Amptweaker - Tight Metal  [traced]

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Re: Amptweaker - Tight Metal

Postby J0K3RX » 21 Sep 2017, 21:34

temol wrote:I've just finished TM build (effectslayouts pcb) and I have a question about "tight" knob. When rotating "tight" there is no change in the sound until last 20 degrees or something like that. Is this normal? Potentiometer is B100k.

T.


not normal.. Tight pot should be C100k. I can say that with 100% certainty because I am sitting here looking right at it :wink:

I would like to know why the "Tight" pot on the BE-OD works so good and not so much on the Amptweaker pedals? I haven't built the BE-OD yet so, I am only going by what I have heard people say.. I can't stand it on the amptweaker boxes, sounds like it's sucking the life out of it when you dial it up!
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Re: Amptweaker - Tight Metal

Postby bmxguitarsbmx » 22 Sep 2017, 00:02

Is it because the Be-od is "Tight before clipping", and the Amptweaker has clipping before tight?

I don't know myself, I haven't played the tight metal.
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Re: Amptweaker - Tight Metal

Postby J0K3RX » 22 Sep 2017, 04:31

bmxguitarsbmx wrote:Is it because the Be-od is "Tight before clipping", and the Amptweaker has clipping before tight?


I don't know but, I wouldn't think so..? I never really experimented with the tight pot on the tight metal or tight rock because they both seem to be already about as tight as you would ever want... Adding a tight control to them is like adding wetness control knob next to the water on/off knob in your shower... Maybe if it made it less tight (loose) it could serve a purpose because I find the Amptweaker pedals to be a bit stiff and unforgiving especially for playing lead solos. The clipping in the first stages of the tight metal don't seem to have much affect if I my memory is correct because i have removed them and it made little to no difference in the over all gain, sound or feel.. The BE-OD tight pot is connected to vref instead of gnd but I am not sure if that makes much difference either..? Maybe the placement in the circuit makes a difference like sticking it after the first opamp which is also before the clipping, dunno... I will have to mess around with it when I get a chance...
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Re: Amptweaker - Tight Metal

Postby plush » 22 Sep 2017, 08:25

temol wrote:I've just finished TM build (effectslayouts pcb) and I have a question about "tight" knob. When rotating "tight" there is no change in the sound until last 20 degrees or something like that. Is this normal? Potentiometer is B100k.

T.


Just use c100k
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Re: Amptweaker - Tight Metal

Postby temol » 22 Sep 2017, 08:45

not normal.. Tight pot should be C100k. I can say that with 100% certainty because I am sitting here looking right at it :wink:


Changed the pot to C taper, now there is a full range adjustment. Thanks!

T.
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Re: Amptweaker - Tight Metal

Postby bool » 22 Sep 2017, 11:58

>>>> Maybe if it made it less tight (loose) it could serve a purpose because I find the Amptweaker pedals to be a bit stiff and unforgiving especially for playing lead solos.

Adding a "loose" switch to the "tight" control could be made by simply breaking the continuity to the pot with a simple on-off switch; and adding a "just right" resistance in parallel to that switch (possibly a 100k preset/trimmer - or another pot) - meaning that if you had the tight pot sitting at your favorite setting with X kOhm; by flipping a switch you would jump to X + Y kOhm for your lead etc.

Or just mod the thing to switch between two "tight" pots; one being "looser" and the other "tighter" (say, one being a default 100k and the loose one a 200k ...).
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Re: Amptweaker - Tight Metal

Postby bmxguitarsbmx » 22 Sep 2017, 21:54

J0K3RX wrote:
bmxguitarsbmx wrote:Is it because the Be-od is "Tight before clipping", and the Amptweaker has clipping before tight?


I don't know but, I wouldn't think so..? I never really experimented with the tight pot on the tight metal or tight rock because they both seem to be already about as tight as you would ever want... Adding a tight control to them is like adding wetness control knob next to the water on/off knob in your shower... Maybe if it made it less tight (loose) it could serve a purpose because I find the Amptweaker pedals to be a bit stiff and unforgiving especially for playing lead solos. The clipping in the first stages of the tight metal don't seem to have much affect if I my memory is correct because i have removed them and it made little to no difference in the over all gain, sound or feel.. The BE-OD tight pot is connected to vref instead of gnd but I am not sure if that makes much difference either..? Maybe the placement in the circuit makes a difference like sticking it after the first opamp which is also before the clipping, dunno... I will have to mess around with it when I get a chance...



