Welcome, Guest. Please login or register.
May 16, 2022, 11:42:11 PM
Home Help Search Login Register
News: Ceriatone Forums are up and running!!!
 
Guests please register
Note: If you want to help you can donate to keep the forums alive.










Do you want to advertise on this forum ? Send me a private message.



Amplified Parts
+  Ceriatone Forum
|-+  Ceriatone
| |-+  Overtone
| | |-+  Boxy PAB? Ineffective tone controls? I've found the design flaw!
« previous next »
Pages: 1 [2] 3 4 Go Down Print
Author Topic: Boxy PAB? Ineffective tone controls? I've found the design flaw!  (Read 29738 times)
captainbackfire
Full Member
***
Offline Offline

Posts: 113



View Profile
« Reply #15 on: November 22, 2012, 11:52:59 AM »

This is great overall but I'm now more confused

Pickmaster indeed said that lowering the slope resistor to 68k does wonders in "bloom" and "touch responsiveness"

Now just what exactly does modding the other way (increasing slope resistor) do to the sound? Please elaborate to me kindly and thanks a lot.

And about the "high plate" and "low plate" thing. COuld you guys explain that concept and what made the difference between the two and how they impact the response given the slope resistor values. ..I've read that "high plate" versions yield a stiffer feel. Now those who know me know that I am rather allergic of anything stiff. What can I do for more responsive compression then? You know, so I can strum colorful chords and yield a glassy pleasing chirpy sound as opposed to ear fatigue inducing stiffness.

Kinda like John's tone here (he is indeed using one of his early Dumbles here through a Fender 2x15 most probably)
<iframe width="420" height="315" src="http://www.youtube.com/embed/gya94ScUKPc" frameborder="0" allowfullscreen></iframe>

I'm sorry fo r asking these I have a rather lower average knowledge in amps.

THanks for all the well meaning modders and tweakerses you guys.
« Last Edit: November 22, 2012, 12:01:07 PM by captainbackfire » Logged
Thilo278
Jr. Member
**
Offline Offline

Gender: Male
Posts: 85



View Profile
« Reply #16 on: November 22, 2012, 05:19:37 PM »

I would say, just try it out. I like the 68k resistor, although I don't know if the difference I hear is the resistor or the LNFB... Smiley Anyways, it was an easy mod. We just snipped the old resistor and didn't have to get the turret board out. If you do it, make sure you record soundclips of both variants Wink Smiley
Logged
Kevster
Jr. Member
**
Offline Offline

Posts: 92


View Profile
« Reply #17 on: November 22, 2012, 06:02:22 PM »

I would say, just try it out. I like the 68k resistor, although I don't know if the difference I hear is the resistor or the LNFB... Smiley Anyways, it was an easy mod. We just snipped the old resistor and didn't have to get the turret board out. If you do it, make sure you record soundclips of both variants Wink Smiley

This is a cheesy fix, but you don't HAVE to remove the other resistor.  Stack the right values in parallel you get the same thing.  IF you don't like it later, you haven't disturbed the board.
« Last Edit: November 23, 2012, 08:11:33 AM by Kevster » Logged
captainbackfire
Full Member
***
Offline Offline

Posts: 113



View Profile
« Reply #18 on: November 22, 2012, 09:17:55 PM »

Thilo didn't you make a switch for LNFB? Why not switch it on and see what the 68k slope did?
Logged
Thilo278
Jr. Member
**
Offline Offline

Gender: Male
Posts: 85



View Profile
« Reply #19 on: November 23, 2012, 03:33:02 AM »

Oh... you're right Cheesy Totally forgot about that, cause I never switched it on again  Grin
I'll see if I can trust my memory enough to make out the difference... The only thing I can say atm is, that I didn't get a significant increase in bloom. (Maybe a strat is the wrong guitar for that anyway... I'll try it with an ES-335 Smiley )
Well, I think if I use the settings I always did before the mod and still have more bass and low mids, we know what the slope resistor did.
Logged
captainbackfire
Full Member
***
Offline Offline

Posts: 113



View Profile
« Reply #20 on: November 27, 2012, 08:42:18 AM »

I should re phrase my post. I read back the thread and I think I get it better how the 180k slope resistor concept could work well. Perhaps I'm just a bit baffled cause I am about to do the new Dr. Ika (Pickmaster) FM ME / OTS "TR" mod with the suggested 68k slope.

I just hope bluesking could read this and shed some light into other aspects of the mod like is it more punchy or what other than being more scooped. And also I hope Pickmaster could chime in too so he could share his ideas on this.
Logged
Kevster
Jr. Member
**
Offline Offline

Posts: 92


View Profile
« Reply #21 on: November 27, 2012, 08:52:38 AM »

Captainbackfire,

For determining what is the right voicing for the slope resistor, you can bench test lower values without a soldering iron.  If you are uncertain as to the effect of the mod or which value is "you", calculate and parallel a resistor with some alligator clips.  Be careful doing it, but it saves time...
Logged
captainbackfire
Full Member
***
Offline Offline

Posts: 113



View Profile
« Reply #22 on: November 27, 2012, 09:14:23 AM »

THats very interesting on the alligator clips. Could I just clip it on and off while amp is operating ? Better to turn off?
Logged
Kevster
Jr. Member
**
Offline Offline

Posts: 92


View Profile
« Reply #23 on: November 27, 2012, 09:50:24 AM »

THats very interesting on the alligator clips. Could I just clip it on and off while amp is operating ? Better to turn off?
Definitely OFF!  Yeah, you want the test resistor in place, stable, and isolated from adjacent components when you power it up.  To determine the right values for testing, just use the formula:

               1/R1 (Existing Slope) + 1/R2 (secondary test value) = Total R.

