Amptweaker - Tight Metal  [traced]

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Re: Amptweaker - Tight Metal

Postby Ichabod_Crane » 20 Oct 2018, 15:01

Replace the 10k linear Volume pot qith a 5k linear. There's still an abrupt bump of volume in the very early part of the pot range.
Even when the volume pot of the Tight Metal is fully turn down I can hear the sound.

Looking at the schematic I'm using I have no sound at TL074 pin 2 and a big boost at pin 1. The R6 is a 1M and the orientation of D11 is right. What I have to check? Everything seems ok.
A 10k log pot (or a 5k log) could be adjust the range, but it's all so weird. :scratch:
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Re: Amptweaker - Tight Metal

Postby Ichabod_Crane » 23 Oct 2018, 11:26

Replacing the 10k linear pot with a 5k linear pot the issue is NOT solved.

Could somebody probe the own Tight Metal to compare the volume in the varoiuos stages, please?
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Re: Amptweaker - Tight Metal

Postby temol » 23 Oct 2018, 13:04

Ichabod_Crane - Maybe you should try to make another one TM, on a breadboard?

T.

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Re: Amptweaker - Tight Metal

Postby Ichabod_Crane » 23 Oct 2018, 14:10

I am frightened that my breadboard is not so reliable for a big circuit. I could have problems.

My last chance will be to build it again, or maybe using this layout:
http://effectslayouts.blogspot.com/2015 ... metal.html
It's the same schematic, just a bit different in the order of the pin of the TL074. It is verified, except for the famous 4.7k, the layout is not update, but it's ok.
(A strange thing: an user built that protoboard layout and got the same issue wth the volume. With a different layout? :shock:

The veroboard I built should work, I really can't understand why it doesn't. Could be the TL074 from Tayda defective? Everything seems ok.
Actually, I prefered the veroboard layout becuase it's simple to build and I can modify, indeed I'm trying to replace the Trash switch with a Scoop pot. Almost done, but I got some problem. I followed the Aeons schematic, but maybe the problem is the position of the 220nF cap in the Scoop pot section. Maybe we could see it later.
The protoboard layout is a bit hard to build and to modify.

I'm trying to probe the circuit because I would like to understand where I get the unexpected volume boost, but I don't know what I have to expect without compare my circuit with a working circuit.
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Re: Amptweaker - Tight Metal

Postby temol » 23 Oct 2018, 14:53

Ichabod_Crane wrote:I am frightened that my breadboard is not so reliable for a big circuit.


You have nothing to loose, just try it.

My last chance will be to build it again, or maybe using this layout:
http://effectslayouts.blogspot.com/2015 ... metal.html


I've built TM usung this layout, no problems with volume.

T.
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Re: Amptweaker - Tight Metal

Postby Ichabod_Crane » 23 Oct 2018, 15:20

I used breadboard just for little circuit, sometime some contacts failes.
Anyway, I tried to redraw that layout you built to replace the trash switch and add the the Scoop pot. Indeed, seems even easier than mod the veroboard I found.

Image

I don't know if you tried something like that, but maybe we could:
1. Remove the 100nF close the the Return 2
2. Replace the 330R (Aeons by Grind Custom doesn't include it) with a 47nF cap.
3. Exclude, of course, the Trash Switch
4. Use the Scoop pot 100k Log
4. Trash SW 1 of the board goes in the Scoop 1
5. Trash SW 2 of the board goes in the Scoop 3
6. Scoop 2 to the ground

We should get the Trash sound with the Scoop pot full clockwise.
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Re: Amptweaker - Tight Metal

Postby Daza » 23 Oct 2018, 21:22

I built the version of grindcustomfx and the one of brejna, in both I had problems with the volume, it is very strong.
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Re: Amptweaker - Tight Metal

Postby Ichabod_Crane » 23 Oct 2018, 21:58

It's very probably my built is perfect, but I found at least three person with this problem. Though some people built thiese circuit withotu this issue.
There's some components that make the output volume so variable. ICs? Pots?
Where you, guys, bought the TL074, TL072 and the Potentiometers?

And I want to ask how solve this issue? Replace the volume pot with another value, maybe log? Or use a resistor or a trimmer and add an alternative volume pot in the end of the circut?
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Re: Amptweaker - Tight Metal

Postby sixthfloor » 24 Oct 2018, 20:27

Ichabod_Crane wrote:And I want to ask how solve this issue? Replace the volume pot with another value, maybe log? Or use a resistor or a trimmer and add an alternative volume pot in the end of the circut?


