Covid19...and spare time..

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Bieworm
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Covid19...and spare time..

Post by Bieworm »

Well...covid 19...
Looks like I am going to have a lot of time at the house . We can 't leave home except for work or buying food . Lockdown..sort of..

I ordered the chassis and parts for the TMB tremolo build after all. The board is ready, now lets build the rest

The intention is to build the complete amp so I can swap amps 1 on 1 in the same combo shell.

Some recreation for the time in lockdown. Let's use our time wisely ;)
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Re: Covid19...and spare time..

Post by JMPGuitars »

Dude, you've got the time, you might as well build a head cabinet or two.
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Re: Covid19...and spare time..

Post by Bieworm »

JMPGuitars wrote:
Sun 03/22/20 4:52 pm
Dude, you've got the time, you might as well build a head cabinet or two.
Now that's a thought !!!! hurray
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Re: Covid19...and spare time..

Post by JMPGuitars »

Seriously though. You did a great job on the other cab, might as well make some more variety.
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Re: Covid19...and spare time..

Post by Bieworm »

JMPGuitars wrote:
Sun 03/22/20 5:23 pm
Seriously though. You did a great job on the other cab, might as well make some more variety.
+1 on that!
And after I hear the amp I can determine the color of the tolex. When the amp sounds really hot I can tolex it red or yellow...seriously.

BTW I'm serious about giving you credits on the design. Was thinking about making a metal plate labelled '18W TMB tremolo, JMP Guitars Design'. A brass plate with waterslide lettering and then lacquered.
Do you have a template I can work with?
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Re: Covid19...and spare time..

Post by JMPGuitars »

Thanks, but there's no need to do that. But if you really want to, then just use plain text.

I'm looking forward to hearing/seeing it!
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Re: Covid19...and spare time..

Post by crgfrench »

Waiting for a Mouser order for more Hellhound components during lockdown, I had to burn something with the Hakko. My 2-night stompbox, Lil' Slice o' Pi.
20200324_125109.jpg
20200324_125446.jpg
20200323_010103.jpg
20200323_094739.jpg
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Re: Covid19...and spare time..

Post by JMPGuitars »

crgfrench wrote:
Tue 03/24/20 1:09 pm
Waiting for a Mouser order for more Hellhound components during lockdown, I had to burn something with the Hakko. My 2-night stompbox, Lil' Slice o' Pi.
That's funny, I did too. I like GGG's stuff. I just recently built the violet version of the BMP into a double distortion box with a rat circuit:
jmpguitars-rat-pie.png

Which version did you build?

Thanks,
Josh
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Re: Covid19...and spare time..

Post by crgfrench »

Josh I dig that -- nice combination of circuits and fantastic graphics too. The led switches are a sweet touch!

I built my own circuit on the GGG BMP board.

Its mainly based on the 1973 Violet Ram's Head.

I call it the "Lil' Hare Pi" (as in a small rabbit...) This one is a mono version of the stereo one I made last year on Tommy's prototyping board. I didn't document this build but it's similar. Besides the mono/stereo difference, this one omits the mid-cut tone pot and uses 2N5088s instead of the button-top 2N5133s I used before.

Here are my design notes from the stereo Lil' Hare Pi:

1) The LHP is based primarily on the EHX Violet Ram’s Head 1973 model BMP. All components except as discussed below correspond to the VRH ’73;
2) The LHP “Volume” knob controls the output volume, as in every EHX BMP model. I used the Alpha 100k Log pot.
3) The LHP “Fuzz” knob controls the distortion tone, as in the 1969 EHX “Triangle” model (all later EHX models renamed this “Tone”). I used the Alpha 100k Lin pot.
4) The LHP “Sustain” knob controls the sustain of the signal, as in every EHX BMP model. I used the Alpha 100k Log pot.
5) The LHP “Tone” knob is not a traditional EHX BMP feature. It controls the Mid frequency response. I used the Alpha 20k “W” Tube Screamer pot.
6) The clipping caps C6 and C7 are 1.0uF from the Siamese Dream Big Muff model, for a little more Black Sabbath sound;
7) The gain collector resistors R11 and R18 are 15k, also from the Siamese Dream, for higher gain;
8 ) The output bias resistor R4 is 2.2k, also from the Siamese Dream, for higher gain;
9) The high pass filter resistor R5 is modified to 2.2k from the EHX values 22k – 100k, to accommodate the mid control “Tone” pot;
10) The high pass filter cap C9 is modified to 0.01uF from the EHX values 0.039uF – 0.047uF, to accommodate the mid control “Tone” pot;
11) The voltage divider resistor R7 is 470k from the EHX Creamy Dreamer, Green Russian, Black Russian, and Civil War models;
12) The low pass filter resistor R8 is 33k, in a tilt toward the 1991 Green Russian BMP, to boost the treble slightly at low Fuzz settings vs. the VRH ‘73 model;
13) The transistors Q1-Q4 are 2N5133 NPN silicon in the TO-106 “button top” package, as in the original 1969 “Triangle” and early ’70s “Ram’s Head” BMPs.
14) The output is dual-channel with a stereo feature. This is why there are 3 footswitches. Most EHX BMPs are mono single channel with one footswitch.
15) The footswitches are True Bypass Alpha SF17020F-0302 3PDT. Most EHX BMPs are not True Bypass.
16) All resistors are Dale Milspec ½W metal film 500V. Vintage EHX BMPs used carbon composition 1/4W resistors.
17) All wire is Teflon-insulated Alphawire Mil-Spec (Mil-W-16878) aerospace grade, silver plated, 20AWG copper.
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Re: Covid19...and spare time..

Post by JMPGuitars »

Ha, you put WAY more thought into it than I did. I don't do the kits either, I just get the boards. I chose the violet version because I like Pink Floyd. I did the volume on the input instead of the output because it's supposed to be less noisy that way. That was literally the extent of my thought process. ;)
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Re: Covid19...and spare time..

Post by JMPGuitars »

One other thing. I wanted to call it "Rat Pie" and that's the only reason they're in that order. It sounds great, but I think it might sound better with the rat first. So I might make a different version called the "Pi RATe" with a stupid rat in a pirate hat or something.
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Re: Covid19...and spare time..

Post by crgfrench »

I like "Rat Pie"! Reminded me of an interview I read once in which Eddie said they almost named Van Halen "Rat Salad".
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Re: Covid19...and spare time..

Post by crgfrench »

You could probably just add a DPDT or 3PDT mini-toggle to switch the circuit order.
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Re: Covid19...and spare time..

Post by crgfrench »

That top image shows a miswired Switchcraft 12A input jack on the left. I thought I had a 12B there and that, as you can imagine, didn't produce any sound. I need to order a 12B so in the meantime I resoldered the 12A properly. Now, sick distortion! The 12A just won't disconnect the battery when the input plug is removed the way a 12B would. Time for another Mouser order I guess...
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Re: Covid19...and spare time..

Post by crgfrench »

Here is my project guide for the stereo version:

https://m.youtube.com/watch?feature=you ... 7m7T9DN090
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