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Re: Josh's 18W Tremolo TMB Builds
Posted: Mon 02/22/21 2:55 pm
by Bieworm
What wattage did you use on that resistor?
I have got 5W in my tremolo TMB 's...
Or does it have anything to do with the 36W power compared to 18W?
Re: Josh's 18W Tremolo TMB Builds
Posted: Mon 02/22/21 3:11 pm
by JMPGuitars
That resistor is about 8W. But yes, it's because of the 36W amp. Normally I use a 20W resistor there on 36W amps, but 20W is overkill, so I wanted to see how hot a lower wattage resistor would get.
Re: Josh's 18W Tremolo TMB Builds
Posted: Mon 02/22/21 3:14 pm
by Bieworm
JMPGuitars wrote: ↑Mon 02/22/21 3:11 pm
That resistor is about 8W. But yes, it's because of the 36W amp. Normally I use a 20W resistor there on 36W amps, but 20W is overkill, so I wanted to see how hot a lower wattage resistor would get.
Good!!! I was starting to get worried
Re: Josh's 18W Tremolo TMB Builds
Posted: Sat 02/27/21 8:50 pm
by JMPGuitars
I got my double switch PCBs in:
grounding double switch.jpg
Re: Josh's 18W Tremolo TMB Builds
Posted: Sun 02/28/21 12:11 am
by TriodeLuvr
crgfrench wrote: ↑Sat 02/20/21 2:05 am
The gain of a LTP is equal to the gain of a single gain stage for a given tube. The mu of a 12AX7 is 100 and the mu of a 12AT7 is 60. So that's why the 12AT7 LTP is lower volume.
The gain of a LTP is typically less than half the gain of the tube in grounded cathode (bypassed) mode. With the Presence control at minimum resistance and no NFB, the Marshall 12AX7 LTP exhibits a voltage gain of approximately 22. Substituting a 12AT7 with no other changes, gain falls to about 16.5. That's a difference of 2.5 dB. I would have thought you'd need to pay close attention to hear that.
Jack
Re: Josh's 18W Tremolo TMB Builds
Posted: Sun 02/28/21 12:22 am
by TriodeLuvr
JMPGuitars wrote: ↑Mon 02/22/21 3:11 pm
That resistor is about 8W. But yes, it's because of the 36W amp. Normally I use a 20W resistor there on 36W amps, but 20W is overkill, so I wanted to see how hot a lower wattage resistor would get.
Is that a cathode bias resistor you're discussing?
Jack
Re: Josh's 18W Tremolo TMB Builds
Posted: Sun 02/28/21 3:07 am
by Bieworm
TriodeLuvr wrote: ↑Sun 02/28/21 12:22 am
JMPGuitars wrote: ↑Mon 02/22/21 3:11 pm
That resistor is about 8W. But yes, it's because of the 36W amp. Normally I use a 20W resistor there on 36W amps, but 20W is overkill, so I wanted to see how hot a lower wattage resistor would get.
Is that a cathode bias resistor you're discussing?
Jack
Yes.
Re: Josh's 18W Tremolo TMB Builds
Posted: Tue 03/02/21 5:34 pm
by JMPGuitars
I got the 2.2Ks in finally, and put in the 20W cathode resistor. Here's what it looks like now:
_JMP1974.jpg
Re: Josh's 18W Tremolo TMB Builds
Posted: Tue 03/02/21 11:20 pm
by crgfrench
I mean, even a 12W brown devil is overkill.
Re: Josh's 18W Tremolo TMB Builds
Posted: Tue 03/02/21 11:25 pm
by crgfrench
TriodeLuvr wrote: ↑Sun 02/28/21 12:11 am
The gain of a LTP is typically less than half the gain of the tube in grounded cathode (bypassed) mode. With the Presence control at minimum resistance and no NFB, the Marshall 12AX7 LTP exhibits a voltage gain of approximately 22. Substituting a 12AT7 with no other changes, gain falls to about 16.5. That's a difference of 2.5 dB. I would have thought you'd need to pay close attention to hear that.
