khstudio
Well-known member
Tell me how & I'll do it... Do you mean ohm resistance on my meter. Sorry to sound dumb but I always hear about DC resistance on the transformer & I'm not sure what they mean... I think I don't know 
API Mic pre (with Yamaha parts) ***COMPLETED***
- Thread starter khstudio
- Start date
Help Support GroupDIY Audio Forum:
mattmoogus
Well-known member
Yep just the resistance of the two windings with yr multimeter.
M
M
khstudio
Well-known member
Cool, now I don't have to wonder...
OK, The tranny in question is GA80980
I have 1 PM2000 ch & 16 M1516 channels... that's where all my parts are from. The numbers match for the input tranny (GA80980) but the one on the M1516 has the ratio on the sticker 300:2.7k. I think I have to pull the one in the PM2000 to check but I don't want to, it sounds great & it's just about in the rack. I really think it's a mistake. That 150k makes me wonder.
How do you check the ratio with the resistance? I'd like to learn.
BTW, I've had the worst tech day... a lot of work but nothing worked
I tried to roughly hook up an M1516 channel but just from the normal XLR input (so it would go thru the gain switching) then I tried grabbing the signal just after the NE-80200 output cap... no-work :?
I guess it would help if I had a schematic. I just wanted to see what a single NE-80200 sounded like in an original form/circuit, then adjust the feedback a little to see what's up.
I was able to see signal at the op-amp input +/- but the output wouldn't go... O well, I should have just did the API today but got caught up with the Zobel & comparing schematics.
Do you think I need to have an input cap like Yamaha did or just do the API design with the Yamaha Zobel :?:
I was also considering the JLM basic single op-amp circuit to see how these components would work in there. What I'm thinking of doing is building an 8ch DRUM Pre-amp... you don't need that much gain on drums. The Presonus M80 I have is a Broadcast vers. & is WAYYYYYYYYYY TOO HOT.
It's very interesting how these mic pre's have different ways of handling gain adjustment. Is there a preferred design :?: The JLM looks like it might be more adaptable to my parts the more I look at it.
Kevin
OK, The tranny in question is GA80980
I have 1 PM2000 ch & 16 M1516 channels... that's where all my parts are from. The numbers match for the input tranny (GA80980) but the one on the M1516 has the ratio on the sticker 300:2.7k. I think I have to pull the one in the PM2000 to check but I don't want to, it sounds great & it's just about in the rack. I really think it's a mistake. That 150k makes me wonder.
How do you check the ratio with the resistance? I'd like to learn.
BTW, I've had the worst tech day... a lot of work but nothing worked
I tried to roughly hook up an M1516 channel but just from the normal XLR input (so it would go thru the gain switching) then I tried grabbing the signal just after the NE-80200 output cap... no-work :?
I guess it would help if I had a schematic. I just wanted to see what a single NE-80200 sounded like in an original form/circuit, then adjust the feedback a little to see what's up.
I was able to see signal at the op-amp input +/- but the output wouldn't go... O well, I should have just did the API today but got caught up with the Zobel & comparing schematics.
Do you think I need to have an input cap like Yamaha did or just do the API design with the Yamaha Zobel :?:
I was also considering the JLM basic single op-amp circuit to see how these components would work in there. What I'm thinking of doing is building an 8ch DRUM Pre-amp... you don't need that much gain on drums. The Presonus M80 I have is a Broadcast vers. & is WAYYYYYYYYYY TOO HOT.
It's very interesting how these mic pre's have different ways of handling gain adjustment. Is there a preferred design :?: The JLM looks like it might be more adaptable to my parts the more I look at it.
Kevin
rafafredd
Well-known member
Really, why don´t you just MOD those and rack it, wth the EQ and all? You can have killer channelstrips at much less work than taking the transformers out and making brand new API modules with those. I would change caps, maybe changing opamps, and even messing with the circuit / signal routig, but I wouldn´t take it apart. I don´t see the point. What will you make with the boards without transformers, then? Just put it away?
