Best sounding Fender push pull 6V6 amp?

[M Fowler]

I built the Fender Bassman 5B6 with octal preamp tubes and it has a great tone it it.

I have an updated schematic and data if you choose to go that route as the Fender schematic shows remote face plate.

[Cliff Schecht]

So I talked with the local amp guy and while he didn't have anything on hand as far as amps, he had some transformers that I'm thinking about picking up. The power transformer is a Hammond 272BX which would be perfect for either a dual 6L6 amp or a quad 6V6 amp with 3 or 4 12A*7's in the preamp. The output transformer he had was a Mercury Magnetics FBFVL-0 which I believe is a 4000Ohm CT to 8 Ohm transformer. I can live with more power in an amp which is why I'm really starting to consider the dual 6L6/quad 6V6 option (you could go between the two no problem). If I can work him down on the price of the OT, I may pick up the set. Would there be an advantage to using a MM transformer here? I know they are nice but I'm just not sure it's worth the price.

Perhaps I'll find something more interesting at the Hamfest on Saturday. I'm in no rush to get this amp built so it may be smart for me to wait a while before I splurge on parts..

[FYL]

The FBFVL-0 is 4K3 to 8R. It is supposed to be a repro of the Fender 125A7A, a small core OT, not a great choice if you want something beefy.

[mcrracer]

I built the Fender Bassman 5B6 with octal preamp tubes and it has a great tone it it.

I have an updated schematic and data if you choose to go that route as the Fender schematic shows remote face plate.

I would like to take a look at it. I have been considering a Bassman build just have not decided on what flavor yet.

[David Root]

I have a 62 DeLuxe (6G3) which I put a ceramic ToneTubby in and I think I prefer the reconed original Oxford, the Tone Tubby is a great speaker but I think it's too "modern" for this old warhorse.

I recently bought two pairs of old Altec 417s, all original cones. One is currently "unassigned". Anyone ever tried a 417B in a brown Fender?

Interestingly this circuit has a resistor instead of a choke, but I'm not about to do that mod because other than one dropping resistor and the PS caps it's completely original.

I have heard that the 5G9 Vibrolux is killer too and I could believe it, with the right 6V6s. I use RCA grayglass in my DeLuxe. No headroom but great tone! Maybe if I put JJ 6V6s in it the Tone Tubby would sound better.

[Cliff Schecht]

The FBFVL-0 is 4K3 to 8R. It is supposed to be a repro of the Fender 125A7A, a small core OT, not a great choice if you want something beefy.

Yeah it looked a bit wimpy and I don't like the fact that it restricts me to just an 8 Ohm tap. I do have two unused Stancor A-3851's (30W, 4400CT to 4, 8, 16, 250, 500 taps w/UL tap as well). I wanted to use these in an 807 hifi build but if I can't find a suitable transformer elsewhere I may put on of these to use in a guitar amp. That 272BX is perfect for what I'm trying to do and $60 is about what they go for new (this one is brand new in box) so I'll probably still pick that up.

I think I've mentioned that hamfest a good 10 times now.. Can you tell I'm excited about it? I used to go to them with my dad all the time as a kid, this will be my first time being at one without him .

[orrong65]

My contribution for what its worth -

best sounding fender amp is the 1963 Brownface Vibroverb 6G16, with:

. original Oxford or Jensen 2 x 10" ceramic speakers,
. vintage RCA 1960s blackplate 6L6s,
. vintage 1960s 12AX7s,
. vintage ceramic caps where they were originally intended (CRL, circle D or RMC),
. vintage paper foil caps elsewhere (blue molded, CDE, sprague etc)
. modern electrolytics
. carbon comp resistors (mox on plates if you like)

The tone of this beast is to die for, especially with some good pre-amp tube drive. In this build it sounds like an iron fist in a velvet glove.

The 220k plate resistors on the second pre-amp stage in both channels and the older-style pre-amp coupling into the PI gives this amp an almost unique tone, which is why it is so sought after.

