Capactiors, resistors, Tone Bender MKI

[mmmguitar]

Hi,

New to all of this, for a first project I though I would try and build a Sola sound Tone Bender MKI (I need a fuzz and theres a good video on the interweb, http://www.youtube.com/watch?v=ClexKXeLi5E)

Will using the "old fashion" style components make any difference to the sound? I'm guessing not (well except for the transistors)

I've tracked down some cheaper carbon composite resistors from http://www.rapidonline.com/ but I have no idea about what capacitors to use.  Cant seem to find any that look like his, but I feel there is a basic understanding about capacitors I do not have.  I understand what they do and some of the differences between capacitors, i.e. electrolytic with an ionic fluid inside and a dry one like polycarbonate, and certainly appreciate the difference between standard / polarised ones -- but is there a particular type that is usually used for audio?

I'm also confused about wattage, I seem to have a choice between .25W and .5W.  Its a simple 9V battery, I would guess the 0.5W ones would be more suited?

Anyone know any good reference meterial for audio electronics?  I did a gcse in electronics like 10 years ago, so I remember half of the basics and can still build a 555 timer

Thanks for any help, need to learn some more electronics me thinks.
cheers.

[Magnus]

Hello mmmguitar,
I have build a Tone Bender MKI and a Tone Bender MKII and I would suggest you to build a Tone Bender MKII,
because the Tone Bender MKI has a negative-grounding, that means that the power is direct on ground
and you can't use this pedal with other pedals together!
So if you don't have a layout which has negative-ground it is better to build the MKII,
there are enough layouts online, here is my layout:
http://forum.musikding.de/cpg/albums/userpics/17258/Tone_Bender_MKII_Professional.jpg

You can use Resistors with 0.25 watts or more, it does not make any difference
if you choose the same material and I would suggest you not to use the carbon-comp-types
because of they are noisier than normal metal-film-resistors.
If you still want to have the old look you can use transohm-resistors, 2 watts,
they look like the old ones but are metal-film-types...

The next one, capacitors:

You can use any cap you want, they have different sounds
and everyone has a different preferred type...
My preferred choice for electrolytics is the Panasonic FC-Series.
The other capacitors (non-polarized) can be Mallorys, Polyester or Polypropylene for example.
I used Cornell Dubiliers (DME Series - 250V) as the have the nearest to the original voltage-value...


Greetings
Magnus

[Scruffie]

Hello mmmguitar,
I have build a Tone Bender MKI and a Tone Bender MKII and I would suggest you to build a Tone Bender MKII,
because the Tone Bender MKI has a negative-grounding, that means that the power is direct on ground
and you can't use this pedal with other pedals together!

Pretty sure both Tone Benders Mk 1&2 are Positive ground which is what you don't want to work with most of your pedals, you want your pedals to be negative ground usually and reversing the schematic to work with negative ground rather than positive ground can cause problems so it's better to just use a battery and no DC or the R.G -9v or +9v from one supply circuit if you need a DC socket for it http://www.geofex.com/circuits/+9_to_-9.htm (but the original ran from just a battery and lasts along time so I wouldn't sweat needing a DC jack unless you don't use batteries in general).

Resistors, the old style carbon comp resistors, they look prettier but they are just noisier in the long run and also suffer alot of drift in value so could lead to a mis-biased pedal so you would be better of using new resistors metal or carbon, metal film are quieter, some find carbon to sound warmer but either will work.

Capacitors are where people claim to hear differences, personally I can't really hear that much difference to warrant spending lots of money but some caps will have better tollerances and life spans etc. but overall your capacitors just have to have a voltage rating that will withstand your power supply so giving yourself leeway for spikes from DC power supplys go for something over 16v rating but any capacitor other than that aslong as it is the right value will work, there is info here at danos site on cap choices http://www.beavisaudio.com/techpages/Caps/

Other than that yup, some good transistors (though tonebenders even like leaky germaniums which is useful) and you're pretty much set.

If you're in the U.K (assuming you are as you took GCSE) try out www.bitsbox.co.uk for a cheap source of parts, there's also the store above but that does mean shipping from America.

[John Lyons]

There is no problem with using either MKI or II with other pedals.
Just don't use the same power supply for both.
Use a battery for them...

