ovation fuzz from the late 60's/// help me resurrect it?

[Rob Strand]

It's a cool looking thing.

The numbers are the tracks from left to right, and my guesses on what they are.

I did a hand drawing last night but didn't get a chance to draw it up.
I got the same as Marcos-Munky.

As far as the part values go I was thinking:
- 180k not 680k
- 3.9k not 1.5k

What stage comes first and how they connect together to the other boards is a mystery.
So too is the pot connections.

That unit only has a Fuzz-Blend pot.   So obviously a single pot like that  cannot resolve all the unknown connections.

So thinking bit outside of the box:

I have a feeling some of those 1n caps connect to the two Top Boost switches.   [Doubt it, see EDIT 1] 

There's also the possibility some of the connections aren't used.   One of the other amp models (K-2002) has two Fuzz pots: Fuzz Blend and Fuzz-Shift.   The same board might be used for both amps so some connections might only used on that other model.

Lasty, there's a preamp section with Bass an Treble controls.   That section is likely to have some gain so the Fuzz board might not Fuzz unless it has the gain from that first stage present.

The only way to resolve all this is to trace through the wiring in the unit to know which Fuzz Wire numbers goes to which board and which pot, and which Fuzz Wire numbers are unused.
------------------------
EDIT 1:
Looking at the manual,
http://www.ovationtribute.com/Catalogues/Amplifiers%20Owner%20Manual/K-6001/K-6001.PDF

The way the TOP BOOST functions are described it seems unlikely these have anything to do with the Fuzz.
For a start, there's two switches which work independently on each channel.

the fuzz will be cool to mess with hopefully. looking at it, it looks like they f'd up and put the wrong value caps in... 10n maybe, but 1n? no way. i bet they were supposed to be 10n or 100n.

So ... maybe !

[pinkjimiphoton]

It's a cool looking thing.

The numbers are the tracks from left to right, and my guesses on what they are.

I did a hand drawing last night but didn't get a chance to draw it up.
I got the same as Marcos-Munky.

asap i will trace what goes where. there is only one fuzz pot, it has a switch on it. these things are weird. REAL weird!!!

As far as the part values go I was thinking:
- 180k not 680k
- 3.9k not 1.5k

i can verify the values on the resistors too, but the values posted most def are right according to the color bands. the suck thing is i can only really see that shit in super bright light now.

What stage comes first and how they connect together to the other boards is a mystery.
So too is the pot connections.

all stages are in parallel bro.
if ya pull one preamp card, the rest of the circuit still functions. if ya pull the fuzz, reverb, tuner, or trem boards, it still functions. it all sums together at that mixing board in the back, and then is output to the jacks from what i could see yesterday.

That unit only has a Fuzz-Blend pot.   So obviously a single pot like that  cannot resolve all the unknown connections.

nope. pretty sure the extra pads were for the extra functions this particular unit doesn't have <yet>

So thinking bit outside of the box:

I have a feeling some of those 1n caps connect to the two Top Boost switches.   [Doubt it, see EDIT 1] 

top boost is functional and independent of the fuzz completely. you can pull the fuzz board out and the top boosts still work normally.

There's also the possibility some of the connections aren't used.   One of the other amp models (K-2002) has two Fuzz pots: Fuzz Blend and Fuzz-Shift.   The same board might be used for both amps so some connections might only used on that other model.

same board was definitely used on both models. but its fed by each preamp as far as i can tell, so two inputs to one output.
but its a "paralell" fuzztone, its not mixed in series with the signal, its brought up in parallel with it i think.

Lasty, there's a preamp section with Bass an Treble controls.   That section is likely to have some gain so the Fuzz board might not Fuzz unless it has the gain from that first stage present.

yeah, the preamps are supposed to be loud as hell. the single pre from the channel two only jack is LOUD AS HELL. the goal is to get the parallel channel output loud as hell too...

or do parallel channels cut the signal in half? i don't know how that works, but i expect it should be about the same like AnyFenderAmp kinda

The only way to resolve all this is to trace through the wiring in the unit to know which Fuzz Wire numbers goes to which board and which pot, and which Fuzz Wire numbers are unused.

agreed.
gotta gig tonite but will be on it asap

------------------------
EDIT 1:
Looking at the manual,
http://www.ovationtribute.com/Catalogues/Amplifiers%20Owner%20Manual/K-6001/K-6001.PDF

The way the TOP BOOST functions are described it seems unlikely these have anything to do with the Fuzz.
For a start, there's two switches which work independently on each channel.

the fuzz will be cool to mess with hopefully. looking at it, it looks like they f'd up and put the wrong value caps in... 10n maybe, but 1n? no way. i bet they were supposed to be 10n or 100n.

