The Acoustic Club

[JacklegBass]

For diagnosing the low volume level the obvious place to start would be to test the preamp output into another power amp and the power amp input from another preamp. Maybe before that you could try using an instrument cable to jumper the preamp out into the power amp in... sometimes the normal-through contacts get dirty. Speaking of dirty, try vigorously working those switches, they may have oxidized contacts too.

 

[Bulltrout]

For diagnosing the low volume level the obvious place to start would be to test the preamp output into another power amp and the power amp input from another preamp. Maybe before that you could try using an instrument cable to jumper the preamp out into the power amp in... sometimes the normal-through contacts get dirty. Speaking of dirty, try vigorously working those switches, they may have oxidized contacts too.

Thank you.
Jumpering the preamp out into the power amp in did not increase the volume.

Running the preamp out into my 361 cabinet may result in my divorce. Stupidly I left the amp volume at full when I tried that, and there is plenty of volume on tap from the preamp to drive the 361 cabinet. My wife had been asleep at the beginning of that experiment…

I'll try running a different preamp into the 126 power amp tomorrow.

The switches were a little different. I tried cleaning both and vigourously turning them on and off to remove any oxidization. No change to the boost switch, which still does not function. The brightness switch worked with the 361 cabinet, but not when using the amps internal power amp.

 

[JacklegBass]

Running the preamp out into my 361 cabinet may result in my divorce. Stupidly I left the amp volume at full when I tried that, and there is plenty of volume on tap from the preamp to drive the 361 cabinet. My wife had been asleep at the beginning of that experiment…

Sounds like you're gonna have plenty of extra time to spend working on this problem!

The switches were a little different. I tried cleaning both and vigourously turning them on and off to remove any oxidization. No change to the boost switch, which still does not function. The brightness switch worked with the 361 cabinet, but not when using the amps internal power amp.

So the preamp and bright switch are probably fine and the power amp has a problem. Until you can diagnose what's going on with that module I wouldn't worry too much about the boost function for the time being. But since I see the boost switch has quick connect terminals I suppose just for grins you could temporarily move the white/black wire from the top switch terminal to the bottom one just to test out the unused contact on that side of the rocker switch. If that works you could just flip the switch around in the chassis.

 

[Syncopation]

Hi everyone. I recently bought a pristine looking Acoustic 126 combo. Probably the best looking vintage acoustic piece I've come across. Unfortunately the amp has really low output, and the boost and bright switches aren't working - the good news is that the EQ does. Anyone else have experience with this or this model - I took some gut shots, but nothing immediately jumped out to me. Regrettably, none of my local techs seem inclined to take on a vintage solid state amp.

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Thats interesting! There seems to be variations of this model. Your 126 is completely different from my 126, which is only slightly different from my 120 head. Both sound pretty much identical .
I had to wire out my main on/off switch because it had intermittent problems.
It seems strange that a tech wouldn't work on an amp like this. The circuits seem fairly simple and everything is easily accessed.

 

[Bulltrout]

Changed the contact on the boost switch and still no dice. Time to dig out the multi meter and run some tests on the power module - starting with confirming the caps are discharged.

Thats interesting! There seems to be variations of this model. Your 126 is completely different from my 126, which is only slightly different from my 120 head. Both sound pretty much identical .
I had to wire out my main on/off switch because it had intermittent problems.
It seems strange that a tech wouldn't work on an amp like this. The circuits seem fairly simple and everything is easily accessed.

I've noticed that as well, looking at pictures of other 126's. I guess most of my locals techs prefer working on tube amps and already have a strong backlog of those.

 

[Syncopation]

Changed the contact on the boost switch and still no dice. Time to dig out the multi meter and run some tests on the power module - starting with confirming the caps are discharged.



I've noticed that as well, looking at pictures of other 126's. I guess most of my locals techs prefer working on tube amps and already have a strong backlog of those.

Good luck with it and let us know how it goes!

 

[JacklegBass]

Thats interesting! There seems to be variations of this model. Your 126 is completely different from my 126, which is only slightly different from my 120 head. Both sound pretty much identical .

Correct, you may recall when you posted your pics HERE of your 120 & 126 internals it finally dawned on me that sometime around 1980 or so they revised the 126 to incorporated the new design for the 100W chassis as used in the 120 and 122. Before seeing your pics I had always assumed what @Bulltrout has was the one-and-only version. Your revamped version has a dual polarity power supply, no output capacitor, and a combo preamp & EQ board. His more common version has a single polarity power supply, an output capacitor, and a separate EQ board. I've never seen a schematic for the combo preamp/EQ board or the newer power supply (which appears to be partially integrated onto the new power amplifier board).

 

[Bulltrout]

Mine is from 1977.

