Layout 18 watt classic

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JMPGuitars
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Re: Layout 18 watt classic

Post by JMPGuitars »

Bieworm wrote:
Sat 04/25/20 11:13 am
Wow!!! Very clear!!!
Now I can ditch the normal channel and make room for reverb :P
Lol, you could certainly do that. But you could also build a Tremolo TMB with Reverb if you want. There is plenty of room on a Tremolo TMB board to do that. My personal version of the Tremolo TMB with Reverb fits on a 285mm board. Of course, I'm probably never going to share that layout, but it can be done. ;)

If you just want Tremolo and Reverb, without the TMB, then go for it. It could be fun too. But I will laugh if you build it and miss the TMB controls.
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Re: Layout 18 watt classic

Post by Bieworm »

JMPGuitars wrote:
Sat 04/25/20 11:40 am
Bieworm wrote:
Sat 04/25/20 11:13 am
Wow!!! Very clear!!!
Now I can ditch the normal channel and make room for reverb :P
Lol, you could certainly do that. But you could also build a Tremolo TMB with Reverb if you want. There is plenty of room on a Tremolo TMB board to do that. My personal version of the Tremolo TMB with Reverb fits on a 285mm board. Of course, I'm probably never going to share that layout, but it can be done. ;)

If you just want Tremolo and Reverb, without the TMB, then go for it. It could be fun too. But I will laugh if you build it and miss the TMB controls.
Nasty!!
BUT you're right. I am just trying to give purpose to the classic 18 here. Since the TMB tremolo is ready it is obsolete
You know what?... I was actually really considering converting the classic to the same TMB tremolo. I like the combo housing better... But a better idea is to rebuild the classic to perfection and sell it. So I can buy new stuff to build a completely new one..TMB trem with that shell
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Re: Layout 18 watt classic

Post by bvayling »

You've no doubt seen it, but it seems Richie's 2008 layout of the classic actually reduces the wires crossing without changing the place of the tubes.
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Re: Layout 18 watt classic

Post by Bieworm »

bvayling wrote:
Sat 04/25/20 12:45 pm
You've no doubt seen it, but it seems Richie's 2008 layout of the classic actually reduces the wires crossing without changing the place of the tubes.
Yes but still...it seems weirdly positioned with the PI in between
I like the normal channel better than the tremolo channel. But would it be possible to do the normal channel wiring and components on the tremolo channel?
The normal channel has more low on the whole dial on the volume. The tremolo channel needs to be cranked to have some bottom end
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Re: Layout 18 watt classic

Post by bvayling »

I’ll have to pay more attention. I’ll confess to not actually having played my classic combo that much yet, having been so far mostly obsessed with voltages and dissipation. I hadn’t noticed that much difference between the two channels though, so I’ll look into that. Maybe I’ll turn down the volume knob!
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Re: Layout 18 watt classic

Post by Bieworm »

bvayling wrote:
Sun 04/26/20 7:31 am
I’ll have to pay more attention. I’ll confess to not actually having played my classic combo that much yet, having been so far mostly obsessed with voltages and dissipation. I hadn’t noticed that much difference between the two channels though, so I’ll look into that. Maybe I’ll turn down the volume knob!
It really sounds so much better...with creamy OD on top. The bright cap is the first to go..seriously
I'm just gonna do it. Trem channel with normal channel parts
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Re: Layout 18 watt classic

Post by JMPGuitars »

Bieworm wrote:
Sun 04/26/20 11:02 am
It really sounds so much better...with creamy OD on top. The bright cap is the first to go
I'm just gonna do it. Trem channel with normal channel parts
That's funny, most people prefer the tone knob on the trem channel compared to the normal channel. That's why the Lite series of builds use the trem channel tone stack, even though they've basically just cut the trem channel out of the build.

What you sound like you're describing to me is the desire to revoice the channel. You can change the values in the tone stack to adjust the sound how you like it.
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Re: Layout 18 watt classic

Post by Bieworm »

JMPGuitars wrote:
Sun 04/26/20 11:07 am
Bieworm wrote:
Sun 04/26/20 11:02 am
It really sounds so much better...with creamy OD on top. The bright cap is the first to go
I'm just gonna do it. Trem channel with normal channel parts
That's funny, most people prefer the tone knob on the trem channel compared to the normal channel. That's why the Lite series of builds use the trem channel tone stack, even though they've basically just cut the trem channel out of the build.