So ... maybe !

hahahah yeah, ovation was overconcerned with TREBLE RESPONSE. i can't see a 1n cap allowing enough WOOOOOOF thru to actually fuzz

betting 100n will sound way better in the end

[Marcos - Munky]

What stage comes first and how they connect together to the other boards is a mystery.
So too is the pot connections.

all stages are in parallel bro.

I think what Rob means is looking just at the fuzz, not at the whole unit. There's 2 transistors, so 2 stages. On the schematic I drew, I guessed where's the input and where's the output, and so I guessed which one is the 1st stage and which one is the 2nd stage. But I may have guessed wrong and they're actually reversed.

[Rob Strand]

i can verify the values on the resistors too, but the values posted most def are right according to the color bands. the suck thing is i can only really see that shit in super bright light now.

OK cool.  The 680k looks really high to me in that position (doesn't mean it's not correct).

all stages are in parallel bro.

Ah, OK.  That puts a different spin on things for the fuzz.

same board was definitely used on both models. but its fed by each preamp as far as i can tell, so two inputs to one output.
but its a "paralell" fuzztone, its not mixed in series with the signal, its brought up in parallel with it i think.

OK got it.

but i expect it should be about the same like AnyFenderAmp kinda

I'd expect the same.

hahahah yeah, ovation was overconcerned with TREBLE RESPONSE. i can't see a 1n cap allowing enough WOOOOOOF thru to actually fuzz

betting 100n will sound way better in the end

Since the distortion is in parallel, maybe their thinking was to blend in the upper frequency dirt with the blend control.  The lows coming from the clean path.   I suppose it's more a concept than what would sound better.

I think what Rob means is looking just at the fuzz, not at the whole unit. There's 2 transistors, so 2 stages. On the schematic I drew, I guessed where's the input and where's the output, and so I guessed which one is the 1st stage and which one is the 2nd stage. But I may have guessed wrong and they're actually reversed.

Yes I was thinking just that.

The whole two-stage thing could go anywhere.   Like it could be two parallel circuits for all we know!   The missing emitter resistor seems to point to a pot to ground being there.   If the emitter fed the Fuzz-blend pot and the wiper goes to the mixer that make sense for the emitter.  However it doesn't make sense for the two(!) connections on the collector - where do they go?

Very confusing.

[Marcos - Munky]

I guess we'll need pictures of the main board, where the cards are attached. Then we'll be able to get those connections.

Edited: looking again at the pictures you took, looks like there's no "main board", just wires. So we'll need to trace those wires.

[pinkjimiphoton]

yeah, its all like connectors for inside a tower computer, where ya plug differnt cards into it... i forget the nomenclature.
its gonna be a LOT of tracing. that suckers wired like an electric organ!! its a real shame no schematics seem to exist. a testament to sucky tone? lol

and yes, the fuzz is kinda blended in the background, just adding bite to the preamps. the preamps SHOULD have ample gain, but its gotta be that one mixer stage thats messed up.

i pulled the cards for the preamps, cuz they were identical, and the problem stayed either way, so i know the preamp cards are working, the tremolo is working, the topboost is working, the reverb is working on both channels only with the parallel outputs, which isn't right. even the "e" tuner oscillator card is working! its really cool, each part is its own discrete circuit wired in parallel so if one part goes down the rest keeps working.

hopefully tomorrow or saturday i can get some quality bench time with it and my meter.

[Rob Strand]

but its gotta be that one mixer stage thats messed up.

There could be more opportunities for stuff-ups.