 

[Doombuggy68]

Im curious what the power boost switch does

 

[DJ Bebop]

Im curious what the power boost switch does

I remember it adding more grit.
It seemed to be a boost of mids, or maybe uped the pre output from the pre amp to the power amp, IDK. I ran it off, it seemed to add something I didn't like.

 

[JacklegBass]

Im curious what the power boost switch does

It's sort of an overdrive. Here's what Acoustic said in one of their owner's manuals:

POWER BOOST SWITCH: "Depressing this switch provides an increase in volume and
a reduction in high frequencies and allows more apparent volume."​

TBH, I never really cared for it all that much either.

 

[DJ Bebop]

It's sort of an overdrive. Here's what Acoustic said in one of their owner's manuals:

POWER BOOST SWITCH: "Depressing this switch provides an increase in volume and
a reduction in high frequencies and allows more apparent volume."​

TBH, I never really cared for it all that much either.

And I've been that way ever since.

When I hear the young people talk about grit or grind, tube distortion and Darkglass and all.

My reaction is...

I dig it as an effect, just not all the time.

 

[Analogeezer]

It's sort of an overdrive. Here's what Acoustic said in one of their owner's manuals:

POWER BOOST SWITCH: "Depressing this switch provides an increase in volume and
a reduction in high frequencies and allows more apparent volume."​

TBH, I never really cared for it all that much either.

Yes that is very much what the owner's manual says.

My personal experience has been it seems to act like the "Loudness button" on old stereo receivers, most noticeable at lower volumes.

If you have the amp turned up a lot it doesn't seem to affect the actual volume much at all.

I've never used it much either.

Analogeezer

 

[jj4001]

I love the power boost switch but I don't use it because it makes the 320 too damn loud!

I've been gigging my 370 lately because it sounds gnarly like the 320 with the power boost on. Also, it's gotta be in the power section because it still works when I run an external preamp directly into the power amp

 

[Analogeezer]

Can someone summarize the "Series" production of Acoustic (ACC) bass gear?

I am sure this information is spread around the 315 pages of this thread but I'm too lazy to read/search through 315 pages LOL

I came to the brand circa 1978 with my 220, but I believe that was like the 3rd generation of the amps.

When I first started playing the cool cats with money (I only ever saw two) often had a 370 head with the matching cabinet. So I know this series and styling predated mine (370 got replaced by the 320).

Seems like the 370 came with a graphic whereas the smaller heads and combos from that era did not.

So I know it all started with the 360/371 which was what, 1967? 1968?

So what series of amps came after that, did Acoustic even make a combo until a few years later?

I believe another series of amps post dated my 220 and the 320 but I don't know how different they were internally. I think this era was when they came out with the single 15" cab and the 120 head.

But yeah I just know bits and pieces so a summary of the line through the ages until they went under would be cool.

Thanks!

Analogeezer

 

[StereoPlayer]

Can someone summarize the "Series" production of Acoustic (ACC) bass gear?

I am sure this information is spread around the 315 pages of this thread but I'm too lazy to read/search through 315 pages LOL

I came to the brand circa 1978 with my 220, but I believe that was like the 3rd generation of the amps.

When I first started playing the cool cats with money (I only ever saw two) often had a 370 head with the matching cabinet. So I know this series and styling predated mine (370 got replaced by the 320).

Seems like the 370 came with a graphic whereas the smaller heads and combos from that era did not.

So I know it all started with the 360/371 which was what, 1967? 1968?

So what series of amps came after that, did Acoustic even make a combo until a few years later?

I believe another series of amps post dated my 220 and the 320 but I don't know how different they were internally. I think this era was when they came out with the single 15" cab and the 120 head.

But yeah I just know bits and pieces so a summary of the line through the ages until they went under would be cool.

Thanks!

Analogeezer

History of Acoustic Amplification | Acoustic Amplification

 

[Analogeezer]

History of Acoustic Amplification | Acoustic Amplification

Thanks but that page is essentially worthless. All it tells people is it all started with the 360 and Jaco played one.

Gee any sentient bass player knows these facts....

It's just meant to pimp the heritage of the brand with the intent some of it rubs off on the Guitar Center Acoustic brand.

I actually own a GC Acoustic, the B300HD head.

I mainly bought it as an entry into the Class D world and I like it a lot, but the only Acoustic in the thing is the logo; sounds nothing like an ACC era product but I did not expect it to.

I bought it on a great sale, with tax it was $210. I run it into a RevSound RS28V and it sounds great, but not like an actual ACC Acoustic, but that's ok. Did I mention I only paid $210 total for it?

I've said this a number of times before but I believe the GC Acoustic brand is circling the drain. If you look on the GC website, they have hardly any products left, you have not been able to get the Neo cabinets for some time and the B1000HD head is no longer available.

GC came out of bankruptcy in December of 2020 and after that they just seemed to stop stocking much GC Acoustic product. I think they are just drawing down what is left in the warehouse.

