Tubescreamer TS9

[liagasg]

Hello there,
I've build the TS9 (shem from tonepad http://www.tonepad.com/getFile.asp?id=81) in the past, and I've started building another one. The 1st one (built 4 years ago) roars like a beast. Even with it's gain out, and it's level up, it amplifies the guitar signal.

The one I am building today, it's based on the same schematic, but it sounds extremely different. It's not a high output device (it even lowers the signal of the guitar), and I am disappointed. Although biasing is correct (compared to the old one) it sounds different. it's more "quiet" and I don't like it.

Is it the Op amp that messes me up ? It's an RC4558.

Another interesting observation is that if i use a single 2N4048 diode (or two in the same direction) it sounds louder, but it doesn't distort as much.
If i use asymmetric clipping the loudness goes significantly lower, but it distorts better.

The transistors are 2N3904. Tried 2N5088, no difference.

Any suggestions?

I also wanted to create a second mode on this pedal, something like Hard clipping, but it sounds even "quieter" than the soft clipping. Where in the schem should i shunt the diodes to ground to create Hard clipping? I tried on the junction of IC1a lug 1---1K---(hard clipping diodes) ---  IC1b Lug 5

Any help, suggestions would be great.

[R O Tiree]

2N4048 is a PNP power transistor. Very old, very expensive... 1N4148, perhaps?

Post pics of both sides of the board. High quality, well-focused. The bigger and clearer the better. Maybe sharp eyes can spot something wrong with a resistor value, polarised cap orientation or something.

[liagasg]

You are right, sorry for the mistake : the diodes are 1N4048.

The circuit is on pefboard, I didn't solder it yet, 'cause I want to try some mods. But so far, I am unhappy with it.

[Kesh]

Diode clipping means nothing more than about -0.6 to +0.6V will leave the clipping stage. Without the diodes you could have about 7V peak to peak, limited only by the 9V battery and the headroom below that the op amp needs. So diode clipping seriously cuts level in a TS.

If you take one diode out you can get about 3.5V on one swing and 0.6V on the other, the extra level you are getting.

Perhaps your previous TS was made with different diodes. LEDs allow much more voltage before clipping, for example. Or maybe one of the old diodes broke during soldering. Or in the new unit the diodes aren't connected properly.

[liagasg]

unfortunately i am using the same components.
I just measured the Op amp lugs, and all the biasing points. They are almost the same ±0.05

[liagasg]

My major problem is that of the level control. It goes "quiet". I mean it's like it's got not enough gain to output the signal to the amp. Can't figure it out. I've even measured the pots and their soldering.. My brain is about to explode out of the confusion!

[R O Tiree]

Check you really have got a 500k Drive pot. Check that the cap connected to the 51k (which in turn is connected to the Drive pot) (check that resistor value as well) is actually 47nF. Check that the resistor going from that cap to Vb is actually 4.7k. Check that the little ceramic across -ve and output of IC1a is actually 51pF (or 47pF). For the resistors, lift one leg out of the board and physically measure them.

Also, if you have an audio probe, check you are getting a strong signal from the emitter of Q1. Check again at pin 1 of IC1a.

I really wish Tonepad would put component identifiers on their schems

I hope this helps, but if not, then we can continue through the circuit looking for snags.

[liagasg]

Today I soldered the TS on the board I etched using tonepad's layout. It's the 2nd time I m doing this. And for my confusion, it still sucks..
I though that I've made a mistake while on pefboard, but unfortunately the problem remains : Very low output. When I use one diode, the output level is high. When I use all (3) diodes , the level goes down.

I've swapped the OP Amps (from my old build to the new one) but no luck : The old circuit is 10 times louder.

Don't know what to say. Are there many categories of 914 (4148) diodes? I mean, is there a possibility that they gave me the wrong type of diodes? (there is the 4148 printed on them).

I've measured the 2N3904 transistors. Hfe is about 190. I even used 2N5088 (Hfe about 460-500), no luck.
I guess there is something wrong on the clipping stage. The 500K pot is OK. It's a 500K pot and works great (measured it). The resistors/caps are all ok.

Don't know..Can't figure it out.

Can the Tant Caps 0.22uf be the problem?

