Official Luthiers Forum! :: View topic - What's Happening In YOUR Shop?

I would hope that nothing is going on in my shop, as I am on vacation with family in the wonderful weather of sunny Orlando, Florida. I hope that I find that - upon return tomorrow - the same beings (shop fairys? luthiery gnomes?) that appear to hide parts, tools, and even work on occasion relent and finish up a project or three whilst entertaining my feline shop assistants. I'm expecting disappointment, but you never can tell.

Nice work! Very clean work! For what it is worth, most of my issues had to do with dressing power and signal wiring, with power wiring as far away from the board as possible (mine went along the bottom of the chassis) and two rounds of signal wiring cleanup to shorten connectors to the tubes and jacks, as well as running crossing wires as far away from and at as close to 90 degree crossing angle as possible. The result was a very quite amp, which is a notable accomplishment for a Tweed-era amplifier, given the usual lack of quietude on Fender-built units. And it only consumed a week worth of research and futz-with time! gaah

On your amplifier power-up: do you have a Variac (variable voltage AC power supply), a light-bulb current limited, and a hand-held non-contact thermometer with laser pointing guide available? All were very useful in the Greenridge amplifier build start-ups and troubleshooting process when used as suggesting in Mr. Robinette's excellent guide linked below.

https://robrobinette.com/Tube_Amp_Startup.htm

The troubleshooting gear was of particular use in diagnosing an incorrectly placed jumper on the back side of one of the turret boards (no - not my board...but only because Mr. Robinette had redrawn the amp topography graphic to highlight the back side jumpers before I committed to soldering). Other than a resister warming up to an unreasonably high temperature and revealing the jumper issue, no smoke produced.

Other tools we found useful for amp start-up and troubleshooting were a sine and square wave signal generator, an analog/digital oscilloscope, and a dummy speaker load.

The signal generator was a relatively inexpensive purchase from Amazon, but a local ham radio festival/table sale might be a better source for working US or Canadian-made analog units from the time of automotive tailfins and bee hive hairdos (yes... we still see both in my part of the country, but that could be because all things - even really odd things like mullet haircuts on professional football players - eventually come back into fashion).

While we used a US-made Tektronix two channel digital o-scope picked up from an industrial rebuilder of tech gear, we could have easily used one of the Siglent or Rigol two channel or four channel digital units available new for under $200. The o-scope proved to be very useful in identifying issues with the signal flow through the preamp stages and fine-tuning the negative feedback circuit on the Bassman Micros. Messrs. Stock and Morelli likely made their choice based on country of origin, but if a 'Made in China' sticker is something that does not generate a heightened level of consternation, adequate and inexpensive digital o-scopes made in the land of social credit ratings and knock-off Louis Vuitton handbags are available.

Last, when troubleshooting with the power tube(s) installed, a load of some sort must be placed on the output to the loudspeaker(s) to both get accurate voltages on the tubes and to protect upstream circuitry. The 8 ohm, 200 watt power resistor used as a dummy speaker load was useful in current checks and o-scope troubleshooting of the power side of the amp, although at 3.5 watts output on the Bassman, the potential for damage to the 10" Eminence Cannibis Rex loudspeakers I initially used was minimal (but not so for higher power projects!).

Author:	Hesh [ Thu Nov 11, 2021 6:06 am ]
Post subject:	What's Happening In YOUR Shop?
OMG it's not a guitar....... Hopefully nearing the end of my 1959 15 watt StewMac Tweed amp kit build and it's been a very good time. I think I will be doing another amp with this one is done. As mentioned my initial issue with the speaker fit was completely resolved and then some by StewMac with their legendary Customer Support. Ran into an issue that is my fault that I am resolving now. When I fired this one up I was hoping to have the same result as when I fired up the 1957 Tweed Champ that I built last month, no issues and it worked like a ..... champ the first time. But not so lucky with this one and it's an error on my part. I jumped two eyelets incorrectly with 22 to 23 being 22 to 19 and that smoked a 22K resistor and stunk up the shop. With the help of StewMac's excellent support we found the problem pretty quickly. Without me asking Tommy at StewMac put some new 22K resistors in the mail to me, that's very cool! The real problem was that the incorrect jumper was between the eyelet board and it's backer board and now as you can see I have all the components wired in making removing the boards a nightmare. So I had the idea being one of them there Loofiers.... ya know (attribution to the Padma) of making a tool to get between the boards, hook the jumper and with a little help from the Hakko top side release the SOB and pull one end out so I could get my needle nose on it. Using the Hakko once more the jumper was successfully removed 20 minutes ago. So now when the new resistors are here I can install one of them and start the initial testing from step one again in case I knocked anything loose in the servicing of the amp. I love my tweed Champ and have high hopes for "momma bear" here since I have a 1959 Bassman that is poppa bear and the Champ is baby bear. . Yep Hesh talks to his amps, guitars too. So what's happening in your shops? Pictures encouraged!

