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Discussion Starter · #1 ·
Started getting into this elsewhere, but putting it out there to see if any techies surface.

My vintage Traynor Super Custom Special YBA-3A has always been hard to get much deep bottom end out of. I've used many cabs over the years but I've always found it necessary to EQ more 100-150hz into it. Main axe has been a 1970 Fender Jazz, which certainly isn't thunderous on the bottom as it is, but I'm talking in comparison to other amps. A little less of an issue with active basses, like my Ibanez STR-500, but same issue overall. I'm seeing other guys out there commenting that their 3A rattles the walls, including use with a Jazz.

I have the Bass control pinned at 11. Neither the Bass Expander nor Bass Boost switch do anything to bump down at, say, 100-150hz, but they bump significantly around, I'm guessing, 400-500hz, which isn't a very pretty range. So tons of level, but light on the thunder. I can get there with input EQ, but it's far beyond what I normally use with other amps.

Obvious 1st thought is tubes, but it's always done this, through generations of tubes, and I've owned it for many years. A vintage amp buff I know suggested suspect/weak capacitors. Any thoughts out there?
 

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Might as well take it to an amp tech to have it looked at. Could be any number of things in the circuit that have aged/drifted/broke in the signal chain causing this.
 

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Discussion Starter · #4 ·
Might as well take it to an amp tech to have it looked at. Could be any number of things in the circuit that have aged/drifted/broke in the signal chain causing this.
The odd thing is that, as mentioned, it's really always been like this, and I've had it since it was probably 5 years old. Now, that doesn't mean that it didn't already have a problem, which is what I'm wondering about. Lots of level and tons of top end. So, to Frenchy's point, I've never really had a major diagnostic done; just replaced all the tubes every few years. Since there's never really been any big change in tone or performance, I've had nothing to compare to, it's never occurred to me to get it checked. Just thought that was the amp, until I started checking some threads in this forum. Now I'm wondering what I should be looking for. After all, good tech's for vintage amps are getting scarce.
 

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Was a previous use of this head as a guitar amp? Perhaps an interstage coupling cap may need replacing with a bass friendly value.
 

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Have you tried the bass with other heads?

I ask because there's a huge difference between our bass player's MIA jazz and his MIM. One sounds massive on the lowest open string, and the other one sounds weak there, yet packs a wallop on his 3rd string. Same SD pickups, same settings.

If you've never had the amp thoroughly checked out, I'd second that idea.
 

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Discussion Starter · #7 ·
Was a previous use of this head as a guitar amp? Perhaps an interstage coupling cap may need replacing with a bass friendly value.
Not that I know of. They were very bass focused when they were introduced, and I've owned it since shortly after that. But who knows?
 

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Discussion Starter · #8 ·
Have you tried the bass with other heads?

I ask because there's a huge difference between our bass player's MIA jazz and his MIM. One sounds massive on the lowest open string, and the other one sounds weak there, yet packs a wallop on his 3rd string. Same SD pickups, same settings.

If you've never had the amp thoroughly checked out, I'd second that idea.
Yeah, I've had the bass for pretty much my whole playing career, so it's been run through most of the classic brands in about every kind of venue you can imagine, as well as extensive studio use. It's light compared to some, but by no means inherently 'thin'. Most recently, I've been running a Mesa Pulse 600w with 2x10 and 1x15 cabs. Identical rig and input pedals, just with heads swapped, and the bottom end is night and day.
 

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I'm no amp tech but I might be able to steer you in the right direction.
Some years ago, when I owned a Blues Junior, I studied at length the BillM website and learned a few things about changing the tone of an amplifier.
I opted for several of his mods and did the work myself, slowly, carefully and realizing I was risking screwing it all up.
I was successful on every mod I did and the amp was improved.
Unfortunately, it wasn't improved enough for my tone-snob ears and I eventually sold the amp.
Actually, I think I gave it away to a friend.
In later years I learned of the real cure for the BJ which was a larger cabinet but by then I had moved on.

One of the things BillM does to modify the little BJs for more low end grunt is to swap out a coupling capacitor in the tone stack.
Raising the value of the cap, measured in microfarads, allows more bass frequencies to pass through the preamp and get to the power section.
You might be well served to find a schematic of your specific amplifier and do some studying.
If memory serves I believe many coupling caps on the bass control are in the range of .022 μf - .1 μf.
If you find your schematic and determine that yours is a .022 μf cap then you can consider replacing it with something closer to .1 μf.
If you find it's already at .1 μf then you might consider trying a move to .47 μf.
The operation itself is pretty simple.
You snip one out and solder another in.
It looks far more daunting than it really is.
You just have to be 100% sure of a few things.
- that your information and interpretation of the information is correct.
- that you have identified the correct location for the surgery
- that the new cap has the same rating* as the existing one.

