Baldwin-Burns - Buzzaround

Waimana · Post by **Waimana** » 07 Jun 2010, 03:12

Made a compact version on 12x16 perfboard using Carells schematic
Used 2SB172 for Q1 & Q2 (hfe 54 & 70 respectively), AC138 with hfe 114 in Q3
Mallory small signal caps for 4.7u and Wima's for 100n & 1 n
5KB balance works well as a volume control
Sounds great, lots more harmonic texture copared to my 60's Fuzzface
However, doesnt clean up as well when you roll back the volume
Thanks for the guidance on FSB's

Waimana · Post by **Waimana** » 07 Jun 2010, 03:57

photos of compact perfboard Buzzaround build

Waimana · Post by **Waimana** » 07 Jun 2010, 03:59

perfboard buzzaround photo

Greg · Post by **Greg** » 07 Jun 2010, 06:18

Waimana - you were posting the Buzzaround-ALIKE thread, which is an updated circuit that uses an opamp..
so I moved your posts here..

Neat build BTW.

Waimana · Post by **Waimana** » 07 Jun 2010, 23:16

Thanks for putting those images in the right thread

Got confused with the 'Buzzaround-alike'...might try that one as well soon
Cheers

bootle · Post by **bootle** » 26 Jun 2010, 12:42

is about 2v right for Q3C?
I put a 25k pot in for the balance control so I can get up to about 3.5v there, but it sounds ok from around 1.5v up.
its much louder so I put in a volume control too.
I read somewhere biasing Q3 any higher can cause thermal problems?
anyone got any insight on this?

johnnyg · Post by **johnnyg** » 28 Sep 2010, 15:13

I didn't know whether to ask this question here, or in Mictester's op-amp buzz-a-like... or maybe somewhere else! I don't know - but hopefully someone with an answer will see the question anyway!

Given that darlington pairs have long been available in a single package - and I've seen pnp silicon darlingtons... has anyone tried replacing the first two low hfe germs with a silicon darlington (instead of using an op-amp as in Mictester's version)? Is this even possible? I'd have a go - but have no idea how to go about choosing what resistor you would fit from the emitter to ground!

I think... but can't remember where I picked this up... that the total hfe with two transistors used in a darlington pair is just Q1 hfe multiplied by Q2 hfe? In my build of the buzzaround it's something like 40hfe x 70hfe = 2,800hfe... so perhaps I'd need to start out with a silicon darlington of say 2000 and upwards (assuming you can find that - possibly most are much higher total hfe?).

johnnyg · Post by **johnnyg** » 28 Sep 2010, 19:51

johnnyg wrote:I didn't know whether to ask this question here, or in Mictester's op-amp buzz-a-like... or maybe somewhere else! I don't know - but hopefully someone with an answer will see the question anyway!

Given that darlington pairs have long been available in a single package - and I've seen pnp silicon darlingtons... has anyone tried replacing the first two low hfe germs with a silicon darlington (instead of using an op-amp as in Mictester's version)? Is this even possible? I'd have a go - but have no idea how to go about choosing what resistor you would fit from the emitter to ground!

I think... but can't remember where I picked this up... that the total hfe with two transistors used in a darlington pair is just Q1 hfe multiplied by Q2 hfe? In my build of the buzzaround it's something like 40hfe x 70hfe = 2,800hfe... so perhaps I'd need to start out with a silicon darlington of say 2000 and upwards (assuming you can find that - possibly most are much higher total hfe?).

Scrap this idea!

I tried out low gain pnp si transistos in Q1 and Q2 with a couple of germs in Q3 I already know sound great in this circuit (a 2SB54 and a AC142). The sound just does not compare with what you can get with three good germaniums. I also tried using just the one si transistor - even as a way of using up a very low gain germanium (a 30hfe ge in Q1 and 80hfe si in Q2). Got a more than useable sound this way... but again, nothing to compare to what you get with three good germaniums.

ppluis0 · Post by **ppluis0** » 30 Sep 2010, 03:10

Hi there,

After read the entire 15 pages of this thread I cannot find the annexed leakage resistors that mictester mentioned.

