Tube boost + overdrive running off a 9 volt battery

[Dongle]

Well, its not oscillating. It is a steady tone. Quite constant.

I would like to post soundfiles, but I lent my recording device to so and will get it back next Tuesday... So long time to wait. In the meantime, I will breadboard the thing again and make sonme tests - like adding grid stoppers, raise resistor at Pin 8.
I will try without adding high cut filters.
I will keep you updated!

[waltk]

Well, its not oscillating. It is a steady tone. Quite constant.

Is it very high-pitched?  I built a circuit using a 7660S, and even with pin 1 connected to raise the frequency of the chip, it was running at 16-17KHz.  I couldn't hear it, but it was a deafening loud high-pitched tone to my 11-year-old.  I thought the 7660S would be a drop-in replacement for the MAX1044, but it wasn't.  Using a real MAX1044 with pin 1 connected actually raised the frequency above the range of hearing.

[Dongle]

Thanks for the hint! But the oscillation frequency of the 7660S with PIn 1 connected is 35kHz - I think, even your son is not able to hear it.
The pitch I am hearing is for sure below 10kHz - I even thik belo 5 kHz. I will try to find an app to measure the frequency and post again..

[waltk]

Thanks for the hint! But the oscillation frequency of the 7660S with PIn 1 connected is 35kHz - I think, even your son is not able to hear it.
The pitch I am hearing is for sure below 10kHz - I even thik belo 5 kHz. I will try to find an app to measure the frequency and post again..

What I saying was that even though the 7660S with pin 1 connected is SUPPOSED to run at over 30KHz, the chips I had were NOT.

If your tone is 5 or 10KHz, is it possible that your frequency boost pin is not really connected (to V+ right?) ?
Is it possible that you have a 7660 instead of a 7660S?
Is it possible that you have a chip MISMARKED as a 7660S that is really a 7660?

[Dongle]

Lots of things are possible... I am not very into the industrial production and labeling of chips. But I just found an app for frequency measurements and will try this night.

Still, I think it is more likely, that my design is not so perfect because, if it was the chip: I would not only have this tone with high gains (I guess?!?), but always?!?

I will post the frequency tomorrow. Also, I will continue breadboarding and try some things like gridstoppers...

Thanks!

[waltk]

I am not very into the industrial production and labeling of chips. But I just found an app for frequency measurements and will try this night.

OK.  Let us know what you find.  I'm planning to build this also, and am very interested to see what you end up with.  Can you post the schematic for your current implementation? 

I may way off-base with my conjecture about the source of your problem.  How are you getting 30-40V out of the 7660?  Starting with a high voltage (15 or 20) and doubling, or multiplying with additional diodes?

One more theory involving the frequency of the VR... According to the Intersil ICL7660S datasheet:

"Since the ESRs of the capacitors are reflected in the output
impedance multiplied by a factor of 5, a high value could
potentially swamp out a low 1/f PUMP
x C 1 ) term, rendering
an increase in switching frequency or filter capacitance
ineffective. Typical electrolytic capacitors may have ESRs as
high as 10Ω.
"
Are you using high-ESR caps?  Is it possible that turning up the gain is somehow "rendering an increase in switching frequency or filter capacitance ineffective"?

[Dongle]

Sorry for my long silence... I was too busy at work. But yesrterday I could take have an hour for breadboarding everything.
Result: NO anoing sound anymore...
I am not sure what happend... I only had few changes:
1. No input buffer (I am quite sure, that this is not the reason)
2. No LCL-filter of the power supply: might be the reason, if I chose wrong values, so that it started oszillating
3. reduced gain pot from 100 k to 50 k and connected Pin 1 with Pin 2
4.. I used schotky diodes - no idea if this can be the reason...

I will keep you updated...

To your questions: I am using "normal" electrolyt caps.
I am getting the high voltage by using about 11 V for input, and cascade the diodes and caps: always start with diode, than cap between diode and PIN 2, another diode, cap to ground, diode, cap to pin 2, diode, cap to ground, ...

After each stage, you get 2 * input V - diode V. But its not "multiplying, but always adding the inout voltage.

[zambo]

see how your bread board signal routing is and then compare to how you have it in the enclosure. layout can be pretty annoying with these types of devices. another thing you can do is when the thing is on and oscilating take a wooden chopstick or drum stick and move wires carefully to see if it changes or stops the offensive sound. got to be very careful though. one hand in pocket, thick rubber soled shoes, not standing in shower etc.

[iccaros]

in case anyone is interested, here is my first recording test of my valvecaster. Its in a Cheap Radio Shack ABS box. http://www.youtube.com/watch?v=kgKxwAIpK78
I have the super overdrive in front as it kills some buzz I am getting as its not on. With the plastic case I was having issues with the iron melting plastic so some of my grounds may have cold joints.

Its 12v (11.9 after rectifier) running a HE 12Au7. I changed the .047 to .022 and I put a red led under the tube to know when I have the pedal enabled. The tube always gets power

the amp is a Vintage 16 unmodified with the cestion vintage 30 speaker, reverb is @ 1 or 2 set to 5 watt triode mode

I have a high pitch noise at higher volumes, which I belive is the ground. the overdrive before it kills some of that.

