New TMB w/reverb Build

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foreverstrung
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Re: New TMB w/reverb Build

Post by foreverstrung »

OK. So here's a couple scope screenshots. Both have the V1 tube removed. Probe ground is on the output jack busbar/ground. (not input jack). The amp is off. I set the audio generator to 300mV. (I switched to #1 port, probe is set to 10x, not 1x)
SDS00029.png
Here is the measurement page
SDS00030.png
Should I post screenshots of the measurements of all the points we've gone through tonight?
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Re: New TMB w/reverb Build

Post by JMPGuitars »

foreverstrung wrote:
Fri 01/06/23 10:39 pm
OK. So here's a couple scope screenshots. Both have the V1 tube removed. Probe ground is on the output jack busbar/ground. (not input jack). The amp is off. I set the audio generator to 300mV. (I switched to #1 port, probe is set to 10x, not 1x)
SDS00029.png
Here is the measurement page
SDS00030.png
Should I post screenshots of the measurements of all the points we've gone through tonight?
No, let's focus on the jack first. Also, change your Measure settings so it shows just the ones I mentioned at the bottom. You need to hit the back button after pressing autoset for it to show everything correctly.

I wonder if there's something wonky with your shielded input wire. Try raising it off the chassis, and see if that changes anything. If not, disconnect it from the terminal strip, and connect the probe to it while floating.
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Re: New TMB w/reverb Build

Post by foreverstrung »

OK. Power is still off. V1 is still removed. Probe is in the exact same points. Audio gen is set just as it was, so is the scope, but I'm not even getting close to the same reading on the scope
SDS00033.png
I specifically chose PK-PK, Ampl, Mean and RMS in the measurement page. This scope reading as I just described above is wonky, active. I took 2 screenshots of the measurements as they were changing quickly as this reading was active
SDS00031.png
SDS00032.png
I hope I'm being thorough. I'm doing my best to post the info as I get it as accurately as possible. I don't want to waste anyones time.
I moved the shielding wire. No change. I disconnected the terminal strip with no change at all.
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Re: New TMB w/reverb Build

Post by JMPGuitars »

Post high resolution photos of your build. Also post photos of your testing setup with the amp off, but the scope and signal generator active. Post a photo of the signal generator screen as well.
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Re: New TMB w/reverb Build

Post by foreverstrung »

OK, so here's a pic of the signal generator. Plugged into and on channel 2
today1.jpg
This is the wave pattern on the scope
today2.jpg
And then this is the set up. Probe ground is on input jack busbar ground. Probe itself is on the input jack. (I get the exact wave pattern at the shielded wire @ the terminal strip, (Connected and disconnected from chassis. Same both ways). In the background we can see the AWG and scope.
today3.jpg
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Re: New TMB w/reverb Build

Post by foreverstrung »

So I had to step away for a couple days and let this stuff go. Settle down a bit. So I'm going to "ease" back into it.
One thing to note, the input jack appears to have grounded out on the chassis and this caused a ground loop which was throwing my scope off.
I'm going to go through now and the next day or 2 and meticulously clean up everything and run it through again.
Temporarily removing the FX stuff so that I've got better access to everything.
ground loop.png
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Re: New TMB w/reverb Build

Post by foreverstrung »

Back on page 14 of this thread Josh, you've got screenshots of an amp on your bench. One of the screenshots is of "PI P1 (anode)". Where exactly is this for me to probe on my build? I assumed it was the phase inverter, V4, pin 1. I'd like to get this cleared up as this is just one side of that tube and is at about 225v.
I've cleaned up much of this amp and tho my scope readings aren't as clean as the ones you've posted, I'm happy with them up to the point noted above. I'm happy because the sine waves are relatively clean and I'm keeping the 1 kHz signal
The points I've probed are. AWG, Input, V2P2, .047-56, Treble P2, Volume P2. (up to here, everything is good except for some background noise. I'll post pics of screen shots when I get past the next/last 2 positions).....So the PI P2 anode I need clarification and last, but no way the least is the output. I'm getting a poor reading and not nearly enough juice going out to move the speaker. I went through and checked all my voltages and there all still spot on.
I've got a few more areas I'd like to clean up before testing with the scope again.
So another quest for advice.
I've got a solder sucker and it does ok when I'd like to clean up a joint to resolder, but the wick braid is probably better right? Either way, once I remove the old solder, any recommendations to prep before applying new solder?
TIA
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Re: New TMB w/reverb Build