The signal flow isn't clear to me:
- If the Fuzz/Reverb are all parallel then the mixer must be post everything.    I can't imagine the Tremolo being parallel (?) so that would be post the mixer (?)
- *If* the main mixer is post everything  then the two channels must be mixed together before the Reverb and before the Fuzz.   Then the combined signal would then need to be split-off to the Reverb and the Fuzz.
- The outputs of the Reverb and Fuzz would then be mixed with the output of each channel.
- If there's extra mixing and splitting going on, the fault could occur in the earlier stages.

The more I think about it more confused I get with option overload.

[pinkjimiphoton]

but its gotta be that one mixer stage thats messed up.

There could be more opportunities for stuff-ups.

everything else is working.

The signal flow isn't clear to me:
- If the Fuzz/Reverb are all parallel then the mixer must be post everything.

yes, exactly. the only thing NOT in parallel, its hard wired to the chassis, and the only part NOT on a plug in card.

   I can't imagine the Tremolo being parallel (?) so that would be post the mixer (?)

no, you can pull the entire tremolo card, and the thing still works. its not post mixer, its before it. i told ya this thing is weird. ALL you need working to get sound to pass thru is ONE of the preamp cards.
you can make it work with the reverb other channel, fuzz, tuner or tremolo boards pulled. seriously.

- *If* the main mixer is post everything  then the two channels must be mixed together before the Reverb and before the Fuzz.   Then the combined signal would then need to be split-off to the Reverb and the Fuzz.

nope. all that shit is BEFORE the mixer board. the last thing in line is the mixer board before the outputs.
remember, the reverb is switchable on/off for each channel, so it obviously is NOT gonna be dependent on being AFTER everything. this is NOT a fender style amp at all. like i said, parallel. they even brag/rave about it in their literature. it was designed so that if any card went down, the rest would still function. the fuzz is universal to the two channels, as is the reverb... tho the reverb has individual controls for off n on, it only has ONE mix control. the fuzz is always on once ya click the switch on the pot, and turn it up.

in order, from right to left from the back, you have channel one, channel two, then the fuzz and reverb boards are next, facing each other mirrored, then the tuner board, then the tremolo board. all of these are individual boards with computer style plugs that they plug into.
all the pots and switches mount to the front face of the chassis by flying leads.

the mixer stage is the very LAST PART of the entire assembly, and it has both channels and the reverb (not sure on the reverb yet) enter it, and off the back, there is one out put for channel two only, and one output with two jacks of the two channels in parallel. the second channel has a switching jack that  splits the two outputs, which is the  purpose of the mixer stage apparently. it runs on one transistor and a couple passives. there are pictures of it posted already earlier in the thread... there are 4 wires coming off the top, to the output jacks, and all the stuff going in is along the bottom edge

here's the mixer stage i just described. last thing before the output jacks. this is where the entire unit is f'n up.

- The outputs of the Reverb and Fuzz would then be mixed with the output of each channel.

in parallel, not series.

- If there's extra mixing and splitting going on, the fault could occur in the earlier stages.

it can't. is you use the summed outputs, the thing works exactly as its supposed to, all the other cards are working, as can be proven by simply pulling them and putting them back in, as i said. the problem is the output is WAY below unity. the last thing before the outputs is... again... the mixer stage.

the channel two output also comes from there, but appears to be a straight shot thru. when you use the channel two out, it splits the channels to  the two sets of outputs, and the channel two only output is LOUD N PROUD the way it SHOULD be... but the reverb doesn't work, which it should. the reverb appears to also hook to this mixer stage.

so... all the channels cards work. the fx cards work. the tuner card works. there are no other circuit board in the unit other than the output board at the very end.

if all the circuits work at the for all intents mono output, and i can again, switch the preamp cards for each other, and both work identically regardless of which is which, obviously the preamp cards are working. the problem, much like in a tube amp, stays with the socket, not the card.
the reverb is working, or there would be no reverb.
the trem is working, or there would be no trem
the tuner part is working as well.

all thats left is that mixer stage, and one side is obviously not working right. that is also the side with the unmarked button transistor that connects to the parallel's output jacks with the low volume, and sounds like playing thru a circuit with a blown transistor. lower volume, more distortion than it should have... but it still passes signal. years ago, i had an old kustom i used as a preamp.. the power amp was cooked, so i took the line out/slave out from it and used it as a preamp for my jcm800 so i had more drive, and reverb and tremolo.
the amp still functioned, and added a good bit of overdrive... but less than unity gain. same exact sympton here bro.

