I had great results on mine by removing the power section grounds and the heater circuit from the PCB. I mounted the PT center tap & power supply cap ground at the PT. Mounted the heaters directly to V8 and made up a new ACT grounded at the PT as well. No more hum and as a pleasant additional benefit it killed the tremolo tick. While I was in there I changed the NFB resistor to 820 ohm and killed the hiss. Pretty easy mods that work.
Hi thans for your share, i just understand the NFB resistor who killed the hiss, sound is better with the vanilla resistor? Cause negative feedback etc.. is à particularity of this DR 68 ri. I have à Hiss too, i change juste power tubes by blackplate RCA... for the préamp tube i dont know what change? An idéa.
I know your reply was 6 Mo ago, but did changing the NFB resistor to 820 ohms change the lively feel of this amp? I love the reduced NFB over the 65 DRRI but not the hiss. Thanks!
@@Olivier.Colonna-Comedien I was primarily trying to kill the noises that were present in the amp. Trading touch for more noise isn’t a good transaction to me. As for preamp tubes, I’ve been partial to the Tungsol 12AX7s, but because of the Russians’ invasion of Ukraine I will not buy Russian products. My next choice is the JJ 12AX7, although they do seem to lack top end.
Just wanted to drop ya a note on this video (I watch um all but don't always comment) Thanks for all the fine work you do on the amps for us Memphis players. The videos are a cool bonus behind the scenes for us too.
These are noisy amps, but they do sound and feel great. As stock out of the box amps, I do prefer them over the 65 DRRI for live situations. That said, if there is a relatively simple way to reduce some of the idle noise without performing major surgery and risk changing the amp's character, I'm all ears.
my friend has this amp ive tried swapping all the tubes but it's not the problem. i gave him my attenuator so he could get more gain and guess what? i'm telling people that ive found a solution but they argue without knowing or trying...anyway you get a dr z brake lite attenuator i have the old white one i'm not sure if the new black version does the same trick ,you hook it between the amp and speaker like you should when the amp is fully off and take 2 db down. now you can crank the volume to 10 with zero hum. i'll say it again you can get maximum volume and zero hum. the attenuator's side effect is reducing highs i guess the buzz is in that range otherwise i have no explanation why but it just works.
@@yaniv-nos-tubes My 68 was noisy... Use it with a Ironman II Mini and the noise goes completely away .. and ... when playing at home I can put the volume at 5 .. the sweet spot.
I picked one of these up used for a killer deal. The guy said there was zero noise, however was using it with an attenuator. I got it home, tons of noise, tremolo tick and a loud pop when putting it on standby. I hooked up my two notes captor in attenuation mode and all of those issues are gone. I haven't tried running it on speaker thru to see if that fixes the issues but running it right into the two notes it sounds fantastic. Not an ideal solution but it worked none the less on both channels without having to modify the Amp itself.
Hey Chris, I just picked up a 68 DR yesterday. I've always wanted one, despite knowing how loud they can be in a home environment(one day I'll have more space). How have things been working out with the Two Notes Captor & DR combo? Which Captor version do you have?(8, X8, etc). Thanks!
@@erdtree_larry I wanted more control over the level of attenuation so I picked up a Weber Mini Mass. It really helped out. Still no noise and no tremolo ticking. The level of attenuation isn't as high as the Captor being at 20db, but it works well. The captor I was using was the original 8ohm model. If you go the route of the Mini Mass, be aware that the more you attenuate, pedals will become more difficult to dial and can sound dark. So you need to find a happy medium between a volume you're comfortable with and utilizing the treble/presence boost. Good luck!
Tonecraft Audio out of La Jolla CA, makes pilot light wrenches. Depending on shipping, they are about US$15. Google will help you find it. Bought one and it works wonderfully.
I have this amp and let me tell you how quiet it is....NOT! With no instrument plugged in and all pots at minimum and vibrato off on footswitch, a good amount of white noise is present. Then the reverb above half and there's a lot of hum added on top of that white noise. Turn on the vibrato (tremolo) and it clicks with the speed and is fully audible on the lowest intensity. I've had this amp for over a year and I've left it stock. It's on my project list to open it up and at least move some leads around to get the tremolo clicking to stop. Also, the standy switch pops when putting it into standby, so I just leave it out of standby and only use the power switch. Thank you for these videos. I always pick up new bits of knowledge that is only gained through years of experience doing this every day. I only work on tube amps occasionally for the last 15 years.