Post by JMPGuitars »

foreverstrung wrote:
Sat 01/14/23 11:02 am
Back on page 14 of this thread Josh, you've got screenshots of an amp on your bench. One of the screenshots is of "PI P1 (anode)". Where exactly is this for me to probe on my build? I assumed it was the phase inverter, V4, pin 1. I'd like to get this cleared up as this is just one side of that tube and is at about 225v.
I've cleaned up much of this amp and tho my scope readings aren't as clean as the ones you've posted, I'm happy with them up to the point noted above. I'm happy because the sine waves are relatively clean and I'm keeping the 1 kHz signal
The points I've probed are. AWG, Input, V2P2, .047-56, Treble P2, Volume P2. (up to here, everything is good except for some background noise. I'll post pics of screen shots when I get past the next/last 2 positions).....So the PI P2 anode I need clarification and last, but no way the least is the output. I'm getting a poor reading and not nearly enough juice going out to move the speaker. I went through and checked all my voltages and there all still spot on.
I've got a few more areas I'd like to clean up before testing with the scope again.
So another quest for advice.
I've got a solder sucker and it does ok when I'd like to clean up a joint to resolder, but the wick braid is probably better right? Either way, once I remove the old solder, any recommendations to prep before applying new solder?
TIA
Correct, PI P1 is V4 Pin 1. You said both P1 and P2, P1 is plate (anode) P2 is grid. Scope P1 of V4. That's the main signal path. P6 of V4 is the signal that will come from the reverb, but scoping reverb is goofy anyway, because it's reverb.

Try setting your bandwidth limit to 20M (channel button, look for options). If you haven't already done that, then it might reduce the noise.

I use the desoldering gun on my soldering station. I don't have the patience for the other stuff. If it's a good braid, it might work better. To clean stuff, desolder as well as possible, and then use a coarse brush to try and clean further. You can use a tiny amount of solder to clean as well, but that's tricky.

I'm glad to hear you're making progress!
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Re: New TMB w/reverb Build

Post by foreverstrung »

So hopefully this thread ends with a happy ending. LOL. I really got tired of dickin around and not getting anywhere with the idiosyncrasies I was finding with the scope. At one time the amp was putting out good sound but I had the reverb not performing. At all. The more I dicked with it, the better it did NOT get. Just seemed like more obsticles.So I've upgraded many of my tools and enough parts for the next build, and then just pretty much took this thing apart. De-wired and de-soldered the heaters and pots and all wires to the PCB board. Now I'm putting it all back together. I watched all the soldering videos recommended, again, plus many more, from the same outfit, that don't really apply.
One thing I did diff is that the reverb rca jacks I had installed with a washer on each side of the chassis as the predrilled holes were way too big for the rca jacks themselves. To get rid of any potential/probable continuity issues, I drilled 2 hole just next to these at the right diameter that rca jacks anchor directly on the chassis itself. Figured it can't hurt.
I'm also doing my best to get better solder connections.
Anyways, that's where I'm at with this build right now. I'm looking fwd to building the cabinet as I've got all the components, but I just can't go there till this amp is kickin.
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Re: New TMB w/reverb Build