That will allow you to hear before you commit.

If you aren't comfortable moving around in an amp, you might want to get around somebody with experience.  It can hurt you quick.
Logged
mr fabulous
Full Member
***
Offline Offline

Posts: 114


View Profile
« Reply #24 on: November 27, 2012, 10:07:05 AM »

THats very interesting on the alligator clips. Could I just clip it on and off while amp is operating ? Better to turn off?
Definitely OFF!  Yeah, you want the test resistor in place, stable, and isolated from adjacent components when you power it up.  To determine the right values for testing, just use the formula:

               1/R1 (Existing Slope) + 1/R2 (secondary test value) = Total R.

That will allow you to hear before you commit.

If you aren't comfortable moving around in an amp, you might want to get around somebody with experience.  It can hurt you quick.

a couple of points:

1. placing a resistor in parallel will always decrease resistance. therefore to get an increase in resistance you either need to  change the resistor or add another resistor in series
2. a correction on the parallel resistor formula posted earlier:

 1/R1 (Existing Slope) + 1/R2 (secondary test value) = 1/Total R.

lowering the slope resistance will decrease the overall insertion loss of the tonestack and therefore provide more signal to the overdrive section. hence giving more bloom, however also with an increase in bass and mids
increasing the slope resistor has the opposite effect, it increases the insertion loss and there the result will be a more pristine signal to the overdrive section, with less bass and mids, but the overall tone is much more natural. to compensate for the loss, i have turned up the overdrive somewhat when needed, however the sound is tighter and clearer.

each to his own.... however a customer has heard my amp many times before, however after hearing it last week with the resistor mod, has decided to place an order.

i cannot stress enough for those using EV12L's, putting them in a tuned box such as the TL606 makes the world of difference to the overall sound and response too ....tightens the bass up without loss of highs
Logged
captainbackfire
Full Member
***
Offline Offline

Posts: 113



View Profile
« Reply #25 on: November 27, 2012, 11:44:11 AM »

Thanks for elaborating.

Looks like lowering the slope resistor is my cup of tea. I have one concern though. If the sound "blooms" with more signal hitting the OD stage does it stand to reason that there will be more flub to the bass particularly when you leave your clean EQ settings ( I usually put treb and bass on 7 with mids on 3 ) and use the drive?

I don't believe so though cause I thought the lifted LNFB and bass cap mod will introduce more signal to the rest of the amp and cause bass distortion/flub but nooo, my OD became thicker but more defined with much less flub.
Logged
Pickmaster
Hero Member
*****
Offline Offline

Gender: Male
Posts: 506



View Profile WWW
« Reply #26 on: November 28, 2012, 07:26:41 AM »

Hi there tone lovers,

Once again:
Low slope resistor (not very low though!). Fat sounding Bluesmaster has 47k but there is a  0,02mf after it which cuts down to much bass in comparison to 0,1mf on OTS.
68k slope on OTS is MY PERSONAL favourite which introduces little bit more bass and low mids but most importantly adds natural clean compression to the first tube, so clean gets so called CHIRP and singing quality. Iím a very light touch player and I use very thick pick 3mm Stubby. Compressed clean sound allows me to have less drive on OD trimmer which is kind of clean but fat singing, bloomy, touch sensitive drive tone which does not need PAB to sound great.
In short lower slope resistance and less or no  capacitance on NFB gives me more TWEED tone enhanced in high frequencies with higher capacitor value on the clean volume pot. Personally I always prefer TWEED to Blackface, more correctly tweed fatness with blackface glassy tone added.

Mr. Fabulous is right in case that higher slope resistor gives you more clean, less fat non compressed (more classic blackface) tone and Iím sure many players love this tone but not me. I like rubbery, spongy, fat, wet, syrupy, singing clean and drive tone.

But I totally agree!   Tone is very individual and you have to try to find the best for yourself, tone which makes you play and feel better.

I love my amps. No D-lator in the loop !!! just Digitech RP200

 
 
Logged

Founder and technical director of the Custom Cabinet Company Ė CCC
http://www.customcabcom.com
mr fabulous
Full Member
***
Offline Offline

Posts: 114


View Profile
« Reply #27 on: November 28, 2012, 09:04:34 AM »

thanks dr ika
yes music and sound is such a personal think and we all have our own perceived conceptions of what a great tone is

its is wonderful that Nik has buils such a wonderful platform upon which with a little experimentation and tweaking you can make the amp sound perfect to your own tastes.

i reckon if we compiled a list of all the mods done by various people in this forum, it would read like a nice little cookbook of dumlesque tones
Logged
captainbackfire
Full Member
***
Offline Offline

Posts: 113



View Profile
« Reply #28 on: November 28, 2012, 10:26:54 AM »

Thanks I think I will indeed go with the 68k and I will try to do a before and after sound demo.

Logged
hywelg
Hero Member
*****
Offline Offline

Posts: 897


View Profile
« Reply #29 on: December 04, 2012, 04:06:10 PM »

That sounds fantastic Doc. Are you using the cut control on the OD channel?
Logged
Pages: 1 [2] 3 4 Go Up Print 
« previous next »
Jump to:  


Login with username, password and session length

Powered by MySQL Powered by PHP Powered by SMF 1.1.12 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!

CeriaTone Forum is not afiliated with Ceriatone Amplifications. The CeriaTone and name, logo and related trademarks and service marks, owned by CeriaTone. , are registered and/or used in the U.S. and many foreign countries. All other trademarks, service marks, and trade names referenced in this site are the property of their respective owners.