Well of course it's hissy ---- it's a *re-hissue* Deluxe Reverb! 🤣 Honestly, though, it's as if the designers watched Back to the Future, saw Marty McFly turn the gynormous guitar amp to 10, heard all the buzzing and hiss and thought "yeah, that's what an amp should sound like!"
Discovered something on my 2020 '68 CDR, it doesn't have the 18k resistor on the bass pot. It's either got a '65 DRRI pots & jacks board installed by mistake or they changed the circuit maybe?
I actually prefer the sound of this 68 Custom to the 65.....I don't know if it's mostly the speaker difference but I find the 65 reissue standard version to be tinny or bright. I Luke the mids of the 68 Custom normal channel and the overall sound of both channels to not as bright as the 65. So I guess I like the mods they have added to the 68Custom. Only problem is every time I have played a 68 Custom at GC which has been many times they have problems cutting out and making noise when I get the volume up over halfway. So I held off of buying one. I haven't experienced that with a 65 reissue. I guess they need more training south of the border or do they get a different tube supply? Hopefully they have iron things out since then. I'm curious if both amps pretty much use same parts and transformers???
@@PsionicAudio The reduced negative feedback makes the speaker impedance curve more pronounced in the frequency response of the amplifier itself. The fs impedance hump will definitely impart a more spongey bass feel on a lower NFB amp!
I have the twin version. A week ago I don’t know why I did it I checked on the speaker cable in the back and yes it is the problem. I pushed it straight into the socket so that the back wall that’s over the tubes hold it in place and the noise it’s completely gone.
On my 68 Deluxe... There's a rattle coming from the handle... If I push or squeeze the metal parts of handle, the rattle disappears... What could be the fix for that? Thank you
@psionic audio I have the 68 Twin and it has similar noise issues. Can you tell me what I should expect to pay to have someone do what you would do to mitigate the noise so I don’t get ra…I mean, uh…taken advantage of? I like the idea of still having trem and reverb on both channels, and you said in this vid that you could undo it and put in a terminal strip to hold some new components and do it well-that’s the option I’d prefer, honestly. And I also love the idea of replacing those capacitors (the preventative maintenance thing you mention in this vid and others about the leaky caps). Just wondering what I should expect. I’d sure appreciate any answer. Thank you. Great video, as always.
The noise/hiss is common to the 68 Custom series. It's because they removed the negative feedback loop. The upside is better tone and better responsiveness/dynamics. The downside is the high noise floor. I have the 68 Custom Twin Reverb and it has this problem
Bought one last week. Un packed it, hooked it up and the noise floor was so high that I boxed it back up and returned it. Plus the custom channel didn't convey a signal (neither jacks). What a piece of crap.
I have since had my 68 custom twin reverb modified by a tech to reduce the hiss which was successful! He did this by installing a different size resistor in the negative feedback loop
It’s the principle of the thing. You buy a brand new amp and have to have it worked on by a tech (xtra dinero) to make it playable. All because the mfg installs junk resistors and related components? Screw that. Besides the Bassman tone stake doesn’t send or receive a signal. More crap. I knew from experience and test driving them that Fender amps had noise problems. But this beastie was way over the top.
@@coachtd2163 it's not crappy resistors, it's the impedance value they chose to use in the resistor for the sound + dynamics they were looking for. upside: great sound downside: hiss!!!
Thanks. Want to be accurate and appreciate the clarification. Don’t want to misrepresent the issue. But the bottom line for me is that the hiss was unacceptable to me in a home use environment. The unit Psionic is working on in this video was quiet compared to what I was experiencing.
I have a 65 Super Reverb Reissue and I'd love to see the hardest way possible but the rightest way possible to feed 1 into the same insertion location as 2 to have reverb and trem on both channels (plus the extra gain stage that 2 gets that 1 doesn't). If the owner doesn't want to do this do you think you could still cover it? I've been looking at the layouts for both my vintage fender and my reissue and the vintage one seems way easier to accomplish. You basically just take off of the "X" send (usually a blue wire after the 0.047 cap) before the twisted pair blue/yellow skyway across all the bypass caps and send it where channel 2 hits the reverb circuit after the .02 and before the 500pf cap ("Z" on the vintage pro reverb schematic). At least this is how I assume it would work. The 220k that the normal channel used to connect to would just be not used anymore. If there is a flaw in my idea please let me know as I'd really like to not blow my super up. :D If that was too confusing, basically how do you give channel 1 reverb and tremolo on a reissue fender the RIGHT way. I've been too lazy to pull my chassis out and look so I've been looking at schematics/layouts for the reissues but you can't read a single damn label on those things. Blur city.
without watching this channel, I'd never have considered these things being noisy soon. The only reason I hadn't bought one yet is covid made them pointless to buy used -same with the tweed tonemaster or whatever they call the DSP version. this channel makes me realize that it may be worth it just to buy quality components and make one of the long-time simpler fender circuits and defer to the pedal board for anything more complex.
have a peavey classic 50 that has a moderate hiss, too - too bad. good clean sounding amp but not sure if it's more valuable just to auction off the head, keep the tubes and use the cabinet as a drone instead of wasting time taking it apart.