Post by JMPGuitars »

foreverstrung wrote:
Fri 01/20/23 5:13 pm
One thing I did diff is that the reverb rca jacks I had installed with a washer on each side of the chassis as the predrilled holes were way too big for the rca jacks themselves. To get rid of any potential/probable continuity issues, I drilled 2 hole just next to these at the right diameter that rca jacks anchor directly on the chassis itself. Figured it can't hurt.
I'm also doing my best to get better solder connections.
Anyways, that's where I'm at with this build right now. I'm looking fwd to building the cabinet as I've got all the components, but I just can't go there till this amp is kickin.
Hmmm, I sent you Switchcraft RCA jacks thinking they'd be easier to solder. These are the ones I normally use: https://www.amplifiedparts.com/products ... old-plated - but if you get those, make sure they're tight and you use some kind of loctite. The solder cups are a little tricky at first, so get extras if you go that route. ;)
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Re: New TMB w/reverb Build

Post by foreverstrung »

So this morning I fired it up with dim bulb tester. Glad I did instead of being so arrogant, believing I had everything dialed in nicely, (which did cross my mind) as I found a point on V6 between pins 5 and 6 which were arcing as I had a little too much solder on pin 5. Cleaned it up, tried again and appeared good with the tester. So plugged it into the wall and found all the voltages good. Then I put it on the scope and found all these readings acceptable. Not as clean a sine waves as Josh, but much better than before.
The main thing(s) I've done diff is that I upgraded my solder station with a good suction (desoldering) tool. I rewatched the soldering videos recommended. In these videos I most notably caught how to set the tip, applying the "bridge" from the tip to the surface and then using the solder to "paint" the area concerned. One of the things I was doing wrong was thinking like soldering with a torch and pipe when plumbing. That kind of soldering, the solder follows the heat, so I would apply solder and use the solder iron tip to move the solder, rather than "painting" it on, as described in the educational videos.
Another thing I did wrong before is that after I'd solder a joint, I immediately move to the next position without giving the newly soldered point I'd just done, adequate time to fully cool allowing for possible compromised joints.
So, this is where I'm at now. I'm going to plug it in and do a sound check after everyone is up and awake. Then complete the FX stuff and give the reverb a spin.
More to come.
Thx
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Re: New TMB w/reverb Build

Post by foreverstrung »

OK. So everything is hooked up. Amp sounds amazing. Tremolo is awesome. Amp is quiet. (P90's are kinda loud no matter what). Pedal works as it should with the tremolo. BUT, i've still got the reverb problem. It hasn't changed. This is where I was at awhile back and I ended up making things worse dickin around. Like I mentioned a post or 2 back, the scope shows relatively healthy sine waves from input to output with the AWG set at 1 kHz, I've got this reading at the input to the output........So what's next for checking my reverb? I doubt you guys recall, but in this thread, awhile back, I had the reverb issue. Got a scope and an audio generator, initially for chasing down the reverb issue, but could never get past the issues I was having just following the path from input to output until I re did most everything and am back here now.
Suggestions moving fwd chasing the reverb bug would be very much appreciated.
Thx
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Re: New TMB w/reverb Build

Post by JMPGuitars »

foreverstrung wrote:
Sat 01/21/23 9:07 pm
OK. So everything is hooked up. Amp sounds amazing. Tremolo is awesome. Amp is quiet. (P90's are kinda loud no matter what). Pedal works as it should with the tremolo. BUT, i've still got the reverb problem. It hasn't changed. This is where I was at awhile back and I ended up making things worse dickin around. Like I mentioned a post or 2 back, the scope shows relatively healthy sine waves from input to output with the AWG set at 1 kHz, I've got this reading at the input to the output........So what's next for checking my reverb? I doubt you guys recall, but in this thread, awhile back, I had the reverb issue. Got a scope and an audio generator, initially for chasing down the reverb issue, but could never get past the issues I was having just following the path from input to output until I re did most everything and am back here now.
Suggestions moving fwd chasing the reverb bug would be very much appreciated.
Thx
The answer is always the same:
Voltages
Highlighter test
Photos
Sound sample

Did you redo the reverb pot? Are the RCA jacks good?

Congrats on getting everything else to awesome!
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