The more I think about it more confused I get with option overload.

hahah.... welcome to MY world.
i assure ya, i spent hours headscratching to figure out what and where the fault is. if it looks like a duck and acts like a duck, its probably not the president. <at least not normally>

this thing is weird, i told ya!!

anyways, process of elimination, the ONLY thing left in the end that can be @#$%ing up is that mixer board at the end. i think its just supposed to be a buffer to stop crosstalk between the channels most likely, which is probably why its just a single transistor.

i couldn't make this stuff up if i tried . seriously!!!!

i would gladly send it to you if you really want to see for yourself. its as @#$%ed up as a soup sandwich. but when its working again, it will be cool.
its literally those 6 cards, the mixer stage, a bunch of switches and pots and an ass-load of wiring.

[pinkjimiphoton]

chassis layout



mixer board front. those two switches are the reverb off and on for the two channels, they are part of the mixer board. the left side of the board is where the summed output feeds from.



the back of the mixer board.  don't have it in front of me, so don't remember which wires were hot and which ground, but i do recall brown and blue go straight from this board to the channel two only output.

red and black wires to the right go directly to summed channel output. ya plug in there to drive up to two amps in parallel, or split off the channel two to be independent for stereo applications.



this is where the rubber meets the road in terms of messing up. the channel two side looks like its a straight shot thru, to me, at least, and the both channels side appears to be buffered by that transistor and passively mixed (?)

and it appears that yes, the last thing before the mixer, or maybe AT the mixer, is the reverb returns. i'm imagining the reverb returns feed into it, and the trem modulates that board somehow, probably its input.

like i said, this thing is extremely weird!!!

[Rob Strand]

no, you can pull the entire tremolo card,

Perhaps the tremolo is done by the channel board?

it was designed so that if any card went down,

Yes, I read that in the manual.  It was like a concept behind the whole design
and perhaps explains why it has a certain weirdness.

the rest would still function. the fuzz is universal to the two channels, as is the reverb... tho the reverb has individual controls for off n on, it only has ONE mix control. the fuzz is always on once ya click the switch on the pot, and turn it up.

Funny thing is, when I read the manual it says Fuzz is only on Channel 2.    In  separate/stereo mode,  only channel 1 has reverb and channel 1 is louder than channel 2.  (See manual: page 3 point E and page 4 point S.)

the mixer stage is the very LAST PART of the entire assembly, and it has both channels and the reverb (not sure on the reverb yet) enter it,

The reverb must enter there somehow because the reverb switches are on that board.   It's not clear to me if the Reverb signals are Raw Reverb or Reverb+Channel already mixed together.

the channel two output also comes from there, but appears to be a straight shot thru. when you use the channel two out, it splits the channels to  the two sets of outputs, and the channel two only output is LOUD N PROUD the way it SHOULD be... but the reverb doesn't work, which it should. the reverb appears to also hook to this mixer stage.

I'm still struggling with the signal flow. Like where do the channel outputs go?  and where do the output jacks connect.

I've drawn a schematic of the mixer.   It might be a good start to help you piece the puzzle together with the unit in front of you.



There's obviously some mods made with the resistors on the back of the board.  These look like factory mods.
However, the resistor on the emitter appears to be shorted out by a solder blob.    It might be worth checking this.  It could even be the fault which is stuffing up your mixer board.

[pinkjimiphoton]

no, you can pull the entire tremolo card,

Perhaps the tremolo is done by the channel board?

nope, the tremolo, other than the on/off switches and the depth and rate, is all on one pcb, the last one to the left in the pic above of the circuit cards. you can pull it completely out of the entire assembly, no connections, and the only thing that changes is the trem switches and knobs have no effect.

it was designed so that if any card went down,

Yes, I read that in the manual.  It was like a concept behind the whole design
and perhaps explains why it has a certain weirdness.[/quote]

definitely. they, i think, really thought their amps and stuff would take off, but nobody wanted crystal clear solid state with ample treble other than like, the partridge family

the rest would still function. the fuzz is universal to the two channels, as is the reverb... tho the reverb has individual controls for off n on, it only has ONE mix control. the fuzz is always on once ya click the switch on the pot, and turn it up.

