Josh's 18W Tremolo TMB Builds

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geoff 1965
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Re: Josh's 18W Tremolo TMB Builds

Post by geoff 1965 »

interesting point Jack! one of my friends used to play pub gigs and he just used a preamp for the guitar into a PA system which had peavey speakers with tweeters,sounded really good!
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Re: Josh's 18W Tremolo TMB Builds

Post by JMPGuitars »

TriodeLuvr wrote:
Sat 03/13/21 6:34 pm
Just wondering, has either of you (Josh or Bieworm) ever built a guitar cabinet with a tweeter? Seems like that would provide a big range of additional high end response. Maybe it would make the amp a little less dependent on the tonal quality of the main speaker.

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Not me. IME, guitar speakers are usually too bright. If you look at the published tone curves for most speakers, you can see emphasis on high mids and trebles already.
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Re: Josh's 18W Tremolo TMB Builds

Post by TriodeLuvr »

Don't most guitar speakers roll off pretty fast above 4K or 5K? That truncates a lot of harmonics. I was thinking about this because of my experience with the Leslie. That high frequency horn really makes it shimmer. Maybe I'll clip lead something together and give it a try...

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Re: Josh's 18W Tremolo TMB Builds

Post by JMPGuitars »

Yes, but that 2K to 5K range can be ear piercing. I suppose it could be an interesting and/or painful experiment.
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Re: Josh's 18W Tremolo TMB Builds

Post by TriodeLuvr »

JMPGuitars wrote:
Sat 03/13/21 9:43 pm
Yes, but that 2K to 5K range can be ear piercing. I suppose it could be an interesting and/or painful experiment.
The concept I'm thinking about is to pull back that upper-mid response with the tone controls, then accentuate the area above it with the tweeter. The tweeter output will of course bleed into the mids, but again, the tone controls should be able to correct for that. It just seems to me that a speaker system like this would allow the amp to really show its stuff. Didn't Mesa Boogie or some other manufacturer make amps like this, a woofer plus a mid/tweeter cone?

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Re: Josh's 18W Tremolo TMB Builds

Post by Bieworm »

Would be a great experiment though. Keep us posted. Always interested in tonal excursions...
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Re: Josh's 18W Tremolo TMB Builds

Post by JMPGuitars »

TriodeLuvr wrote:
Sat 03/13/21 10:30 pm
The concept I'm thinking about is to pull back that upper-mid response with the tone controls, then accentuate the area above it with the tweeter. The tweeter output will of course bleed into the mids, but again, the tone controls should be able to correct for that. It just seems to me that a speaker system like this would allow the amp to really show its stuff. Didn't Mesa Boogie or some other manufacturer make amps like this, a woofer plus a mid/tweeter cone?
I don't remember. It's common practice for bass cabinets, but not guitar. The lazy skeptic in me assumes it's not common for guitar because it doesn't add enough benefit compared to the cost. But, I'd still love to hear what you come up with.
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Re: Josh's 18W Tremolo TMB Builds

Post by geoff 1965 »

maybe with Mesa that's where they got the idea of a tonestack and built in graphic equalizer like the studio & mk5 amps?
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Re: Josh's 18W Tremolo TMB Builds

Post by JMPGuitars »

geoff 1965 wrote:
Sun 03/14/21 8:43 am
maybe with Mesa that's where they got the idea of a tonestack and built in graphic equalizer like the studio & mk5 amps?
Or maybe it was the only way to get any decent tones out of them. ;)

I did like their amps before discover 18 watters, but after that they felt dull and lifeless.
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Re: Josh's 18W Tremolo TMB Builds

Post by Bieworm »

JMPGuitars wrote:
Mon 02/15/21 3:59 pm
Some more progress today. I wire prepped and connected the pots, and PCB.

