graybench wrote: ↑28 Jun 2021, 13:23
Don't tell the cork sniffers their new germanium tone bender has a *gasp* silicon transistor in the signal path

I would not dream of it

I've not looked at the schematic for an orginal tonebender, but I'm guessing it hasn't got a FET after the first Ge transistor.

The Muamps could have been biased for lower noise. Compare the way Q5 is biased to Q2 & Q4. Q5 is the smarter way, which doesn't add any thermal noise. When I roll my own F55, I'll be feeding all of the bias points from a single voltage divider for less noise and a lower parts count (can save 2...

Thank you for the table Mike, alas in the UK the copper thickness is quoted in Microns, not ounces for example: Specifications Thickness: 1.6mm Copper foil: 35 micron Dissipation factor: 35 Dielectric constant: 5.4 However, using your table 26ga has a cross-section of 0.1288sq.mm and 28mil 1-oz copp...

Hi Mike, I have revised the board layout as follows: 1. C16 is now closer to the filtering section. 2. The output is further away from the input and to the left of C16 3. The LED is now powered after the series resistor. 4. Power now comes in at the bottom. 5. Input and Outputs have additional groun...

Alas I'm tide up for the next few evenings but will try and implement your suggestions in a revised board layout and will put it in the drop box folder once done over the weekend.

Thank you again for taking the time to respond to my questions,

Chris

Hi Mike, I need to look further at details, here's what I see in initially looking at it: It's is organized, and nice attention to clean routing. In and outs are separated from each other and it makes for a nice counterclockwise signal flow. We can do a lot with this layout and I think you will like...

Hi Mike,

Thank you for taking the time to look over my schematic and board layout. It will be this evening before I can really turn my attention to your suggestions, but I'm very grateful for your advice, and probably have many follow up questions.

Chris

The file upload didn't work, here is the PDF of the board.

I apologise for my poor choice of words. My Dad got into electronics, many years ago, and I well remember as a kid him using sheets of mylar, reels of thin black tape, and pads on letraset, he would trace off a diagram he'd made on graph paper. It is through him that I have access to a UV box and we...

Following a discussion in another thread, https://www.freestompboxes.org/viewtopic.php?f=7&t=29980&start=20#p277589 I have asked Mookyj, if he would be so kind as to suggest how I improve the PCB layout for a BMP that I have recently etched a board for. I can only upload one file in this pos...

Dear Mookyj, I'm interested in PCB layout, and I'm sure my attempts would be deservedly looked down upon by yourself, so would you be open to passing on some of your knowledge? I could post a schematic and the top and bottom PCB layout for say a Big Muff (Eagle PCB file) and you could educate me and...

Just discovered my mistake, I used a 1k resistor instead of a 10k resistor after the drive pot.

better carry on checking in case I've made any other slip ups!

Thanks for your help Seiche, What happens when you turn the presence all the way "up"? It gets brighter. Check all your resistors and caps around the tone and presence control as well as potentiometer pinout. I don't have time right now, but will double check again tonight. I take it from ...

I have just breadboarded this pedal, and although I don't anticipate ever running it with the gain wide open, I was just wondering if it's normal for it to get very very bright when you do so. There is a point from about 3 O'clock onward where it the brightness noticeably increases with the gain inc...

Hello Manfred, I dug out my oscilloscope this morning and a 5.2V drain voltage gives me symmetrical clipping, but as this adjustment was done via the trim pot I can't say what the resistance value is. And to be fair my oscilloscope skills are a little limited, I used the tone generator in the oscill...

I put a 2K2 in series with a 25K trim pot for Q1 and this gives me a bias voltage range of 3.18v - 8v. I'm using SMT J201. Thank you chasbenson for providing the biasing voltages, and for clarifying aspects of this circuit. It's a very compelling design to play, especially with all the shades you ca...

Looks very interesting, could one of the pots be a 'Blend' pot?

aionios wrote:...And yes, there is an opto-isolator

I hope it's not one of the hard to find or rather expensive ones?

Hi Knttypine,

Does it still squeal when the drive is turned up beyond 12 O'clock?

Pedal PCB has leg 3 of the treble pot connected to the 22nF cap, 2 to ground and 1 not connected, is this how you had yours wired up?

Any chance SMD FETs are more consistent than their through hole ancestors? I've got some MMBFJ201 on order, but don't relish the idea of sorting through them to find a matched trio! Wouldn't be so bad if they could be tested as easily at the through hole variety. Thanks for the link to the Fetzer Va...