Author:	Woodie G [ Thu Nov 11, 2021 7:24 am ]
Post subject:	Re: What's Happening In YOUR Shop?
I would hope that nothing is going on in my shop, as I am on vacation with family in the wonderful weather of sunny Orlando, Florida. I hope that I find that - upon return tomorrow - the same beings (shop fairys? luthiery gnomes?) that appear to hide parts, tools, and even work on occasion relent and finish up a project or three whilst entertaining my feline shop assistants. I'm expecting disappointment, but you never can tell. Nice work! Very clean work! For what it is worth, most of my issues had to do with dressing power and signal wiring, with power wiring as far away from the board as possible (mine went along the bottom of the chassis) and two rounds of signal wiring cleanup to shorten connectors to the tubes and jacks, as well as running crossing wires as far away from and at as close to 90 degree crossing angle as possible. The result was a very quite amp, which is a notable accomplishment for a Tweed-era amplifier, given the usual lack of quietude on Fender-built units. And it only consumed a week worth of research and futz-with time! On your amplifier power-up: do you have a Variac (variable voltage AC power supply), a light-bulb current limited, and a hand-held non-contact thermometer with laser pointing guide available? All were very useful in the Greenridge amplifier build start-ups and troubleshooting process when used as suggesting in Mr. Robinette's excellent guide linked below. https://robrobinette.com/Tube_Amp_Startup.htm The troubleshooting gear was of particular use in diagnosing an incorrectly placed jumper on the back side of one of the turret boards (no - not my board...but only because Mr. Robinette had redrawn the amp topography graphic to highlight the back side jumpers before I committed to soldering). Other than a resister warming up to an unreasonably high temperature and revealing the jumper issue, no smoke produced. Other tools we found useful for amp start-up and troubleshooting were a sine and square wave signal generator, an analog/digital oscilloscope, and a dummy speaker load. The signal generator was a relatively inexpensive purchase from Amazon, but a local ham radio festival/table sale might be a better source for working US or Canadian-made analog units from the time of automotive tailfins and bee hive hairdos (yes... we still see both in my part of the country, but that could be because all things - even really odd things like mullet haircuts on professional football players - eventually come back into fashion). While we used a US-made Tektronix two channel digital o-scope picked up from an industrial rebuilder of tech gear, we could have easily used one of the Siglent or Rigol two channel or four channel digital units available new for under $200. The o-scope proved to be very useful in identifying issues with the signal flow through the preamp stages and fine-tuning the negative feedback circuit on the Bassman Micros. Messrs. Stock and Morelli likely made their choice based on country of origin, but if a 'Made in China' sticker is something that does not generate a heightened level of consternation, adequate and inexpensive digital o-scopes made in the land of social credit ratings and knock-off Louis Vuitton handbags are available. Last, when troubleshooting with the power tube(s) installed, a load of some sort must be placed on the output to the loudspeaker(s) to both get accurate voltages on the tubes and to protect upstream circuitry. The 8 ohm, 200 watt power resistor used as a dummy speaker load was useful in current checks and o-scope troubleshooting of the power side of the amp, although at 3.5 watts output on the Bassman, the potential for damage to the 10" Eminence Cannibis Rex loudspeakers I initially used was minimal (but not so for higher power projects!).

Author:	joshnothing [ Thu Nov 11, 2021 7:31 am ]
Post subject:	Re: What's Happening In YOUR Shop?
Binding today, on the first of a new body shape for me. It’s in the region of an OM-size, a little wider in the lower bout, rounder shoulders. If it sounds good it’s destined to be the shop strummer for customers / courtesy guitar. My tower-style binding jig has served me well for many years but it has its limitations and I’m a little tired of messing with the body carriage, of swapping bearings and of sometimes not having exactly the size of bearing I need for an oddball purfling or binding… on my next guitar it may be time to try the other style of binding jig.