Can anyone explain this matter ? How level of leakage are suggested to have ?

Also I found a source of some 2SB54 Ge pnp transistors.

Someone think that this model can adapt to build a clone of this unit ?

Thanks and Regards,
Jose

roseblood11 · Post by **roseblood11** » 30 Sep 2010, 07:55

You should have read the thread about mictesters Buzzaround-Alike, this is about the original Buzzaround.

ppluis0 · Post by **ppluis0** » 01 Oct 2010, 01:09

I will look and read the posting you mentioned.

Thank you !!

johnnyg · Post by **johnnyg** » 18 Oct 2010, 14:05

Just a couple of quick things about the original buzzaround I'm not sure have been discussed before or not?

The wiring of the balance pot in the original (assuming the schematics are correct) is 'back to front' - i.e. you turn the pot anti-clockwise to raise volume. But this seems intentional I think(?). The balance pot 'follows' the timbre pot (which also affects volume of course in this quirky circuit). So as you turn the tone pot in one direction you turn the balance pot the same way to adjust the volume up or down as necessary... there's probably a better way to describe what I'm trying to say, but it becomes clear when you fiddle about with the actual pedal.

Looking at the Dizzytone pcb the 'back to front' wiring of the balance pot was 'corrected' (the 27k resistor connected to lug 3 not lug 1 of the volume pot). So you turn it clockwise to raise volume. Personally I prefer this - and it is how I have my builds wired.

Also the 100k pot for sustain is too much. It's better, I think, to use a lower value pot - I have 47k in my most recent build and it works better. I think you could even drop to 25/22k I guess.

kbgreenall · Post by **kbgreenall** » 27 Jan 2011, 04:27

OccasionalFX wrote:I just created a tagboard layout...this is pretty close both to the original based on Graeme's pics, and to David Main's recreation.

Haven't built one yet, but I hope to soon...

Let me know what you think & if you see any errors.

I used this layout thanks! Transistors were donated from an old Wurlitzer organ.

timsmcm · Post by **timsmcm** » 09 Apr 2011, 01:48

I am going to try to build one of these is there any place I could look to get a set of nkt213 trannies

mictester · Post by **mictester** » 09 Apr 2011, 12:43

timsmcm wrote:I am going to try to build one of these is there any place I could look to get a set of nkt213 trannies

Probably not. You could try ebay, but you'll probably get ripped off even if you manage to find any. You can use almost any medium gain germanium transistor in this circuit (I've built them with NPN germaniums and inverted battery and electrolytics).

phibes · Post by **phibes** » 09 Apr 2011, 18:51

There a bitch to get and if you do find em, your going to need to buy at least 20 to get a good trio. Get a pre-measured 3 Knob Tone Bender trio from Smallbear. That will get you into Buzzaround territory and it will save you from a lot of face-palming!

kinski · Post by **kinski** » 29 May 2011, 14:47

Okay, am I crazy? I built the Madbean Buzzaround. Sounds great. BUT, I can't seem to add a DC Jack? When I do this, nothing works and the battery gets hot? WTF? I've never run into this problem before? I'm sure I'm doing something stupid. Any help would be appreciated!

Here is a link to the layout file:

http://www.madbeanpedals.com/projects/B ... ver2.5.pdf

rbstep · Post by **rbstep** » 29 May 2011, 16:28

It's a positive ground pedal, jack is neg ground....I think

kinski · Post by **kinski** » 29 May 2011, 17:32

THis is the first pedal i built that says -9v off the board. Not +9v. So how would this change the wiring layout?

Alex Frias · Post by **Alex Frias** » 30 May 2011, 01:11

You can not use a positive ground pedal, like the original ancient Buzzaround, sharing the same power supply with others positive ground pedals ( the modern standard for pedals ).

You will simply short the power supply this way!

Baldwin-Burns - Buzzaround [schematic]