Word is that Fender added the tube cages to their amps because folks would just swipe the tubes out of the amps on the floor of Guitar Centers and the like.
What is considered an Active DC mixer? you mention something about when you tied two plates of the tubes to one DC voltage node this causes a noise problem
It's also called a "tweed mixer" if you tie the two plates of *one* tube to a common plate resistor and DC voltage. It works quite well in that case. But that isn't what Fender did. Fender tied the two plates of *separate* tubes together to get the same (general) effect. "The schematic is the same, what could go wrong?"
@@edwardleaver7838 Thanks for the information I have seen this on schematics but I guess the 90s and 2000s fender amps they are tied the two plates of "separate tubes" together which I'm guessing is creating noise issues because you need some type of DC offset to prevent noise?
That's for mixing small signals. For large signals (as here) the distortion characteristics of the mixer segments can differ between using a common plate resistor and using separate plate resistors plus the two additional mixing resistors Lyle might suggest as one of his fix. Four resistors instead of one. In his Concert harmonic tremolo circuit Leo chose four. In 1960 AC30 vibrato, Vox essentially used three -- still with separate plate resistors -- but the third resistor cuts the signal sent to the subequent mixing stage which (as Lyle explains) will also cut the noise. The signal may be made up with more drive.
@@waynegram8907 No, I don't think DC offset is it. I was originally thinking possibly separate power supply nodes and lead dress. But V2 is powered from the same node as V1 - the last, quietest node - and the relevant plate resistors are adjacent in this reissue layout, so I'm now thinking the separate tubes are likely not the noise source (unless one is bad). But I've never A-B compared a single-tube tweed mixer with separated halves. But neither do I (4am) intuitively see how tying two separate 100k plate resistors together through 220k mixing resistors results in substantially less stage gain than just tapping the effective 50k (100k || 100k) plate resistor at the plate. So at this point I have to admit "I don't know" and acceed to Lyles actual experience. In other reissue videos Lyle has said that separating the plate resistors and adding back the separate mixing resistors decreases the noise in these things. He's worked on 'em and I haven't. 'Nuff said.
@@edwardleaver7838 The Datasheets of a 12AX7 plate impedance should tell you because when you're adding a mixing resistor network this is adding impedance. The Tweed mixer is an addition network that is AFTER the plate resistors so its 50K plus in series a tweed mixer to the Power supply NODE? I'm thinking this is an tube plate impedance issue that is causing the noise or the resistor types can cause thermal noise or it can be two different stages that is interference coupling because V1 and V2 are in different stages but tieing the plates together is causing a coupling issue of the Signal gain to Noise ratio.
@Psionic Audio So, If I can live without reverb/trem on the normal channel I can simply remove that plate resistor jumper and lower the background noise?
Not quite, you'd have no Normal channel then. Compare the '65 RI schematic to the '68 Custom schematic. PS if you can't read the schematics, don't change anything in the amp.
That reverb tube issue is so disheartening if there isn't a reason to not do it the right way. They aren't even saving a penny with a cheap part...just wiring it in a noisy way?
I had great results on mine by removing the power section grounds and the heater circuit from the PCB. I mounted the PT center tap & power supply cap ground at the PT. Mounted the heaters directly to V8 and made up a new ACT grounded at the PT as well. No more hum and as a pleasant additional benefit it killed the tremolo tick. While I was in there I changed the NFB resistor to 820 ohm and killed the hiss. Pretty easy mods that work.
Hi thans for your share, i just understand the NFB resistor who killed the hiss, sound is better with the vanilla resistor? Cause negative feedback etc.. is à particularity of this DR 68 ri. I have à Hiss too, i change juste power tubes by blackplate RCA... for the préamp tube i dont know what change? An idéa.
I know your reply was 6 Mo ago, but did changing the NFB resistor to 820 ohms change the lively feel of this amp? I love the reduced NFB over the 65 DRRI but not the hiss. Thanks!
