Fender did a great job with the 59 Bassman reissue circuit. The B+ is my biggest gripe with these. Yes, vintage Bassman’s had a higher B+ than the 435dvdc on the layout/schematic but it wasn’t anywhere near the ~475 we see in these. 445 to 455vdc is about right at around 60% idle bias. The Pacific Audio Vibrolux PT is a fix to get that right on if anyone cares.
LOL, no my genuine 5F6A from 1960 will easily go over 500v with 120VAC or higher line voltage, as we have today. I keep it on a voltage bucker at 110VAC, as that's what the genuine power transformer was wound for. That was a more common household voltage when it was made.
This is right up my alley 😃👍👍 Been happy with my '59 Narrow Panel LTD, and have played it since its release.👍 The finished work and comparison with the '58 will be a MUST SEE/HEAR for me👍 😎👍👍
What a coincidence - I picked up an early 1990 '59 Reissue a few weeks back for a ridicolous price because the amp was getting brief volume drops under load at random times and the former owner got it back from a "tech" who deemed it "unrepairable". Opened it up and saw the still original IC caps (alongside some sloppy work on the bias pot and screen grid resistors), so I replaced the ICs with new FTs and voila - works as a charm! I'm really curious who this "tech" was, but I guess I need to thank him for getting a bargain of the year! Lyle, could you throw in a few pointers on what's worth upgrading/changing on these reissues in part 2? Much appreciated! Love the channel btw! 😉
I'm at the point in life where I don't even care what is inside an amp, I just want to go to someone like Psionic and know I'm getting hooked up with a great amp that has the details right. No one asked but that's my story.
It would be interesting to see what state of decay the filters are in. Though would really need to be done with an analyzer capable of delivering the proper voltage, like a Sencore LC103
Yup - my amp has the same (self build), but it's will have a switchable tube and SS rectification. I'm using F&T but the B+ is too close to the rating, so bunk up to 500V.. (reserve is 47uF on the tube rect but I'll be increasing that when the SS is switched in which should clear it up)
Being my clutch drive Torx, & British cross points, triwings, etc. are here, My Pozidriv stuff grew legs. I'd go to Harbor Freight & buy #1-#3 Phillips and grind the tips down, but someone turned my local Harbor Freight into a drive thru.
You can buy a set of so-called "security" bits for about $15-20 at Autozone or O'Reilly's auto parts, containing Pozidrive as well as bits to fit most of the other formerly uncommon, so-called "security" screws. Grinding the tips off Phillips screwdrivers might help them fit JIS Philips better, but won't substitute for Pozidrive bits. One does wonder, what the heck is going on with this magnetic attraction between buildings and cars anyway? My local Harbor Fright 😱 has big yellow bollard posts in front of the entrance way....
I had one of these. It was a good amp but I hated the speakers. They just couldn't take the output and they never handled the low frequency stuff. Cones fractured. In stock form it'd be a good guitar amp with decent speakers, but the voltages seemed very high compared to the 5F6A. I tried a 5V4 recto and it got the voltages down nicely.
I should add, I liked it but it was just too much amp for what I needed. So I sold it and used the proceeds to buy very choice parts to build a clone of a 5F4 tweed Super. Similar to the Bassman in overall sound (different phase inverter), but less output and pushing only half the air. And lighter. Win, win, win. :D
Actually the earlier versions had the Blue Frame Eminence speakers that had the exact same cones made by Donal Kapi that were used on the original Jensens from the ‘50’s.
How can we be sure the PT will be happy driving the 5U4 vs the GZ? I ask because I did the very same thing with mine and I did it nervously knowing that the 5u4 is hungrier
Because it’s rated for 3A@5V. You can find the OEM Schumacher part number specifications if you don’t believe me. A 5U4G will run in that amp forever and be completely fine.
"Parasitic oscillations often occur at frequencies of the order of 100 Mc/s with leads from valve sockets forming resonant circuits and with a feedback path provided by a few micromicrofarads of capacitance between plate and grid circuits. In such a case a suitable remedy is a non-inductive resistor (say 50 000 ohms, 1/2 watt, carbon) wired *directly to the grid pin*. This increases the losses in the high frequency circuit to such an extent that oscillation is not possible." - Radiotron Designer's Handbook, 1952 So mixer resistors on the eyelet board 4" away from the grid pin are not "grid stoppers".
Now define mixer resistors and notice that for modern use (one instrument at a time per channel) these aren’t that. They’re a voltage divider and sub-optimally applied grid stoppers. Adding a second smaller (10Kish) resistor directly at the grid pin to this kind of circuit can sometimes be beneficial. But it’s not always needed. Joel, keep in mind I’m mostly talking to an audience of guitarists, not trying to teach an electronics course. I know more about this than I mention in a video, unless it’s a concept crucial to an issue in the amp on the bench.
