Okay, I'm a hack, but I'm learning. HMP mistake.

[RDV]

I just discovered a HUGE mistake I've been making all along with parametric section of the HMPs. I thought I had to bias the output opamp section, not realizing it gets it's bias through the frequency pot! UGH!!
What I've been doing is un-doing the whole gyrator concept! I was wondering why R.G. never commented on my little adaptation of his EQ circuit. He knew it wouldn't work, or would be hamstrung at best. I removed the 100k to Vr from the second section of the 2nd opamp and BOOM: I got a sweepable EQ.

Any body that's built this thing, remove that sucker and hear what the damn thing's really supposed to do!

I'll be updating all schems and layouts for the next hour.

RD(umbass)V

[RDV]

While I'm at it you don't need the 1uF right beside it either.

RDV

[John Egerton]

So you would now reccomend the HMP rather than the HMP lite becuase of the functional eq?


John

[ragtime8922]

I just discovered a HUGE mistake I've been making all along with parametric section of the HMPs. I thought I had to bias the output opamp section, not realizing it gets it's bias through the frequency pot! UGH!!
What I've been doing is un-doing the whole gyrator concept! I was wondering why R.G. never commented on my little adaptation of his EQ circuit. He knew it wouldn't work, or would be hamstrung at best. I removed the 100k to Vr from the second section of the 2nd opamp and BOOM: I got a sweepable EQ.

Any body that's built this thing, remove that sucker and hear what the damn thing's really supposed to do!

I'll be updating all schems and layouts for the next hour.

The HMP (REV 5) was first on my build list. I'm out of town at the moment. I'm glad to hear you found that problem. You've worked so hard on that thing. BTW, you didn't have rev 5 posted on your site. When I try to print it from your link it cuts off the end and I have to draw it out. Any chance of posting it?
                              -Chris

RD(umbass)V

[ragtime8922]

Sorry, I logged on and replied before seeing the HMP 6 thread. Great job.

[RDV]

I'm going to pare all this down to 2 versions very soon. One will have a BMP tone control, the other the RAT style. I'm going to stop when I get them finalized cause it has to stop somewhere. The "light" version will be posted with the same 2 options.

RDV