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I checked the connections but there is still a lot of noise. I'm still tangled up with the connection

Talion777 wrote:The humbucker I use is 4 drivers + bare

EMG pickup has less turns than your typical humbucker. Additional winding usually introduces more noise.
Also, shielding your pcb might help.

plush wrote:

Talion777 wrote:The humbucker I use is 4 drivers + bare

EMG pickup has less turns than your typical humbucker. Additional winding usually introduces more noise.
Also, shielding your pcb might help.

But they don’t. I thought so too. They are the same as their HZ passive pickups. The 81 is a pretty hot humbucker.

They are totally shielded though.

DavidRavenMoon wrote: But they don’t. I thought so too. They are the same as their HZ passive pickups. The 81 is a pretty hot humbucker.

Wait, really?
Emg HZs have around 13k dcr
81's coils are ~4k dcr each.

plush wrote:

DavidRavenMoon wrote: But they don’t. I thought so too. They are the same as their HZ passive pickups. The 81 is a pretty hot humbucker.

Wait, really?
Emg HZs have around 13k dcr
81's coils are ~4k dcr each.

81s are wound with 43 gauge wire. They are hotter than that. The bobbin is very full. 4 k would be hardly any wire.

DavidRavenMoon wrote:

plush wrote:

DavidRavenMoon wrote: But they don’t. I thought so too. They are the same as their HZ passive pickups. The 81 is a pretty hot humbucker.

Wait, really?
Emg HZs have around 13k dcr
81's coils are ~4k dcr each.

81s are wound with 43 gauge wire. They are hotter than that. The bobbin is very full. 4 k would be hardly any wire.

I'd appreciate you posting dcr

Afaik, they are wound using 42s (.06mm), and have arount 6 to 6.5k turns. Using any web tool you can calc around 4.2-4.7 kOhms of DCR per each.

HULISRAKA wrote: ↑30 Oct 2014, 21:31 we have Blackouts ahb-1
http://imglink.ru/show-image.php?id=6f5 ... 209127ae98

Hi,
I know, it's a old thread, but it's too a reference thread on active differential onboard guitar preamp, and lot of knowlege have been yet shared here. I'd like to ask about more information about EMG and Seymour blackout mismatch loading. EMG uses resistor, Seymour a 680n cap for their blackout, see the shematic still alive posted by hulisraka.

I was septical about the blackout ahb1 shematic, but looking at a real seymour bmp-1 pcb, it is exacty the same topology (differential constant current source + op amp). I've not looked at all components values since i don't want to unsolder the pot. There's of course some differences in resistor values, but the biggest difference between the bmp-1 preamp and the posted schematic of the integrated preamp of blackout ahb-1 is the lack of the mismatched capacitor in parrallel with the input (the 680n caps).
The fact is that i love the tone of the ahb-1, but it lack of wiring option because it's integrated to pickup. So i go for BMP-1, and changed the stupid tl062 for OPA1692 (i feel there's no need of voltage noisy fet low with low current noise, since it's drived from transistors).

And here where i need help : to get the same input imbalance as the ahb-1 on the linked schematic but with the bmp-1 , do i really need to add the 680n at the same position as on the schematic, between left transistor input and ground, wich means between smd components, or would putting this cap directly between input+ and ground of the preamp would be the same? I'm not comfortable with filtering effects...
I understood that simply putting the cap in parrallel with one coil would lower resonance of this coil by a fair amount, but in not sure if it would lead to something else wired as in the shematic.

Said in another simplier way, on the linked shematic, do putting the 680p cap before 47n-18kohm network would change something ?

Best regards,
Damien

papasteack wrote: ↑21 Jan 2021, 10:31between left transistor input and ground, wich means between smd components

Assuming the coils are the same, you do have to put it after the 18 K resistor to get the same response: it should act to lower the resonant peak (in Q, not ƒ), just like a passive tone control in a guitar.
However... 680 nF clearly makes no sense as it would shut all audio. 680 pF sounds more reasonable, though with the specified 1.3 H coils the peak would be in the high treble (for guitar).
I'd say play around with different capacitor values until it sounds right to you. You can tack them on the input if it's easier to solder, just use a separate 18 K damping resistor (or better yet a trimmer).
Here's a popular article that describes how LRC filtering in guitar pickups work: http://www.buildyourguitar.com/resources/lemme/

I was septical

Take care man, that's a medical emergency!

I was septical

Take care man, that's a medical emergency!
[/quote]


Thanks a lot about capacitor value advice. I was looking at this thread : https://guitarnuts2.proboards.com/threa ... nipulation and didn't even notice about the unit difference !

Have a nice day,

Damien

From https://forum.seymourduncan.com/forum/t ... iew=thread
It should be the bump we see in clean around 500-700 khz, and so it induced harmonics, that i like when passing throught distortion (?) compared to EMG. That seems a pretty low coil resonance to target with a cap. Maybe the 680pf could reduce that much resonance of one coil on the blackout pickups, so that for a more standard pickup, i'll have to aim for even higher value. I hardly think to be on the right way, but i'll try !

I built the bajaman version identical to the Electrosmash schematic and Im having issues. The circuit/opamp is distorting from the pickup input.

I am using a 12.5K ceramic seven string humbucker. Ive built the circuit multiple times and can rules out error.

I am using two 12v batteries for 24V and the Opa1641 opamp.

Ive been experimenting trying to minimize the distortion and thus far raising the 30K input resistor to 68K has ALMOST completely stopped the dist, its still happening occasionally on the peak/hard strums BUT the output is so neutered and lifeless at this point that passive is better.

Any ideas? Has anyone else had mixed results with high output pickups and these preamps?

moltenmetalburn, maybe decrease the input caps would avoid these distortion by reducing bass frequences.