@@goodun2974 "Fritz Langford-Smith (29 June 1904 - 3 December 1966) was an Australian electrical engineer. He was the author of the classic engineering reference Radiotron Designer's Handbook (RDH)."
Great, a "beat-box" disguised as a guitar amp. Fender should make the ghost-notes and fuzzy tones switchable; they might be missing a marketing opportunity.....😖
I was wondering why you don’t like metal oxide resistors? If the carbon film resistors burn and leave carbon in the amp, metal oxide resistors only discolour. Typically, I use metal oxide only in the power supply. Lyle, do you subscribe to the idea that different resistor types sound different. I have heard it said but I can’t say that I have heard a difference.
I'm experiencing that same sound weak/loud sound with my Super Reverb. Last recap was in 1999. Definitely time for new electrolytic caps. Is it worth spending more and using F&T or should I use MOD?
I know that you're scrupulously objective, Lyle...but it seems to me that every time you do a presentation on one of these major brand re-issues...it might as well be a plug for all the smaller repairmen/builders out there, and I don't have a problem with that.
Fran Blanche at FranLab had her *livestream* pulled, in mid-stream apparently, because of her "potty mouth", as she put it. It seems that the more subscribers a channel has, the more likely it is that RUclips, in their zeal to monetize a popular channel while avoiding an inadvertent association between advertisers and controversial speech, will clamp down on freedom of expression in the form of swear words. And yet, misinformation, and spam/ spammers, are rarely booted off.
There's a reason you have more subs than some of your contemporaries! Keeping it real! [ comment for the algorithms Lol! ]
Fender did a great job with the 59 Bassman reissue circuit. The B+ is my biggest gripe with these. Yes, vintage Bassman’s had a higher B+ than the 435dvdc on the layout/schematic but it wasn’t anywhere near the ~475 we see in these.
445 to 455vdc is about right at around 60% idle bias. The Pacific Audio Vibrolux PT is a fix to get that right on if anyone cares.
LOL, no my genuine 5F6A from 1960 will easily go over 500v with 120VAC or higher line voltage, as we have today. I keep it on a voltage bucker at 110VAC, as that's what the genuine power transformer was wound for. That was a more common household voltage when it was made.
This is right up my alley 😃👍👍
Been happy with my '59 Narrow Panel LTD, and have played it since its release.👍
The finished work and comparison with the '58 will be a MUST SEE/HEAR for me👍
😎👍👍
What a coincidence - I picked up an early 1990 '59 Reissue a few weeks back for a ridicolous price because the amp was getting brief volume drops under load at random times and the former owner got it back from a "tech" who deemed it "unrepairable". Opened it up and saw the still original IC caps (alongside some sloppy work on the bias pot and screen grid resistors), so I replaced the ICs with new FTs and voila - works as a charm! I'm really curious who this "tech" was, but I guess I need to thank him for getting a bargain of the year!
Lyle, could you throw in a few pointers on what's worth upgrading/changing on these reissues in part 2? Much appreciated!
Love the channel btw! 😉
I will stay tuned. Thanks
Ah, modern Fender QA. Awesome.
I really appreciate your time Lyle.
Thought you were going to play "The Last Time" for a moment there, Lyle.
I'm at the point in life where I don't even care what is inside an amp, I just want to go to someone like Psionic and know I'm getting hooked up with a great amp that has the details right. No one asked but that's my story.
Thanks for posting.
This one will be very interesting to follow!
Yeah a comparison wd be good to hear Lyle.
It would be interesting to see what state of decay the filters are in. Though would really need to be done with an analyzer capable of delivering the proper voltage, like a Sencore LC103
Yup - my amp has the same (self build), but it's will have a switchable tube and SS rectification. I'm using F&T but the B+ is too close to the rating, so bunk up to 500V.. (reserve is 47uF on the tube rect but I'll be increasing that when the SS is switched in which should clear it up)
IC caps...as in I C better caps in the near future going into this thing!
to paraphrase Paul Maurice (Florida Panthers coach), "sometimes amps need a little profanity in their lives. and Lyle brought some."
Being my clutch drive Torx, & British cross points, triwings, etc. are here, My Pozidriv stuff grew legs. I'd go to Harbor Freight & buy #1-#3 Phillips and grind the tips down, but someone turned my local Harbor Freight into a drive thru.
You can buy a set of so-called "security" bits for about $15-20 at Autozone or O'Reilly's auto parts, containing Pozidrive as well as bits to fit most of the other formerly uncommon, so-called "security" screws. Grinding the tips off Phillips screwdrivers might help them fit JIS Philips better, but won't substitute for Pozidrive bits. One does wonder, what the heck is going on with this magnetic attraction between buildings and cars anyway? My local Harbor Fright 😱 has big yellow bollard posts in front of the entrance way....