If that´s the case, I´ll let you have my adress, for sending this stuff to me.
khstudio
Well-known member
Well, I'm trying to get them hooked up to see how they sound but I don't have a schematic for the M1516
Also, the M1516 strips are too big & full of stuff I don't need or want... like the EQ is IC based & needs it's own voltage - 16v. I don't really mind that though.
I got the board dirt cheap so I'm just having some fun with it :wink:
I'm still learning too... wish I new it all.
Kevin
If anyone does have a schematic for the M1516 PLEASE let me know. It's close to the M1516 but not close enough.
Also, the M1516 strips are too big & full of stuff I don't need or want... like the EQ is IC based & needs it's own voltage - 16v. I don't really mind that though.
I got the board dirt cheap so I'm just having some fun with it :wink:
I'm still learning too... wish I new it all.
Kevin
If anyone does have a schematic for the M1516 PLEASE let me know. It's close to the M1516 but not close enough.
khstudio
Well-known member
rafafredd,
You got me looking @ this thing again damit :green:
It looks like there might be a voltage step down/divider right on the M1516 boards for the 16v to the IC's... I'm checking now.
Is there any info available on the 6552 IC's or on the SIP's that Yamaha uses :?:
Thanks,
Kevin
You got me looking @ this thing again damit :green:
It looks like there might be a voltage step down/divider right on the M1516 boards for the 16v to the IC's... I'm checking now.
Is there any info available on the 6552 IC's or on the SIP's that Yamaha uses :?:
Thanks,
Kevin
khstudio
Well-known member
UPDATE:
rafafredd got me to keep on keepin on & I got a M1516 channel strip going :green: It doesn't sound bad, not quit as nice as the PM2000 but I didn't do any mod yet like up the output cap value, etc... The damn things are about 3in too long to fit in a rack too
TRANSFORMERS:
I measured the DC resistance of the Yamaha Trannys:
Input - GA80980 (300:2.7k)
Primary: 34ohm
Secondary: 410ohm
Output - GA81720 (600:600)
Primary: 20ohm
Secondary: 20ohm
Can someone teach me something here:
How & what info can be gotten from these resistance measurements?
& How can I do it
Kevin
rafafredd got me to keep on keepin on & I got a M1516 channel strip going :green: It doesn't sound bad, not quit as nice as the PM2000 but I didn't do any mod yet like up the output cap value, etc... The damn things are about 3in too long to fit in a rack too
TRANSFORMERS:
I measured the DC resistance of the Yamaha Trannys:
Input - GA80980 (300:2.7k)
Primary: 34ohm
Secondary: 410ohm
Output - GA81720 (600:600)
Primary: 20ohm
Secondary: 20ohm
Can someone teach me something here:
How & what info can be gotten from these resistance measurements?
& How can I do it
Kevin
mattmoogus
Well-known member
[quote author="khstudio"]I was also considering the JLM basic single op-amp circuit to see how these components would work in there. What I'm thinking of doing is building an 8ch DRUM Pre-amp... you don't need that much gain on drums. The Presonus M80 I have is a Broadcast vers. & is WAYYYYYYYYYY TOO HOT.
Kevin[/quote]
Like we said, the Yamaha opamps may not work in the Baby Animal PCB because its powered by a single rail. They WILL work in the 99V MB PCB as it uses symetrical rails.
The only benefit of using the BA PCB for what you want to do is that its smaller and you could fit 8 in a single rack case, whereas the 99V PCB I think youd probably only fit 4.
Did you say you have a full working PM1516? Why not use that as your drum preamp? Take the output from the inserts...change all the audio path caps, should be great! Will save you lots of time and money aswell.
M
Kevin[/quote]
Like we said, the Yamaha opamps may not work in the Baby Animal PCB because its powered by a single rail. They WILL work in the 99V MB PCB as it uses symetrical rails.