I contacted the company about the Neo cabs last Spring and they told me they were no longer available and there were no plans to replace them. That kinda said a lot to me about the future of the brand.

Sheesh Yamaha should buy the rights to the name and come out with a modern line that still gets some of the old ACC vibe.

Analogeezer

 

[Stugilliam]

Thanks but that page is essentially worthless. All it tells people is it all started with the 360 and Jaco played one.

Gee any sentient bass player knows these facts....

It's just meant to pimp the heritage of the brand with the intent some of it rubs off on the Guitar Center Acoustic brand.

I actually own a GC Acoustic, the B300HD head.

I mainly bought it as an entry into the Class D world and I like it a lot, but the only Acoustic in the thing is the logo; sounds nothing like an ACC era product but I did not expect it to.

I bought it on a great sale, with tax it was $210. I run it into a RevSound RS28V and it sounds great, but not like an actual ACC Acoustic, but that's ok. Did I mention I only paid $210 total for it?

I've said this a number of times before but I believe the GC Acoustic brand is circling the drain. If you look on the GC website, they have hardly any products left, you have not been able to get the Neo cabinets for some time and the B1000HD head is no longer available.

GC came out of bankruptcy in December of 2020 and after that they just seemed to stop stocking much GC Acoustic product. I think they are just drawing down what is left in the warehouse.

I contacted the company about the Neo cabs last Spring and they told me they were no longer available and there were no plans to replace them. That kinda said a lot to me about the future of the brand.

Sheesh Yamaha should buy the rights to the name and come out with a modern line that still gets some of the old ACC vibe.

Analogeezer

I know what you mean about a standard transmission, my motorcycle is only kick start and if you do not get the starting procedure just right, your screwed!

 

[Analogeezer]

ACC GEAR STREET PRICING FROM BACK IN THE DAY

Interesting cost data from 1980...

So I was doing my periodic searching around for an Acoustic 402 cab to go with my 220 head, I need to stop doing this because eventually a really nice one will turn up locally and then I will have to buy it LOL

Anyway some guy on Reverb is selling a matched set, a 220 head and TWO 402 cabinets. Strangely enough the cabinets look to be in better shape than the head (one of the EQ sliders is kinda wonky).

Anyway in addition to a lot of nice pictures (people who try and sell **** online and post only one or two iffy pictures annoy me) he included one of the original bill of sale. He states he bought the head and one cabinet, then later bought the second cabinet, so one owner all original.

His bill of sale is from 1980 and totals up to $720 for the pair. You can only see the item price for the cab which was $310. (note the $720 includes a small amount of sales tax, it was the out the door total).

So this means the head in 1980 was about $400 which tracks because I paid $330 for mine in 1978.

People are all freaking out at the moment about inflation because it's not been around in a big way for a couple of decades or more, but man back in the stagflation 1970's inflation was a total bitch. The price of gear went up annually. Looks like this guy paid about 21% more than I did two years earlier and that tracks with 1978 - 1980, inflation was rampant then across all goods.

Oh I have a Music Emporium catalog from 1982 (basically the mail order business of Veneman Music in Rockville) and the 220 head in that catalog ran $446.

So the price of a 220 head went up 35% in four years....think about THAT for a bit.....

Analogeezer

 

[lug]

ACC GEAR STREET PRICING FROM BACK IN THE DAY

Interesting cost data from 1980...

So I was doing my periodic searching around for an Acoustic 402 cab to go with my 220 head, I need to stop doing this because eventually a really nice one will turn up locally and then I will have to buy it LOL

Anyway some guy on Reverb is selling a matched set, a 220 head and TWO 402 cabinets. Strangely enough the cabinets look to be in better shape than the head (one of the EQ sliders is kinda wonky).

Anyway in addition to a lot of nice pictures (people who try and sell **** online and post only one or two iffy pictures annoy me) he included one of the original bill of sale. He states he bought the head and one cabinet, then later bought the second cabinet, so one owner all original.

His bill of sale is from 1980 and totals up to $720 for the pair. You can only see the item price for the cab which was $310. (note the $720 includes a small amount of sales tax, it was the out the door total).

So this means the head in 1980 was about $400 which tracks because I paid $330 for mine in 1978.

People are all freaking out at the moment about inflation because it's not been around in a big way for a couple of decades or more, but man back in the stagflation 1970's inflation was a total bitch. The price of gear went up annually. Looks like this guy paid about 21% more than I did two years earlier and that tracks with 1978 - 1980, inflation was rampant then across all goods.

Oh I have a Music Emporium catalog from 1982 (basically the mail order business of Veneman Music in Rockville) and the 220 head in that catalog ran $446.

So the price of a 220 head went up 35% in four years....think about THAT for a bit.....

Analogeezer

I bought a Ric 4001, Acoustic 220 and a 402 cab in 77 for $700. They were all less than a year old and in mint condition. I don't recall that even being some great deal at the time.