Build Your Own Clone Message Board

Hi guys. So, I want to do a mod of the Large Beaver Ram's Head to match what would be the 1973 version (the one just before the Violet but very similar to it). According to Kit Rae, who I consider the master of the Big muff, this is the Muff he believes Gilmour is using - which is exactly what I'm looking for.

I have BYOC schematic (well, a poor quality one from the internet) - BYOC's schematic just loads the build docs and the schematic in the build doc is chopped up for some reason. The link in the doc for the hi res version takes you to a "this page doesn't exist" web page. The rev for the schematic I am using is 2.0.

My issue is with the tone section. I can't quite figure out what it is doing. There are 3 switches listed (but only 2 on the build). There is also 2 .0039 (C7 and C9) and two .01 (C8 and C10) caps listed on the schematic but the kit only comes with one of each. I do not have a circuit board layout to know what is used where.

According to the Kit Rae (KR for short) schematic, the tone uses a 33k resistor to the tone pot (BYOC is 39k). Kit Rae uses a 33k to ground (BYOC is 22k). That's all good.

What I am trying to figure out is the caps. KR shows a 0.004uF cap going to the pot (I'm assuming that is the 0.0039 on the BYOC shecmatic). I will probably just leave this value 0.0039. KR also has a .012uF going to ground. Is this the .01uF (C8) that BYOC has going to ground at the top of the tone section? Do I just need to swap the C8 out with the .012? I don't see another cap going to ground in the tone section.

Do I even need to swap the .01 out for the .012? Will it make that big a difference?

Any help you can give me will be appreciated. I haven't checked with BYOC yet to see if they will switch those components out if I buy the Large Beaver Ram's but I'm hopeful they will. I'll email them once I get this sorted out.

I've attached pics of the BYOC tone section and the KR. The first is BYOC's tone switch section. The second is the Kit Rae tone section.

_________________
-Jamie

It appears the schematic I have is old. The schematic has a 43K but the BOM does not. It has a 47k, which is not on the schematic. If anyone happens to have the latest rev of the schematic, I'd appreciate it.

_________________
-Jamie

That's the old version of the large beaver with a 4-way rotary. The current schematic is on the website.

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*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com

I cannot find the current schematic. The schematic link on the pedal page takes you to the build document. The link in the build document takes you to “page not found.” The schematic in the build document has technical difficulties and does not look right. If you can provide me with a link that works, that would be great.

_________________
-Jamie

Try this link for the current schematic; the one in the instructions contains a typo: http://www.byocelectronics.com/largebea ... ematic.pdf

The cap and resistor values you have listed are for the older rotary switch version of the LB.

The purpose of the on-off-on toggle switch is two change the effective capacitance value of C12. With the toggle in the off middle position, C12 is 3.9nf which gives the classic Big Muff "scooped" midrange at the mid-point on the tone control. Since caps in parallel give the additive capacitance of the two, switching on the 8.2nf cap (Flat setting) raises the effective C12 capacitance to 12.1nf, giving a flat frequency response at the midpoint. Switching on the 47nf cap (Hump setting) will give an effective capacitance of 51nf, resulting in a midrange hump in the control.

Because of the flexibility of these three settings and the frequency range afforded by the tone control across its sweep, I'm quite confident that you can achieve that that '73 tone you're seeking with a bit of tweaking. You can always change R19 to a 33K to match the KR data, if you wish. I'm sure BYOC would include one with your kit if you request it. The cap values you mentioned are close enough to the BYOC caps that the differences are inconsequential.

The other toggle switch takes the tone stack out of the signal path completely, giving a louder, flat frequency output, since there isn't signal loss or frequency response alteration through the tone stack.

Hope this helps....

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

Thanks again! Got the latest schematic downloaded. I'll probably leave those 2 values the same since they are so close. A lot of them are a little further off. If you are interested, here's the complete list of components changing (according to the old schematic) - I will check the new schematic before i purchase the ram's kit and the components to build the customizations.

Do you by chance have a copy of the locations of components on the circuit board (like where R1, R2, etc. is located)? I think that may be helpful to me.

These are listed as "component value I need" > "Schematic Location” “original value listed at location on schematic"...
Resistors...
100k > R3 43k
100R > R1 120R
100R > R8 150R
10k > R19 15k
10k > R23 15k
33k > R13 22k
33k > R5 39k
33k > R14 39k
470k > R22 430k
560R > R12 1k

Capacitors...
470pF > C2 560pF
470pF > C5 560pF
470pF > C12 560pF
0.1uF > C6 1uF
0.1uF > c13 1uF
0.1uF > C15 1uF
0.1uF > C1 10uF

_________________
-Jamie

Unfortunately, no, we don't have a PCB map for the latest Large Beaver versions. Our resident forum schematic guru hasn't been able to create these in recent years. A lot of the components can be identified by correlating the labeling on the PCB, the parts list and the connection traces on the PCB.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

OK. Well, hopefully I won't have any duplicate values that will confuse the situation. If so, I think I should be able to read the schematic and follow the trace on the board to pinpoint the location.

Anyways, this will be a fun little project. I'm looking forward to it. I'm going to align the recent schematic you sent to the 73 then I'll order the kit and all my parts to build. I don't get to build as many pedals these days as I've build about every I need and more. This will be fun.

That said, I am still awaiting the Super 8. I need to build 2 of those. I have 2 already that run my dirt pedals for home and the practice space. Want the other 2 to run my effects loops.

_________________
-Jamie

In case anyone's curious, here are the new values based on the current schematic.

'1973 value' > 'BYOC location' 'BYOC value'
Resistors...
100R > R4 120R
100R > R11 150R
100R > R16 150R
560R > R7 1K
2.7k > R23 3.3k
10k > R17 15k
10k > R22 15k
33k > R19 22k
100k > R3 47k
470K > R20 430k

Capaictors...
0.1uF > C6 1uF
0.1uF > C9 1uF
0.1uF > C15 1uF
0.1uF > C1 10uF
0.012uF > C13 0.01uF

_________________
-Jamie