I picked up a cheap passive preamp out of fear a cheap powered one would mess with the signal too much, but I learned that tone controls need a dedicated preamp just to get the levels back up after filtration. Luckily I had an extra preamp so nothing lost, but thought I would share that in case anyone was unaware.
Hi Dave, I ordered a couple of these for amp projects. The volume pot is linear so will need to swap this if you're driving a high output power amp, otherwise its a good board. Thanks
Thanks! That's what I need, but would be better to have it handle a DC single supply, or at least a +/- 6VDC. Maybe with some small modifications, but I guess the NE5532 won't be at ease with only 6V. I'm going to try with an LM675 splitter.
Useful unit spoiled by the + and minus a/c power requirement. Most of us do not have a suitable bare 12-0-12 transformer hanging around. If you are stuck,it should work with + and minus d/c. I am pretty sure 9 volt batteries will work despite the 12 volt regulators,if not just bypass them.
I bought one of those from Aliexpress. I was quite disappointed it wasn't a kit! It worked fine but it wasn't much better than any other circuit. I was thinking of adding it in to a guitar amp circuit using the left and right channels separately, depending on which channel was selected earlier in the chain or just sticking them in parallel before the final pa stage. In the end, I actually went a simpler route but it is useable in other projects for sure.
Is your transformer a 12V CT (6V/side) or a 24V CT (12V/side)? A 12V CT would only give about plus and minus 9V which would probably still work but not be regulated by the 7812/7912. I Ran into this one time with a board similar to this and didn't realize the problem until I was tracking down a low level hum that was coming from the power supply.. A lot of amp boards are usually specified to require 12-0-12V to avoid any ambiguity. As always, thanks for the video and a big thumbs up.
I need a source for a 12v ac transformer like that. I have several of these boards which came with no instructions. I’ve been wondering how to power. Please advise. Thx!!
Hello. I have this preamplifier and the bass correction does not work on one channel. I changed the bass potentiometer but it still doesn't work. does anyone have the schematic of this preamplifier?
360MIX At the 12 o clock position it sounds pretty flat. Yes the tone controls cut and boost. I don't have the cross over frequencies as they are not listed on the specs. Sounds around 130 1k 7.5k ish boost cut.
Would have liked it to have more if it would have a 60 to 70Hz boost, as that is what most small speakers have issues with. Probably 2 caps, but a schematic would be nice to see if that is easy doable.
Thanks for your reply.. If you put the BASS / MID and TRE all the way DOWN/COUNTER CLOCKWISE do you hear anything? If you do then it does not do a full EQ cut... just wanted to know since thats what I'm looking for a full cut EQ
It's not mounted at an angle. The idiot postal worker jammed the package into the mail slot and bent the control and the regulators over. I have since straightened it. No big deal, not broken, just bent the pins going into the board.
be neat to-install those good op-amps the full component / discrete opamp in this or similar board .Burson vs Sparkos vs Staccato are good ones or ebay off brand versions seem to have good reviews . i am going to get a set for A sansui rebuild but ill bet ill try them in my mini preamp very much like this one but it has a butt load a caps only real difference i can see
@@12voltvids Thanks for explaining a bit more about this split voltage system. I have several units similar to the tone control you demonstrate, and also some Chinese power amps, that seem to require this split voltage system, but I have not managed to get them to work. The plan was to use them in a 48 channel pipe organ to give a very three dimensional sound (computer running Hauptwerk, sound via optical to two Motu 24ao). All the other amps and solenoids etc run on 12 volts DC.
Unfortunately no supply coupling capacitors near ICs. Seems like no separation between left signal ground line and right signal ground line. Cheers from Indonesia.
The problem with them broads is they use 12v power regs they shood have 15V regs and then people used 12V power supplies.. so your not even getting 12v to the op amp due to drop out.. 2# the op Amps work like shit with 12v they need 15v~18V to work good
Acyually the input after rectification is +16 -16 and the regulated output is +-12 volts. The op amps operate perfectly fine at +-12 volts. They will operate fine between 3 and 20 volts. Go look up the specs before you open your mouth and insert your foot in it. www.jameco.com/Jameco/Products/ProdDS/903963.pdf
Those NE-5532 OP amps are very old and compare in performance badly to a modern high end OP amps like the LME49720NA. At least they are socketed so you could swap various ones in/out.
Although the NE5532 chips are old, they are still a great opamp. While the newer ones do have better specs, Most people will never hear the difference. They still have lower distortion than most other things in the signal chain.