I've taken a look at the schematic (version 3g) http://www.freestompboxes.org/download/file.php?id=21886&mode=view, and I think reducing the value of R27 would reduce the overall volume.
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Re: Amptweaker - Tight Metal

Postby Ichabod_Crane » 24 Oct 2018, 21:36

Thanks, sixthfloor! :wink: That is one of the thing I taken on count but I still didn't touch.
The PAD 3 & 4 (as the PAD 1 & 2) are jumpered to exclude the two loops effect.
So we have R27 in parallel with R28: 47k || 100kk ≃ 32k. The same trick on the Aeons by Grind Custom FX built, which has 33k, so it is pretty the same value of my schematic.

At this point is easier for me with this layout replace R28 100k with a 12k, and get 47k || 12k ≃ 9.6k.

Does this reasoning make sense?
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Re: Amptweaker - Tight Metal

Postby sixthfloor » 25 Oct 2018, 11:31

You're welcome Ichabod ;)

I assume you mean R38 (100k between out1/pad4 and ground) rather than R28 which is in the power supply section. So yes, lowering either R27 or R38 should reduce the output volume.
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Re: Amptweaker - Tight Metal

Postby mnemonic » 26 Oct 2018, 19:41

I made a version this week on veroboard using this layout:

http://guitar-fx-layouts.42897.x6.nabbl ... d9212.html

And I’m not having any volume issues, it seems to be about the same as most other preamp pedals I have (ISP, AMT, etc). I guess you could compare that layout to what you have?

Image Image

Kind of a rats nest, I need to work on wire management with veroboard.

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Re: Amptweaker - Tight Metal

Postby Ichabod_Crane » 26 Oct 2018, 21:56

That issue is really strange, though with me also Daza got it with two different layout. And I read about another user on http://effectslayouts.blogspot.com/2015 ... metal.html, but reading better I guess he had some other problems with the circuit, not just the "insane volume".

I built the layout with the external Gate control, and even this should be verified, and it is just a little bit modified to have a easier wiring of the Gate pot.

So, or there's something wrong with the layout I opted, or there something in the component I used.
I used ICs and pots from Tayda. As well the resistors and the caps, but I cannot see how they can influence the volume.
What about the 1N4733? From Tayda, again. I think those are in a critical spot about the gain and the volume of the circuit.

I still didn't try to replace the R38 100k (NOT 328, indeed). I really afraid that it will change nothing. I hope I'm wrong. :shock:
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Re: Amptweaker - Tight Metal

Postby Ichabod_Crane » 27 Oct 2018, 12:02

I finally replace the R38 100k with 15k, then 12k and then 8.2k, getting less than 7k. The volume is pretty the same. Using a 680R :shock: I got a bit of volume cut and a resistor really low, close to 680R, but I cut low range and fatness, and the sound is now nasal.

I'm going to restore the 10k volume pot (I replaced it with a 5k), but probably I will not solve the issue.

This thing is absurd! :scratch:

Edit: I just replaced the TL074 with another, (bought always from Tayda, but the text printed on it looks different). And replaced the TL074 with a NE5532. Volume is always the same.

How I can fix this?
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Re: Amptweaker - Tight Metal

Postby phatt » 28 Oct 2018, 01:37

I'm not about to plow through 30 pages but have you considered that one or more of your resistors could be the wrong value or worse mis labeled.
If you are using metal resistors with the Blue base colour then they can be hard to read.
I'm not colour blind but I struggle to read those. :twisted: I often have to double check with meter to make sure. :roll:
The old cream base coat made it so much easier to read.
Also I once purchased resistors that were labeled wrong so it can happen so worth checking.
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Re: Amptweaker - Tight Metal

Postby marshmellow » 28 Oct 2018, 01:54

There are several possible adjustments to decrease volume.