Author:	johnparchem [ Thu Nov 11, 2021 8:07 am ]
Post subject:	Re: What's Happening In YOUR Shop?
Finishing up a canarywood/spruce concert ukulele. A lot more shell (Paua Abalone) than I normally use. I am making it for a friend who loves it. I need to drill for the tuners (waiting for them to arrive) and prep for finish. I will spray post cat Royal Lac. Also my bridge needs string holes.

Author:	Hesh [ Thu Nov 11, 2021 9:18 am ]
Post subject:	Re: What's Happening In YOUR Shop?
Woodie G wrote: I would hope that nothing is going on in my shop, as I am on vacation with family in the wonderful weather of sunny Orlando, Florida. I hope that I find that - upon return tomorrow - the same beings (shop fairys? luthiery gnomes?) that appear to hide parts, tools, and even work on occasion relent and finish up a project or three whilst entertaining my feline shop assistants. I'm expecting disappointment, but you never can tell. Nice work! Very clean work! For what it is worth, most of my issues had to do with dressing power and signal wiring, with power wiring as far away from the board as possible (mine went along the bottom of the chassis) and two rounds of signal wiring cleanup to shorten connectors to the tubes and jacks, as well as running crossing wires as far away from and at as close to 90 degree crossing angle as possible. The result was a very quite amp, which is a notable accomplishment for a Tweed-era amplifier, given the usual lack of quietude on Fender-built units. And it only consumed a week worth of research and futz-with time! On your amplifier power-up: do you have a Variac (variable voltage AC power supply), a light-bulb current limited, and a hand-held non-contact thermometer with laser pointing guide available? All were very useful in the Greenridge amplifier build start-ups and troubleshooting process when used as suggesting in Mr. Robinette's excellent guide linked below. https://robrobinette.com/Tube_Amp_Startup.htm The troubleshooting gear was of particular use in diagnosing an incorrectly placed jumper on the back side of one of the turret boards (no - not my board...but only because Mr. Robinette had redrawn the amp topography graphic to highlight the back side jumpers before I committed to soldering). Other than a resister warming up to an unreasonably high temperature and revealing the jumper issue, no smoke produced. Other tools we found useful for amp start-up and troubleshooting were a sine and square wave signal generator, an analog/digital oscilloscope, and a dummy speaker load. The signal generator was a relatively inexpensive purchase from Amazon, but a local ham radio festival/table sale might be a better source for working US or Canadian-made analog units from the time of automotive tailfins and bee hive hairdos (yes... we still see both in my part of the country, but that could be because all things - even really odd things like mullet haircuts on professional football players - eventually come back into fashion). While we used a US-made Tektronix two channel digital o-scope picked up from an industrial rebuilder of tech gear, we could have easily used one of the Siglent or Rigol two channel or four channel digital units available new for under $200. The o-scope proved to be very useful in identifying issues with the signal flow through the preamp stages and fine-tuning the negative feedback circuit on the Bassman Micros. Messrs. Stock and Morelli likely made their choice based on country of origin, but if a 'Made in China' sticker is something that does not generate a heightened level of consternation, adequate and inexpensive digital o-scopes made in the land of social credit ratings and knock-off Louis Vuitton handbags are available. Last, when troubleshooting with the power tube(s) installed, a load of some sort must be placed on the output to the loudspeaker(s) to both get accurate voltages on the tubes and to protect upstream circuitry. The 8 ohm, 200 watt power resistor used as a dummy speaker load was useful in current checks and o-scope troubleshooting of the power side of the amp, although at 3.5 watts output on the Bassman, the potential for damage to the 10" Eminence Cannibis Rex loudspeakers I initially used was minimal (but not so for higher power projects!). Many thanks Woodie for this it's great, lots for me to unpack and learn from. I only used so far a cheap multi-meter but Dave wanted to take the FLIR camera we have at the shop home to look for anything glowing when it shouldn't be. He uses it for wildlife searches for his photography. I'm finding this to be a great deal of fun so there may be another amp project in my future and maybe I can utilize some of the things you mentioned. Thanks again Woodie.

