Well, I finally got back to the Gretsch on Monday and it is now up and working quite nicely.
I took care of the death cap and the owner is fitting a new 3 prong power cord.
I wasn't satisfied with the different voltages on the 6973s and new valves made no real difference, so I went looking and found the problem.
The Output Transformer was wired incorrectly, with B+ wired to one end and the valve wired to the centre tap.
Swapped the wires over and after checking voltages again and swapping one valve for one of the new ones, to get a better match, it is sounding good and the voltages are close enough to what they should be.
What has surprised me is, the caps all appear to be OK, which is good because the owner wanted it to remain original; and very little hum.
A very nice vintage amp is back to working again and sounding like it should.
Thanks for being interested and offering advice and comments.
Cheers, Noel
GRETSCH 1962 6161 COMBO - INFO & ADVICE NEEDED
Moderators: pompeiisneaks, Colossal
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Stevem
- Posts: 5144
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- Location: 1/3rd the way out one of the arms of the Milkyway.
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Re: GRETSCH 1962 6161 COMBO - INFO & ADVICE NEEDED
I can’t understand how someone would not have put the red center tap feed to the OT back to the power supply node.
Anyway tell the owner to play the amp at least twice a week to keep those 59 year old filter caps formed as best as possible !
Gez, some people are so thick headed!!
Anyway tell the owner to play the amp at least twice a week to keep those 59 year old filter caps formed as best as possible !
Gez, some people are so thick headed!!
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: GRETSCH 1962 6161 COMBO - INFO & ADVICE NEEDED
I have to agree with you Stevem.
It is a very basic operation, to wire an OT and a simple exercise to verify that the wires have gone to where they belong.
I told the owner and he told me that he had taken some pix of the the internals when he got the amp and on checking them, the wires were on the same tags then, as shown in my first posted pic.
Once I spotted the 1k screen resistor under the tag strip, I knew it was wrong and traced the anode wires to verify they were correct.
Whoever did that didn't have a clue; just as well it wasn't something that could cause damage or injury.
He has a collection of vintage amps and guitars, which he plays regularly so I think the GRETSCH will get plenty of action, but I'll suggest that to him anyway.
It is a very basic operation, to wire an OT and a simple exercise to verify that the wires have gone to where they belong.
I told the owner and he told me that he had taken some pix of the the internals when he got the amp and on checking them, the wires were on the same tags then, as shown in my first posted pic.
Once I spotted the 1k screen resistor under the tag strip, I knew it was wrong and traced the anode wires to verify they were correct.
Whoever did that didn't have a clue; just as well it wasn't something that could cause damage or injury.
He has a collection of vintage amps and guitars, which he plays regularly so I think the GRETSCH will get plenty of action, but I'll suggest that to him anyway.
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Needs Coffee
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- Joined: Thu Feb 04, 2021 1:56 pm
- Location: Brooklyn, NY
Re: GRETSCH 1962 6161 COMBO - INFO & ADVICE NEEDED
I'm a few days late to this party (because I'm new to the forum) but I felt like chiming in because I restored the identical amp about 15 or 20 years ago.
In my case the owner was me so I didn't have to worry about appealing to someone else's sensibilities. As a matter of course I replaced the power cord with a grounded one, removed the "death" cap and replaced all of the electrolytics in the amp. I also ended up replacing a lot of the signal caps due to leakage. I can appreciate your client's desire to keep the amp original but keeping 60-year-old caps is a little like keeping 60-year-old tires on a vintage automobile. Even if they're fine right now, they're likely to fail soon enough. Regardless, it's what your client wanted so....
Upon completing the restoration my impression of the amp was nothing special. Cosmetically it was a 10 out of 10; just a fantastic looking amplifier. Sonically, it sounded like a lot of other amps from the era. Not bad at all, but not amazing. I think there's a reason those oval speakers don't show up in other guitar amps! I ended up selling it to a local guitar shop owner who had two other versions of the same amp. He didn't gig with them, he just loved the way they looked. I'm not usually into the idea that a vintage amp should be a shelf queen but, in this case, I feel like these particular models are best suited to collectors.
I'm glad your restoration worked out!
In my case the owner was me so I didn't have to worry about appealing to someone else's sensibilities. As a matter of course I replaced the power cord with a grounded one, removed the "death" cap and replaced all of the electrolytics in the amp. I also ended up replacing a lot of the signal caps due to leakage. I can appreciate your client's desire to keep the amp original but keeping 60-year-old caps is a little like keeping 60-year-old tires on a vintage automobile. Even if they're fine right now, they're likely to fail soon enough. Regardless, it's what your client wanted so....
Upon completing the restoration my impression of the amp was nothing special. Cosmetically it was a 10 out of 10; just a fantastic looking amplifier. Sonically, it sounded like a lot of other amps from the era. Not bad at all, but not amazing. I think there's a reason those oval speakers don't show up in other guitar amps! I ended up selling it to a local guitar shop owner who had two other versions of the same amp. He didn't gig with them, he just loved the way they looked. I'm not usually into the idea that a vintage amp should be a shelf queen but, in this case, I feel like these particular models are best suited to collectors.
I'm glad your restoration worked out!
Re: GRETSCH 1962 6161 COMBO - INFO & ADVICE NEEDED
Yeah those oval speakers don't scream quality.
Shocks, either A.C. or D.C., 60V OR 600V, If they occur during the right part of the cardiac cycle (T-wave), will cause Ventricular Fibrillation. If no defibrillator is handy we have an organ donor.
For vocalists that wear guitars, use windscreens on mics. Or better yet play instrumental music.
Shocks, either A.C. or D.C., 60V OR 600V, If they occur during the right part of the cardiac cycle (T-wave), will cause Ventricular Fibrillation. If no defibrillator is handy we have an organ donor.
For vocalists that wear guitars, use windscreens on mics. Or better yet play instrumental music.
Tube junkie that aspires to become a tri-state bidirectional buss driver.
Re: GRETSCH 1962 6161 COMBO - INFO & ADVICE NEEDED
Needs Coffee,
I tend to agree that the sound is OK, but not amazing, but it is what it is; an example of an old original amp from the early days that is working well (until the old caps crap out).
I couldn't convince him to let me make it like new spec., but that's what he wanted.
It sure is a nice looking amp; and he has the original cover as well.
TUBEDUDE,
The oval speakers work OK but Valco/GRETSCH changed to 2x10", on later models, so they must have thought that was a better sound and I would agree.
Shocks are not fun and can be life shortening, which is why I wouldn't work on it until I removed the death cap and grounded the chassis.
The owner is on his way now to pick it up and maybe bring me something else interesting to look at.
I tend to agree that the sound is OK, but not amazing, but it is what it is; an example of an old original amp from the early days that is working well (until the old caps crap out).
I couldn't convince him to let me make it like new spec., but that's what he wanted.
It sure is a nice looking amp; and he has the original cover as well.
TUBEDUDE,
The oval speakers work OK but Valco/GRETSCH changed to 2x10", on later models, so they must have thought that was a better sound and I would agree.
Shocks are not fun and can be life shortening, which is why I wouldn't work on it until I removed the death cap and grounded the chassis.
The owner is on his way now to pick it up and maybe bring me something else interesting to look at.