Interesting.

The Tightmetal does already have treble emphasis early on (c4 R5= 720Hz 1st order Highpass ) Then again (c7&R9 make a 2nd order High Step @ 3.2kHz) Then it hits the "Tight control". Usually, there is only one, and sometimes two stages of treble emphasis, if it is highly saturated. Integrating the tight control earlier or replacing one of the existing treble emphasis stages would probably make it more useful. The BEOD tight is useful and also the only treble emphasis stage in that pedal.
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Re: Amptweaker - Tight Metal

Postby Ichabod_Crane » 06 Oct 2018, 13:59

I built the Tight Metal on a verified veroboard layout following this schematic:
Image
I jumpered the loop effects.
It sounds ok, but it is hugely LOUD! I can't go over 1/10 of the volume pot, it's really hard to set the right level, and the 90% of the pot is unusable and dangerous.
The volume pot is a B10k.

I could change the pot, but I don't want to modify the schematic and to change the sound.
I power it up at 9v. And I'm not using the charge pump, I have built it later.

Help, please!
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Re: Amptweaker - Tight Metal

Postby J0K3RX » 06 Oct 2018, 15:56

Shouldn't be that loud... Try connecting the output jack directly to lug2 of the volume pot and see if it makes any difference with the overall volume. This has nothing to do with the volume issue but I believe R27 should be 4k7 instead of 1k5.
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Re: Amptweaker - Tight Metal

Postby Jan1966 » 06 Oct 2018, 18:20

You have done something wrong. Go over The circuit again. I have built loads of these.
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Re: Amptweaker - Tight Metal

Postby Ichabod_Crane » 07 Oct 2018, 08:48

That resistor it's been replaced in the layout, so it's the 4.7k. :wink:

With the lug 2 of the Volume pot directy in the output makes almost any difference, I guess. The volume pot is still unusable, and in the first 10% boost a lot.

Even louer at lug 2 of the Tone pot and at the pin 1 of the TL072. Still loud, but with less distortion at pin 14 of the TL074.

Edit:
In the schematic the Tight pot has connected the lug 2 & 3. I connected 1 & 2, I guess it's just reverse.

TL072 voltages:
1 - 4.99v
2 - 4.99v
3 - 4.61v
4 - 0.00v
5 - 6.41v
6 - 6.50v
7 - 6.50v
8 - 9.00v
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Re: Amptweaker - Tight Metal

Postby Ichabod_Crane » 07 Oct 2018, 11:59

IC - TL074

1 - 4.99v
2 - 4.99v
3 - 4.70v
4 - 9.00v
5 - 5.85v
6 - 6.51v
7 - 6.51v
8 - 6.51v
9 - 6.51v
10 - 4.40v
11 - 0.00v
12 - 4.69v
13 - 4.69v
14 - 4.98v

I'm probing the circuit.
It sounds clean and ok until the first loop effect. Loose volume after R5 47.5k, still no volume at TL074 pin 2.
I got a volume boost at TL074 pin 1, the same volume at pin 10 and pin 8.
At TL074 pin 14 volume the same boosted but even slightly dirty sound.
At TL072 pin 2 I get more dirty sound
At pin 1 TL072 I got more distortion and more boost volume.

I think I never loose volume after it. No at lug 2 of the Tone pot, no at lug 2 of the Volume pot.
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Re: Amptweaker - Tight Metal

Postby Ichabod_Crane » 08 Oct 2018, 17:28

If the voltages are ok I don't see anything wrong. I have the temptation to use a B2k as Volume pot.
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Re: Amptweaker - Tight Metal

Postby J0K3RX » 09 Oct 2018, 15:12

If there is no difference in volume when you wire lug 2 of the volume pot directly to the output then I think you should focus on IC2B and the surrounding componenet values and connections...
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Re: Amptweaker - Tight Metal

Postby Ichabod_Crane » 09 Oct 2018, 17:53

I assume you mean there's someone in the last stage, so after the Volume pot, that should reduce the volume before the final output. :hmmm:

I'm looking at that now.

