- Joined
- Jan 15, 2016
- Messages
- 19
- Reaction score
- 2
As a long time lurker, I sought information about 1x12 combos that would be suitable for my regular out of town gig, 1.5 kilomiles north of my usual haunts. Found one and signed up to post about it (and other stuff).
Here's my notes and some pictures:
Mesa Son of the Original Boogie
Arrived 1/16/16 to FedEx Office after trying to get it delivered since 1/14/16
Inspection on arrival:
Non-original snakeskin tolex peeling because glue is not holding. Needs repair or I will strip and recover some time. OK for now.
Non- original plastic corners installed on rear top. One is broken, perhaps due to blow in shipping. Will replace with metal corners.
Checked tubes. All intact.
Mesa branded Celestion MC-90 8 ohm 90W Black Shadow said to be Kurt Mueller 444 recone obtained by seller.
SOB fired up OK.
Pots were a bit scratchy.
Volume 2 (lo input) OK up to 5, but amp started to cut out and get what sounds like blocking distortion with the master up all the way. When vol 2 was dialed below 5, sounded ok, but noisy.
Volume 1 (hi) relies on vol 2 as well. This channel sounded unhealthy. Likely microphonic v1 Sovtek 12AX7wB.
Presence control said to be not working. Noticed it intermittently cut output to zero after above 2 on the knob. Suspect this is no presence...likely Limit control (current limiter at PI).
Initials and names in chassis: Tina near main board, LJ by OT, BA by power supply board
Markings on chassis rim: SOB, JC, J2
Markings on both chassis ends: SOB
Markings on chassis top - between V1 and V2: 12AX7, at V3: 12AT7, between V4 and OT: LJ then J1382
Might this be an early 1982 build?
Serial number stamped by speaker jacks: S404
Tubes look new or low hours.
V1 Sovtek 12AX7wB
V2 Sovtek 12AX7wB
V3 EH branded 12AT7
V4 GT branded GT6L6B Sovtek 5881WXT stamped 98
V5 GT branded GT6L6B Sovtek 5881WXT
Observations from under the hood:
Replaced electrolytic caps in power supply. Cannot see marking of values. Bundle of caps on board proximal to controls replaced with one on board JJ 47M/500VDC and one off board and unsecured multi section radial can supported only by soldered leads near rear of chassis. Not stock. Main filter caps unknown make and specs (clearly electrolytic, though marked PET which I usually see associated with plastic caps...). Two smaller electrolytics on PS board replaced axials with Xicon radials (47M/160VDC?).
Presence (Limit?) has wiper to ground and A (1) to a transistor-like component, likely a diode, marked from top to bottom:
?? TC
?508
8121
Where ? Indicates uncertainty of the making
There is also an unused socket for a transistor with the middle leg disconnected but also possessing a solder ball. Looks like it could have held the Limit diode but currently unused. I heard that this was used but in the chassis shots I have seen, this socket was either absent or not located at this precise point on the board.
Some orange peeling on the Sprague 0.1/400VDC caps on V2.
Sprayed out pots with Deoxit and ran wiper back and forth ten times. Need to chase with CaiLube, but I'm out at the moment.
Sprayed jacks out with Deoxit and plugged/unplugged TS plus ten times.
Sprayed out switches with Deoxit and flippped switches ten times.
Sprayed out tube sockets with Deoxit, waited 2 min, chased with Deoxit Gold, plugged and unplugged tubes ten times.
Cleaned chassis.
Removed knobs from pots and reinstalled so they lined up with the markings except for Master control which was frozen to the the shaft, so I left it alone.
Play testing:
Reinstalled chassis, plugged speaker into 8 ohm jack and turned on power. Tubes lit up OK. After 5 min warm up, flipped standby and started working knobs. Diming the master led to hiss and high pitched hash. Turning up volume 2 added hum. Turning up 1 did not add as much noise and found that using input 1 with volume 1 at 9 o'clock and volume 2 at 3-5 on the dial sounds pretty good for big clean tones (as I prefer). Needed to keep master down to 2 to keep neighbors in my beach condo happy, but turning it above 4 added unwanted noise anyway. Was able to get a gigable volume :twisted: before the neighbors howled in protest :lol: . Need to dial in the EQ, but looks like with humbuckers on my Axis SS rosewood, a setting of 777 for Treble Bass and Mids is OK. More time at volume needed to get the Strat in the ballpark, but shouldn't be tough on the gig. The Limit knob now works, since I lifted the middle leg of the unused transistor socket that was up soldered but contacting the board.
Except for tolex peeling up and the corner being broken, I am satisfied. I will likely replace the corners with metal corners and try to glue down the tolex better before I schlep it up to New England. Will roll tubes to see if I can get the noise down. Will try a excellent NOS 5751 in V1 for sure. Must secure power supply cap that is not mounted to chassis before I gig this!
tldr, right? :lol:
As soon as I get the pictures up in my account, I'll post them here. I want to thank the many of you that provided content that helped me hunt this puppy down and get it sussed out swiftly. I hope the info I posted (and pics to come) will assist somebody else some time. I will also try to help out around here as I can. I have been performing and recording for a few decades, built a couple amps, maintain my amps, and might be able to share a few things that are useful.