Where did the Level output go? 

[GibsonGM]

If they're the same circuit, you should be able to audio probe the 'good' one, and check the same point in the 'bad' one.  You will find the location where there is a noticeable difference in level.  Then, you can tell what parts are CAUSING the drop.   Something with the feedback loop, perhaps?   My guess is you'll find an error in there.

There is no other (easy) way to really know what is going on.  Voltage measurements can *help*, but we're talking about an AC voltage here.  You've already said your bias is correct...time for audio probing!!!!    Use a steady tone as an input for this....I burned a CD with 10 minutes of 440Hz "A" on my computer, and run that from a stereo into audio circuits at anywhere from .5 to 1VAC.     

I predict if you do this, you will come back and tell us "at pin such and such, it is the same, but from pin such to pin XYZ, the signal dropped!".    Then you/we will know exactly where to focus!!!  Tantalum caps should be fine if they're not damaged, BTW.  They don't have THAT much ESR  ;o)

[R O Tiree]

I remember the first one of these I ever built was from a tatty scan of a schem... I mis-read ".22µF" as "22µF". Unsurprisingly, it didn't do much at all. Really quiet.

[liagasg]

Problem solved. The faulty point is ME! On Tonepad's schem, the R going form the Q2 Emitter to the 10uF Cap is marked as Ra. That R has to be 470R.
I've plugged in a 470K. The point is, that I've copied by mistake the wrong value, bought the wrong value and used the wrong value.

Also, the Ra marking didn't help. I by curiosity / frustration was studying the schem once again, and I've noticed the Ra=470R. BOOM!!! I knew i had soldered 470K.

Problem solved. I am a fool. MEGA FOOL!

Sorry for bothering you guys.

GLad my circuit SCREAMs as it should!

[Kipper4]

we've all been there at some time or another. Glad its working. Scream onnnnnn.

[liagasg]

This stompbox, still keeps me confused. I've noticed noise on the output even when all knobs are down. So today I've started audio probing. I've noticed some noise on the feedback path of the transistors but that's quite normal due to the distortion.

The problem lies somewhere else :
Even when the output pot (100K) is disconnected I still get signal on the amp. I mean, the loop I've got playing on the input goes through the circuit and then to the output.
When I connect the pot the sound gets amplified. When there is no pot, I do get a sound signal, but with a low volume output.

Is this normal?

[liagasg]

CORRECTION BELOW :

This stompbox, still keeps me confused. I've noticed noise on the output even when all knobs are down. So today I've started audio probing. I've noticed some noise on the feedback path of the DIODES  but that's quite normal due to the distortion.

The problem lies somewhere else :
Even when the output pot (100K) is disconnected I still get signal on the amp. I mean, the loop I've got playing on the input goes through the circuit and then to the output.
When I connect the pot the sound gets amplified. When there is no pot, I do get a sound signal, but with a low volume output.

Is this normal?

[ricky1918]

hey guys,
sorry for posting on this old thread but I didn't think my question is worth a new one. I'm searching for schematics+PCB layout of the ts9, but unfortunately tonepad's link of the tsp does not work, at least for me... can someone please post it?

thank you!!


Ricky

[Gus]

I put "schematics+PCB layout of the ts9" into google and got hits  
Then I then tried "schematics+PCB layout of the ts9 tonepad"

[Fp-www.Tonepad.com]

It's right where it's been for more than a decade:
http://www.tonepad.com/project.asp?id=1
Maybe try a different browser or update your reader plugin would work.

Fp

[ricky1918]

I don't know guys I tried 3 different browsers and it just opens up the pdf page but with no document inside!!! It just happens with the ts9, I tried with other schematics and it worked... idk 

However thank you @liagas for the email!!

[J0K3RX]

I tried it also just for the hell of it and it says "To Download File...   Click Here" and then the download doesn't work.  Easy enough to find but download link seems to be non-working. No, I don't need it, I was just testing the link.

Here's the direct link... give it a try
http://www.tonepad.com/getFile.asp?id=81

[karul]

Everything is fine - try with right click on the "To Download File...   Click Here" and then select Save Link As in the menu

I'm using Firefox, sometimes the browser can't properly open PDF files for viewing. Try to download the file instead.