@@imanalien2222 It behaves like a normal DR in terms of touch.
@@Olivier.Colonna-Comedien I was primarily trying to kill the noises that were present in the amp. Trading touch for more noise isn’t a good transaction to me. As for preamp tubes, I’ve been partial to the Tungsol 12AX7s, but because of the Russians’ invasion of Ukraine I will not buy Russian products. My next choice is the JJ 12AX7, although they do seem to lack top end.
Quite a bit of white noise
Just wanted to drop ya a note on this video (I watch um all but don't always comment) Thanks for all the fine work you do on the amps for us Memphis players. The videos are a cool bonus behind the scenes for us too.
These are noisy amps, but they do sound and feel great. As stock out of the box amps, I do prefer them over the 65 DRRI for live situations. That said, if there is a relatively simple way to reduce some of the idle noise without performing major surgery and risk changing the amp's character, I'm all ears.
Hit some drums and you won't hear the noise any more.
my friend has this amp ive tried swapping all the tubes but it's not the problem. i gave him my attenuator so he could get more gain and guess what?
i'm telling people that ive found a solution but they argue without knowing or trying...anyway you get a dr z brake lite attenuator i have the old white one i'm not sure if the new black version does the same trick ,you hook it between the amp and speaker like you should when the amp is fully off and take 2 db down. now you can crank the volume to 10 with zero hum. i'll say it again you can get maximum volume and zero hum. the attenuator's side effect is reducing highs i guess the buzz is in that range otherwise i have no explanation why but it just works.
@@yaniv-nos-tubes My 68 was noisy... Use it with a Ironman II Mini and the noise goes completely away .. and ... when playing at home I can put the volume at 5 .. the sweet spot.
Damn,Lyle. That’s some great customer service! I can fix most basic issues on amps and I’d prolly pay you to fix an amp if I lived close by,lol!
I picked one of these up used for a killer deal. The guy said there was zero noise, however was using it with an attenuator. I got it home, tons of noise, tremolo tick and a loud pop when putting it on standby. I hooked up my two notes captor in attenuation mode and all of those issues are gone. I haven't tried running it on speaker thru to see if that fixes the issues but running it right into the two notes it sounds fantastic. Not an ideal solution but it worked none the less on both channels without having to modify the Amp itself.
Hey Chris, I just picked up a 68 DR yesterday. I've always wanted one, despite knowing how loud they can be in a home environment(one day I'll have more space). How have things been working out with the Two Notes Captor & DR combo? Which Captor version do you have?(8, X8, etc). Thanks!
@@erdtree_larry I wanted more control over the level of attenuation so I picked up a Weber Mini Mass. It really helped out. Still no noise and no tremolo ticking. The level of attenuation isn't as high as the Captor being at 20db, but it works well. The captor I was using was the original 8ohm model. If you go the route of the Mini Mass, be aware that the more you attenuate, pedals will become more difficult to dial and can sound dark. So you need to find a happy medium between a volume you're comfortable with and utilizing the treble/presence boost. Good luck!
Interesting what Fender "use to know" about amps haha. That reverb fix is funny.
Tonecraft Audio out of La Jolla CA, makes pilot light wrenches. Depending on shipping, they are about US$15. Google will help you find it. Bought one and it works wonderfully.
I have this amp and let me tell you how quiet it is....NOT! With no instrument plugged in and all pots at minimum and vibrato off on footswitch, a good amount of white noise is present. Then the reverb above half and there's a lot of hum added on top of that white noise. Turn on the vibrato (tremolo) and it clicks with the speed and is fully audible on the lowest intensity. I've had this amp for over a year and I've left it stock. It's on my project list to open it up and at least move some leads around to get the tremolo clicking to stop. Also, the standy switch pops when putting it into standby, so I just leave it out of standby and only use the power switch. Thank you for these videos. I always pick up new bits of knowledge that is only gained through years of experience doing this every day. I only work on tube amps occasionally for the last 15 years.
The mods I mentioned above killed the tremolo tick as well.
@@jerrymcgeorge4117 Thanks! I already took a screen shot of your mods comment to act as notes when I work on this amp. I appreciate the info!
@@wadereynoldsgm If it helps I did a post on TDP with a pic.
@@jerrymcgeorge4117 I’m interested to see this too, where exactly can I find your post? Can you paste a copy of the url? Thx
Not trying to steal Lyle's thunder here.
