Fender Deluxe 6G3 Rebuild

[David Root]

I would stay with carbon comp, Allen-Bradley if you can get them, however don't use carbon comps in the power supply as dropping resistors. Use 2W metal oxide power resistors there.

Yesterday I hauled my '62 6G3 and its matching 6G15 reverb unit out of the shipping box they've been in the last two years.

Pulled the 6G3 chassis, tubed it up and checked voltages. B+1, Vp and Vs 40V higher than the schematic! Corrected to 120VAC wall voltage. Pulled the GE 5AR4, replaced it with a RCA 5R4GYB, dropped that by 20V. Now have V1 at 190 Vp vs 165 on the schematic. Sounded much better than with the 5AR4, a little more compression. Vk are all very close to the schematic.

I should add I had previously changed the bias resistor to 27K from 22K as -26V is too hot for '50s RCA grayplate 6V6GTs. Bias is now -35V.

The reverb unit was spot on at 120VAC wall. Sounded great with the amp's tremolo on too! The tremolo on the brown Deluxe is unbelievably good!

[billyz]

So I think i've decided on a few of the parts for this amp.

I've looked into the Sozo Blue Molded caps and they look like they should give me a pretty close approximation to the original sound of this amp. I'll also be using Sprague Atom caps for the power supply.

Now comes a few questions for everyone again.

The original unit used carbon composition resistors, and obviously there is some discussion as to whether or not this has a large effect upon the tone. I'm thinking about going with Carbon or Metal film resistors just to reduce some of the possible hiss issues that carbon comp can have.

The other question revolves around the grill cloth and tolex colors. I've got two ideas as to how I could possibly do this. One is to go for looks and sound for the amp and go with the traditional fender brown and wheat combo. The other option is to go with surf green tolex to give it a unique appearance while still retaining the vintage look. Not sure what grill cloth I would use with surf green.

Opinions?

I would stick with the CC resistors, the reason is they are non Magnetic and usually have plated copper leads. If you go with Metal film use something like a Dale or PRP, Carbon film use Takeman. The cheapies are very magnetic and have steel leads, it does affect the tone. Actually I don't find CC resistors noisy unless they have absorbed moisture. I have had just as many noisy cheap metal films .

The same tan grill would look good with a green tolex , brown grill too or old marshall tan cane. add some gold piping and you are really uptown.

[XgamerGt03]

I have access to a giant supply of AB resistors. If I was going to use metal comp I was going to go with PRP though.

I do agree about the tremolo sounding great, I had the opportunity to play one that was in immaculate condition about a year after getting this amp and loved it.

I'm thinking I really like the idea of surf green. I would either do tan or oxblood grill.

[David Root]

Tan would look better than Oxblood with Surfgreen, IMHO!

[rp]

I should add I had previously changed the bias resistor to 27K from 22K as -26V is too hot for '50s RCA grayplate 6V6GTs. Bias is now -35V.

David, a side note, what is the current draw you like with these tubes? With my old '50s 6V6Gts I usually set amps at 35mA. My Harvard has -26V bias. You think it sounds better cooler? All tubes are different though, I have a set of matched NOS '50s 7408s that need -18V to give 305V @ 35mA in the Harvard. I have to change the dropping resistor to use them.

OP: Definitely NOS CC and I would just use 150s or 6PS just to get started and then down the road as you come across sound old plastic molded ones you can swap them in.

If you restore it 100% inside out you won't have any regrets, or at least you shouldn't, if you make it surf green you might grow tired of it. You might want to save the surf green for a bottom up build - which this practically is, so... yeh... er...what was I saying?

[David Root]

rp, it does depend on how hard or soft the individual tubes are. The tubes that are in my 6G3 now test 31 and 35mA at 400V and -36V on my MaxiMatcher. They are both used RCA, a '51 and a '56, neither are military tubes. Interestingly the '51 has a dark chocolate brown base instead of the ubiquitous black base, only one like it I've seen.

Those 7408s of yours are operating at only 305V plate, I am at 385 plate and screen, 20V above the schematic. Sounds approximately normal for that low voltage. How do you like them at that voltage? 7408s can handle higher voltages, it's a premium 6V6GT.

I have other pairs of 6V6GTs. Tested on the Maximatcher at 400V and -36V bias, a pair of '71 RCA 6V6GTA are 16.4mA each, a pair of '72 Sylvania JAN 6V6GTY are 25mA each, and a pair of '86 JAN Philips are 30 and 34 mA.

I also have a quad of '40s RCA grayplate 6V6GT/G, all military VT107A, at about 25mA each. These are reserved for a build I'm working on now, a four tube version of the classic DeArmond R-25. These are bassier than later production and will be running a bit above 300V most likely.

[XgamerGt03]

David,

From what I'm gathering you have one of these amps. I need to have some face plates made and need to lay them out etc. Do you have any, or could you take, some high resolution or high quality shots of the front and back plates?

Thanks

[David Root]

Xgamer, I do indeed have one, it's a '62. Sure, I'll be happy to take some faceplate/backplate pics and give you the measurements too. May take me a day or two.

These plates are aluminum, and thick by modern standards, I would highly recommend Joe Vallina at amplates.com, I have used his services several times, he is first rate and good to work with. He has a very close '60s Fender look-alike font too.

Attached is a pic of my Bloozman faceplate that shows this font.

[David Root]

Faceplate is 19.75" x 1.75". Backplate is 12.375" x 1.75". See pix. Will try to get better pix on the weekend. Material is aluminum, nominal thickness, 0.058" incl. paint.

[XgamerGt03]

Good Stuff, thanks man. I can start some work on the face plates now. I think I may actually have a guy locally that can do this for me so I'll look into working with him first.

I decided I'm going to do the cab like it was originally.

[XgamerGt03]

So I'm finally picking this project back up. I planned on getting it done over the summer, but life got in the way. I haven't ordered any of the parts for this project yet, but it looks like I might be placing an order sometime in the next week or so.

My next question involves what speaker to use with this amp. It originally had an Oxford, but that was damaged before I ever got the speaker. There was spray paint all over the voice coil/magnet/spider/basket. I've looked into some of the Weber clone speakers but I've also heard about other brands.

I've heard that the Scumback Scumnico or the Celestion Gold sound great in these amps. Does anybody have an opinion on either of these speakers, or an other speaker they suggest I look into for this amp.

[David Root]

If the voicecoil is still good get the Oxford reconed. The early ones are nice speakers, the Oxfarts only happened later on when Oxford opened up the voicecoil tolerances to make them easier to build, and let all that good tone out.

When I got mine the cone was gone but I had it reconed by Orange County Reconers in L.A. Now it sounds great, very like a contemporaneous Jensen.

I've also had both a red Alnico and green ceramic Tone Tubby in it and didn't like either in the amp, especially not the green one.

The 6G3 is a different Deluxe because its preamp stages are high-plate 220K, not low plate 100K like most Fenders of the era.