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Line 6 Spider IV 75W schematic
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ohg...@gmail.com
Jan 23, 2014, 12:53:28 PM1/23/14
to
Does anyone have a schematic for this amp? It runs, but is distorted, particularly when high levels are played (test guitar: Strat with standard pickup). It has a TDA7293 output, which I replaced. B+/B- at 45V. Standby and mute lines 6.5v (well above 3.5 min).
I checked the ESR on the smd caps on the digital board, but turned up nothing. Before I go any farther, I'd love to have a schematic.
I checked the ESR on the smd caps on the digital board, but turned up nothing. Before I go any farther, I'd love to have a schematic.
ohg...@gmail.com
Jan 23, 2014, 1:11:30 PM1/23/14
to
I forgot to mention that the digital board has some dc levels screened on the board (5, 8, -6.8, 3.3), all read on target except for the -6.8, which reads -5.9v. I got all excited until I saw that it is sourced from an LM7906, which is a -6v regulator, not -6.8 (which doesn't exist). I can't help wonder if if the silk screen value is wrong, or if it really should run at -6.8v..
Message has been deleted
ohg...@gmail.com
Jan 28, 2014, 6:49:37 PM1/28/14
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On Thursday, January 23, 2014 1:54:27 PM UTC-5, Rick N. Backer wrote:
>
>
> Good luck. That amp is cheap enough a person might buy a working one
>
> and use the broke one for spare parts. I did find a place that carrys
>
> Line 6 parts. They may be able to point you the right direction.
>
> They're in Madison, WI.
>
>
>
> http://www.fullcompass.com
>
"
I don't work on them as a rule (unless one of my good customers brings one in), but it's my son's amplifier...
It's fixed, but here's the story: The replacement TDA output IC I installed decided to vent itself, so it's toast. I pulled the guts out of the cabinet completely and put it on my bench. I reinstalled the original TDA output, and connected it to my bench speaker (maybe a 15 W test speaker), and it sounded normal, except that I didn't want to pump 50 plus watts into my test speaker. I reconnected it with jumper wires to the original speaker, and it sounded like garbage again. Resistance was OK and it showed normal reaction to a ringer, so I reached in to push the cone and the coil was locked tight.
I pulled the speaker out of the cabinet and found the cone fully, and I mean fully extended all the way out to the point where the cone was distorted from the throw, and the voice coil cap was also bent and half off. The voice coil plastic bobbin (kapton?) was melted and distorted.
My son had let someone at college borrow the amp, and this is the way it came home. The mystery though is why the speaker was so badly overheated and mangled, yet the original output IC was intact. The only way I can see this happening is if someone intentionally connected the speaker to a DC supply for spite, or maybe the original TDA output is intermittent. Since this amp has no DC detection shutdown, I'm going to add a fuse to it.
If anyone wants to see the speaker, I can probably upload a picture of it. Any thoughts?
>
>
> Good luck. That amp is cheap enough a person might buy a working one
>
> and use the broke one for spare parts. I did find a place that carrys
>
> Line 6 parts. They may be able to point you the right direction.
>
> They're in Madison, WI.
>
>
>
> http://www.fullcompass.com
>
"
I don't work on them as a rule (unless one of my good customers brings one in), but it's my son's amplifier...
It's fixed, but here's the story: The replacement TDA output IC I installed decided to vent itself, so it's toast. I pulled the guts out of the cabinet completely and put it on my bench. I reinstalled the original TDA output, and connected it to my bench speaker (maybe a 15 W test speaker), and it sounded normal, except that I didn't want to pump 50 plus watts into my test speaker. I reconnected it with jumper wires to the original speaker, and it sounded like garbage again. Resistance was OK and it showed normal reaction to a ringer, so I reached in to push the cone and the coil was locked tight.
I pulled the speaker out of the cabinet and found the cone fully, and I mean fully extended all the way out to the point where the cone was distorted from the throw, and the voice coil cap was also bent and half off. The voice coil plastic bobbin (kapton?) was melted and distorted.
My son had let someone at college borrow the amp, and this is the way it came home. The mystery though is why the speaker was so badly overheated and mangled, yet the original output IC was intact. The only way I can see this happening is if someone intentionally connected the speaker to a DC supply for spite, or maybe the original TDA output is intermittent. Since this amp has no DC detection shutdown, I'm going to add a fuse to it.
If anyone wants to see the speaker, I can probably upload a picture of it. Any thoughts?