I had one of these. It was a good amp but I hated the speakers. They just couldn't take the output and they never handled the low frequency stuff. Cones fractured. In stock form it'd be a good guitar amp with decent speakers, but the voltages seemed very high compared to the 5F6A. I tried a 5V4 recto and it got the voltages down nicely.
I should add, I liked it but it was just too much amp for what I needed. So I sold it and used the proceeds to buy very choice parts to build a clone of a 5F4 tweed Super. Similar to the Bassman in overall sound (different phase inverter), but less output and pushing only half the air. And lighter. Win, win, win. :D
Changing the speakers and rectifier… That’s a lot of “buts”
Actually the earlier versions had the Blue Frame Eminence speakers that had the exact same cones made by Donal Kapi that were used on the original Jensens from the ‘50’s.
@@vayabroder729 "Actually", mine had the Jensen P10Rs, and they sucked.
@@Splattle101 yes those are the Italian made Alnicos. Did you give them time to mellow out with play time?
How can we be sure the PT will be happy driving the 5U4 vs the GZ? I ask because I did the very same thing with mine and I did it nervously knowing that the 5u4 is hungrier
Because it’s rated for 3A@5V. You can find the OEM Schumacher part number specifications if you don’t believe me. A 5U4G will run in that amp forever and be completely fine.
@@matthewf1979, 50 mfd is pushing the 5U4 pretty hard (above max ratings, IIRC). Would you trust a Russian or Chinese 5U4 here? NOS would be better.
If you read the video description this is already addressed.
"Parasitic oscillations often occur at frequencies of the order of 100 Mc/s with leads from valve sockets forming resonant circuits and with a feedback path provided by a few micromicrofarads of capacitance between plate and grid circuits. In such a case a suitable remedy is a non-inductive resistor (say 50 000 ohms, 1/2 watt, carbon) wired *directly to the grid pin*. This increases the losses in the high frequency circuit to such an extent that oscillation is not possible."
- Radiotron Designer's Handbook, 1952
So mixer resistors on the eyelet board 4" away from the grid pin are not "grid stoppers".
Now define mixer resistors and notice that for modern use (one instrument at a time per channel) these aren’t that.
They’re a voltage divider and sub-optimally applied grid stoppers.
Adding a second smaller (10Kish) resistor directly at the grid pin to this kind of circuit can sometimes be beneficial. But it’s not always needed.
Joel, keep in mind I’m mostly talking to an audience of guitarists, not trying to teach an electronics course.
I know more about this than I mention in a video, unless it’s a concept crucial to an issue in the amp on the bench.
Was there a British printing of the Radiotron Designer's Handbook that substituted "valve" for *vacuum tube*? 😉
@@goodun2974 "Fritz Langford-Smith (29 June 1904 - 3 December 1966) was an Australian electrical engineer. He was the author of the classic engineering reference Radiotron Designer's Handbook (RDH)."
@@joeltunnah I actually own a copy of the radiotron designer's handbook but I haven't looked at it in years.
Great, a "beat-box" disguised as a guitar amp. Fender should make the ghost-notes and fuzzy tones switchable; they might be missing a marketing opportunity.....😖
I was wondering why you don’t like metal oxide resistors?
If the carbon film resistors burn and leave carbon in the amp, metal oxide resistors only discolour.
Typically, I use metal oxide only in the power supply.
Lyle, do you subscribe to the idea that different resistor types sound different. I have heard it said but I can’t say that I have heard a difference.
I'm experiencing that same sound weak/loud sound with my Super Reverb. Last recap was in 1999. Definitely time for new electrolytic caps. Is it worth spending more and using F&T or should I use MOD?
Lyle has used both; he seems to have switched to MODs lately.
Had a couple of people including Mr. Audio have told me the MOD’s are good. I’ve put them in all my old Fenders and no issues so far.
Yes
Ok. It’s a 59 in need of help.
i never liked those caps, thought it was just me.
I know that you're scrupulously objective, Lyle...but it seems to me that every time you do a presentation on one of these major brand re-issues...it might as well be a plug for all the smaller repairmen/builders out there, and I don't have a problem with that.
Is this a way of implying Lyle is subtly dissuading folks from sending their amps to Fender authorized repairmen?
"RUclips does have some standards for language and such" but no-one told @BradsGuitarGarage
Fran Blanche at FranLab had her *livestream* pulled, in mid-stream apparently, because of her "potty mouth", as she put it. It seems that the more subscribers a channel has, the more likely it is that RUclips, in their zeal to monetize a popular channel while avoiding an inadvertent association between advertisers and controversial speech, will clamp down on freedom of expression in the form of swear words. And yet, misinformation, and spam/ spammers, are rarely booted off.