Well of course it's hissy ---- it's a *re-hissue* Deluxe Reverb! 🤣 Honestly, though, it's as if the designers watched Back to the Future, saw Marty McFly turn the gynormous guitar amp to 10, heard all the buzzing and hiss and thought "yeah, that's what an amp should sound like!"
😂
Haha… best comment by far!
Discovered something on my 2020 '68 CDR, it doesn't have the 18k resistor on the bass pot. It's either got a '65 DRRI pots & jacks board installed by mistake or they changed the circuit maybe?
Is there any Fender amp worth buying now?
I actually prefer the sound of this 68 Custom to the 65.....I don't know if it's mostly the speaker difference but I find the 65 reissue standard version to be tinny or bright. I Luke the mids of the 68 Custom normal channel and the overall sound of both channels to not as bright as the 65. So I guess I like the mods they have added to the 68Custom. Only problem is every time I have played a 68 Custom at GC which has been many times they have problems cutting out and making noise when I get the volume up over halfway. So I held off of buying one. I haven't experienced that with a 65 reissue. I guess they need more training south of the border or do they get a different tube supply? Hopefully they have iron things out since then. I'm curious if both amps pretty much use same parts and transformers???
Same amp. Different speakers. About ten different parts used.
@@PsionicAudio The reduced negative feedback makes the speaker impedance curve more pronounced in the frequency response of the amplifier itself. The fs impedance hump will definitely impart a more spongey bass feel on a lower NFB amp!
I have the twin version. A week ago I don’t know why I did it I checked on the speaker cable in the back and yes it is the problem. I pushed it straight into the socket so that the back wall that’s over the tubes hold it in place and the noise it’s completely gone.
Great video as always.
On my 68 Deluxe... There's a rattle coming from the handle... If I push or squeeze the metal parts of handle, the rattle disappears... What could be the fix for that? Thank you
@psionic audio I have the 68 Twin and it has similar noise issues. Can you tell me what I should expect to pay to have someone do what you would do to mitigate the noise so I don’t get ra…I mean, uh…taken advantage of? I like the idea of still having trem and reverb on both channels, and you said in this vid that you could undo it and put in a terminal strip to hold some new components and do it well-that’s the option I’d prefer, honestly. And I also love the idea of replacing those capacitors (the preventative maintenance thing you mention in this vid and others about the leaky caps). Just wondering what I should expect. I’d sure appreciate any answer. Thank you. Great video, as always.
@dermensch980 did you ever "de-noise" it? bought my 68 twin this week and I have exactly the same doubts as you do
@@nirgoth no, I haven’t yet. Might do it one day.
The noise/hiss is common to the 68 Custom series. It's because they removed the negative feedback loop. The upside is better tone and better responsiveness/dynamics. The downside is the high noise floor. I have the 68 Custom Twin Reverb and it has this problem
Bought one last week. Un packed it, hooked it up and the noise floor was so high that I boxed it back up and returned it. Plus the custom channel didn't convey a signal (neither jacks). What a piece of crap.
I have since had my 68 custom twin reverb modified by a tech to reduce the hiss which was successful! He did this by installing a different size resistor in the negative feedback loop
It’s the principle of the thing. You buy a brand new amp and have to have it worked on by a tech (xtra dinero) to make it playable. All because the mfg installs junk resistors and related components? Screw that. Besides the Bassman tone stake doesn’t send or receive a signal. More crap. I knew from experience and test driving them that Fender amps had noise problems. But this beastie was way over the top.
@@coachtd2163 it's not crappy resistors, it's the impedance value they chose to use in the resistor for the sound + dynamics they were looking for. upside: great sound downside: hiss!!!
Thanks. Want to be accurate and appreciate the clarification. Don’t want to misrepresent the issue.
But the bottom line for me is that the hiss was unacceptable to me in a home use environment. The unit Psionic is working on in this video was quiet compared to what I was experiencing.
I have a 65 Super Reverb Reissue and I'd love to see the hardest way possible but the rightest way possible to feed 1 into the same insertion location as 2 to have reverb and trem on both channels (plus the extra gain stage that 2 gets that 1 doesn't). If the owner doesn't want to do this do you think you could still cover it?