That difference gets amplified again in the output stage.
Re: Josh's 18W Tremolo TMB Builds
Posted: Wed 03/03/21 3:59 am
by TriodeLuvr
crgfrench wrote: ↑Tue 03/02/21 11:25 pm
TriodeLuvr wrote: ↑Sun 02/28/21 12:11 am
The gain of a LTP is typically less than half the gain of the tube in grounded cathode (bypassed) mode. With the Presence control at minimum resistance and no NFB, the Marshall 12AX7 LTP exhibits a voltage gain of approximately 22. Substituting a 12AT7 with no other changes, gain falls to about 16.5. That's a difference of 2.5 dB. I would have thought you'd need to pay close attention to hear that.
That difference gets amplified again in the output stage.
The output stage is a linear amplifier. One dB difference at the input produces one dB difference out. Maybe this was being used at a volume level where smaller differences are more obvious. I might try it myself, just to see if it helps with the High input volume.
Jack
Re: Josh's 18W Tremolo TMB Builds
Posted: Sun 03/07/21 11:42 am
by JMPGuitars
I posted a quick demo of where it's currently at:
https://www.instagram.com/p/CMH9cJXg1iQ/
It was super clean on the scope.
There's something going on with the reverb though. I think either the reverb transformer is bad, or the connection to it is. The tube voltages are perfect, except pin 1 coming from the transformer, I can't get a read. I will investigate...eventually.
Re: Josh's 18W Tremolo TMB Builds
Posted: Sun 03/07/21 5:50 pm
by JMPGuitars
Aaaaaaaaaaaand there was nothing wrong with the reverb circuit at all...just the cable or tank I was testing with. I connected the tank actually going in the amp with a new cable, and it's juicy.
Here's a demo with reverb turned to around 65%:
https://www.instagram.com/p/CMIoFL9AzV-/
Thanks,
Josh
Re: Josh's 18W Tremolo TMB Builds
Posted: Mon 03/08/21 3:45 am
by Bieworm
KICKA$$ amp as usual, Josh!!!
Now I start doubting which amp will be next. The 36W tremolo TMB.. or that 2204 project I'm preparing.. ah cr@ppp!!!
BTW, my modern classic changed from owner last saturday. I traded it for a hand built tele. I was planning on building one myself.. but the proposal was too tempting, since I know who built it. It's a local luthier that forged this fine instrument. Man that thing sounds awesome!!! He even winds his own pickups... It's thàt kind of builder
20210306_185802.jpg
Re: Josh's 18W Tremolo TMB Builds
Posted: Mon 03/08/21 5:02 am
by TriodeLuvr
JMPGuitars wrote: ↑Sun 03/07/21 5:50 pm
Aaaaaaaaaaaand there was nothing wrong with the reverb circuit at all...just the cable or tank I was testing with. I connected the tank actually going in the amp with a new cable, and it's juicy.
Here's a demo with reverb turned to around 65%:
https://www.instagram.com/p/CMIoFL9AzV-/
Thanks,
Josh
Josh, I liked this clip so much, it made me regret omitting tremolo from my build. And if you knew how much I generally dislike Fender-style tremolo, you'd know what a big deal that is. Darn, now I'll probably have to add it into my do-all loop effects.
Re: Josh's 18W Tremolo TMB Builds
Posted: Mon 03/08/21 5:46 am
by Bieworm
TriodeLuvr wrote: ↑Mon 03/08/21 5:02 am
JMPGuitars wrote: ↑Sun 03/07/21 5:50 pm
Aaaaaaaaaaaand there was nothing wrong with the reverb circuit at all...just the cable or tank I was testing with. I connected the tank actually going in the amp with a new cable, and it's juicy.