* rating not to be confused with value
 

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Discussion Starter · #10 ·
I'm no amp tech but I might be able to steer you in the right direction.
Some years ago, when I owned a Blues Junior, I studied at length the BillM website and learned a few things about changing the tone of an amplifier.
I opted for several of his mods and did the work myself, slowly, carefully and realizing I was risking screwing it all up.
I was successful on every mod I did and the amp was improved.
Unfortunately, it wasn't improved enough for my tone-snob ears and I eventually sold the amp.
Actually, I think I gave it away to a friend.
In later years I learned of the real cure for the BJ which was a larger cabinet but by then I had moved on.

One of the things BillM does to modify the little BJs for more low end grunt is to swap out a coupling capacitor in the tone stack.
Raising the value of the cap, measured in microfarads, allows more bass frequencies to pass through the preamp and get to the power section.
You might be well served to find a schematic of your specific amplifier and do some studying.
If memory serves I believe many coupling caps on the bass control are in the range of .022 μf - .1 μf.
If you find your schematic and determine that yours is a .022 μf cap then you can consider replacing it with something closer to .1 μf.
If you find it's already at .1 μf then you might consider trying a move to .47 μf.
The operation itself is pretty simple.
You snip one out and solder another in.
It looks far more daunting than it really is.
You just have to be 100% sure of a few things.
- that your information and interpretation of the information is correct.
- that you have identified the correct location for the surgery
- that the new cap has the same rating* as the existing one.

* rating not to be confused with value
Awesome tips BMW-KTM. My first step is to find out if this thing isn't sounding like it's supposed to in the first place, so I don't screw up what would otherwise have been great. Beyond that, I'll be looking at your info.

Thanks!
 

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The odd thing is that, as mentioned, it's really always been like this, and I've had it since it was probably 5 years old. Now, that doesn't mean that it didn't already have a problem, which is what I'm wondering about. Lots of level and tons of top end. So, to Frenchy's point, I've never really had a major diagnostic done; just replaced all the tubes every few years. Since there's never really been any big change in tone or performance, I've had nothing to compare to, it's never occurred to me to get it checked. Just thought that was the amp, until I started checking some threads in this forum. Now I'm wondering what I should be looking for. After all, good tech's for vintage amps are getting scarce.
I repaired a mid 70's Marshall that was complained about being overly hot in the treble when the amp was at low value. The treble bleed cap that is found on the Gain pot was soldered on the MV pot from the factory. For 40 or so years, this thing was overly trebley because no one took it to a competent tech to troubleshoot the issue.
 

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Since you've had it from when it was around 5yr old, it's possible it was like this from new. If you'd got it more recently, I'd suspect it may have been modded, but back then modding wasn't all the rage. (as RG Keen would say, B.U.M.S or blind urge to mod syndrome :D )
I like dcole's idea of a part in the wrong place or maybe an incorrect value coupling cap somewhere. Maybe the guy working in QC the day it rolled off the line was a guitar player and didn't notice or thought 'this one sounds special'. ;)
From the other thread I got the impression it may be going to Yorkville? If so, I'm sure the shop can figure it out.
 

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Peavey Wolfgang EVH Wolfgang Charvel Style 2
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If you have changed the tubes and that didn't fix it then you will need to check whether the caps have been either swapped out in the past with a wrong value ( not uncommon ) or a capacitor is failed. I would not dismiss a failing capacitor but that would likely give you other indications you could hear. Those amps get modded lots by guys. unless you are the original owner or know the circuit well and have looked for mods... my guess is a poor mod done by someone looking to either tighten up the low end or thin it out because they didn't like that vintage low end sound.
Also... even the best Electrolytic capacitors, ie; Sprague, are recommended to be changed out once every 10 years. That's the life expectancy. so its safe to say if your running caps older than that you can expect problems.
 

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Discussion Starter · #15 ·
Could well be jb. From-day-1 is a possibility that Yorkville people have commented on. And yeah, as the near-original owner, I highly doubt there have been any mods.

Good points Lemmy. Not noticing other signs. Sounds about like it always has, but long overdue for a good overhaul, especially after hibernating for several years.

Fortunately there are still a couple guys at Yorkville from the days when these beauties were built, so she's going in, rather than mess around with someone who's unfamiliar with 3A's. I think they're kind of eager to see her. So thanks for the great tips guys. I'll pass along. Let you know what happens once she's out of the hospital.
 
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