UPDATE
This is the corrected schematic (resized):
Image

Anyway, I can't find anything! :scratch:
R32, R33 and R34 are right and in the right position on the board.
Alright even C23 and C24.
Alright R35, C25, R36 and R38. R36 and R38 are in parallel and my multimeter show about 32k.
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Re: Amptweaker - Tight Metal

Postby Jan1966 » 09 Oct 2018, 19:20

Not sure if your schem is correct. There are a couple around which should be correct.
Or refer to storyboardist which is verified and compare to that.

http://effectslayouts.blogspot.com/search?q=Tight+metal
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Re: Amptweaker - Tight Metal

Postby J0K3RX » 09 Oct 2018, 20:55

Ichabod_Crane wrote:R36 and R38 are in parallel and my multimeter show about 32k.


If you're not using the loop then one of those is not needed.. your choice R36 or R38.. 100k should be fine.
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Re: Amptweaker - Tight Metal

Postby Ichabod_Crane » 09 Oct 2018, 21:59

Jan1966 wrote:Not sure if your schem is correct. There are a couple around which should be correct.
Or refer to storyboardist which is verified and compare to that.

http://effectslayouts.blogspot.com/search?q=Tight+metal


Actually, I find out in your schematic a resistor (R8?) 1.5k. In all schematic I see a 15k.

Anyway, the schematic should correct and the layout verified.

J0K3RX wrote:
Ichabod_Crane wrote:R36 and R38 are in parallel and my multimeter show about 32k.


If you're not using the loop then one of those is not needed.. your choice R36 or R38.. 100k should be fine.


Indeed, I'm not using neither the first loop, so the same thing worth for R3 and R4.
But the Aeons by Grind Custom FX has none loops and has in the first loop a 320k resistor (like R3 || R4 -> 475k || 1M = 322k). This is why I got 32k with R36 and R38. 47k || 100k = 32k.
So, yes, I could leave out R4 and R38 (I see schematic with a 47k grounded before the output). But I have the doubt I can't solve the issue. Though I worreid about that R38 resistor.

Then, If my build is extremely loud, so should be Grind Custom FX's one?. :hmmm:

R36 and R38 can adjust the amout of volume? The only thing I think I have to do is to adjust that value (100k as J0K3RX suggested?) or add a trimpot as output volume. Or replace the B10k Volume pot with a B2k.
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Re: Amptweaker - Tight Metal

Postby J0K3RX » 11 Oct 2018, 17:04

Hmm.. not really sure why you are getting such high output volume? You could go over it with an audio probe again and see if you can find where it jumps in volume.. :scratch:

Is this the Grind Customs schematic you used? Looks good to me but I only spent a couple minutes looking at it.
https://www.dropbox.com/sh/200s6g8gdcln ... ildDoc.pdf

On another note: I would be interested to see if the tight pot preforms any better if we relocate it between C4 and C5. As it stands the tight pot is useless in my opinion..
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Re: Amptweaker - Tight Metal

Postby Ichabod_Crane » 11 Oct 2018, 18:25

The schematic used for the veroboard layout I used is the one I posted. The layout has the stock Tone pot and the charge pump is missing.

I already probed it.
Ichabod_Crane wrote:IC - TL074
[...]
It sounds clean and ok until the first loop effect. Loose volume after R5 47.5k, still no volume at TL074 pin 2.
I got a volume boost at TL074 pin 1, the same volume at pin 10 and pin 8.
At TL074 pin 14 volume the same boosted but even slightly dirty sound.
At TL072 pin 2 I get more dirty sound
At pin 1 TL072 I got more distortion and more boost volume.

I think I never loose volume after it. No at lug 2 of the Tone pot, no at lug 2 of the Volume pot.


I got the boost twice, pin 14 TL074 and at pin 1 TL072.
I see that the original Tight Metal is pretty loud, too. Sometime the volume pot is at 9 o'clock. Maybe my built is a bit more loud, I really can't see anything wrong, and maybe there's nothing wrong.

I guess a B5k pot could be more useable as volume, do you think it has also some side effect?
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