Nate Dort wrote: Fri Nov 19, 2021 10:27 am Looks like somebody did a teardown of one of those here: https://www.freestompboxes.org/viewtopic.php?t=30423

Two FETs, looks like they simulated it and it produced a gain of 2.9 V/V (~9 dB).

One FET, one BJT. The first schematic in the thread is incorrect.

Dr Tony Balls wrote: Fri Nov 19, 2021 10:48 am

Nate Dort wrote: Fri Nov 19, 2021 10:27 am Looks like somebody did a teardown of one of those here: https://www.freestompboxes.org/viewtopic.php?t=30423

Two FETs, looks like they simulated it and it produced a gain of 2.9 V/V (~9 dB).

One FET, one BJT. The first schematic in the thread is incorrect.

In that thread someone referred to a gain of 10, or 3dB. Seems pretty weak for something that's described as a transducer preamp. Was that thing meant for acoustic piezo transducers or something?

Nate Dort wrote: Looks like somebody did a teardown of one of those here: https://www.freestompboxes.org/viewtopic.php?t=30423

I somehow missed that thread. Thanks for sharing!

twelvepoint wrote: Fri Nov 19, 2021 10:55 am In that thread someone referred to a gain of 10, or 3dB. Seems pretty weak for something that's described as a transducer preamp. Was that thing meant for acoustic piezo transducers or something?

No idea what the intended application was, but yeah, not tonnes of gain happening.
It certainly seems to be working as it should, but on 10 into my silverface(vibrato channel on 4) things are still pretty clean.

Don't really want to mess with it, but I might as well replace the electrolytics and see what is happening then.
I'll have to do some proper investigation(n00b googlez) later, but I'm curious about upping the voltage/headroom.
Maybe even swap the BJT for a 2n5089 or something higher gain?

twelvepoint wrote: Fri Nov 19, 2021 10:55 am

Dr Tony Balls wrote: Fri Nov 19, 2021 10:48 am

Nate Dort wrote: Fri Nov 19, 2021 10:27 am Looks like somebody did a teardown of one of those here: https://www.freestompboxes.org/viewtopic.php?t=30423

Two FETs, looks like they simulated it and it produced a gain of 2.9 V/V (~9 dB).

One FET, one BJT. The first schematic in the thread is incorrect.

In that thread someone referred to a gain of 10, or 3dB. Seems pretty weak for something that's described as a transducer preamp. Was that thing meant for acoustic piezo transducers or something?

Further down that thread, they revised the gain calculation after correcting the schematic.

Regardless, a voltage gain of 10 is 20 dB, not 3 dB.

Nate Dort wrote: Fri Nov 19, 2021 7:56 pm
Regardless, a voltage gain of 10 is 20 dB, not 3 dB.

Oops, that’s more like it! my bad

Alembic F1X preamp.

The only thing I suck at more than playing drums, is tuning drums so I bought one of those Tunebot drum tuner things. It still takes forever to tune a drum with it, especially the bottom heads, which is where I usually have a hard time. The results are OK. I always have a really hard time getting the floor tom to sound good and now it is... fine. Better than I have been able to do it. Kinda worth the price because now after a ton of time tuning the drum, it sounds ok instead of still bad.

C+

Kniferide wrote: Mon Nov 22, 2021 3:10 pm The only thing I suck at more than playing drums, is tuning drums so I bought one of those Tunebot drum tuner things. It still takes forever to tune a drum with it, especially the bottom heads, which is where I usually have a hard time. The results are OK. I always have a really hard time getting the floor tom to sound good and now it is... fine. Better than I have been able to do it. Kinda worth the price because now after a ton of time tuning the drum, it sounds ok instead of still bad.

C+

Are you trying to get to actual notes on the drums? And are you doing some kind of unison or perfect interval on the heads? If I have a drum that has already been seated and tensioned I’ll just go clockwise and get every lug to a reference. However, and here’s where it gets weird: if a particular note at a lug isn’t getting a clear pitch, it’s usually another lug, often adjacent, but not always so, that is out and throwing me off. So it’s like a “do what you can and fine tune it the next time around” situation. Do these drum tuners have you work in a similar way?

twelvepoint wrote: Mon Nov 22, 2021 3:23 pm So it’s like a “do what you can and fine tune it the next time around” situation. Do these drum tuners have you work in a similar way?

It works like a guitar tuner. you place it next to the lug, smack it, and it tells you the Freq in HZ that that lug is tuned to. Its fairly accurate, but as you move around the drum you gotta keep adjusting as usual. I don't care about specific notes. My issues come with getting consistant results with the top and bottom heads. Deciding if I want a thud or a ring, and making it happen. I have a hard time getting the bottom head tuned in a way that is complimentary with the top. after fudging around with it forever, I end up tuning everything too high, and have to start over. Tuning drums specifically feeds the worst parts of my OCD. having a number on a thing to shoot for gives me a "Stopping point" so I can walk away.

Again, I am NOT a drummer. I can barely keep my guitar in tune and I've been doing that for almost 30 years.

Kniferide wrote: Mon Nov 22, 2021 3:39 pm after fudging around with it forever, I end up tuning everything too high, and have to start over.

Instead of starting over, if you get to the point where the drum is in tune but too high, just go around the lugs and drop them all the same amount. Really helps to have two drum keys and do this on opposite lugs in pairs. Just back them off like an 1/8 turn at a time, keep going till it sounds nice. This should get you better results than starting over from scratch.

Very generally, having the bottom head a 4th or 5th higher than the top head is a good place to start.

Don't get discouraged! Tuning drums is hard, especially toms, and extra especially floor toms.