Funny thing is, when I read the manual it says Fuzz is only on Channel 2.    In  separate/stereo mode,  only channel 1 has reverb and channel 1 is louder than channel 2.  (See manual: page 3 point E and page 4 point S.)[/quote]

i will check... fuzz is definitely bleeding thru both channels, much stronger on channel 2. channel 2 is louder than channel one by way more than double. perhaps it IS working right for the most part and my memory is corrupted.
messing with it tho, i DID get it for a flash here and there to work as i recalled, with both channels working. i'll look at the manual, thanks rob, good call. maybe i'm just stupid. wouldn't be the first time!

the mixer stage is the very LAST PART of the entire assembly, and it has both channels and the reverb (not sure on the reverb yet) enter it,

The reverb must enter there somehow because the reverb switches are on that board.   It's not clear to me if the Reverb signals are Raw Reverb or Reverb+Channel already mixed together.[/quote]

it seems to be each channel gets reverb, but only in the parallel mode where its suffering the big volume drop. since the only thing there is that board, seems the most likely culprit going by all the crap i learned reading jack darr columns forever

the channel two output also comes from there, but appears to be a straight shot thru. when you use the channel two out, it splits the channels to  the two sets of outputs, and the channel two only output is LOUD N PROUD the way it SHOULD be... but the reverb doesn't work, which it should. the reverb appears to also hook to this mixer stage.

I'm still struggling with the signal flow. Like where do the channel outputs go?  and where do the output jacks connect.[/quote]

the output jacks connect to the mixer board, if ya look at the last pix i posted, you can see where the output wires are from the mixer board. the blue and brown are channel 2, the black and red channel 1 AND 2.



I've drawn a schematic of the mixer.   It might be a good start to help you piece the puzzle together with the unit in front of you.

[/quote]

dude... thanks!! that will definitely help!!!

There's obviously some mods made with the resistors on the back of the board.  These look like factory mods.
However, the resistor on the emitter appears to be shorted out by a solder blob.    It might be worth checking this.  It could even be the fault which is stuffing up your mixer board.

i will look, that would likely explain it!! thanks rob for all the help and patience man!
i will try and look tonite or tomorrow at it closely. and will post results.

[Rob Strand]

nope, the tremolo, other than the on/off switches and the depth and rate, is all on one pcb, the last one to the left in the pic above of the circuit cards. you can pull it completely out of the entire assembly, no connections, and the only thing that changes is the trem switches and knobs have no effect.

I was think more the lines that the tremollo board had the oscillator and depth control then the output of the oscillator fed back to the channel amps.   The channel amps would each have a way to do the gain variations (JFET, vactrol or whatever).

but nobody wanted crystal clear solid state with ample treble other than like, the partridge family

People soon learnt   

i will check... fuzz is definitely bleeding thru both channels, much stronger on channel 2. channel 2 is louder than channel one by way more than double. perhaps it IS working right for the most part and my memory is corrupted.

I was getting desperate so I had to go to the manual.

it seems to be each channel gets reverb, but only in the parallel mode where its suffering the big volume drop. since the only thing there is that board, seems the most likely culprit going by all the crap i learned reading jack darr columns forever

OK.   I wonder where the switching is done in Stereo mode?  It's not like it has a lot of switching going on.  Maybe something on one of the output jacks.

the output jacks connect to the mixer board, if ya look at the last pix i posted, you can see where the output wires are from the mixer board. the blue and brown are channel 2, the black and red channel 1 AND 2.

When I was looking at it I wasn't sure if "channel 2 out" meant "the output of the channel 2 preamp" and the "channel 2 output jack".   The circuit doesn't yet make sense to me so it could be either of those in the fuzzy Ovation universe.

i will look, that would likely explain it!! thanks rob for all the help and patience man!
i will try and look tonite or tomorrow at it closely. and will post results.