Jim Litz No it was bent when the postal worker stuffed the bag it was shipped in through the mail slot. They just throw stuff around. I just received another package that was totally crushed on one side. I have since straightened the pot. Didn't want to do it before shooting video in case I broke the control.
Be nice to see the output compared to the input on an ass silly scope Err-Oscilloscope, Even if-n yo use one of those cheap ass single channel one's for under $20 Bucks would be noise Err-Nice.. Dropped a Like and Subbed, Coz I wanna see how you go with the Power Amp Err-Amps if-n yo B do-n a Stereo PA/Disco System, Coz right now.. I B ass M ball-N a Stereo Class D 400WRms System using an un-ass-M-Balled Tone controller that's much like this a here one in yo vid..
I picked up a cheap passive preamp out of fear a cheap powered one would mess with the signal too much, but I learned that tone controls need a dedicated preamp just to get the levels back up after filtration. Luckily I had an extra preamp so nothing lost, but thought I would share that in case anyone was unaware.
Dear Dave, thanks for your nice review about the Tone board. ^0^
Hi Dave, I ordered a couple of these for amp projects. The volume pot is linear so will need to swap this if you're driving a high output power amp, otherwise its a good board. Thanks
Wow, great video as always
Does this works good with 300 watt amp...? I have used but don't have a good response.
sir , how to connect this board on mp3 module ?
Similar board a blue color having red type components is it good or this borde is good my brand?
Thanks! That's what I need, but would be better to have it handle a DC single supply, or at least a +/- 6VDC. Maybe with some small modifications, but I guess the NE5532 won't be at ease with only 6V. I'm going to try with an LM675 splitter.
Useful unit spoiled by the + and minus a/c power requirement.
Most of us do not have a suitable bare 12-0-12 transformer hanging around.
If you are stuck,it should work with + and minus d/c.
I am pretty sure 9 volt batteries will work despite the 12 volt regulators,if not just bypass them.
12 0 12 transformers available good
I bought one of those from Aliexpress. I was quite disappointed it wasn't a kit! It worked fine but it wasn't much better than any other circuit. I was thinking of adding it in to a guitar amp circuit using the left and right channels separately, depending on which channel was selected earlier in the chain or just sticking them in parallel before the final pa stage. In the end, I actually went a simpler route but it is useable in other projects for sure.
Its isnt purpose for guitar at all
Nice review keep it up👍
I am looking for the schematics of this preamplifier
Is your transformer a 12V CT (6V/side) or a 24V CT (12V/side)? A 12V CT would only give about plus and minus 9V which would probably still work but not be regulated by the 7812/7912. I Ran into this one time with a board similar to this and didn't realize the problem until I was tracking down a low level hum that was coming from the power supply.. A lot of amp boards are usually specified to require 12-0-12V to avoid any ambiguity. As always, thanks for the video and a big thumbs up.
Dave, is the acrylic box something you made yourself or are they available to buy somewhere? jodie
I need a source for a 12v ac transformer like that. I have several of these boards which came with no instructions. I’ve been wondering how to power. Please advise. Thx!!
To those wondering , Antek a company in N.J. makes excellent toroidal transformers. The an-212 or the an-215 will work.
Nice ground plane shielding. Even when you were handling the board,I did not hear any annoying hum thru the video. Was listening with headphones on.
Yes, a good sound.
Hello. I have this preamplifier and the bass correction does not work on one channel. I changed the bass potentiometer but it still doesn't work. does anyone have the schematic of this preamplifier?
Nice sound, i love it. XH-M164.
how to connect RCA OUTPUT?
When you turn down the BASS / MID / TRE does it do FULL EQ cut?
360MIX
At the 12 o clock position it sounds pretty flat. Yes the tone controls cut and boost. I don't have the cross over frequencies as they are not listed on the specs. Sounds around 130 1k 7.5k ish boost cut.
Would have liked it to have more if it would have a 60 to 70Hz boost, as that is what most small speakers have issues with. Probably 2 caps, but a schematic would be nice to see if that is easy doable.
Thanks for your reply.. If you put the BASS / MID and TRE all the way DOWN/COUNTER CLOCKWISE do you hear anything? If you do then it does not do a full EQ cut... just wanted to know since thats what I'm looking for a full cut EQ
Can i feed it with a AC to DC wall adapter, or do i absolutely need a center tapped transformer?