The only benefit of using the BA PCB for what you want to do is that its smaller and you could fit 8 in a single rack case, whereas the 99V PCB I think youd probably only fit 4.
Did you say you have a full working PM1516? Why not use that as your drum preamp? Take the output from the inserts...change all the audio path caps, should be great! Will save you lots of time and money aswell.
M
mattmoogus
Well-known member
[quote author="khstudio"]
Can someone teach me something here:
How & what info can be gotten from these resistance measurements?
& How can I do it
Kevin[/quote]
CJ!?
Can someone teach me something here:
How & what info can be gotten from these resistance measurements?
& How can I do it
Kevin[/quote]
CJ!?
khstudio
Well-known member
[quote author="mattmoogus"][quote author="khstudio"]I was also considering the JLM basic single op-amp circuit to see how these components would work in there. What I'm thinking of doing is building an 8ch DRUM Pre-amp... you don't need that much gain on drums. The Presonus M80 I have is a Broadcast vers. & is WAYYYYYYYYYY TOO HOT.
Kevin[/quote]
Like we said, the Yamaha opamps may not work in the Baby Animal PCB because its powered by a single rail. They WILL work in the 99V MB PCB as it uses symetrical rails.
The only benefit of using the BA PCB for what you want to do is that its smaller and you could fit 8 in a single rack case, whereas the 99V PCB I think youd probably only fit 4.
Did you say you have a full working PM1516? Why not use that as your drum preamp? Take the output from the inserts...change all the audio path caps, should be great! Will save you lots of time and money aswell.
M[/quote]
I think your mis-understanding me... I was under the impression I could use just a single op-amp in the 99v, NO? That's what I mean by basic configuration. Also, I have a whole console but NO power supply so I stripped it. Im gonna have enough pre-amps without adding these too. Not to mention my studio's full of shit now.
I just email JLM for a price quote for power supplies & 2 99v boards. I'll then have 2x 99v, 2x PM1000, 2x PM2000, 2x MP20, 8x M80... that should be enough for me to get some nice, diverse colors & layers in the mix :wink:
BTW, I'm wiring up the API circuit with the Yamaha parts right now. I'm using the Zobel from the Yamaha though & probably a cap on the output... just having fun, it might be cool :roll:
How do I checkto see if the Zobel is correct? Can I just run test signal thru & look at it on my computer test software, Audio Tester. I have a good sound card, Lynx One.
Kevin[/quote]
Like we said, the Yamaha opamps may not work in the Baby Animal PCB because its powered by a single rail. They WILL work in the 99V MB PCB as it uses symetrical rails.
The only benefit of using the BA PCB for what you want to do is that its smaller and you could fit 8 in a single rack case, whereas the 99V PCB I think youd probably only fit 4.
Did you say you have a full working PM1516? Why not use that as your drum preamp? Take the output from the inserts...change all the audio path caps, should be great! Will save you lots of time and money aswell.
M[/quote]
I think your mis-understanding me... I was under the impression I could use just a single op-amp in the 99v, NO? That's what I mean by basic configuration. Also, I have a whole console but NO power supply so I stripped it. Im gonna have enough pre-amps without adding these too. Not to mention my studio's full of shit now.
I just email JLM for a price quote for power supplies & 2 99v boards. I'll then have 2x 99v, 2x PM1000, 2x PM2000, 2x MP20, 8x M80... that should be enough for me to get some nice, diverse colors & layers in the mix :wink:
BTW, I'm wiring up the API circuit with the Yamaha parts right now. I'm using the Zobel from the Yamaha though & probably a cap on the output... just having fun, it might be cool :roll:
How do I checkto see if the Zobel is correct? Can I just run test signal thru & look at it on my computer test software, Audio Tester. I have a good sound card, Lynx One.
mattmoogus
Well-known member
If by correct you mean flat, or fairly flat, you need some test software like Rightmark Audio Analyzer (what we use). You then just run the test signals thru it and check the freq graph.