_JMP1918.jpg

_JMP1925.jpg
Josh, what are the dimensions of the PCB?
Edit: found the measurements when rereading this entire thread... wow.
3.75x12.1. Its 95mm x 307mm
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Re: Josh's 18W Tremolo TMB Builds

Post by JMPGuitars »

Bieworm wrote:
Wed 03/17/21 10:25 am
Josh, what are the dimensions of the PCB?
Edit: found the measurements when rereading this entire thread... wow.
3.75x12.1. Its 95mm x 307mm
Hahahaha, yup. It's a beast. And wait until you see it in person, you'll never compare it to the crap Mesa or Bogner put out again. ;)
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Re: Josh's 18W Tremolo TMB Builds

Post by Bieworm »

JMPGuitars wrote:
Wed 03/17/21 2:43 pm
Bieworm wrote:
Wed 03/17/21 10:25 am
Josh, what are the dimensions of the PCB?
Edit: found the measurements when rereading this entire thread... wow.
3.75x12.1. Its 95mm x 307mm
Hahahaha, yup. It's a beast. And wait until you see it in person, you'll never compare it to the crap Mesa or Bogner put out again. ;)
I anticipated this by ordering a dumble style chassis blank
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Re: Josh's 18W Tremolo TMB Builds

Post by lavrgs »

Josh, what are the dimensions of the PCB?
Edit: found the measurements when rereading this entire thread... wow.
3.75x12.1. Its 95mm x 307mm
I believe when I asked before about using a "standard" chassis the response was yes. What's driving the 3.75 dimension? Can it be shrunk? I'll have to check my CAD model...

Other amp issues are requiring some attention...my tremolo has stopped working and it seems like the intensity control greatly reduces volume...I will start with a voltage check and some tube swappin'...oh yeah, it was starting to make whooshy noises, that would stop with a moderate beating of the head cab...9-)
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Re: Josh's 18W Tremolo TMB Builds

Post by JMPGuitars »

lavrgs wrote:
Mon 03/22/21 11:58 pm
I believe when I asked before about using a "standard" chassis the response was yes. What's driving the 3.75 dimension? Can it be shrunk? I'll have to check my CAD model...
3.25" is pretty standard. That extra half inch won't likely be the dimension that limits the chassis you can use. 12.1" is pretty long, but should fit most 18W chassis.
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Re: Josh's 18W Tremolo TMB Builds

Post by Bieworm »

For a standard turretboard there wouldn't be space issues, although the standard boards are a little difficult in length unless it's pretty crowded.
I make my own turretboards nowadays from 3mm thick fiberboards that measure 80x500mm. I cut those to 70x340mm.
In case of the use of the dedicated PCB I'd use a dumble style chassis. It's about 2" longer and 1" wider.
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Re: Josh's 18W Tremolo TMB Builds

Post by lavrgs »

In case of the use of the dedicated PCB I'd use a dumble style chassis. It's about 2" longer and 1" wider.
I'd prefer not to need another cab... I'm curious about the term dedicated PCB - are you referring to the board shown for the rectifier or the main PCB?
I did a quick search for dumble style chassis and there seem to be some options...I used to have a press brake years ago but maybe it's time to see if a hand brake could be used for chassis builds...
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Re: Josh's 18W Tremolo TMB Builds

Post by Bieworm »

lavrgs wrote:
Wed 03/24/21 12:29 pm
In case of the use of the dedicated PCB I'd use a dumble style chassis. It's about 2" longer and 1" wider.
I'd prefer not to need another cab... I'm curious about the term dedicated PCB - are you referring to the board shown for the rectifier or the main PCB?
I did a quick search for dumble style chassis and there seem to be some options...I used to have a press brake years ago but maybe it's time to see if a hand brake could be used for chassis builds...
I meant Josh’s tremolo TMB reverb PCB.
If the new chassis works out nice I'll be ordering more of those.
For 2mm aluminium a hand brake should be plenty ok.
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Re: Josh's 18W Tremolo TMB Builds

Post by Bieworm »

Josh, do you ground your reverb jacks directly to the chassis?
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Re: Josh's 18W Tremolo TMB Builds

Post by JMPGuitars »

Bieworm wrote:
Thu 03/25/21 3:10 pm
Josh, do you ground your reverb jacks directly to the chassis?
I do. I haven't tested it compared to isolating them, but it has generally worked fine for me.
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Re: Josh's 18W Tremolo TMB Builds

Post by Bieworm »

I do. I haven't tested it compared to isolating them, but it has generally worked fine for me.
Thanks! I'm gonna put a dwell control in the 36.. I did this on my 18 too.. on the back panel though
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