No problem.   Good luck, sometimes you just have to keep poking around with these things until you hit the jackpot.

[digi2t]

but nobody wanted crystal clear solid state with ample treble other than like, the partridge family

My new sig line. Thanks bro!

[Rob Strand]

but nobody wanted crystal clear solid state with ample treble other than like, the partridge family

Treble, A conspiracy to stop Danny from being heard,


Signature Partridge family basses,

[pinkjimiphoton]

nope, the tremolo, other than the on/off switches and the depth and rate, is all on one pcb, the last one to the left in the pic above of the circuit cards. you can pull it completely out of the entire assembly, no connections, and the only thing that changes is the trem switches and knobs have no effect.

I was think more the lines that the tremollo board had the oscillator and depth control then the output of the oscillator fed back to the channel amps.   The channel amps would each have a way to do the gain variations (JFET, vactrol or whatever).

i can easily take pics of the tremolo board, and the channel boards, too if ya would like. hoping to get to beep out which wires go where anyways and write it down. everything appears to be on the trem board but the two switches and two pots.
did i mention this thing is weird??

but nobody wanted crystal clear solid state with ample treble other than like, the partridge family

People soon learnt   [/quote]

yeah man, lsd25 has a strange effect on some people. its tough when ya smell the sound of purple. lol

i will check... fuzz is definitely bleeding thru both channels, much stronger on channel 2. channel 2 is louder than channel one by way more than double. perhaps it IS working right for the most part and my memory is corrupted.

I was getting desperate so I had to go to the manual.[/quote]

i've been chuckling about that for like, 20 minutes!!! lol
its entirely possible it works right and i just don't recall, as it was 1980 on my birthday the last time i used one of these!! long time ago!!! lol
back when the only effects i had were a kay fuzztone, a violet rams head big muff, a clone theory and a guild wahwha. oh yeah, and the marlboro quadra sound blender reverb/ "echo" / tremolo. back then <mighta been that lsd again> it was important for me to have that tremolo running at a different clock then the trem in my sunn 1200s stacks... it was cool, double outta sync tremolos are highly underrated!!! lol it was almost like a phaser and a reverse attack kinda sound. very trippy. or maybe it was that lsd. i dunno. surprised i survived the 60's. and the 70's. and the ... well.... lol

it seems to be each channel gets reverb, but only in the parallel mode where its suffering the big volume drop. since the only thing there is that board, seems the most likely culprit going by all the crap i learned reading jack darr columns forever

OK.   I wonder where the switching is done in Stereo mode?  It's not like it has a lot of switching going on.  Maybe something on one of the output jacks.[/quote] there's a switching jack on the channel two only output, and that jumpers over to the "mono" outputs. its a normally closed jack switch, so when its unplugged,  the reverb works on both channels, and both channels come out the mono outputs. when ya plug it in, it kills the reverb to channel two, and the volume goes WAY up.
so maybe it IS working.... again... and i am just a forgetful moron. my money's on the last one more by the minute lol

the output jacks connect to the mixer board, if ya look at the last pix i posted, you can see where the output wires are from the mixer board. the blue and brown are channel 2, the black and red channel 1 AND 2.

When I was looking at it I wasn't sure if "channel 2 out" meant "the output of the channel 2 preamp" and the "channel 2 output jack".   The circuit doesn't yet make sense to me so it could be either of those in the fuzzy Ovation universe.[/quote]

the channel 2 out is channel 2 only, with no channel one and no reverb. the dual "mono" outputs both preamp channels come thru with reverb. so i am suspecting from what you found it is indeed working, and i am just a fool with a bad memory

i will look, that would likely explain it!! thanks rob for all the help and patience man!
i will try and look tonite or tomorrow at it closely. and will post results.

No problem.   Good luck, sometimes you just have to keep poking around with these things until you hit the jackpot.
[/quote]

indeed! gonna check the mixer part, and see if that "blob" is actually a bridge. something tells me that may have been a fudge cuz they didn't think the parallel thing thru all the way

[Rob Strand]

i can easily take pics of the tremolo board, and the channel boards, too if ya would like. hoping to get to beep out which wires go where anyways and write it down. everything appears to be on the trem board but the two switches and two pots.
did i mention this thing is weird??