Here's a demo with reverb turned to around 65%:
https://www.instagram.com/p/CMIoFL9AzV-/
Thanks,
Josh
Josh, I liked this clip so much, it made me regret omitting tremolo from my build. And if you knew how much I generally dislike Fender-style tremolo, you'd know what a big deal that is. Darn, now I'll probably have to add it into my do-all loop effects.
You have to know that the blackface style optocell tremolo is totally different from the bias vary tremolo. I hate the opto tremolo too.. I even converted the opto style of my vibro king to bias vary for that reason
Re: Josh's 18W Tremolo TMB Builds
Posted: Mon 03/08/21 9:14 am
by JMPGuitars
TriodeLuvr wrote: ↑Mon 03/08/21 5:02 am
Josh, I liked this clip so much, it made me regret omitting tremolo from my build. And if you knew how much I generally dislike Fender-style tremolo, you'd know what a big deal that is. Darn, now I'll probably have to add it into my do-all loop effects.
Thanks! I wasn't a fan of tremolo in general, but playing this version changed my mind too.
Re: Josh's 18W Tremolo TMB Builds
Posted: Mon 03/08/21 9:16 am
by JMPGuitars
Bieworm wrote: ↑Mon 03/08/21 3:45 am
KICKA$$ amp as usual, Josh!!!
Now I start doubting which amp will be next. The 36W tremolo TMB.. or that 2204 project I'm preparing.. ah cr@ppp!!!
BTW, my modern classic changed from owner last saturday. I traded it for a hand built tele. I was planning on building one myself.. but the proposal was too tempting, since I know who built it. It's a local luthier that forged this fine instrument. Man that thing sounds awesome!!! He even winds his own pickups... It's thàt kind of builder
20210306_185802.jpg
Thanks!
Nice looking guitar. I think we're gonna need to hear a demo to see if that guy makes good pickups.
I don't like when big guitar manufacturers make pickups, but some small luthiers do a good job. I hate almost all the PRS or Gibson or Fender pickups I've ever played. Lace, DiMarzio, Fralin, even Kent Armstrong, etc... are sooooooooooooooo much better.
Re: Josh's 18W Tremolo TMB Builds
Posted: Mon 03/08/21 9:48 am
by Bieworm
JMPGuitars wrote: ↑Mon 03/08/21 9:16 am
Bieworm wrote: ↑Mon 03/08/21 3:45 am
KICKA$$ amp as usual, Josh!!!
Now I start doubting which amp will be next. The 36W tremolo TMB.. or that 2204 project I'm preparing.. ah cr@ppp!!!
BTW, my modern classic changed from owner last saturday. I traded it for a hand built tele. I was planning on building one myself.. but the proposal was too tempting, since I know who built it. It's a local luthier that forged this fine instrument. Man that thing sounds awesome!!! He even winds his own pickups... It's thàt kind of builder
20210306_185802.jpg
Thanks!
Nice looking guitar. I think we're gonna need to hear a demo to see if that guy makes good pickups.
I don't like when big guitar manufacturers make pickups, but some small luthiers do a good job. I hate almost all the PRS or Gibson or Fender pickups I've ever played. Lace, DiMarzio, Fralin, even Kent Armstrong, etc... are sooooooooooooooo much better.
I hear you! My guitars all have special pickups:
Strat: chevalier pickups
62 jag: its originals ofcourse
Home made jag: lollars
Home made jazzmaster: novaks (p90 bridge)
...
No fan of fender pickups either.. I hate duncans. They always sound cheap and blah
Re: Josh's 18W Tremolo TMB Builds
Posted: Mon 03/08/21 10:24 am
by JMPGuitars
Bieworm wrote: ↑Mon 03/08/21 9:48 am
No fan of fender pickups either.. I hate duncans. They always sound cheap and blah
SD pickups are still better than Fender/Gibson pickups. Lace and DiMarzio are my favorites. They make pickups that sing and/or scream.
