Ceriatone Forum

Ceriatone => Overtone => Topic started by: hywelg on September 12, 2008, 06:55:37 PM



Title: HRM Questions
Post by: hywelg on September 12, 2008, 06:55:37 PM
For those who know about these things since layout isn't up on the site yet!

There is now a deep and a mid switch. I guess the Pull switch on input volume is now the bright switch? (photos don't show it).

It appears the OD trimmer is now on the rear panel (thought the board mounted one is still in place), but what does the switch below it do. It appears to be a 3 position switch.

FET input is gone but are the two inputs different levels?

3 internal trimmers are I guess tmb for OD?



Title: Re: HRM Questions
Post by: mx on September 13, 2008, 02:35:18 AM
Hello,

From an earlier post by Nik on the imminent release of the HRM:

"As for the issue, ie the bright cap -

  I think it'd be nicer if by default (normal mode) that some value of bright is there.

  The bright cap not only adds brightness, but some dimension/hair to the sound, which I like.

  The 120 in normal mode, and 120 + 180 = 300pf seems like a good idea.

  Thought of using 3 way switch, but the slot for the toggle has been taken by the Deep, Mid boost, and Rock/Jazz."


Seems like that 3-way on the back underneath the OD pot might be for the tone cap options referred to above....

Matt


Title: Re: HRM Questions / toggle switch on back
Post by: mx on September 13, 2008, 07:28:47 AM
Hi again,

Looking more closely at the pictures, I think I was mistaken about any caps being introduced into the tone stack by that toggle switch;

It has only a resistor and a couple of white wires: http://www.ceriatone.com/images/completeAmpsPic/Overtone_HRM50/b3B.jpg

One of the wires terminates on the 4 ohm lug (green) of the impedance selector: http://www.ceriatone.com/images/completeAmpsPic/Overtone_HRM50/b25B.jpg

The other white wire off the toggle looks to be equivalent to the B-24 wire of the ODS layout but comes off the toggle switch instead of the 4 ohm lug and then continues as B-13 to the Presence pot.

So, this seems to give some added manipulation to the Presence circuit but I am not quite sure how....or why  :-\ 

BTW, here's a good snap of a pull switch added to the Overdrive Level pot (3rd from left): http://www.ceriatone.com/images/completeAmpsPic/Overtone_HRM50/b10B.jpg Looks like Nik added a bright/boost to the OD section because the HRM EQ is set by internal trimmers....

Those three internal trimmers are definitely the fabled HRM (Hot Rubber Monkey) passive EQ for the OD circuit.  Nik added them as a new board to the exiting layout (bottom left):
http://www.ceriatone.com/images/completeAmpsPic/Overtone_HRM50/b25B.jpg

My kit was to ship this coming week.  Now the ? is whether ODS or HRM....?  I think the HRM is a little grittier, has lead clean headroom and has more of a Marshall quality drive compared to the smoother ODS but I could be dead wrong!

Input?

Matt




Title: Re: HRM Questions / toggle switch on back
Post by: hywelg on September 13, 2008, 08:25:07 AM
BTW, here's a good snap of a pull switch added to the Overdrive Level pot (3rd from left): http://www.ceriatone.com/images/completeAmpsPic/Overtone_HRM50/b10B.jpg Looks like Nik added a bright/boost to the OD section because the HRM EQ is set by internal trimmers....

Hmm missed that one. I guess thats so you can set the HRM to a warm Rf tone then add bright thro that switch if needed.



Title: Re: HRM Questions
Post by: hywelg on September 13, 2008, 09:11:52 AM
Just had this quote from Nik

 
As for the HRM, I am locked out of the forum cant seem to remember which email address I used to register :)
 
The switch at the back was a custom. It's Marin's HRM. That's a feedback resistor switch to select no res, 4K7 and 8K2.
 
The standard ones dont have that.
 
The OD trim is indeed set at the back.
 
The one INSIDE is another trimmer to allow for value determination of resistor before the OD trim.
 
The HRM usually has 200K.
 
But I made the fixed resistor to be 100K + 250K trim so you can go anywhere between 100K and 350K value. Default set 200-220K total value (ie 100-120K for that trimmer).
 
I thought long and hard - I really dont want ppl having to mod. I wanted to put ALL switches to select values in the HRM. But, instead of buying an amp, people would be buying a fighter jet flight console instead, too many switches and pots.
 
One of these days, I'll do that. Perhaps the techs would be able to enjoy the "Overtone TMP" - Tweak my P....layer" :) ie if anyone come to them for a custom overtone, they'd be able to switch, and tweak many possible configs inside the amp.
 
Can you post inside the forum while I figure out the login thing? :)
 
Thanks!

Nik