know whats wrong.......
Working on a rather battered Vox right now, but I found all that was wrong was this dry joint;
![Click image for larger version.
Name: IMG_20170626_190107167.jpg
Views: 3
Size: 432.9 KB
ID: 43930]()
↧
↧
Adding spring reverb to a practice amp board already printed for spring reverb?
I picked up a Dean Markley K-20X practice amp the other day. Very loud for 10-15 actual watts. Not bad sounding at all. Overdrive is pretty good. Probably going to be part of a starter package for my best friend's daughter who turns 16 in a couple weeks.
Naturally i opened it up. Curiosity, plus wondering if anything needs to be replaced or upgraded. Turns out they use LED clipping in their OD circuit.
The board is etched, drilled, and printed both sides for spring reverb. All of the component values are marked. The hole for the potentiometer is already in the chassis, just not through the control panel sticker.
Of course, I don't know the properties of the reverb tank, but i can see that it was a small one from the mounting holes. I have an Accutronics blue spring reverb i was going to use for another project, which would absolutely fit in this but maybe not on the existing mounting holes (I haven't checked). The board is printed for JST type connectors for the reverb tank, exactly like are already on the accutronics blue tank.
I can't find much info on obsolete DM practice amps. They've scrubbed their website of any information. Haven't been able to determine if there was a version of this amp with reverb.
The blue tanks come with 150 ohm, 600 ohm, or 1.5kohm input . All of them have 1.5k output. Since this design would drive and recover the tank with a TL072, I think it's probably a fair guess that 150 ohm was maybe what they used, with 600 ohm also possible. There are no transistors following the output of the TL072.
Granted, i should probably trace out the circuit and determine what was most likely from there. If it turns out they designed for 600 ohm, that tank is only $15 away.
There is no position for a switch to disable reverb. Just the mix knob.
Anyone ventured out this way before?
Naturally i opened it up. Curiosity, plus wondering if anything needs to be replaced or upgraded. Turns out they use LED clipping in their OD circuit.
The board is etched, drilled, and printed both sides for spring reverb. All of the component values are marked. The hole for the potentiometer is already in the chassis, just not through the control panel sticker.
Of course, I don't know the properties of the reverb tank, but i can see that it was a small one from the mounting holes. I have an Accutronics blue spring reverb i was going to use for another project, which would absolutely fit in this but maybe not on the existing mounting holes (I haven't checked). The board is printed for JST type connectors for the reverb tank, exactly like are already on the accutronics blue tank.
I can't find much info on obsolete DM practice amps. They've scrubbed their website of any information. Haven't been able to determine if there was a version of this amp with reverb.
The blue tanks come with 150 ohm, 600 ohm, or 1.5kohm input . All of them have 1.5k output. Since this design would drive and recover the tank with a TL072, I think it's probably a fair guess that 150 ohm was maybe what they used, with 600 ohm also possible. There are no transistors following the output of the TL072.
Granted, i should probably trace out the circuit and determine what was most likely from there. If it turns out they designed for 600 ohm, that tank is only $15 away.
There is no position for a switch to disable reverb. Just the mix knob.
Anyone ventured out this way before?
↧
DC on input jacks
Dang had this problem on a clone before but this is a real '57 5E3 Fender tweed deluxe.
The worst jack is about .3 volts unloaded, maybe 10mv with a guitar plugged in causing scratch noise when guitar pot is turned.
And no, it isn't the guitar.
Gotta' be leaky 60 yr old board material, right?
Does it without preamp tubes installed, 1M resistors are good, 68k resistors are good.
This guy always gives me old stuff that's a pia!
I don't think it's worth it to replace all the front end stuff on an original amp.
Anything else I could possibly check?
The worst jack is about .3 volts unloaded, maybe 10mv with a guitar plugged in causing scratch noise when guitar pot is turned.
And no, it isn't the guitar.
Gotta' be leaky 60 yr old board material, right?
Does it without preamp tubes installed, 1M resistors are good, 68k resistors are good.
This guy always gives me old stuff that's a pia!
I don't think it's worth it to replace all the front end stuff on an original amp.
Anything else I could possibly check?
↧
FX Amplification DG20 Demo Video
Hello Guys,
It is a long time since I published a video, here is our last one.
This is the DG20 from FX Amplification. This is a 20w handwired head inspired by an old Hiwatt DR103.
Great amplifiers!
Tell us what you think. If you want to support us, please like and subscribe the video!
Cheers!
It is a long time since I published a video, here is our last one.
This is the DG20 from FX Amplification. This is a 20w handwired head inspired by an old Hiwatt DR103.
Great amplifiers!
Tell us what you think. If you want to support us, please like and subscribe the video!
Cheers!
↧