Projects suitable for a 5k > 16Ω SE output transformer

[eurekaiv]

I picked up a really cool looking but pretty gross sounding series filament combo I'd like to rebuild into something cooler. Basically, I've got a chassis and an output transformer I'd like to use. The transformer is about 2.5k into 8 or 5k into 16Ω. I have a single volume control and 3 inputs. I'd like to keep this one cosmetically original since it's quite attractive so I don't want to add any additional controls. Any suggestions?

[Latole]

We need more information .
Which tubes ? 50C5, 35W4........? Or ......?

I rebuilt some combo what is looking close to yours. Picture is the last one I rebuilt.

Pictures please ; combos , chassis, circuit.

Click on Regal copie 3.pdf  to see  schematic

[eurekaiv]

It had the 50c5 35w4 but I really only need to use the output transformer and front panel controls so this could go anywhere. After doing some reading last night, leaning towards trying a 6AQ5/6X4 (or SS rect) power section and a 2 stage 12AX7 pre but would still love some suggestions for a good schematic, and maybe something a little different than a champ clone since I’ve built a couple of those, to base this off of.

[sluckey]

This may give you some ideas. Schematic at bottom of page...

     http://sluckeyamps.com/smoky/smoky.htm

[Williamblake]

Do you have any 100ohm reverb springs laying about?

[kagliostro]

Other option

https://el34world.com/charts/Schematics/files/Gibson/Gibson_ga_5t_61_skylark.pdf






with a bit less than 200V B+ you will be near the 5K load for the pentode power section

Franco

[eurekaiv]

I played through a friends GA5 years ago and loved it. Any suggestions for a suitable power transformer for a <200V B+? Seems like this won't be common.

[shooter]

just an example, BUT, need SS rectifier as there is no CT, Gibson won't care 


https://www.edcorusa.com/xpwr085

[eurekaiv]

SS rectifier is no problem, and this is priced well, but 6-8 weeks to build like pretty much everything on the Edcor site. 

[kagliostro]

With 200v B+ you will have a bit of mismatch but not impossible to afford


Franco

[shooter]

but 6-8 weeks

   it comes with an American flag sticker
I just place my order, then I'M "committed" to the build, start; schematic, layout, BOM, chassis........and Damn 6weeks later I'm ready for that tranny 

[2deaf]

6AQ5
OT:  5K : 16r  Single Ended
PT:  Hammond 269EX   380VCT @ 75mA   6.3V @ 2.5A
Rectification:  SS
Cathode Resistor:  330r  3W
Cathode Capacitor:  47uF  25V
First Power Supply Dropping Resistor:  2K  0.5W   (Between Plate node and Screen node)

 

[kagliostro]

GA-5 other version (use 6V6 but can be swapped for 6AQ5 with a bit lower B+)

https://el34world.com/charts/Schematics/files/Gibson/Gibson_ga_5.pdf



--

If you can find a 6AK5 (5654) tube .... give a try to Sluckey's suggestion

http://sluckeyamps.com/smoky/smoky.pdf

Franco

[eurekaiv]

So I wrapped up this project so I would like to thank everyone here for the suggestions and share a couple pics.

The amp was a Custom Kraft widowmaker I picked up on eBay for ~$100. Basically, I just really liked the look of it so I wanted to see if I could turn it into something nice. The cabinet and baffle were made from some of the worst particleboard ever so I added a bunch of re-enforcement to the former using some 3/4" trim pieces and built a new plywood baffle to fit the 10" speaker. I still need to make a back. Does anyone know a source for amp covering material similar to the Silvertone 148X series? This is nearly identical, just a bit more brown.

As for the insides, I ended up building a GA-5 schematic (no trem) almost exactly as posted above but with a 6X4 and 6AQ5. The voltages are a bit low with the 6X4 so I re-biased it to create a bit more headroom in the preamp. I added a pull bright switch which bypasses the volume with a 150pf cap for a touch of additional versatility and a little LED with a chrome bezel since there really wasn't room for a proper 6V pilot light. It's not super loud, even full up, but I can get great clean sounds and moderate distortion if I want, and the Celestion Ten 30 I bought for $35 from AES is great. I chose that speaker mainly because the sensitivity rating was the lowest I could find in 10" (and 16Ω) but it's far better than I expected it would be for the money. I wouldn't hesitate recommending this speaker for a small combo project, or a rebuild like I've done here.

[bmccowan]

Very nice. I have good luck matching amp covering at bookbinding supply companies. Most amp companies used materials lighter than Tolex, and the book coverings seem to be about the right gauge with many colors available. Hollander's is a good source: https://hollanders.com/
Online fabric stores are another option.
I have a DanElectro Cadet widowmaker that is just sitting around because it looks cool. I should follow your lead.

[eurekaiv]

Thanks for the suggestion. It seems so obvious now that you mention it but I would have never thought of that! I don't need it to match exactly so I should be able to find something close enough. I mainly just want to give it a finished look and keep hands from being able to find their way into the chassis.

[PRR]

At one point I was looking at high-end "wall paper" for a mid-century cabinet. Really several sorts of cloth and plastic. "Grasscloth" may find the right types of shops.