If you want I can look at it.  Not sure if it will help fix the unit but it might help understand the unit.
Yes, it is weird.   Normally I can guess stuff but the whole topology of this thing is different so trying to guess comes up with 10 answers - totally useless!

its entirely possible it works right and i just don't recall, as it was 1980 on my birthday the last time i used one of these!! long time ago!!! lol
back when the only effects i had were a kay fuzztone, a violet rams head big muff, a clone theory and a guild wahwha. oh yeah, and the marlboro quadra sound blender reverb/ "echo" / tremolo. back then <mighta been that lsd again>

Do you remember if the tuner light was purple

it was important for me to have that tremolo running at a different clock then the trem in my sunn 1200s stacks... it was cool, double outta sync tremolos are highly underrated!!! lol it was almost like a phaser and a reverse attack kinda sound. very trippy. or maybe it was that lsd. i dunno. surprised i survived the 60's. and the 70's. and the ... well.... lol

I've never tried that.  Only tried the stereo left/right pan thing.

there's a switching jack on the channel two only output, and that jumpers over to the "mono" outputs. its a normally closed jack switch, so when its unplugged,  the reverb works on both channels, and both channels come out the mono outputs. when ya plug it in, it kills the reverb to channel two, and the volume goes WAY up.
so maybe it IS working.... again... and i am just a forgetful moron. my money's on the last one more by the minute lol

That makes a lot of sense.  Kind of lines up with the manual as well.

the channel 2 out is channel 2 only, with no channel one and no reverb. the dual "mono" outputs both preamp channels come thru with reverb. so i am suspecting from what you found it is indeed working, and i am just a fool with a bad memory

So does that.    So your memory is fine!

indeed! gonna check the mixer part, and see if that "blob" is actually a bridge. something tells me that may have been a fudge cuz they didn't think the parallel thing thru all the way

Maybe you should measure the +V rail on the mixer board and the voltage on the collector of the transistor.  That might help identify a problem with that stage.

I really think something *is* wrong.   It doesn't make sense that the channel 1 is so low.    It make even less sense when you look at the manual because it states channel 1 gain should be higher than channel 2 in stereo mode.    Channel 1 is coming off the output of Q1 on the mixer board.    The things that don't add-up all point to Q1.

FYI:  There's a bug on my mixer schematic. One of the 2x100k's  between the transistor and the switches should go to the other vertical strip of switch connections.  I'll fix it later.

[pinkjimiphoton]

cool.... so yer saying the manual says i'm a moron, huh?? lmao!!



the purple kinda had lime green perimeters as i recall....

i think that transistor isn't working too. too sick today to venture to the dungeon, but hopefully tomorrow. thanks bro!

[pinkjimiphoton]

found this, which i hadn't seen til now... it says what you said, rob.
only diff is that channel TWO is the louder of the two... not channel one.
really thinking i am whats wrong with the circuit!




it pretty much acts as described, other than channel 2 being louder, and it seeming to be totally castrated out of the parallel jacks.

[Rob Strand]

cool.... so yer saying the manual says i'm a moron, huh?? lmao!!

(No way I'd say that.)

the purple kinda had lime green perimeters as i recall....

i think that transistor isn't working too. too sick today to venture to the dungeon, but hopefully tomorrow. thanks bro!

It's looking like that.  The DC rail and the collector voltage should give a hint of any problems.

found this, which i hadn't seen til now... it says what you said, rob.
only diff is that channel TWO is the louder of the two... not channel one.
really thinking i am whats wrong with the circuit!

it pretty much acts as described, other than channel 2 being louder, and it seeming to be totally castrated out of the parallel jacks.

That's it, that's the part I read.
So it seems channel 1 is the problem.

[pinkjimiphoton]

no, its not channel one, cuz ya can switch the preamp cards, and the problem stays with the socket, not the cards.
the only thing after them is... you guessed it... that mixer stage.
i will get at it tomorrow.
immune system is wiped out from one medical issue, which has led to a mrsa infection that is really kicking my ass.

thanks bro... more soon