# Gibson Skylark GA-5



## Gibsonfan (Oct 13, 2014)

Happy Thanksgiving to me! In-laws had this in the basement. Did some quick research on line and I think it is from the 50's. I have always heard tube amps produce better sound, I am a beginner/intermediate player consider getting this amp 'tuned up'. Any ideas, input or feedback would be appreciated.


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## Church-Audio (Sep 27, 2014)

Gibsonfan said:


> Happy Thanksgiving to me! In-laws had this in the basement. Did some quick research on line and I think it is from the 50's. I have always heard tube amps produce better sound, I am a beginner/intermediate player consider getting this amp 'tuned up'. Any ideas, input or feedback would be appreciated.


This is a Canadian Gibson amp made for our market or made here. There were a few. These are great amps will need a cap job. And a grounded plug installed but man they are great amps its from the late 1950s early 1960s. I have the Lespaul Jr amp Blackface from the 1950's and its got pretty much the same circuit. Great amp keep it and get it fixed.
Value properly restored about $450 to $550.
Chris


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## nonreverb (Sep 19, 2006)

If you are using the CSA sticker as a guide to where it was made....don't bother. It says made in USA on the chassis. The CSA sticker was added only to show it passed CSA standards.
Many early amps were unaltered that met CSA. It was only later that they got a bit anal where CSA standards were concerned....the obvious example being the JCM800.


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## Church-Audio (Sep 27, 2014)

nonreverb said:


> If you are using the CSA sticker as a guide to where it was made....don't bother. It says made in USA on the chassis. The CSA sticker was added only to show it passed CSA standards.
> Many early amps were unaltered that met CSA. It was only later that they got a bit anal where CSA standards were concerned....the obvious example being the JCM800.


I agree I was wrong I should have seen the Made in USA  The ones made in Canada said made in Canada on them doh


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## jb welder (Sep 14, 2010)

What tubes are in it? There were a few versions. Gibson tended to use more oddball tubes than the more standard types usually seen in Fender or Marshall. Most should still be available, but if this is the version with 6SJ7, good quality tubes can be more difficult to find compared to the 12AX7 version.
This is a very simple low power amp, similar to the Fender Champ. If you have a use for it you should be happy.
Has it been sitting unused for long? If so, it should not be powered up without use of a variac or limiter lamp, which will allow the caps to reform, or at least allow it to be shut down before damage occurs should there be faulty components.


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## Church-Audio (Sep 27, 2014)

Not a big fan of reforming. Any filter cap over 40 years should be replaced. The esr on these things shoots up and they start drawing more current on the power transformer. Taxing that part is not worth the $40 in parts to recap this amp. Well actually more like $70 in parts with the crazy parts prices lately  also any cap that is lower than its stated value might be unstable at higher voltage I have two Sencore cap analyzers that put real working voltage on a cap and test it for leakage but I also check esr. I like low esr caps in the power supplies I replace parts on. Less than 3 ohms is ideal.


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## jb welder (Sep 14, 2010)

I was not necessarily suggesting reforming as an option to re-capping, more so just saying bringing it up slow is the bare minimum if it has sat unused. 
Some folks just have to fire it up before doing surgery, at least with a variac or limiter lamp it's less likely to suffer any catastrophic failure. Plus we don't know if it's original 40 yr. old caps.
So just as a precaution for any amp that has sat long unused.


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## Church-Audio (Sep 27, 2014)

jb welder said:


> I was not necessarily suggesting reforming as an option to re-capping, more so just saying bringing it up slow is the bare minimum if it has sat unused.
> Some folks just have to fire it up before doing surgery, at least with a variac or limiter lamp it's less likely to suffer any catastrophic failure. Plus we don't know if it's original 40 yr. old caps.
> So just as a precaution for any amp that has sat long unused.


I dont even bother on an old amp I just tell the customer it's time to replace caps. I also replace node resistors while I am at it. I know lots of guys that just replace the one bad cap.. Pretty sneaky they want to make sure this customer keeps coming back year after year  that way they always have business. 
And I see half fixed amps all the time. It's better to give te customer a dead quiet amp that has nice new caps in the power supply. I try not to turn amps on with out doing cap jobs in them if they are older than 40 years old. I use a Sencore variac that has an ajustable trip
from 500ma to 5 amps. It has a voltage and current draw meter. So after I am done with service I can make sure it's ok when I power it up.


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## dcole (Oct 8, 2008)

It looks like you have what is known as a Gibson "Two-Tone" Skylark. It is shown here on the Gibson Garage site: http://www.0rigami.com/gg/amps.html#GA-5_Skylark_Two-Tone

Here is my personal addition to this wonderful website: http://www.0rigami.com/gg/amps.html#GA-5_Skylark_White-Panel

The last 6 pictures are mine. I changed the power supply caps and put new tubes into it as well as replaced the speaker. I later found out after selling the amp that there was a loose wire on the voice coil and have since then fixed the original speaker. I fixed the amp up and sold it for $450 so the value listed above sounds appropriate. My Skylark was a nice sounding amp but a different animal then what you have.


