Small clone problem

[Swirly]

i built the small clone from tonepad and it doesn't get any effected signal at all. I am not using a switch and went straight through to avoid any problems there.
I get tone from my guitar to amp but no effect??? I am using a NTE 1641 for the MN3007. is the pinout the same??

Whats the deal??

Thanks
CS

[Peter Snowberg]

Welcome Swirley,

I don't know about the part number issue, but about the best tool you can use for troubleshooting, is an audio probe. See this file from Paul Marossy for construction:

http://www.diyguitarist.com/PDF_Files/DIY-AudioTester.pdf

That tool will allow you to see how far the signal makes it through your circuit before it stops. Using one of these things, it is not uncommon to find the problem in a few seconds if you are lucky.

They're worth their weight in gold. (well, actually maybe more because it's not a heavy tool) This recent thread http://diystompboxes.com/sboxforum/viewtopic.php?t=18166 talks a little about upgrading the probe.

If you trace things a little, I'm sure the collective "we" of everybody here can help get things working.

Best of luck,
-Peter

[george]

i built the small clone from tonepad and it doesn't get any effected signal at all. I am not using a switch and went straight through to avoid any problems there.
I get tone from my guitar to amp but no effect??? I am using a NTE 1641 for the MN3007. is the pinout the same??

Whats the deal??

Thanks
CS

Have you tried adjusting the trimpot?  You have to turn this to get the delay working, otherwise you don't get any effect.

[Swirly]

oh yeah,
I turned the trim pot untill I couldn't turn it anymore  No luck.
I will try the probe next.
It seems weird that I would get a normal guitar signal and no effect at all. Why would that be??
Why would the circuit let signal pass through without cutting out or a loss of volume or ??

 I connected the out to the tip of the out jack and the in to the tip of the in jack. The ground to the ground lug of the in jack and the neg. 9v lead to the sleeve lug of the in jack. sound right as far as connections go??

Thanks
 S

[Mark Hammer]

The trimpot needs to be set just right for the MN3007/NTE1641 to pass signal.  The bias voltage it feeds the input pin of the BBD cannot be too high or too low, so "turning it up all the way" is no guarantee of anything except maybe preventing the BBD from working.  If that bias is set wrong, it is basically like having no chip plugged in the socket, which is why you and countless others have the pleasure of hearing only dry signal and no effect.  

Start with the trimpot set to the middle and adjust it a little way to one side or the other until you hear a delay sound.

Most designers will specify a trimpot value that goes from less than to more than the actual resistance value needed (or attenuate a voltage more than or less than is actually needed) to make sure the ideal setting is ALWAYS within the range attainable with that trimpot.  If you ever turn up a trimpot all the way, chances are you've gone too far and missed the sweet spot.

[moosapotamus]

The first time I built a small clone I had the same problem, no effect, just straight signal. After a few days of beating my head against the wall, I discovered that I had a diode in backwards, D1 near the center of the board.

I would suggest double checking, several times if necessary, the orientation of all the components that need to be oriented a certain way... diodes, transistors, polarized caps, etc...

If it's still being stubborn, walk away from it for like a day or so, and then go back to it with a clear, rested head. Sometimes that's all it takes to be able to find the problem.

~ Charlie

[Marcos - Munky]

Sorry for steal your topic, but I finished mine today and got the same problem. I got clean signal, tried to turn the trimpot, tried to change the battery and nothing. Didn't recheck the caps, diodes and transistors yet. What is the bias voltage for the NTE1641?

EDIT: I checked the board abain and found a resistor in reverse. I corrected it, plug in my amp and nothing. I tried audio probe a little, but can't followed the signal. I found a place near the CD4047 that I got clicks with speed adjusted by the pot, so I think the clock is all right.

[Muldoer]

I had this same problem...and held it off for about a year. I found that I had badly soldered one of the input caps...the .0033uF one. Recheck all your solder joints, and turn the trim pot slowly while strumming your guitar and it will come to life. FP's layouts work right off the bat, if you're attentive enough.  :wink:

[gtrmac]

I can't offer any information about the NTE replacement part but my Tonepad Small Clone stopped working after a couple of days and the problem was a diode. I had possibly over heated it during the build and it cracked when I was poking around inside. Once I replaced it I got that beautiful analog chorus sound back.

Good luck with yours.

[Marcos - Munky]

I will double check the board again. I tried to turn the trimpot slowly, but didn't got nothing. Anybody have the voltage that the IC need for bias? I think NTE don't have any problem, Charlie used one in his Wavy Gravy.

[Swirly]

OK, how about some pinouts for the ttransistors?? we'll say the 4558 is at the bottom of the board. So looking up from there what should my pinouts be for the 2n5088's?? Also for the 2N5087 I have a 2SB54 in it's place. is that a problem?? what should the pinout from left to right be on all of these transistors looking from the 4558 up??
I don't see any recognition of transistor pinouts on the layout.

thanks S

[Swirly]

actually the more I look at the layout at Tonepad I have no clue where which transistors go??
they are not marked so I may have them all screwed up.
I have the PNP next to the trim pot. Is that wrong??

I have a 100K pot hooked up where the switch should be.

any help??

S

[Swirly]

Charlie,
after listening to your advice I see that I have 4 caps in the wrong way~!!!  what a dumbass! No make that 6 caps!!
I will resolder these and go from there~!!

Thanks so much all!

S

[Swirly]

um.....still no luck.
I guess the transistors are next but I need info for that before I can check them.
will the 2sb54 work in this application in place of the 2N5087??

[gtrmac]

2sb54 is a germanium transistor and it may not work in this circuit.

[moosapotamus]

You have the transistors installed in sockets, right? Pull them out, flip them around and see how it sounds. That's usually what I do when I'm debugging something and I'm not absolutely positive about the pinouts. You could go to google.com and hunt down the datasheets, but trial-and-error is probably a lot quicker.

~ Charlie

[Swirly]

No I don't have them in sockets. I went by the orientation from the layout.
still it doesn't say which one's are 2N5088 and 2N5087?
I have some 2N5087's ordered so that might take care of the problem.
am I missing something or is the layout not clear??
It just shows the transistors and not the pinouts or which one's they are.

  I will put the transistors in sockets but I still need to know which one's go where??

 When I connect the 100K pot instead of the switch do I just use lugs 2 and 3 ? That is the only mod that I want to do to it if I can get it working.

I am very confused here folks.
I will get back to you when my 2N5087's arrive on Tuesday.

thanks
S

[Peter Snowberg]

The 2N5087 is a PNP while the 2N5088 is NPN. The symbols are different in schematics so let the arrow point you in the right direction.

In a PNP symbol, the arrow points toward the base, while in NPNs, the arrow points away from the base, to the outside circle.

One way to rember is to look atthe circle of the transistor symbol as a little Earth, as viewed from the top so that the North pole is in the center. You can then think of PNP as standing for "Pointing to the North Pole". You can think of NPN as "Not Pointing North".

The 2N5087 - 2SB54 substitution could easily be the problem. The bias is entirely different between silicon and germanium.

Best of luck,
-Peter