However, you can play with the loadings and values of the zobel if you want, to see what the transformer sounds like with less dampening.
You might find two settings you like and then you can have a load switch which will basically give you 2 pres in one box.
Yep you can use only one opamp in the 99V MB PCB, just leave out some of the parts and wire from the B output.
BTW, all the prices for PCBs and kits are up on the website.
M
However, you can play with the loadings and values of the zobel if you want, to see what the transformer sounds like with less dampening.
You might find two settings you like and then you can have a load switch which will basically give you 2 pres in one box.
Yep you can use only one opamp in the 99V MB PCB, just leave out some of the parts and wire from the B output.
BTW, all the prices for PCBs and kits are up on the website.
M
khstudio
Well-known member
I know there's prices listed but not for the 99v board & components MINUS the op-amps & a few other thing I don't need like the relays & associated components.
Don't you guys adjust the kits to the customers needs?
BTW, I didn't see a price for the PM2000 EQ board & after listening to my PM1000 again tonite, I am REALLY interested in that mod :!:
How much are they?
& is it both mid bands or just the High mid?
Thanks,
Kevin
Don't you guys adjust the kits to the customers needs?
BTW, I didn't see a price for the PM2000 EQ board & after listening to my PM1000 again tonite, I am REALLY interested in that mod :!:
How much are they?
& is it both mid bands or just the High mid?
Thanks,
Kevin
rafafredd
Well-known member
Really, man, hear what I say...
Like NYDave always says, I also think that there´s too many mixers being striped down these days.
I would keep the mixer as is, and MOD it. MOD the hell out of the strips, aux sections, master, etc... But keep it alive as a mixer. If moded right these things can work great for out of box mixing. Forget Protols. Mix like they used to do. You might get surprised by the results a cheap yamaha mixer can deliver. If it´s really well moded, with higher quality opamps and caps, and maybe minor circuit changes, it can turn into a full blown mixer, with it´s own sound signature, and nobody will have a mixer like yours. You won´t need no racking job. Just use it as it is and make it even better. If you want to track throught it, that can´t be that hard to include some direct outs.
That´s what I would do.
Like NYDave always says, I also think that there´s too many mixers being striped down these days.
I would keep the mixer as is, and MOD it. MOD the hell out of the strips, aux sections, master, etc... But keep it alive as a mixer. If moded right these things can work great for out of box mixing. Forget Protols. Mix like they used to do. You might get surprised by the results a cheap yamaha mixer can deliver. If it´s really well moded, with higher quality opamps and caps, and maybe minor circuit changes, it can turn into a full blown mixer, with it´s own sound signature, and nobody will have a mixer like yours. You won´t need no racking job. Just use it as it is and make it even better. If you want to track throught it, that can´t be that hard to include some direct outs.
That´s what I would do.
khstudio
Well-known member
[quote author="rafafredd"]Really, man, hear what I say...
Like NYDave always says, I also think that there´s too many mixers being striped down these days.
I would keep the mixer as is, and MOD it. MOD the hell out of the strips, aux sections, master, etc... But keep it alive as a mixer. If moded right these things can work great for out of box mixing. Forget Protols. Mix like they used to do. You might get surprised by the results a cheap yamaha mixer can deliver. If it´s really well moded, with higher quality opamps and caps, and maybe minor circuit changes, it can turn into a full blown mixer, with it´s own sound signature, and nobody will have a mixer like yours. You won´t need no racking job. Just use it as it is and make it even better. If you want to track throught it, that can´t be that hard to include some direct outs.
That´s what I would do.[/quote]
Dude, I respect your opinion but for 1, I NEVER MIX IN THE BOX, I already use a console, tried it several times but never liked it. 2, That board needs so much work I wouldn't have a life for a year. I'm already exceeding my free time for DIY + there's NO Schematics to be found & the board has NO power supply & they cost over $500... more than the board itself + IT'S HUGE.
FORGET IT.