That being said, I would not recommend building a germanium pedal first, let alone the MKI.
There is a lot to "go wrong" and there are several finicky issues to deal with including bias and
transistor selection. I would start with something silicon as to cut out a lot of the germanium
subtleties and troubleshooting.

John

[Scruffie]

There is no problem with using either MKI or II with other pedals.
Just don't use the same power supply for both.
Use a battery for them...

Yeah that's what I meant... just getting over flu so my brain didn't wanna write the sentence out correctly, you summed it up better than my confusing rambling 

It's true germaniums can be tricky There's the Hot Silicon schematic and vero layout in the layouts Gallery http://www.aronnelson.com/gallery/main.php/v/ulysses/ulysses_layouts/dh_hot_silicon/ which is a Silicon ToneBender MkII with tone control so that'd be a good place to start if you don't want to mess with germaniums, it also cuts the cost and hassle of finding decent germanium transistors.

[mmmguitar]

Thanks so much for all the help  

The schematic I was working by was the one here (second one)
http://dam.10.forumer.com/a/tone-bender-mki_post744.html

but swapping the 8K2 resistor on the left for a 10K variable pot to bias the circuit easier like the video).  Think it was the one on the left, had not quite worked that one out yet.

Thanks for the silicon schematic, I was thinking I may be able to replace the transistors for silicon ones so I can play about with it and get it working as I imagine getting things wrong can knacker the transistors, so thats also a great help - think I will try that first.  Wanted to pick a small / simple circuit and have always wanted a fuzz pedal (not a great fan of overdrives).  Going to look into to phaser + octaver pedals as well.

Yeah for now I'm just happy with batteries, someday I may look into doing a proper power supply (hopefully by modifying when I learn what needs do be done / why) -- but thats far off.  I want to get into some vacuum tube pedals as well and the dream is a 6W tube amp, but the thought of playing around with 240V is to say the least, unthinkable given my skill / knowledge, maybe in the future tho.  Not too sure about the differences you were talking with about negative / positive ground, but I think I have enough to work on to find the answers / understand that now.

Sounds good about the resistors and capacitors, and definitely makes sense about the germanium / silicon transistors.  Think I will definitely go with the advice and stick to standard components + silicon transistors and if I can produce something half decent then maybe think about spending more money to get some better components / germanium transistors.

That bitbox looks good thanks, much cheaper than the places I found (yeah, I'm from the UK )

Thanks again for the help, was quite confused but think I know enough now to order some stuff and get on cracking.

Cheers!

[Magnus]

Hello,
I found a little error in my message, the bold word must be "positive" for sure!

I have build a Tone Bender MKI and a Tone Bender MKII and I would suggest you to build a Tone Bender MKII,
because the Tone Bender MKI has a negative-grounding, that means that the power is direct on ground
and you can't use this pedal with other pedals together!

Greetings
Magnus

[SonicVI]

I would also recommend against building a MK1 as a first build.  Even experienced builders hate this circuit because it's so finicky with regards to transistor selection and biasing (and subbing silicon in that circuit doesn't make it at all easier, I know from experience).   You can use almost any germanium type in the MK1 and get a good sound, AC128's are a good easy to get a hold of choice.

If you do go for it, replacing the 8.2K resistor off the base of the third transistor will make life easier.  As far as resistors and caps go, there won't be much difference in sound between various types. It's mostly as aesthetic thing, aka "mojo".  Carbon comps and big old caps look cool for sure, but if it's just the sound you want don't worry about it.  A lot of tone bender guys like the BC Components Electrolytics,  Mallory 150 and Ero/Vishay tubular poly, or Wima film caps.    You can find these all at www.mouser.com in the states or maybe www.farnell.com in the UK.

[Magnus]

Yes, I can confirm what 'SonicVI' has written, the MKI needs time
and I spent much time with testing of different transistors and types
to get good results and a great sound - but I finally got it  
I have matched a lot of transistors by ear and my finished transistor-setup
are an Philips OC70 for Q1 and AC125 for Q2 and Q3.

It was surely good that I had enough OC70 and AC125 to choose from...


Greetings
Magnus