Dunlop - JH-F1 Jimi Hendrix Fuzz Face

beedotman · Post by **beedotman** » 25 Apr 2012, 07:19

Here's schematic:

in this case "Contour" knob is 1K pot wich will give You more output than 500R.

BAARON · Post by **BAARON** » 25 Apr 2012, 12:10

How much of an affect does C5 have on the tone? I understand what's going on electrically there, but what does it Sound like?

beedotman · Post by **beedotman** » 25 Apr 2012, 12:25

BAARON wrote:How much of an affect does C5 have on the tone? I understand what's going on electrically there, but what does it Sound like?

You're refering to JF-F1 scehmatic?
I suppose that it tame some high end content...

phil esposito · Post by **phil esposito** » 25 Apr 2012, 16:15

beedotman wrote:
phil esposito wrote:I asked this question in a different thread but I think maybe this is a better location for the question; I'm looking to add a mid's control to my JH-F1 like the Fulltone 70.

Would a 1k pot work as described in the Fuller Mod's in the 'Technology of Fuzz Faces' article? http://www.geofex.com/article_folders/f ... fffram.htm

http://analogguru.an.ohost.de/001/schem ... _JH-F1.gif
Mid's control in '70 is very similar to Contour knob in '69 - it replaces 470R (in standard germanium version of fuzz face circuit) resistor with 220R + 1K pot in series. In '70 it's 220R + 500R pot in place of standard silocon fuzz face value 330R.

So would you suggest a change of R3 to 220R instead of leaving the stock 330R?

beedotman · Post by **beedotman** » 25 Apr 2012, 20:45

phil esposito wrote:
beedotman wrote:
phil esposito wrote:I asked this question in a different thread but I think maybe this is a better location for the question; I'm looking to add a mid's control to my JH-F1 like the Fulltone 70.

Would a 1k pot work as described in the Fuller Mod's in the 'Technology of Fuzz Faces' article? http://www.geofex.com/article_folders/f ... fffram.htm

http://analogguru.an.ohost.de/001/schem ... _JH-F1.gif
Mid's control in '70 is very similar to Contour knob in '69 - it replaces 470R (in standard germanium version of fuzz face circuit) resistor with 220R + 1K pot in series. In '70 it's 220R + 500R pot in place of standard silocon fuzz face value 330R.
So would you suggest a change of R3 to 220R instead of leaving the stock 330R?

If You will use 220R+1K pot You'll get wider range than 330R+500R pot.
With 1K pot You can even go lower - to 100R if You preffer lower settings on '70.
I like fixed resistor here - 820R gives You plenty of output...

phil esposito · Post by **phil esposito** » 26 Apr 2012, 00:07

beedotman wrote:
phil esposito wrote:
beedotman wrote:
phil esposito wrote:I asked this question in a different thread but I think maybe this is a better location for the question; I'm looking to add a mid's control to my JH-F1 like the Fulltone 70.

Would a 1k pot work as described in the Fuller Mod's in the 'Technology of Fuzz Faces' article? http://www.geofex.com/article_folders/f ... fffram.htm

http://analogguru.an.ohost.de/001/schem ... _JH-F1.gif
Mid's control in '70 is very similar to Contour knob in '69 - it replaces 470R (in standard germanium version of fuzz face circuit) resistor with 220R + 1K pot in series. In '70 it's 220R + 500R pot in place of standard silocon fuzz face value 330R.
So would you suggest a change of R3 to 220R instead of leaving the stock 330R?
If You will use 220R+1K pot You'll get wider range than 330R+500R pot.
With 1K pot You can even go lower - to 100R if You preffer lower settings on '70.
I like fixed resistor here - 820R gives You plenty of output...

Cool! Thanks! I'll have to order a pot and try it. I'm going to add an LED as well. Thanks for the help!

phil esposito · Post by **phil esposito** » 04 May 2012, 15:42

SUCCESS! I wired this up last night and it sounds awesome. I realized that the fuzz pot is a 1K and I never turn down the fuzz anyway so I pot a trim pot in for the fuzz and used the orignal pot as the 'Mids' pot. No holes required! This thing has a great range of tones now. I've marked were the original setting is (333R) so I'll know how to get back to stock but I do like it a little hire to help cut a little more.