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## nonreverb (Sep 19, 2006)

Generally not required as I've found most of the customers bringin' me old amps have attempted to power it up before I get it.....case closed, replace the caps.:smile-new:



jb welder said:


> What tubes are in it? There were a few versions. Gibson tended to use more oddball tubes than the more standard types usually seen in Fender or Marshall. Most should still be available, but if this is the version with 6SJ7, good quality tubes can be more difficult to find compared to the 12AX7 version.
> This is a very simple low power amp, similar to the Fender Champ. If you have a use for it you should be happy.
> Has it been sitting unused for long? If so, it should not be powered up without use of a variac or limiter lamp, which will allow the caps to reform, or at least allow it to be shut down before damage occurs should there be faulty components.


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## Church-Audio (Sep 27, 2014)

My personal fav is the customer that keeps upping the amperage on the old fuse  Until things start smoking I get a few of these every once in a while.


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## jb welder (Sep 14, 2010)

Amprepair said:


> I dont even bother on an old amp I just tell the customer it's time to replace caps.
> ...I try not to turn amps on with out doing cap jobs in them if they are older than 40 years old.





nonreverb said:


> Generally not required as I've found most of the customers bringin' me old amps have attempted to power it up before I get it.....case closed, replace the caps.:smile-new:


Ok, maybe you guys have been real lucky, or I've been unlucky. After the one time I did a recap later to find the PT was breaking down at higher voltages (checked fine on meter), I check the transformers first. At operating voltages and loads. In this case the customer declined the repair as it wasn't worth it for him. So I got to go to the extra work of removing all the new caps.
I don't feel comfortable billing for work if the amp doesn't go out the door working. Others may have different approaches that work for them. If it means I have to disconnect bad caps and clip something in temporarily then I will do that. But I won't do any recapping until I verify the transformers. That requires me firing it up with a variac. 
Works for me, your mileage may vary :smile-new:.


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## Church-Audio (Sep 27, 2014)

jb welder said:


> Ok, maybe you guys have been real lucky, or I've been unlucky. After the one time I did a recap later to find the PT was breaking down at higher voltages (checked fine on meter), I check the transformers first. At operating voltages and loads. In this case the customer declined the repair as it wasn't worth it for him. So I got to go to the extra work of removing all the new caps.
> I don't feel comfortable billing for work if the amp doesn't go out the door working. Others may have different approaches that work for them. If it means I have to disconnect bad caps and clip something in temporarily then I will do that. But I won't do any recapping until I verify the transformers. That requires me firing it up with a variac.
> Works for me, your mileage may vary :smile-new:.


I tell customers with really old amps I cant do anything until I replace the caps. But there may be other damage I cant see until the caps are replaced. If I find more damage and the customer does not want to pay the bill I sell the amp and get my repair price out of it the remainder goes back to the customer. In 20 years this have never happened. But thats how I get around the whole deal with more damage than I or the customer bargained for. I have only had to replace maybe 4 power transformers in 20 years but that maybe just luck. Usually thats the main issue. I use an impedance meter to check transformers cant use an ohm meter wont work. I use a BK PRECISION 879B meter for this task works great for output transformers and power transformers as long as you can figure out what the transformers impedance should be.


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## jb welder (Sep 14, 2010)

You mean inductance meter? I have an LC meter also, and it does help, but like you say, you need some reference numbers. Keeping a notebook of benchmark inductance readings makes for some real good data. I also have a neon bulb tester for detecting shorted turns in a winding. But I still like to see the iron running in real world conditions with real loads. Some winding or insulation faults only show up intermittently with high voltage.
My experience is similar to yours, haven't had to replace a lot of transformers. They are probably the most robust components in an amp, certainly not the first suspects like the internet leads users to believe.
That being said, I haven't seen huge amounts of cap failures either. Usually just dried up and not filtering anymore, causing hum. I've never seen any damage worse than a blown fuse due to cap failure, I can't believe it!
Anyway, I'm more into troubleshooting than restorations. If there's no puzzle involved I'm not really interested. Being semi-retired allows me to cherry-pick that way :smile-new:. If someone asks me to re-cap an amp that is otherwise working fine, I'll send them elsewhere. I've got broken tractors etc. to fix lol.
Now if I was still doing it full time, that would be a different story.


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## WCGill (Mar 27, 2009)

Tractor mechanic eh? Make sure you keep your OPT's and PTO's straight. ;-)


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## Church-Audio (Sep 27, 2014)

Sounds like we are alike for me it's the challenge. Yeah I have a notebook as well one day I will put it all together in an excel file and post it to the Internet might be good for someone. Generally speaking load or no load if you have a shorted winding it will show up with a lower than expected voltage or heat especially when there is no load. Most of the power transformers out there qote unloaded voltages in the spec sheet. Also for most output transformers we already have tons of sources for info as you know. Toroidal transformers can be tricky I had a Hughes and ketones quad statesman give me a real problem I tracked it down to an intermitaint short that would only happen when the transformer got to about 150 degrees f had to use a heat gun to get it to show up. Soon as it got to 150 boom half power! Crazy stuff.


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