John Wood
Jan 28, 2014, 11:00:16 PM1/28/14
to
go after the crankmaster who destroyed his amp.
Adding the fuse was probably a good idea to guard against future mishaps.
John
Kaz Kylheku
Jan 29, 2014, 1:58:37 AM1/29/14
to
On 2014-01-29, John Wood <jwoo...@mediacombb.net> wrote:
> Never let bedroom jammers use and/or abuse your gear. Your son needs to
> go after the crankmaster who destroyed his amp.
Yeah; give it someone who plays live; they're easy on amps, in
> Never let bedroom jammers use and/or abuse your gear. Your son needs to
> go after the crankmaster who destroyed his amp.
contrast with bedroom jammers. !?
Amplifiers should be built to be played at full volume, continuously, for
months. You should be able to lock them in a room with a feedbacking guitar
cranked to 11, and go for a vacation.
If it doesn't hold up, the asshole who destroyed it is none other than someone
who works for, or in connection with, Line 6.
Don't scapegoat the "crankmaster" who used it correctly.
Message has been deleted
John Wood
Jan 29, 2014, 10:01:16 AM1/29/14
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On 1/29/14 3:09 AM, Rick N. Backer wrote:
> Well put. An amp that's built properly will have components up to the
> job. Unfortunately, the stuff on the showroom floor is full of
> lowballed parts and circuit work from a lot of the name companys, and
> not just in the 'factory' seconds lines that most of them flog.
>
> Thought I wouldn't be so quick to blame the manufacturer all the time.
> Some people just have a problem with keeping amps running. I've had a
> Lone Star Special for years and it has been flawless other than a
> pre-amp tube that crapped early in its career. They run hot, and I
> know it, so govern myself accordingly (RTFM). A buddy of mine went
> through 3 before he decided he needed an amp he wasn't personally
> capable of blowing up all the time and switched makes and models.
>
Thank you for supporting my position. Some people are just hard on amps
and some amps just can't take it. This is an example of wrong amp in the
wrong hands at the wrong time. Not every amp is built Fender Tweed
tough. And not every player is Les Paul gentle. Match the amp to the
playing style. If you want to yank'em and crank'em get a point-to-to
point. Or a stompbox.
A friend of mine lent out his Marshall once. Came back with a blown OT.
Knowing the player who borrowed it, I'd put even money on how that
happened. He had a problem keeping amps running. And I've known players
who like to swap things around to "see what happens." And sometimes this
is what happens. Just take responsibility.
John
> job. Unfortunately, the stuff on the showroom floor is full of
> lowballed parts and circuit work from a lot of the name companys, and
> not just in the 'factory' seconds lines that most of them flog.
>
> Thought I wouldn't be so quick to blame the manufacturer all the time.
> Some people just have a problem with keeping amps running. I've had a
> Lone Star Special for years and it has been flawless other than a
> pre-amp tube that crapped early in its career. They run hot, and I
> know it, so govern myself accordingly (RTFM). A buddy of mine went
> through 3 before he decided he needed an amp he wasn't personally
> capable of blowing up all the time and switched makes and models.
>
Thank you for supporting my position. Some people are just hard on amps
and some amps just can't take it. This is an example of wrong amp in the
wrong hands at the wrong time. Not every amp is built Fender Tweed
tough. And not every player is Les Paul gentle. Match the amp to the
playing style. If you want to yank'em and crank'em get a point-to-to
point. Or a stompbox.
A friend of mine lent out his Marshall once. Came back with a blown OT.
Knowing the player who borrowed it, I'd put even money on how that
happened. He had a problem keeping amps running. And I've known players
who like to swap things around to "see what happens." And sometimes this
is what happens. Just take responsibility.
John
Message has been deleted
John Wood
Jan 29, 2014, 12:02:54 PM1/29/14
to
On 1/29/14 10:15 AM, Rick N. Backer wrote:
> Fender is even making them tweed tough, it they ever truly were. Most
> of the tweed clones out there are superior in sound and construction
> to any of the current/recent tweed offerings from Fender.
> knowledge, that is. I moved a number of different rectifier, pre-amp,
> and power tubes around in my two tweed clones, with the builders'
> blessings after discussing the changes with both of them. Both want
> to see that their amps work for me and that they will keep on working
> for a long time. When Fender was contacted about some of the same
> changes for their own offerings in this area they passed on it,
> appearing to indicate their amps aren't up to it. At least not these
> days.