I'll do a demo soon.

phil esposito · Post by **phil esposito** » 08 May 2012, 01:24

Here's a crappy demo...ignore the slop!

sinner · Post by **sinner** » 11 May 2012, 17:40

so it looks like 10R really

ThoWmas31 · Post by **ThoWmas31** » 02 Jun 2012, 17:54

sinner wrote:I'm not sure why Chris Brown thanked me for my previous message, perhaps because I made stupid mistake typing Q1 twice and I make him laugh, but, never mind I'm sure it's 0,5v on Q1 and 4,5v on Q2

Anyway, here's the lil perfboard layout I did. I was inspired by EW's perfboard fuzzface layouts he done years ago. I just simply added few components as per schematic, still a lot of vintage charm and vibe. No trimmers, it's easy to set fixed bias, we're not going into mass production, do we?

How to make this 4.5V and 0.5 bias ?

thanks for this layout

beedotman · Post by **beedotman** » 04 Jun 2012, 08:35

ThoWmas31 wrote:
sinner wrote:I'm not sure why Chris Brown thanked me for my previous message, perhaps because I made stupid mistake typing Q1 twice and I make him laugh, but, never mind I'm sure it's 0,5v on Q1 and 4,5v on Q2

Anyway, here's the lil perfboard layout I did. I was inspired by EW's perfboard fuzzface layouts he done years ago. I just simply added few components as per schematic, still a lot of vintage charm and vibe. No trimmers, it's easy to set fixed bias, we're not going into mass production, do we?
How to make this 4.5V and 0.5 bias ?

thanks for this layout

Try different transistors or use trimpots in place of resistors on Q1 and Q2 collectors to get desired voltages.

loylo · Post by **loylo** » 05 Jun 2012, 08:29

I currently have a JHF1 on my bench. Here are some informations:
Q1C = 1.35V
Q2C = 5.75V
C1 is indeed 2.2µ, and C3 is 100n
BUT R5 is 10R, not 100R.

I've also read the trimpots, and VR1 is set at approx. 10K and VR2 at 190R...
So I assume VR1 is 20K trim, and VR2 a 1K trim.

I'll get rid of R1 sothat I can read C5.

sinner · Post by **sinner** » 05 Jun 2012, 08:45

loylo wrote:I currently have a JHF1 on my bench. Here are some informations:
Q1C = 1.35V
Q2C = 5.75V
C1 is indeed 2.2µ, and C3 is 100n
BUT R5 is 10R, not 100R.

I've also read the trimpots, and VR1 is set at approx. 10K and VR2 at 190R...
So I assume VR1 is 20K trim, and VR2 a 1K trim.

I'll get rid of R1 sothat I can read C5.

You're lovely

monkeyxx · Post by **monkeyxx** » 05 Jun 2012, 09:24

can't wait to decode this one...I'm a bit of a fuzz face fanatic

monkeyxx · Post by **monkeyxx** » 05 Jun 2012, 09:27

any chance you could read the transistor gains as well? although that's always fun to tune by ear

loylo · Post by **loylo** » 09 Jun 2012, 11:24

So, here I am again!
C5 is unreadable with my DMM, it should be under 100pF...
Q1 and Q2 seem to have same gain, around 260.

sinner · Post by **sinner** » 09 Jun 2012, 11:57

loylo wrote:So, here I am again!
C5 is unreadable with my DMM, it should be under 100pF...
Q1 and Q2 seem to have same gain, around 260.

As I said before, I'm sure it's 47pF

Thanks for it

monkeyxx · Post by **monkeyxx** » 10 Jun 2012, 02:10

ok here's my layout I just made... checked once but not twice, and not yet built and verified. maybe do a quick check before you build this or I'll report back if I get to it first

edit: removed, see below

here's the schematic I used, even though it is apparently sacrilegious to edit someone else's graphic, sorry if anyone's offended

monkeyxx · Post by **monkeyxx** » 10 Jun 2012, 02:23

my bad I had the wrong output cap value, here's the layout I intended to make (please disregard previous post)

JH-F1 pdf layout.pdf: (76.5 KiB) Downloaded 393 times

Chris Brown · Post by **Chris Brown** » 27 Jun 2012, 06:13

Here's my build that was inspired by this thread. Mine is not an exact clone of the jhf1... feedback r is more like 98K the transistors are ti bc108s 350 and 600 hfe... i suspect the original unit has much lower gains than this. It has external bias and also an external input trim since I already had a box drilled for four knobs... I've used it on stage a lot already... thanks to everyone that contributed to this thread! here it is...

Dunlop - JH-F1 Jimi Hendrix Fuzz Face [schematic]