You do make a good point about mixing out of the box but your telling the wrong guy. I'm on your side with this one. Please don't beat up my thread about wether or not I should strip this board. People do what they have to do. Giving blunt advise when you don't know the FULL story is a little much.
No offense, I know your trying to help.
SOUNDGUY,
That's what I'm going with for now. I started last nite but had to do a quick mix.
Like NYDave always says, I also think that there´s too many mixers being striped down these days.
I would keep the mixer as is, and MOD it. MOD the hell out of the strips, aux sections, master, etc... But keep it alive as a mixer. If moded right these things can work great for out of box mixing. Forget Protols. Mix like they used to do. You might get surprised by the results a cheap yamaha mixer can deliver. If it´s really well moded, with higher quality opamps and caps, and maybe minor circuit changes, it can turn into a full blown mixer, with it´s own sound signature, and nobody will have a mixer like yours. You won´t need no racking job. Just use it as it is and make it even better. If you want to track throught it, that can´t be that hard to include some direct outs.
That´s what I would do.[/quote]
Dude, I respect your opinion but for 1, I NEVER MIX IN THE BOX, I already use a console, tried it several times but never liked it. 2, That board needs so much work I wouldn't have a life for a year. I'm already exceeding my free time for DIY + there's NO Schematics to be found & the board has NO power supply & they cost over $500... more than the board itself + IT'S HUGE.
FORGET IT.
You do make a good point about mixing out of the box but your telling the wrong guy. I'm on your side with this one. Please don't beat up my thread about wether or not I should strip this board. People do what they have to do. Giving blunt advise when you don't know the FULL story is a little much.
No offense, I know your trying to help.
SOUNDGUY,
That's what I'm going with for now. I started last nite but had to do a quick mix.
fyi, you can get acopian supplies for cheaper than dirt on ebay which would be more than likely better than the $500 supply youd buy for the console. Doubt this applies to your situation, but might be good to know for the future.
dave
dave
khstudio
Well-known member
OK, I just finished wiring up the API but I can't find a reveres taper pot
I have audio taper's, 10k & 25k. Can I just wire it backwards (like turn it up to turn down the vol) so I can get the rev taper effect?
I have audio taper's, 10k & 25k. Can I just wire it backwards (like turn it up to turn down the vol) so I can get the rev taper effect?
rascalseven
Well-known member
Yes, you use a standard audio taper backwards.
It'll just mean that you turn the pot counterclockwise to increase gain.
25k is good.
JC
It'll just mean that you turn the pot counterclockwise to increase gain.
25k is good.
JC
khstudio
Well-known member
I'm sorry,
- the wiper connects to one side - is that the high resistance or low res side when the pot is turned counter clock?
Then, where does that side connect? to the 250uf or 200ohm?
Does the volume increase when resistance increases or the opposite?
- the wiper connects to one side - is that the high resistance or low res side when the pot is turned counter clock?
Then, where does that side connect? to the 250uf or 200ohm?
Does the volume increase when resistance increases or the opposite?
rascalseven
Well-known member
The gain will increase with decreased resistance.
For a normal audio taper pot turn the pot completely counterclockwise and measure the resistance between the wiper (center lead) and either of the edges. Find the edge pin that, along with the wiper in this position, measures basically zero ohms.
Connect one of these two pins to the 250uF and the other to the 200ohms. It doesn't matter which pin goes to which. What matters is the total resistance between the two, which is the same regardless of which pin is attached where.
You can comletely disregard the third pin for this circuit.
JC
For a normal audio taper pot turn the pot completely counterclockwise and measure the resistance between the wiper (center lead) and either of the edges. Find the edge pin that, along with the wiper in this position, measures basically zero ohms.
Connect one of these two pins to the 250uF and the other to the 200ohms. It doesn't matter which pin goes to which. What matters is the total resistance between the two, which is the same regardless of which pin is attached where.
You can comletely disregard the third pin for this circuit.
JC