What you sound like you're describing to me is the desire to revoice the channel. You can change the values in the tone stack to adjust the sound how you like it.
Was thinking about making the 500pf cap switchable. But don't know if it will lift the bottom end ... should I go for the. 022 cap too?
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Re: Layout 18 watt classic

Post by zaphod_phil »

JMPGuitars wrote:
Sun 04/26/20 11:07 am
Bieworm wrote:
Sun 04/26/20 11:02 am
It really sounds so much better...with creamy OD on top. The bright cap is the first to go
I'm just gonna do it. Trem channel with normal channel parts
That's funny, most people prefer the tone knob on the trem channel compared to the normal channel. That's why the Lite series of builds use the trem channel tone stack, even though they've basically just cut the trem channel out of the build.

What you sound like you're describing to me is the desire to revoice the channel. You can change the values in the tone stack to adjust the sound how you like it.
The trem channel has two 0.005uF coupling caps in series, effectively the same as 0.0025uF, which are cutting the low frequencies. Using 0.01 or 0.022uF caps instead, will really open up those lows for you.
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Re: Layout 18 watt classic

Post by Bieworm »

zaphod_phil wrote:
Sun 04/26/20 2:49 pm
JMPGuitars wrote:
Sun 04/26/20 11:07 am
Bieworm wrote:
Sun 04/26/20 11:02 am
It really sounds so much better...with creamy OD on top. The bright cap is the first to go
I'm just gonna do it. Trem channel with normal channel parts
That's funny, most people prefer the tone knob on the trem channel compared to the normal channel. That's why the Lite series of builds use the trem channel tone stack, even though they've basically just cut the trem channel out of the build.

What you sound like you're describing to me is the desire to revoice the channel. You can change the values in the tone stack to adjust the sound how you like it.
The trem channel has two 0.005uF coupling caps in series, effectively the same as 0.0025uF, which are cutting the low frequencies. Using 0.01 or 0.022uF caps instead, will really open up those lows for you.
Thx ZP !!! Changed them both in .022uf and I like it much better now :)
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Re: Layout 18 watt classic

Post by Bieworm »

Josh, in your effects loop you have the 2x 68k and 1x 47k with the .01uf caps. Robrob don't do any of these. What's the function of those? And why is yours supreme? Not questioning your design, just curious...
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Re: Layout 18 watt classic

Post by JMPGuitars »

Bieworm wrote:
Mon 04/27/20 1:26 pm
Josh, in your effects loop you have the 2x 68k and 1x 47k with the .01uf caps. Robrob don't do any of these. What's the function of those? And why is yours supreme? Not questioning your design, just curious...
I didn't invent it. I copied it from the downloads section: download/file.php?id=10460&mode=view

It's designed to work with 18Watters and it works great. I assume the resistors are to keep the signal levels in a good spot.

I run it PTP to the board from the jacks. Besides what I assume is for safe signal levels, the resistors also give the caps the length to make it work without adding wires.

Thanks,
Josh
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Re: Layout 18 watt classic

Post by Bieworm »

Josh
I'm thinking about making the amp a 1 input, 2 channel amp with channel selector switch.
Is this layout something I can go on with?
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Re: Layout 18 watt classic

Post by JMPGuitars »

You could try that with shielded wire. If you did that though, I would connect pins 2 and 7 of the first preamp tube so that channel runs the tube in parallel. Or you could add a cascade/parallel switch to the first preamp.

The other option is to run an AB/Y box, but then you wouldn't need to modify the amp, and it wouldn't be as fun.
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Re: Layout 18 watt classic

Post by Bieworm »

JMPGuitars wrote:
Thu 04/30/20 6:43 am
You could try that with shielded wire. If you did that though, I would connect pins 2 and 7 of the first preamp tube so that channel runs the tube in parallel. Or you could add a cascade/parallel switch to the first preamp.

The other option is to run an AB/Y box, but then you wouldn't need to modify the amp, and it wouldn't be as fun.
You can see right through me. Fun is nr1, but all the confusion about inputs on an 18 watt is nr2. PLUS I want to use 2 inputs in the frontpanel for the FX loop..

I guess if I ever get to the point that I'm tweaked out, I will have to get some custom made frontpanels crafted so it all fits. And honestly, that too I will probably do myself ;)
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