I am awaiting a hammond case to fix my lay out (more room and it does not melt.. ),

Gain is set to 75%, vol 100% and the tone pot is replaced with a 100K resister.

[Dongle]

see how your bread board signal routing is and then compare to how you have it in the enclosure. layout can be pretty annoying with these types of devices. another thing you can do is when the thing is on and oscillating take a wooden chopstick or drum stick and move wires carefully to see if it changes or stops the offensive sound. got to be very careful though. one hand in pocket, thick rubber soled shoes, not standing in shower etc.

YES. Noise (frequency) changes, if I move the cables. Shit. How do I find a "good" layout?
Yesterday I managed to add my LC-filter to the breadboard: Still no noise. So it s not the filter. The gain pot was also not the reason...

I also found out, that it is definitely NOT the charge pump. So it probably has something to do with the signal routing. I don't like this...

Does anyone have a nicely routed layout with 40 V???

Thanks for your help!!!

Dongle

[zambo]

try using sheilded wire for your signal path. only ground one end of the sheild and make it the end near the input. keep the input far away from the output. keep the signal wires from running next to each other for long runs. make all your wires cross at 90 degrees as much as possible. i dont have a layout to offer , but if you use a little bigger box it helps. give things a bit more room. if none of that helps then put a small ceramic cap from the plate to ground on pin 1. 500 pf should be good but this is killing off some highs and i hate doing that. also if you use a .002uf  input cap it tames the lows a lot more. hope that helps.

[Dongle]

Finally!!

I
1. used shileded cables for signal pass,
2. soldered every possible thing on the tube socket to keep distances short
3. Spend some mor thoughts on where to connect the grounds...

NOW IT WORKS!! SILENCE!

Thanks to all!

[iccaros]

Here is my completed build..  I have two mess ups I need to fix
Running on 30 volts, has a lm317 for regulating heaters.
Using a JAN/PHIL 5751 as the 12Au7 sounded harsh at this voltage for some reason..

I have to fix the tone cap I put in a 1uf my mistake (the diffrence between 103 and 104 on the green caps is hard to read after 1am..  

Changes
30 volts (DC as AC creates a loud humm, even with the full bridge rectifier)
coupling's cap and plat to Grid cat at .022
100K resister instead of a tone pot.

you can see this is tight and I should have soldered things directly to the socket before installing it..
the rectifier and 317 are at the left
I needed more heat shrink..

Will post to youtube latter the sound.

[PlaidBicycle]

Can anyone verify if this schematic is correct?

Here it is:



Anyone want to figure out where I went wrong too? Volume works, but I just get a hum if I max it. Sounds a bit like when you ground a guitar cord. No signal from my guitar at all.

Here's my attempt:

[PlaidBicycle]

Pinout is as follows
pin1  6.5
pin2 -1.16
pin3  -----
pin4  -----
pin5  13.33
pin6  8.5
pin7 -1.22
pin8  -----
pin9  6.6

I'm using a 12v wallwart with 300ma rating

From the looks of the pinout, it should work. The heaters are nice and bright. Tried several different au7 tubes. When I switch the pedal into bypass (footswitch off) it lets my guitars signal through fine.

[Renegadrian]

As you may have read in the long thread, the Valvy needs a stable regulated power supply with enough current - take a 12V 500mA or better 1A and use 78T12 or 7812 and a filter cap (at least 100µ)

[Renegadrian]

Think I need a vacation...I read The haters are nice and bright. And the HATERS GONNA HATE came to mind.

[PlaidBicycle]

As you may have read in the long thread, the Valvy needs a stable regulated power supply with enough current - take a 12V 500mA or better 1A and use 78T12 or 7812 and a filter cap (at least 100µ)

Tried a 7812, but I'll try it again with a higher ma ps. Can you point me to what page of this thread listed the cap placement and rating? I've read probably 30-40+ pages, but it's a little daunting to try to read all 112.

Think I need a vacation...I read The haters are nice and bright. And the HATERS GONNA HATE came to mind.

lol

[PlaidBicycle]

Alright I changed my ps to a 12v 4amp filtered ps. Should be more than enough. Also added a filter cap (100uf) per the instruction on page 18 (positive and negative lead of the incoming power).

Pinout:
pin1   2.19v
pin2  -0.35v
pin3   -----
pin4   -----
pin5   11.82v
pin6   3.70v
pin7   -0.30v
pin8   -----
pin9   5.87

Can anyone give me what the voltages should be on the pots or anywhere else?

Now I'm getting no hum. Tube warms up (albeit a little less, but still nice and toasty), led turns on when pedal is 'on' and heaters still cherry red. MAKE SOME NOISE NOW!!!!

[Govmnt_Lacky]

Something that MAY help with this thread:

Posting some KNOWN GOOD voltages would go A LONG WAY!!!! 

Voltages based on a regulated 12V supply. I lost count of how many posts are on this thread regarding voltages taken. If they had some "DEFINITE KNOWN GOOD VOLTAGES" to compare with, it may have saved 20-25 pages of this thread 

Just my 2 pennies!