Treble cut control

[ginger]

I added this cut control to a 5E3 , because I had an unused control spot in the chassis... it does nothing... not that it's just subtle..it  does NOTHING. Any thoughts ?

[shooter]

Matchless calls it a brilliant knob, when I tried I called it useless.  try taking the pot/cap out, and replacing it with a switch/cap across the treble cap, so you're switching in a parallel cap with the existing, maybe start at .01uF and decide direction from there 

[ginger]

Thanks... I was trying to find something to match the label on the chassis that says " bass"... I may try your suggestion , or I may just use
 a master volume there

[ginger]

Just going to add a push/pull pot to switch the V2 cathode cap out... I've done that in
 other builds... was just looking for something else , but without being too
 invasive

[d95err]

If it does nothing, you’ve probably got an error somewhere. I’ve used that type of cut control in a few builds and it it has a very noticeable effect.

If the amp has negative feedback, it would probably be less effective, but the 5e3 doesn’t, so a wiring or component error is more likely.

[Ed_Chambley]

That cut control is for a 5f6a Bassman with a LTPI.  Could be different.  I attached the Vox cut control schematic, I know it works.

[ginger]

Yeah I just used the one I did , because Rob Robinette said it was wonderful in a Tweed Deluxe

[dude]

I did Ed's vox cut, in an 18 watt, works very well.

[ginger]

See if I've got this straight .... comparing Ed's schematic to the Robinette layout. The difference is... Ed's cut pot is wired like this.... lug 3 of the pot is wired to the .0047 cap that goes directly to the .1 cap / 220k /and the wire leading back to the grid of 1 output tube . Lug 2  of the pot , ( wiper ) is wired to the .1 cap / 220k / and grid of the other tube . Lug 1 of the pot is connected to nothing .

[Ed_Chambley]

See if I've got this straight .... comparing Ed's schematic to the Robinette layout. The difference is... Ed's cut pot is wired like this.... lug 3 of the pot is wired to the .0047 cap that goes directly to the .1 cap / 220k /and the wire leading back to the grid of 1 output tube . Lug 2  of the pot , ( wiper ) is wired to the .1 cap / 220k / and grid of the other tube . Lug 1 of the pot is connected to nothing .

It is not really Ed's, it is a clip I made from the Vox AC30.


Complete schematic attached. 

[sluckey]

The circuits are identical. Actually, connecting the wiper to one outer leg is preferred

[ginger]

Ok.. just replaced the pot , to see if that was the problem.... there's nothing TO this , so simple.. has to work now

[ginger]

Nope , still nothing, and my board layout is neat... sounds like a really nice 5E3... cut control wired exactly like Robinettes , and what Ed posted . So simple.. I don't get it .

[sluckey]

Show us a pic that clearly shows your actual work.

[ginger]

Ok... same amp with trem thumping

[ginger]

Yeah , things are prettier before you start digging for a problem.... the cut pot in on the left , with the yellow mallory .0047 hanging off lug 3 . Nothing connected to the wiper in this picture... been using jumpers , after nothing seemed to make the cut work . I realize this pic can tell you nothing... but here it is

[sluckey]

The wiper must be connected in order for the pot to work.

[ginger]

Yes.. said that. I've had it connected ... SOLDERED , unsoldered , jumpered...but , thanks for that  ,I know it's hard for you to diagnose problems from the shit people send.... can you just come over ? This problem is idiotic... it's like saying , " I have only TWO straight wires , connected to TWO places ", and the wonderful mod does not work. But , really .. thanks

[sluckey]

Sometimes you just have to cut your loses and move on.

[ginger]

Yeah... there are limits. Good forum though

[shooter]

So, this treble cut, it's the same as Matchless clubman's "brilliant" ?  I'm 2nd guessing myself   

[sluckey]

So, this treble cut, it's the same as Matchless clubman's "brilliant" ?

Same except for the size of the pot. Maybe a 1M pot would help ginger?   

[shooter]

Maybe a 1M pot

I tried that circuit in 2 amps, neither had enough effect on the scope to warrant the solder, and was confirmed by guitar guys.  It did "cut" signal some, but only when you dimed the amp, and not enough to have a stage presence.  That's why I asked because others seem to have had luck with it? 

[sluckey]

I've put that exact circuit in my AC-15 Lite, Dual Lite, and AC-15 amps. I put that same circuit (except using a 1M pot) in my Matchless Lightning. Works fine in all those amps. All those amps have a very similar power amp with LTP PI. I wonder if there is something about the 5E3 cathodyne PI that does not like the cut control?

[2deaf]

I added this cut control to a 5E3 , because I had an unused control spot in the chassis... it does nothing... not that it's just subtle..it  does NOTHING. Any thoughts ?

The output impedance for the two outputs connected like that is very small.  That means they can drive a pretty healthy capacitive load without losing high frequency response.  Therefore, I wouldn't expect your tone control to work with a cathodyne PI.

[PRR]

>> the 5E3 cathodyne PI
> The output impedance for the two outputs connected like that is very small.