DS
Here's my notes and some pictures:
Mesa Son of the Original Boogie
Arrived 1/16/16 to FedEx Office after trying to get it delivered since 1/14/16
Inspection on arrival:
Non-original snakeskin tolex peeling because glue is not holding. Needs repair or I will strip and recover some time. OK for now.
Non- original plastic corners installed on rear top. One is broken, perhaps due to blow in shipping. Will replace with metal corners.
Checked tubes. All intact.
Mesa branded Celestion MC-90 8 ohm 90W Black Shadow said to be Kurt Mueller 444 recone obtained by seller.
SOB fired up OK.
Pots were a bit scratchy.
Volume 2 (lo input) OK up to 5, but amp started to cut out and get what sounds like blocking distortion with the master up all the way. When vol 2 was dialed below 5, sounded ok, but noisy.
Volume 1 (hi) relies on vol 2 as well. This channel sounded unhealthy. Likely microphonic v1 Sovtek 12AX7wB.
Presence control said to be not working. Noticed it intermittently cut output to zero after above 2 on the knob. Suspect this is no presence...likely Limit control (current limiter at PI).
Initials and names in chassis: Tina near main board, LJ by OT, BA by power supply board
Markings on chassis rim: SOB, JC, J2
Markings on both chassis ends: SOB
Markings on chassis top - between V1 and V2: 12AX7, at V3: 12AT7, between V4 and OT: LJ then J1382
Might this be an early 1982 build?
Serial number stamped by speaker jacks: S404
Tubes look new or low hours.
V1 Sovtek 12AX7wB
V2 Sovtek 12AX7wB
V3 EH branded 12AT7
V4 GT branded GT6L6B Sovtek 5881WXT stamped 98
V5 GT branded GT6L6B Sovtek 5881WXT
Observations from under the hood:
Replaced electrolytic caps in power supply. Cannot see marking of values. Bundle of caps on board proximal to controls replaced with one on board JJ 47M/500VDC and one off board and unsecured multi section radial can supported only by soldered leads near rear of chassis. Not stock. Main filter caps unknown make and specs (clearly electrolytic, though marked PET which I usually see associated with plastic caps...). Two smaller electrolytics on PS board replaced axials with Xicon radials (47M/160VDC?).
Presence (Limit?) has wiper to ground and A (1) to a transistor-like component, likely a diode, marked from top to bottom:
?? TC
?508
8121
Where ? Indicates uncertainty of the making
There is also an unused socket for a transistor with the middle leg disconnected but also possessing a solder ball. Looks like it could have held the Limit diode but currently unused. I heard that this was used but in the chassis shots I have seen, this socket was either absent or not located at this precise point on the board.
Some orange peeling on the Sprague 0.1/400VDC caps on V2.
Sprayed out pots with Deoxit and ran wiper back and forth ten times. Need to chase with CaiLube, but I'm out at the moment.
Sprayed jacks out with Deoxit and plugged/unplugged TS plus ten times.
Sprayed out switches with Deoxit and flippped switches ten times.
Sprayed out tube sockets with Deoxit, waited 2 min, chased with Deoxit Gold, plugged and unplugged tubes ten times.
Cleaned chassis.
Removed knobs from pots and reinstalled so they lined up with the markings except for Master control which was frozen to the the shaft, so I left it alone.
Play testing:
Reinstalled chassis, plugged speaker into 8 ohm jack and turned on power. Tubes lit up OK. After 5 min warm up, flipped standby and started working knobs. Diming the master led to hiss and high pitched hash. Turning up volume 2 added hum. Turning up 1 did not add as much noise and found that using input 1 with volume 1 at 9 o'clock and volume 2 at 3-5 on the dial sounds pretty good for big clean tones (as I prefer). Needed to keep master down to 2 to keep neighbors in my beach condo happy, but turning it above 4 added unwanted noise anyway. Was able to get a gigable volume :twisted: before the neighbors howled in protest :lol: . Need to dial in the EQ, but looks like with humbuckers on my Axis SS rosewood, a setting of 777 for Treble Bass and Mids is OK. More time at volume needed to get the Strat in the ballpark, but shouldn't be tough on the gig. The Limit knob now works, since I lifted the middle leg of the unused transistor socket that was up soldered but contacting the board.
Except for tolex peeling up and the corner being broken, I am satisfied. I will likely replace the corners with metal corners and try to glue down the tolex better before I schlep it up to New England. Will roll tubes to see if I can get the noise down. Will try a excellent NOS 5751 in V1 for sure. Must secure power supply cap that is not mounted to chassis before I gig this!
tldr, right? :lol:
As soon as I get the pictures up in my account, I'll post them here. I want to thank the many of you that provided content that helped me hunt this puppy down and get it sussed out swiftly. I hope the info I posted (and pics to come) will assist somebody else some time. I will also try to help out around here as I can. I have been performing and recording for a few decades, built a couple amps, maintain my amps, and might be able to share a few things that are useful.
DS