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Just built a Tone Bender Mk.I . Need advice.

Started by LJN, January 06, 2016, 04:14:45 AM

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LJN

Hello, all. I got tired of dreaming about it, so I went ahead and wired up a Tone Bender Mk.I. It's working and has plenty of sustain, but it's awful dark sounding. Are my transistors' hfe too low?
If it sounds good, USE IT!

Epiphone Les Paul, Kasino U100- P, Sears 125-XL

J M Fahey

Post-the-schematic d*mmit !!!  :trouble     :lmao:

How are we to even guess otherwise?

LJN

I don't have any way of posting the schematic. The one I built is the Sola-Sound. I used all the stock values on the resistors. The caps are the stock values, except for the electrolytic. I used an axial lead 22 uf.  The transistors are AC128 with the and leakage as follows: Q1 hfe  60  with 0.10ma leakage, Q2 the 73 with 0.06 ma leakage and Q3 hfe 62 with 0.06 ma leakage. There's a hissing noise in it and it has way too much low end.
If it sounds good, USE IT!

Epiphone Les Paul, Kasino U100- P, Sears 125-XL

LJN

Okay, so I've reduced the low end response by changing the 470 k resistor out for a 180 k. It's much brighter sounding now and gets close the Yardbirds- era Jeff Beck sound. There's still a problem with the note decay. As the signal fades, there's a sizzling noise. Is it supposed to do that? There's also a bit of hiss when there's no signal going in. Do I need to swap Q3 for one with more leakage? The effect is also pretty gated at maximum attack setting. Is this also a leakage related problem?
If it sounds good, USE IT!

Epiphone Les Paul, Kasino U100- P, Sears 125-XL

phatt


LJN

Okay. I can't post the schematic. I'm doing this from my phone and it keeps saying "low memory". I really hate modern technology. It's the Sola-Sounds LTD. version. 
If it sounds good, USE IT!

Epiphone Les Paul, Kasino U100- P, Sears 125-XL

LJN

Does anyone know the correct voltages for this circuit? I checked them on mine and here's what I got. With attack on zero : Q1- C:-9.61v, B:-1.80v, E: -2.31v. Q2- C: -7.47v, B: 0v, E: 0v. Q3- C: -6.47v, B: -0.02v, E: 0v. With the attack control on full, here's what I got. Q1- C: -9.60v, B: -1.59v, E: -2.05v. Q2- C: -0.13v, B: -0.14v, E:0v. Q3- C: -6.81v, B: -0.03v, E: 0v. Are these even close to being correct?
If it sounds good, USE IT!

Epiphone Les Paul, Kasino U100- P, Sears 125-XL

J M Fahey

How did you build it without the schematic?  ???

LJN

I have a schematic on a piece of notebook paper. It's just that my phone won't post an image on here. I tried last night. I saved an image of the schematic on my phone and it just won't let me post it.
If it sounds good, USE IT!

Epiphone Les Paul, Kasino U100- P, Sears 125-XL

LJN

I give up. This stupid phone won't do what it's supposed to.
If it sounds good, USE IT!

Epiphone Les Paul, Kasino U100- P, Sears 125-XL

LJN

I've been trying to get a schematic posted on here,  but I can't. If someone could just recommend some acceptable voltages for a Sola-Sound Tone Bender Mk.I , it would really help alot. Thanks.
If it sounds good, USE IT!

Epiphone Les Paul, Kasino U100- P, Sears 125-XL


LJN

Yes, that's the one. Identical to the one I have in my binder. Thank you.
If it sounds good, USE IT!

Epiphone Les Paul, Kasino U100- P, Sears 125-XL

phatt

You need to do some reading if you want this to work.
I've already linked this; http://revolutiondeux.blogspot.com.au/2012/03/sola-sound-ltd-tonebender-mki-hornby.html

And I quote from that page;
Now, before you have a go at this there's a few things you need to know - the MKI ~Tonebender is a right bugger to build, it's the most tempermental circuit I've ever messed around with. However, if you get it right the rewards are worth it. For more info and biasing tips check out this article on Geofex: http://www.geofex.com/Article_Folders/zonkmach/zonkbst.pdf (I know it's for the Zonk Machine but they are the same circuit!).

The PDF covers all this in detail,, Obviously the circuit is a royal PITA and even if you get it to work on the test circuit it may not work so well afterwards. Obviously there is no *Right bias voltage* as the whole circuit is component dependent so you will have to find that by trial and error.
I read once that if you put the circuit in the fridge for a while it changes the bias effect.
If that be true then I have NO desire to build one,, positive ground as well can present issues with other pedals. HINT 8|
I think mictester over at FSB commented on these germ circuits way back and noted that the silicon version is the better bet,, far more stable.
One other point regarding residual fizz on decay,
Be aware that modern amplifiers often have much wider bandwidth and that will accentuate the fizz.
Old classic Valve amplifiers often had limited bandwidth and hence the fizz was less intrusive.
Phil.

J M Fahey

#14
You are talking this:

(Photobucket goes to great lengths to hide or obscure direct picture links, so you are forced to view them inside their ad loaded site)

Schematic comment: ugh !!!!  :duh

They don't even care to bias, transistor losses take care of that  :loco

So no 2 units will sound the same (sorry Zepp fans :(  ) , they will vary wildly according to weather (literally)  and looks like you have to carry  both a Thermos with boiling water and some ice in a portable expanded polystyrene fridge just to fine tune it?
Yummy !!!!!!

As mentioned by Phatt, there's no real guarantee that it will sound anywhere close to Jimi's and on a modern amp it may sound fuzzy.

Those old Silvertones often were dark and muddy (that's an understatement) ... proof enough is that a normally bright and jangly Tele was used ... and nobody noticed it until it was published  :duh