Back up. The first post shows a 5F6a long-tail. But we are really in a cathodyne?? 2deaf has it: the CoD is hard to load-down.

Put your 250K + Cap across the plate load of the stage *before* the cathodyne. Cap to plate so you don't whine about DC voltage under a knob, 0-250K adjustable resistor to ground. 0.005u against the simple ~~39K of the 12AX7 plate cuts all above 900Hz; a hundred K series resistance makes it a shelf instead of a fall-to-zero. Depending how out-back you need to be, you might double or half the cap. 250K Linear makes perfect sense; 500K Audio taper may also be interesting if you like a shelf which is deep but not infinite.

[shooter]

This  place IS the best!
thank you

dave

[ginger]

Can someone who has time , put this in schematic form

[sluckey]

.

[shooter]

the CoD is hard to load-down.

You have a cathodyne phase invertor, which as flushed out so far, is hard to effect like you're expecting vs the long tail phase invertor.
when I used that circuit, it was with a Cathodyne 6V6, the other was a inter-stage tranny EL34, both amps are out in the world, both owners did comment, the knob "didn't do much"

[ginger]

I was actually wanting someone to draw out in schematic form , what PRR was describing

[sluckey]

I was actually wanting someone to draw out in schematic form , what PRR was describing

So why didn't you say that! PRR gave very explicit instructions. Surely you can draw that yourself? Learn to fish.

[VMS]

This is the treble control from matchless chieftan amp. I'm guessing PRR was describing something like this:

[ginger]

I was actually wanting someone to draw out in schematic form , what PRR was describing

So why didn't you say that! PRR gave very explicit instructions. Surely you can draw that yourself? Learn to fish.

I CAN... just not sure what he was saying...

[ginger]

Thanks VMS... that's what I needed

[ginger]

Cut control works with this schematic  , but don't know if it was worth the struggle... almost sounds like a second tone control

[sluckey]

It's no longer a cut control. Now it's a simple treble bleed tone control. At least you got the front panel hole filled.

[ginger]

Good one

[ginger]

No... as soon as i found out it sounded like ass... I replaced it with a switch pot... to switch out the V2 cathode cap

[ginger]

I just really want to thank PRR , for his simple treble bleed ... I'm hunting him down

[sluckey]

Good one

I believe that was your original intent?

I added this cut control to a 5E3 , because I had an unused control spot in the chassis...

PRR (and 2deaf) have always been very helpful with understanding issues that seem to be off the beaten path. I hear he likes Ice House beer. 

[ginger]

Sorry... this time  , he gets crap white wine

[shooter]

I hear he likes Ice House beer. 

 
related? 

[Willabe]

Sorry... this time  , he gets crap white wine

It was your idea to try something that doesn't work.

PRR gave you something else to try instead, not his fault you don't like it. Sometimes mods work to someones liking, sometimes they don't and you move on.

We try to be respectful of one another here. 

[sluckey]

Sorry... this time  , he gets crap white wine

I don't much care for your smart ass attitude, especially when people are trying to help you. And I really don't like your "spoon feed me" mentality, but it's been fun watching you slobber around. Good bye ace!

[Ritchie200]

Sometimes you just have to cut your loses and move on.

Ok I guess its just me, but I am still cracking up over this as I thought it had a double "cut" meaning.  Ok it's just me....

Jim

[Ed_Chambley]

I believe I read PRR to write where and what to do, but not exactly the values used.  He did write linear, but suggested 250K but did allude to the possible use of a 500k.  Maybe try reading about high pass and low pass filters and test a few values.  I can assure you a cut control is a tone control as well.


I actually do have 2 tone controls for a tweed deluxe and they are switchable because I like to change speakers.  The stock interactive tone is great to me with Greenback or Alnico Blue, the ceramic Jensen is brittle sounding to me.


Sometimes I put in a GZ34 and speaker out to a Altec 417, 8a which will provide a lot more headroom with the 6G3 tonestack.  Just have to have a dual 1 meg pot for the main tone control.  Probably the most versatile mod I have ever done to any amp. 

[Willabe]

Sometimes I put in a GZ34 and speaker out to a Altec 417, 8a which will provide a lot more headroom with the 6G3 tonestack.  Just have to have a dual 1 meg pot for the main tone control.

Dual 1M pot?

[Ed_Chambley]

Sometimes I put in a GZ34 and speaker out to a Altec 417, 8a which will provide a lot more headroom with the 6G3 tonestack.  Just have to have a dual 1 meg pot for the main tone control.

Dual 1M pot?

I am looking for the drawing, but until... the difference between the 2 are the 220K Resistors and cap values, but still 3, 1 meg pots.  I just use a DPDT to switch out the resistors, but to switch to another tone control pot to get the stock interactive 5e3 tonestack which I like too.


I found the drawing of modding the 5e3 to 6G3, the switching is simple.

[ginger]

Really odd reaction... i was joking... I appreciate all the advice... just trying humor... I KNOW I need to figure it out myself. Really frightening reaction from a couple of people .