It needs a center tap transformer. I believe I covered that at about 1:15 if you bothered to listen.
This tone board can I connect class d amplifier?
Yes
Hi Dave, this was very interesting. Do you mind explaing to me how you made that 2.54mm 3P to RCA cable? Thanks!
That's what i am gonna try today
@@endlesstwisties how did it work out?
Could you use a DC supply instead of an AC supply?
Don't use DC supply it will working with ac 12-0-12 1amp transformer
pitty the treble pot is mounted at an angle (or is it bent in the post?)
It's not mounted at an angle. The idiot postal worker jammed the package into the mail slot and bent the control and the regulators over. I have since straightened it. No big deal, not broken, just bent the pins going into the board.
ah right my 2nd hunch was right that the post did it :(
be neat to-install those good op-amps the full component / discrete opamp in this or similar board .Burson vs Sparkos vs Staccato are good ones or ebay off brand versions seem to have good reviews . i am going to get a set for A sansui rebuild but ill bet ill try them in my mini preamp very much like this one but it has a butt load a caps only real difference i can see
Do these pots reduce bass/treble below a flat response? In other words can they lower tone output rather than only increasing tone?
Thanks,
Jason
nice pair for my 500W amp
is it possible to bypass the rectifier and power this via 12v dc ?
Yes left tarminal 12+ right tarminal - it is work
Can i use a 12v DC ?
Yes left right tarminal use
thanks good video
that one is not old circuit. its still available.
Kyaa Isme 12 0 12. 5amp use kar sakte he
Are ma to khud 2 amp kar use kar raha hu but hit ho raha hai isliye 5 amp ka use karna better hai
upload a full connection video please
18 0 18 volt AC 1 Amper work ?
It working with 12-0-12 1amp
Hi, bro how many amp of 12v ac transformer you use??
If my market i get 7amp of 12ac transformer can i use it???
A little unit like this uses miliamps.
Would this work with just 12 volts DC?
Runs on split voltages no no. Ac is required so both + and - voltages can be generated. You could build a split supply out of a pair or batteries.
@@12voltvids Thanks for explaining a bit more about this split voltage system. I have several units similar to the tone control you demonstrate, and also some Chinese power amps, that seem to require this split voltage system, but I have not managed to get them to work. The plan was to use them in a 48 channel pipe organ to give a very three dimensional sound (computer running Hauptwerk, sound via optical to two Motu 24ao). All the other amps and solenoids etc run on 12 volts DC.
The 3 tone switches have no entire detent?
Terence Lau
No detent linear taper .
Ic 7812 input voltage 14 to 35 dual supply
please pdf fle
Unfortunately no supply coupling capacitors near ICs.
Seems like no separation between left signal ground line and right signal ground line.
Cheers from Indonesia.
Single ended output shares a ground for left and right channel.
How to use this board with 30-0-30
The problem with them broads is they use 12v power regs they shood have 15V regs and then people used 12V power supplies.. so your not even getting 12v to the op amp due to drop out..
2# the op Amps work like shit with 12v they need 15v~18V to work good
Acyually the input after rectification is +16 -16 and the regulated output is +-12 volts. The op amps operate perfectly fine at +-12 volts. They will operate fine between 3 and 20 volts. Go look up the specs before you open your mouth and insert your foot in it.
www.jameco.com/Jameco/Products/ProdDS/903963.pdf
Those NE-5532 OP amps are very old and compare in performance badly to a modern high end OP amps like the LME49720NA. At least they are socketed so you could swap various ones in/out.
Although the NE5532 chips are old, they are still a great opamp. While the newer ones do have better specs, Most people will never hear the difference. They still have lower distortion than most other things in the signal chain.
One of those tone pots is crooked. Poor quality control :)
Jim Litz
No it was bent when the postal worker stuffed the bag it was shipped in through the mail slot. They just throw stuff around.
I just received another package that was totally crushed on one side. I have since straightened the pot. Didn't want to do it before shooting video in case I broke the control.
Be nice to see the output compared to the input on an ass silly scope Err-Oscilloscope, Even if-n yo use one of those cheap ass single channel one's for under $20 Bucks would be noise Err-Nice..
Dropped a Like and Subbed, Coz I wanna see how you go with the Power Amp Err-Amps if-n yo B do-n a Stereo PA/Disco System, Coz right now.. I B ass M ball-N a Stereo Class D 400WRms System using an un-ass-M-Balled Tone controller that's much like this a here one in yo vid..