The LND150 is a MOSFET, generally used in high voltage circuits. I have a pile of them and use them in tube circuits where I need 3 halves of a 12AX7 dual triode but don't want to use 2 tubes. I think they can operate at up to 400v or something crazy like that, and I use them to replace the cathode follower to lower the impedance prior to a tone-stack. I borrowed this idea from Blackstar tube circuits.
This is a 9v circuit, so you MIGHT be able to use a BS170/2N7000, though you might need to add a zener diode to protect the MOSFET because I don't know that a normal MOSFET has the same ESD protection on the gate as the LND150.
I'm more interested in the use of a ferrite bead to suppress high frequency EMF. I've never seen that before in a guitar pedal and I'm wondering about the effectiveness. Ferrite beads are sort of like an inductor, but the ferrite material changes the characteristics in a non-linear way. Used this way it's a low pass filter, but I'm not really sure what frequencies are being suppressed.
peeped the specs on digikey: 500V 30MA. crazy! I tried both BS170 and 2N7000, but neither worked. might be like you said, might need a zener. guess I'll pick up a few of those mosfets from digikey next time i place an order.
I just recently built a pedal a few weeks back that used ferrite beads the same way, but I can't for the life of me remember what it was. I thought that was pretty interesting, too. first time coming across that.
The lnd150 is a depletion mode MOSFET, most (including the bs170 and 2n7000) are saturation mode so they're not going to be drop in replacements. JFETs are depletion mode but I doubt you'll be able to drop one in as is. They're not too hard to get hold of.
Built it and it sounds awesome! The EQ is quite powerful & interacts with the gain nicely. It can get a bit nasty at extreme EQ & Gain settings, but is super responsive & has an almost compressor-like texture at low & mid-gain settings.
Verified aside from two corrections: 1.) Change LND150 pinout from from DGS to SGD (flip the flat side of the transistor 180 degrees, but leave the pin lettering the same). 2.) Mid pot is A10k rather than B10k
Hey fuzzhead... found another for you... EHX Q-Tron... https://drive.google.com/file/d/1rVCUL0mv0xLK4FBuIzHjGOLw1b8fXPXK/view
ReplyDeleteany recommendations on a good alternative to the LND150N3-G?
ReplyDeleteThe LND150 is a MOSFET, generally used in high voltage circuits. I have a pile of them and use them in tube circuits where I need 3 halves of a 12AX7 dual triode but don't want to use 2 tubes. I think they can operate at up to 400v or something crazy like that, and I use them to replace the cathode follower to lower the impedance prior to a tone-stack. I borrowed this idea from Blackstar tube circuits.
DeleteThis is a 9v circuit, so you MIGHT be able to use a BS170/2N7000, though you might need to add a zener diode to protect the MOSFET because I don't know that a normal MOSFET has the same ESD protection on the gate as the LND150.
I'm more interested in the use of a ferrite bead to suppress high frequency EMF. I've never seen that before in a guitar pedal and I'm wondering about the effectiveness. Ferrite beads are sort of like an inductor, but the ferrite material changes the characteristics in a non-linear way. Used this way it's a low pass filter, but I'm not really sure what frequencies are being suppressed.
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Deletepeeped the specs on digikey: 500V 30MA. crazy! I tried both BS170 and 2N7000, but neither worked. might be like you said, might need a zener. guess I'll pick up a few of those mosfets from digikey next time i place an order.
DeleteI just recently built a pedal a few weeks back that used ferrite beads the same way, but I can't for the life of me remember what it was. I thought that was pretty interesting, too. first time coming across that.
The lnd150 is a depletion mode MOSFET, most (including the bs170 and 2n7000) are saturation mode so they're not going to be drop in replacements. JFETs are depletion mode but I doubt you'll be able to drop one in as is. They're not too hard to get hold of.
DeleteBuilt it and it sounds awesome! The EQ is quite powerful & interacts with the gain nicely. It can get a bit nasty at extreme EQ & Gain settings, but is super responsive & has an almost compressor-like texture at low & mid-gain settings.
ReplyDeleteVerified aside from two corrections:
1.) Change LND150 pinout from from DGS to SGD (flip the flat side of the transistor 180 degrees, but leave the pin lettering the same).
2.) Mid pot is A10k rather than B10k
Thanks!
ReplyDeleteTagged and updated.
Fyi it's 18 x 17. Sounds awesome though!
ReplyDeleteLND150s came in yesterday, and I can confirm this pedal is excellent! Thanks for the layout!
ReplyDelete