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What's Happening In YOUR Shop? http://w-ww.luthiersforum.com/forum/viewtopic.php?f=10101&t=54532	Page 1 of 4

Author:	Chris Pile [ Thu Nov 11, 2021 9:25 am ]
Post subject:	Re: What's Happening In YOUR Shop?
Finishing up a new bone nut on a Les Paul I just refretted for one of my oldest clients (not in age, but in years with me).

Author:	banjopicks [ Thu Nov 11, 2021 9:41 am ]
Post subject:	Re: What's Happening In YOUR Shop?
Chris Pile wrote: Finishing up a new bone nut on a Les Paul I just refretted for one of my oldest clients (not in age, but in years with me). No pictures? I'm not sure I believe you.

Author:	Colin North [ Thu Nov 11, 2021 12:40 pm ]
Post subject:	Re: What's Happening In YOUR Shop?
Made a pattern for a "new" model. Married up a Gibson Advanced Jumbo lower bout, a Martin 000 upper bout, and a Kinkade OM waist. Also tested out a vacuum pump/system (for laminated sides) by laminating some bracing stock. My out of date fire extinguisher came in handy for a vacuum reservoir.

Author:	meddlingfool [ Thu Nov 11, 2021 1:13 pm ]
Post subject:	Re: What's Happening In YOUR Shop?
Hesh... How much money do you save buying a kit vs just buying the amp?

Author:	Michaeldc [ Thu Nov 11, 2021 1:44 pm ]
Post subject:	Re: What's Happening In YOUR Shop?
Roughing in another neck -

Author:	Chris Pile [ Thu Nov 11, 2021 2:03 pm ]
Post subject:	Re: What's Happening In YOUR Shop?
Quote: No pictures? I'm not sure I believe you. When it's done, grasshopper.

Author:	Dave m2 [ Thu Nov 11, 2021 2:46 pm ]
Post subject:	Re: What's Happening In YOUR Shop?
Thought I would try something completely different. A flat (well actually domed) top mandolin. Gosh they are so small! Still not sure how to get the geometry right but it goes pretty quickly compared to a guitar. Dave

Author:	Ken Nagy [ Thu Nov 11, 2021 3:03 pm ]
Post subject:	Re: What's Happening In YOUR Shop?
I started a cello 7 years ago, and messed up the back stock sawing the wedge in two. Now I have a 12" ryoba that would take care of that. I tried to save it, and it was just too low. I bought a large slab a couple years ago to make a new back, and made my arch top with it instead. A month or so ago I looked at what was left of the slab, and got it to work. It has some "scars" from some bark that was on the outside; but it should work. The back doesn't have much of the recurve done yet. I drew it up from a photo on a small calendar photo of a cello and a violin by Gagliano. I liked it. For some reason I decided to make the ribs tapered for a smaller back to make it more comfortable to play. I don't play. The angled ribs were a cinch to bend. They are thin because a plan I have of another cello has them thin. We'll see. I'm ready to cut the f holes now. All the layers of the form SHOULD come out from the top, even after gluing the back on. That's the plan anyway. Attachment: IMG_0628.jpg Attachment: IMG_0629.jpg Attachment: IMG_0630.jpg

Author:	banjopicks [ Thu Nov 11, 2021 4:07 pm ]
Post subject:	Re: What's Happening In YOUR Shop?
Now I want to build a cello.

Author:	Brad Goodman [ Thu Nov 11, 2021 7:40 pm ]
Post subject:	What's Happening In YOUR Shop?
Lots going on here now that I’m “retired” Three bodies complete long scale Stella, J -200, Brazilian Rosewood Dreadnought… Boats assembled And tops madefor 12 string dreadnought, sycamore J 45, 2 Stella Parlors Closing the box on a presentation great Cuban mahogany/mother of pearl 0 size Rebuilding three antique 1930s guitars all neck resets in process Sent from my iPhone using Tapatalko

Author:	dzsmith [ Thu Nov 11, 2021 10:01 pm ]
Post subject:	Re: What's Happening In YOUR Shop?
Finished one for my youngest son. African Mahogany and Pau Ferro. Pre-catalyzed nitro lacquer - this stuff was ready to buff in two days. String-through body for good strumming. Dimarzio Air Norton and Tone Zone. These sound amazing.