- R25 bigger
- R15 smaller
- R26 bigger
- Insert a resistor between C16 and the volume pot
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Re: Amptweaker - Tight Metal

Postby Ichabod_Crane » 28 Oct 2018, 10:14

phatt wrote:I'm not about to plow through 30 pages but have you considered that one or more of your resistors could be the wrong value or worse mis labeled.
If you are using metal resistors with the Blue base colour then they can be hard to read.
I'm not colour blind but I struggle to read those. :twisted: I often have to double check with meter to make sure. :roll:
The old cream base coat made it so much easier to read.
Also I once purchased resistors that were labeled wrong so it can happen so worth checking.
Phil.


Thanks phatt. I always measure the resistors before to solder them, and after. And I measured them on board at least three times without to find strange values, though some resistors, because the caps, their value risen up slowly.
I can't measure the caps because my multimeter doesn't have that function.

marshmellow wrote:There are several possible adjustments to decrease volume.

- R25 bigger
- R15 smaller
- R26 bigger
- Insert a resistor between C16 and the volume pot


(This valure follow the last schematic linked).

Thanks, I'll try, because now I'm really hopeless. I wish this mods don't change the tone, but just the volume.
I would ask something more: Those three resistors determine the volume. So probably I'll check them out in case of mistake or kind of. Are there are further parts that could cause this highest volume?
I suppose R6, R17, but maybe that determine the gain, too. What about the diodes 1N4733.
I can't think about none other parts.
I find several boost in almost all the stages, especially after the second "triangle" and the fifth "triangle".
Could someone probe the circuit, please?

Probably I'll try to breadboard it or rebuild it maybe using the layout with trimmer for the gate. But If I don't found the mistake (if there is, a mistake) I'm really afraid to get the same strong volume.

The sound is really ok, its like a really big hi-gain amp, really close to the metal and whatever tone. But this volume is dangerous and unmanageable.

Thanks to all.
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Re: Amptweaker - Tight Metal

Postby J0K3RX » 28 Oct 2018, 12:25

The 3g schematic is 100% correct. I have built too many to count using that schematic and I know many others have also without any issues. If you and others are reporting high output volume and you are all using different layouts then what do they all have in common?

I can tell you as a rule, I will not buy/use any parts from Tayda besides resistors and maybe caps... I just don't need the aggravation and uncertainty that counterfeit components bring to the process! I don't have any spare time in my life to waste snipe hunting my builds only to find the problem was a fake ass junk part! What's worse than buying fake parts? I will tell you... Wasting my mother f%#king time only to figure out that the problem was a Tayda counterfeit POS!
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Re: Amptweaker - Tight Metal

Postby Ichabod_Crane » 28 Oct 2018, 15:36

Thanks for reply, J0K3RX.
The schematic used for that veroboard layout is the same of 3g linked above (except for a resistor near the 33nF and the Tight pot, 1.5k instead 15k, myabe that 3g schematic was an old version. In the layout I used there is a 15k). Anyway, the veroboard layout is verified, as show us mnemonic, (the one with gate trimpot on board). But my version is verified, too.

I don't know if the problem is some parts of Tayda, I don't have any proof that the Tayda's components I bought are fake. I used in the past the same components and the effect worked. Yesterday I replace three ICs I have in the stock, without solve.

In this moment I'm really frustrated, I just would like to spot the problem. Now, I think there are less chances that the problem are the ICs. I'm not an expert, not at all, but I don't think that neither the resistors and caps could be cause this boosts (excluding some wrong resistors value that I didn't find). My doubt, and maybe I wrong, is in the 1N4733s. Spotted in a critical position about the boosting, I guess. First time I buy them, look normal if I see image on the web. I used my multimeter to measure the forward voltage, and I get about over 0.700v, even soldered on board.
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Re: Amptweaker - Tight Metal

Postby J0K3RX » 28 Oct 2018, 18:42

Tayda has no certifications and therefore no guarantees that you are getting genuine components... That means they are sourcing the parts they are selling from wherever they damn well please. There are some small resellers that don't have industry standard certifications but they pride themselves in delivering authentic high quality components. Tayda is not one of them. Bottom line is if your supplier does not have the industry standard certifications such as AS6496, AS9100C etc.. then you run the risk of buying inferior components that have been rebranded to look like the component you ordered.

https://www.aeri.com/counterfeit-electr ... detection/

I ordered about 20 TL074's from Tayda and they were all fake. Compared them to the TL074's that I got from mouser and the differences were visually and electronically obvious. I am not saying that this is why you are having issues but to just assume that it's not the reason is foolish.
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