I've been looking at the layouts for both my vintage fender and my reissue and the vintage one seems way easier to accomplish. You basically just take off of the "X" send (usually a blue wire after the 0.047 cap) before the twisted pair blue/yellow skyway across all the bypass caps and send it where channel 2 hits the reverb circuit after the .02 and before the 500pf cap ("Z" on the vintage pro reverb schematic). At least this is how I assume it would work. The 220k that the normal channel used to connect to would just be not used anymore. If there is a flaw in my idea please let me know as I'd really like to not blow my super up. :D
If that was too confusing, basically how do you give channel 1 reverb and tremolo on a reissue fender the RIGHT way. I've been too lazy to pull my chassis out and look so I've been looking at schematics/layouts for the reissues but you can't read a single damn label on those things. Blur city.
without watching this channel, I'd never have considered these things being noisy soon. The only reason I hadn't bought one yet is covid made them pointless to buy used -same with the tweed tonemaster or whatever they call the DSP version.
this channel makes me realize that it may be worth it just to buy quality components and make one of the long-time simpler fender circuits and defer to the pedal board for anything more complex.
have a peavey classic 50 that has a moderate hiss, too - too bad. good clean sounding amp but not sure if it's more valuable just to auction off the head, keep the tubes and use the cabinet as a drone instead of wasting time taking it apart.
Dont mind me, I'm just telling youtube that I'm here again :)
You played a guitar riff in there that I gotta still. ;)
Word is that Fender added the tube cages to their amps because folks would just swipe the tubes out of the amps on the floor of Guitar Centers and the like.
It might be an EU requirement, at least for export.
@@edwardleaver7838 I've heard those gray rubber switch covers are also a safety requirement possibly for export.
How much is it to replace a tube?
What is considered an Active DC mixer? you mention something about when you tied two plates of the tubes to one DC voltage node this causes a noise problem
It's also called a "tweed mixer" if you tie the two plates of *one* tube to a common plate resistor and DC voltage. It works quite well in that case. But that isn't what Fender did. Fender tied the two plates of *separate* tubes together to get the same (general) effect. "The schematic is the same, what could go wrong?"
@@edwardleaver7838 Thanks for the information I have seen this on schematics but I guess the 90s and 2000s fender amps they are tied the two plates of "separate tubes" together which I'm guessing is creating noise issues because you need some type of DC offset to prevent noise?
That's for mixing small signals. For large signals (as here) the distortion characteristics of the mixer segments can differ between using a common plate resistor and using separate plate resistors plus the two additional mixing resistors Lyle might suggest as one of his fix. Four resistors instead of one. In his Concert harmonic tremolo circuit Leo chose four. In 1960 AC30 vibrato, Vox essentially used three -- still with separate plate resistors -- but the third resistor cuts the signal sent to the subequent mixing stage which (as Lyle explains) will also cut the noise. The signal may be made up with more drive.
@@waynegram8907 No, I don't think DC offset is it. I was originally thinking possibly separate power supply nodes and lead dress. But V2 is powered from the same node as V1 - the last, quietest node - and the relevant plate resistors are adjacent in this reissue layout, so I'm now thinking the separate tubes are likely not the noise source (unless one is bad). But I've never A-B compared a single-tube tweed mixer with separated halves. But neither do I (4am) intuitively see how tying two separate 100k plate resistors together through 220k mixing resistors results in substantially less stage gain than just tapping the effective 50k (100k || 100k) plate resistor at the plate. So at this point I have to admit "I don't know" and acceed to Lyles actual experience. In other reissue videos Lyle has said that separating the plate resistors and adding back the separate mixing resistors decreases the noise in these things. He's worked on 'em and I haven't. 'Nuff said.
@@edwardleaver7838 The Datasheets of a 12AX7 plate impedance should tell you because when you're adding a mixing resistor network this is adding impedance. The Tweed mixer is an addition network that is AFTER the plate resistors so its 50K plus in series a tweed mixer to the Power supply NODE? I'm thinking this is an tube plate impedance issue that is causing the noise or the resistor types can cause thermal noise or it can be two different stages that is interference coupling because V1 and V2 are in different stages but tieing the plates together is causing a coupling issue of the Signal gain to Noise ratio.
Don't change the jewel - on my monitor it matches the displayed model graphic beautifully 🙂.
Wow mine was noisy too
@Psionic Audio So, If I can live without reverb/trem on the normal channel I can simply remove that plate resistor jumper and lower the background noise?
Not quite, you'd have no Normal channel then. Compare the '65 RI schematic to the '68 Custom schematic. PS if you can't read the schematics, don't change anything in the amp.
17:23
That reverb tube issue is so disheartening if there isn't a reason to not do it the right way. They aren't even saving a penny with a cheap part...just wiring it in a noisy way?
I sold my 68 reissue.
99 % of mechanics these days don’t know how to diagnose a problem, lol
Fender sucks now!!!!