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Author:	StevenWheeler [ Thu Nov 11, 2021 6:58 pm ]
Post subject:	Re: What's Happening In YOUR Shop?
meddlingfool wrote: Hesh... How much money do you save buying a kit vs just buying the amp?

Author:	joshnothing [ Thu Nov 11, 2021 7:02 pm ]
Post subject:	Re: What's Happening In YOUR Shop?
Looking good, Ken

Author:	jfmckenna [ Thu Nov 11, 2021 7:22 pm ]
Post subject:	Re: What's Happening In YOUR Shop?
meddlingfool wrote: Hesh... How much money do you save buying a kit vs just buying the amp? Can't speak for Hesh but I built an 18 Watt Marshal clone from a kit that cost $750 bucks. Then I had my amp tech look it over and I think he charged me $50 so lets say $800. A Marshall 18 watt goes for $3500. So it's pretty significant. And the clone amp has a more useful circuitry with the TMB design. The only question is how well can an amateur build an amp? Probably not as good as the techs at Marshall or Fender but if it works it works too and it's probably always a good idea to pay a bit extra to have a pro amp tech look it over. Mine is a friend so he charges me great prices but even so it only adds a bit more to the build to bring it up to a pro level. So in the end, most who build amps from kits probably don't do it to save money but it can.

Author:	Clay S. [ Thu Nov 11, 2021 7:25 pm ]
Post subject:	Re: What's Happening In YOUR Shop?
Not much instrument wise lately, but I did make a spoke for an old wool wheel and reassemble the wheel for mein Frau.

Author:	DennisK [ Thu Nov 11, 2021 9:50 pm ]
Post subject:	Re: What's Happening In YOUR Shop?
That reminds me, my first ever instrument project 13 years ago was a violin, and I still haven't finished it. Sure will be easier with my skills now than it was back then Perhaps I'll add that to my agenda for this building season. Still waiting for the big humidity drop, but it should happen within the next week or two. For the moment I'm finalizing the design of a robot arm 3D printer (which itself is made largely of 3D printed parts) before posting all the files and instructions for anyone who wants to replicate it. Built in my typical style, minimizing space consumption above all other concerns Most printers have a frame which surrounds the bed, but this one is just a 2x4 with a couple of SBR12 rails screwed to it, with hinged bed so it can fold down when not in use. Particularly beneficial when built super tall, as is the case with mine (3.5ft print height) Attachment: v2.jpg Attachment: SpoolHolder.jpg

Author:	Chris Pile [ Thu Nov 11, 2021 11:14 pm ]
Post subject:	Re: What's Happening In YOUR Shop?
Okay, Hesh - feast your eyes. It's not perfect, but it's well done. 12 year old Les Paul. I removed the nibs, planed the fingerboard (2 humps), and installed old school Gibson "school bus" frets - low and wide. This client has been with me since 1979 (he was 14). https://i.imgur.com/jVpjBMR.jpg https://i.imgur.com/otbTCFn.jpg https://i.imgur.com/jlCYaj1.jpg https://i.imgur.com/UYStjNW.jpg https://i.imgur.com/kuqo07T.jpg https://i.imgur.com/VNJcWbX.jpg

Author:	Terence Kennedy [ Thu Nov 11, 2021 11:37 pm ]
Post subject:	Re: What's Happening In YOUR Shop?
My life dream fulfilled. One of these came in the shop and I have a chance to discover it’s magic. 9F63576C-7BD2-430C-BED2-562BDA7C3084 by Terence Kennedy, on Flickr

Author:	Chris Pile [ Fri Nov 12, 2021 12:40 am ]
Post subject:	Re: What's Happening In YOUR Shop?
YE GODS. A plywood nightmare.

Author:	Hesh [ Fri Nov 12, 2021 3:57 am ]
Post subject:	Re: What's Happening In YOUR Shop?
meddlingfool wrote: Hesh... How much money do you save buying a kit vs just buying the amp? I dunno I never looked at that before. I'm building amps for fun so savings is not on my mind. I want to do another one but I certainly don't need any more amps. Maybe do one for the shop. There is a site, Mojotone.com that some of their kits can be purchased assembled. That would be a good place to look for the difference between the kit price and the assembled price.