I need some input from you guys. I'm starting to convert one of my Twin Reverbs to something similar to what's discussed at https://ampgarage.com/forum/viewtopic.php?f=4&t=29417 ... Call it Hotel Hog or Ultraphonix if you want, but I'm thinking Twinmaster Bluesverb or just Clean Machine
I am planning to wire it for reverb/vibrato on both channels, but I would also like to retain the master volume on the second channel only. Basically, I am going for an amp that can switch between an ab763 channel with rev/vib, and a Bluesmaster clean channel with rev/vib. The best of both worlds of clean channels.
Where I need input is on how to retain the master volume on the second channel only.
I am considering doing the standard "reverb on both channels" method of using 220K mix resistors from each channel into the reverb input and then feeding the PI from the reverb output. My plan is just to insert the 1M master pot between the "vibrato" channel mix resistor and the reverb input.
My question is do y'all see any drawbacks to this approach, and is there a better way?
One of the things you are going to need to think about Chris is in order to get the full effects of the B.M clean channel is the P.I which is different than the 12At in your Twin. Most if not all of the Ultraphonix mods I have seen so far have this Marshall type PI.So It would seem that Dumble preferred this PI for modding purposes, However the ultimate judge will be your ears..Dumble would basically choose which stack he thought worked best for that particular players style for the other channels ie Skyliner/Classic/ Bluesmaster or you could keep it stock. As far as the Mstr Vol's go in these amps? as you know this changes the frequency response, and can flatten/kill the tone and sustain unless you have a buffer/Follower driving the stack (5f6-A) or on the Mstr itself (Dumbleator).Just Sayin and not sure there is another way?
(Dumble was constantly changing his Mstr Vol configurations.)
BTW. If I had to go with a Mstr Vol I would prefer it be feeding the B.M ..P.I
Tony
" The psychics on my bench is the same as Dumble'"
talbany wrote: ↑Mon Mar 15, 2021 12:35 am
One of the things you are going to need to think about Chris is in order to get the full effects of the B.M clean channel is the P.I which is different than the 12At in your Twin. Most if not all of the Ultraphonix mods I have seen so far have this Marshall type PI.So It would seem that Dumble preferred this PI for modding purposes, However the ultimate judge will be your ears..Dumble would basically choose which stack he thought worked best for that particular players style for the other channels ie Skyliner/Classic/ Bluesmaster or you could keep it stock. As far as the Mstr Vol's go in these amps? as you know this changes the frequency response, and can flatten/kill the tone and sustain unless you have a buffer/Follower driving the stack (5f6-A) or on the Mstr itself (Dumbleator).Just Sayin and not sure there is another way?
(Dumble was constantly changing his Mstr Vol configurations.)
BTW. If I had to go with a Mstr Vol I would prefer it be feeding the B.M ..P.I
Tony
Awesome, thanks for the tips! I guess I should have mentioned I am planning on using the Bluesmaster PI. I'm thinking that when using the preamp channel with BM values the amp will basically be the BM circuit minus the overdrive and add reverb. I love the clean tones of an ODS with the volume up past noon to even 3oclock where it's still clean and chimey but it has some edge, so that's what I'm hoping to achieve on the BM preamp channel side of things. On the AB763 side of the preamp I just want those big pure cleans, so that's why I am looking to only have the master on the BM preamp channel... no need for it on the AB763 side.
talbany wrote: ↑Mon Mar 15, 2021 12:35 am
One of the things you are going to need to think about Chris is in order to get the full effects of the B.M clean channel is the P.I which is different than the 12At in your Twin. Most if not all of the Ultraphonix mods I have seen so far have this Marshall type PI.So It would seem that Dumble preferred this PI for modding purposes, However the ultimate judge will be your ears..Dumble would basically choose which stack he thought worked best for that particular players style for the other channels ie Skyliner/Classic/ Bluesmaster or you could keep it stock. As far as the Mstr Vol's go in these amps? as you know this changes the frequency response, and can flatten/kill the tone and sustain unless you have a buffer/Follower driving the stack (5f6-A) or on the Mstr itself (Dumbleator).Just Sayin and not sure there is another way?
(Dumble was constantly changing his Mstr Vol configurations.)
BTW. If I had to go with a Mstr Vol I would prefer it be feeding the B.M ..P.I
Tony
Awesome, thanks for the tips! I guess I should have mentioned I am planning on using the Bluesmaster PI. I'm thinking that when using the preamp channel with BM values the amp will basically be the BM circuit minus the overdrive and add reverb. I love the clean tones of an ODS with the volume up past noon to even 3oclock where it's still clean and chimey but it has some edge, so that's what I'm hoping to achieve on the BM preamp channel side of things. On the AB763 side of the preamp I just want those big pure cleans, so that's why I am looking to only have the master on the BM preamp channel... no need for it on the AB763 side.
That sounds doable!. Take a look at the Bluesmaster (Clean Mstr) Layout and how Dumble did it. It's a slightly different setup than the earlier 4th generation amps..Also Just a reminder too. The Reverb will also add that 1/2 stage of gain, that along with the hotter B.M P.I should make for a lively amp with a bit more gain than your typical AB763 with the AT-7. You can always play around with the GNFB to help clean it up if need be..Keep us posted on how it goes..Love your videos.
Tony
" The psychics on my bench is the same as Dumble'"
talbany wrote: ↑Mon Mar 15, 2021 1:57 am
That sounds doable!. Take a look at the Bluesmaster (Clean Mstr) Layout and how Dumble did it. It's a slightly different setup than the earlier 4th generation amps..Also Just a reminder too. The Reverb will also add that 1/2 stage of gain, that along with the hotter B.M P.I should make for a lively amp with a bit more gain than your typical AB763 with the AT-7. You can always play around with the GNFB to help clean it up if need be..Keep us posted on how it goes..Love your videos.
Tony
Thanks very much! I'll be sure to take some footage along the way... I really enjoy putting together those build videos.
I'm thinking a GNFB switch in the death cap switch hole could be useful for sure. Something that can go from lively to tame.
I'm looking at the BM clean master configuration but I haven't quite decided how I'm going to implement switching. Part of me wants to keep the standard fender style two sets of inputs for two individual channels. I am planning on adding relay switching later but not until I've had a chance to really test the different options on stage, so initially I think I am going to hardwire the master into the 2nd channel before the reverb input. When I add in relay switching I will probably test putting the master after the reverb return (sort of like how it's shown on the Jelle HH layout) and just switching it in or out depending on which channel I'm switched to but I'm not sure how different it will be.
My donor amp is a beat up 1976 silverface twin that has been converted to ab763... it's a great sounding twin, but I have two of them and I know it's the perfect donor for this with a hole for the master volume as well as the wasted death cap switch hole.
I ended up building this without the switching just so I could try out some different ideas. I'm still planning to add switching for at least PAB, but as for channel switching, I'm still not sure. I've been using an ABY and it's is kind of cool because you can get the jumpered thing if you want.
I ended up building it with BM PI, ab763 channel 1, and BM channel 2. Both channels into the reverb/trem. In a lot of ways, it's the coolest "Fender" amp I've ever played.
I tried it for a while with a master volume and it was basically useless... in this configuration, it's just not musical like it is on a normal ODS build. I ditched that.
I have also fooled with NFB, but the 100k/4k7 configuration is pretty awesome. It's quite a bit more gnarly than your standard fender amp... quite a bit grittier than your standard twin reverb with the volume on 5.
