New HRM build

[ic-racer]

[IMG:640:480]http://img.photobucket.com/albums/v257/ ... CF5931.jpg[/img]

[ic-racer]

[IMG:640:480]http://img.photobucket.com/albums/v257/ ... CF5933.jpg[/img]

[ic-racer]

[IMG:640:480]http://img.photobucket.com/albums/v257/ ... CF5934.jpg[/img]
[IMG:640:480]http://img.photobucket.com/albums/v257/ ... CF5936.jpg[/img]
[IMG:640:480]http://img.photobucket.com/albums/v257/ ... CF5937.jpg[/img]

[Deric]

Awesome!!! I remember when you first started this. Glad you saw it through!!! Great looking build. Congrats!!

[ic-racer]

Awesome!!! I remember when you first started this. Glad you saw it through!!! Great looking build. Congrats!!

Thanks for checking out the thread.

[ic-racer]

A few more pictures:
[IMG:640:480]http://img.photobucket.com/albums/v670/ ... CF5939.jpg[/img]

[ic-racer]

[IMG:640:480]http://img.photobucket.com/albums/v670/ ... CF5938.jpg[/img]

[ic-racer]

[IMG:640:480]http://img.photobucket.com/albums/v670/ ... CF5904.jpg[/img]

[ic-racer]

No activity on this thread for a while as I have just been playing the amp and burning it in by leaving it on for long periods, if that really does anything.

I got an EVM 12M but am waiting for the reflex cabinet.

I took the chassis out of the cab today to cut back the HRM treble pot but wound up adding more treble. It seems turning the treble down leaves behind a more coarse distortion. Turning it up more covers that up with a more smooth distortion.

I actually cheated in setting the trimmer values. I realized there is a picture of the trimmers of the amp I had cloned I suspect whoever took the picture did not own the amp and did not fiddle with the trimmers, so they should be set to something that sounds good.

I needed to make a few assumptions about the board to interpret the settings. That is, the BASS trimmer is wired to work backwards. I wired mine that way and I believe it is the logical way to interpret the picture. Having the trimmer set the other way does not make any sense because it is "full on" at any setting after about 12:00. In my picture collection I think I can make out the BASS trimmer on other HRM boards with this same architecture and the trimmer is set to about the same place.
[IMG439]http://img.photobucket.com/albums/v670/ ... otated.jpg[/img]
Caveat: I have pictures of at least two different HRM board layouts so all the above may only apply the specific amp that I am modeling.

[ic-racer]

Anyway the amp sounds really fantastic. Really smooth distortion. I'll post some clips soon.

[martin manning]

The pins can be in several configurations on those trimmers, but the markings on the tops is clear, with "3" being the clockwise end. Looking forward to the sound clips!

[ic-racer]

duplicate

[ic-racer]

The pins can be in several configurations on those trimmers, but the markings on the tops is clear, with "3" being the clockwise end. Looking forward to the sound clips!

That is a good point but I have researched it and the two BI Technologies trimmers series #72 that have the 4 notches on the one end (72P and 72PM) both have the orientation of the leads like I have shown. The one that has the single lead on the other side and a flipped orientation is 72RP and it has a different case design than what is shown in the pictures.

http://www.bitechnologies.com/pdfs/72.pdf

[ayan]

I think all the HRM amps I've ever heard of had the trimmers wired the conventional way such that they worked "clowckwise." I hear you on the settings one sees out there, but I'll take that a step further and wonder why Dumble would pick a 1 Meg trimmer for the bass anyway? The on-off effect of the bass is much less pronounced if one uses something like a 250K or 470K trimmer and for me, the usable ranges were achievable with a 250K one. I don't thínk we'll ever get a good answer for this one.

Cheers,

Gil

No activity on this thread for a while as I have just been playing the amp and burning it in by leaving it on for long periods, if that really does anything.

I got an EVM 12M but am waiting for the reflex cabinet.

I took the chassis out of the cab today to cut back the HRM treble pot but wound up adding more treble. It seems turning the treble down leaves behind a more coarse distortion. Turning it up more covers that up with a more smooth distortion.

I actually cheated in setting the trimmer values. I realized there is a picture of the trimmers of the amp I had cloned I suspect whoever took the picture did not own the amp and did not fiddle with the trimmers, so they should be set to something that sounds good.

I needed to make a few assumptions about the board to interpret the settings. That is, the BASS trimmer is wired to work backwards. I wired mine that way and I believe it is the logical way to interpret the picture. Having the trimmer set the other way does not make any sense because it is "full on" at any setting after about 12:00. In my picture collection I think I can make out the BASS trimmer on other HRM boards with this same architecture and the trimmer is set to about the same place.
[IMG439]http://img.photobucket.com/albums/v670/ ... otated.jpg[/img]
Caveat: I have pictures of at least two different HRM board layouts so all the above may only apply the specific amp that I am modeling.

[ic-racer]

This is a clip from yesterday. I'm pretty happy.

http://www.youtube.com/watch?v=W004u97Q2DU