>
Exactly. And it still sounds like the lendee had abused the amp.
> of the tweed clones out there are superior in sound and construction
> to any of the current/recent tweed offerings from Fender.
>
>> And not every player is Les Paul gentle. Match the amp to the
>> playing style. If you want to yank'em and crank'em get a point-to-to
>> point. Or a stompbox.
>> A friend of mine lent out his Marshall once. Came back with a blown OT.
>> Knowing the player who borrowed it, I'd put even money on how that
>> happened. He had a problem keeping amps running. And I've known players
>> who like to swap things around to "see what happens." And sometimes this
>> is what happens. Just take responsibility.
>>
> I swap things. After I've talked to people who have the requisite
>> And not every player is Les Paul gentle. Match the amp to the
>> playing style. If you want to yank'em and crank'em get a point-to-to
>> point. Or a stompbox.
>> A friend of mine lent out his Marshall once. Came back with a blown OT.
>> Knowing the player who borrowed it, I'd put even money on how that
>> happened. He had a problem keeping amps running. And I've known players
>> who like to swap things around to "see what happens." And sometimes this
>> is what happens. Just take responsibility.
>>
> knowledge, that is. I moved a number of different rectifier, pre-amp,
> and power tubes around in my two tweed clones, with the builders'
> blessings after discussing the changes with both of them. Both want
> to see that their amps work for me and that they will keep on working
> for a long time. When Fender was contacted about some of the same
> changes for their own offerings in this area they passed on it,
> appearing to indicate their amps aren't up to it. At least not these
> days.
>
Exactly. And it still sounds like the lendee had abused the amp.
ohg...@gmail.com
Jan 29, 2014, 6:37:19 PM1/29/14
to
On Wednesday, January 29, 2014 12:02:54 PM UTC-5, John Wood wrote:
>
> Exactly. And it still sounds like the lendee had abused the amp.
It certainly was abused, but I have yet another theory...
>
> Exactly. And it still sounds like the lendee had abused the amp.
I'm the type of person who likes to give others the benefit of the doubt until I'm presented with irrefutable evidence, so I revisited the mystery. I reinspected the speaker/driver that was blown out, and now believe the cone should not have distorted in the way it did from full excursion as the result of loud playing, an intermittent output IC dumping one side of the supply into it, or even a maliciously connected car battery across the terminals.
I'm wondering if something wasn't stuffed into the back of the cabinet that pushed on the cone, warping/tearing the cone, and kept the voice coil fully extended on the pole piece.
Question: If the amplifier was played with the cone physically locked to one extreme or the other, the coil would run hot, would it not?
Les Cargill
Jan 29, 2014, 8:47:02 PM1/29/14
to
<snip>
--
Les Cargill
>
> Question: If the amplifier was played with the cone physically locked
> to one extreme or the other, the coil would run hot, would it not?
>
>
Yes.
> Question: If the amplifier was played with the cone physically locked
> to one extreme or the other, the coil would run hot, would it not?
>
>
--
Les Cargill
peterpan...@gmail.com
Aug 22, 2014, 2:44:52 PM8/22/14
to
On Thursday, January 23, 2014 12:53:28 PM UTC-5, ohg...@gmail.com wrote:
> Does anyone have a schematic for this amp? It runs, but is distorted, particularly when high levels are played (test guitar: Strat with standard pickup). It has a TDA7293 output, which I replaced. B+/B- at 45V. Standby and mute lines 6.5v (well above 3.5 min).
>
This will seem like an oddball request, but trust me that I have a good reason to want to insert an added "master volume" in the form of a digital potentiometer into the signal path between the main board and the TDA7293 based power amp board on this amplifier. I thought this would be reasonably easy until I saw with a scope that the chip is being run in differential mode. So there are at least two signal paths, and I'd have to use a dual (or stereo) digital pot to do what I want. I can handle that too, but then I realized ther was audio signal on 4 (not two) lines going through this board, which likely means that in addition to differential signals going in, there is likely feedback traveling back to the main board. I guess I'd expect from a well designed amp/preamp combination to run negative feedback all the way back to the signal processor or pre-amp, but it means my project is now further complicated. So... all this to say, while I realize the schematics are proprietary, the power amp board (the one with the TDA chip) is not all that complex, and is only a two layer board. It sports a 20K 8 section resistor array and a few other discreets, and I'll revers engineer it if I have to. But in the off chance you may have already done some ground work there, I'd be very much obliged if you could share! :-)
>
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