[dave g]

My vote goes for an AA964 princeton with the following tweaks:

Use .01 or .02 power tube couplers rather than .1s
Use a fixed bias PI (Paul C mod)
Use an 18 watt marshall style OT instead of a deluxe style

Or just add one extra preamp tube and build yourself a 6V6 D'Lite...

[Bear]

I have a 62 DeLuxe (6G3) which I put a ceramic ToneTubby in and I think I prefer the reconed original Oxford, the Tone Tubby is a great speaker but I think it's too "modern" for this old warhorse.
[snip]
I have heard that the 5G9 Vibrolux is killer too and I could believe it, with the right 6V6s. I use RCA grayglass in my DeLuxe. No headroom but great tone! Maybe if I put JJ 6V6s in it the Tone Tubby would sound better.

If you've got time to stare, look at schematics for the 6G3 Deluxe, 6G2 Princeton, and 5E11/5F11 Vibrolux. The 6G2 is almost the same as the 5F11 but with a mildly altered trem circuit. Where did the 5F11 trem oscillator go? Pretty much straight into the 6G3. Look at the 5E9 and 5G9 Tremolux, too, and some circuit ideas and continuity get a bit clearer. Also, gives a DIY-er a lot of circuit variations to futz with. That might be a good summer project -- get an experimenter rig together to try all the variants and maybe recombine some more.

[Cliff Schecht]

Thanks for all of the advice guys! I think I'm going to go overboard and build three different Fender style amps. Here's what I'm currently pondering over:

1) 5C3 build using an Arkay A12 build I found (hifi amp). It's already got a Stancor PC8405 PT (540V CT @ 120mA), a C2303 choke (2.5Hy, 100 Ohms @ 130mA) and reusable octal sockets laid out in a very workable fashion. The PT is somewhat low on the HV side so I'm going to use a SS rectifier here to keep the B+ decently high. Not so sure about reusing the choke in this one as I'm thinking it will kill any sag that I could potentially get out of the PT. I'm considering using one of my A3851 transformers so I can throw either 6V6 or 6L6 tubes in the output and add an UL switch. Should be a straightforward build and one that I can finish before the summer.

2) Quad 6V6 amp using an old CB radio chassis I got today at that Hamfest. The chassis was pretty gross inside, complete with a hornets nest and many dead (and a few alive!) spiders but it's not at all rusted and has cleaned up nicely. This will be just a head and it'll also be able to use either 6V6's or 6L6's on the output. I probably won't go octal on this one as I'm thinking this will be a 6G3 style preamp (I want tremolo on an amp damnit!). I will probably use my other A3851 for this build, it's about perfect for what I'm trying to do here. I was saving these OT's for a hifi build but I have enough stereos (but you can never have too many guitar amps ).

3) 5F6A build with 807 output tubes. I miss my Bassman RI, it was loud and proud and sounded pretty darn good with the right tubes. Since I have a lot of 807's and not so many 6L6's, I figure why not. I may not get to this build for a while though as I would need to source transformers and a chassis to complete this build

[Phazor]

orrong65 , You're picture looks like a Brown princeton not a vibroverb. I noticed its only got 2 preamp tubes and a vibroverb has 6.

I have a Brown Vibroverb 1963 and it is my best sounding fender for twang and grit.

Michael

[tubeswell]

So I talked with the local amp guy and while he didn't have anything on hand as far as amps, he had some transformers that I'm thinking about picking up. The power transformer is a Hammond 272BX which would be perfect for either a dual 6L6 amp or a quad 6V6 amp with 3 or 4 12A*7's in the preamp.

The 272BX is rated at 300-0-300 @ 115mA and only has a 3A heater winding and a 2A 5V winding, so it is really only any good for 2 x 6V6s, and 3 or 4 pre-amp tubes (and a 5Y3G or 5AR4 rectifier). I wouldn't run 2 x 6L6s or 4 x 6V6 off that myself.

But could do with the 272FX.

http://www.hammondmfg.com/263.htm

[flood]

I built the Fender Bassman 5B6 with octal preamp tubes and it has a great tone it it.

I have an updated schematic and data if you choose to go that route as the Fender schematic shows remote face plate.

I would like to take a look at it. I have been considering a Bassman build just have not decided on what flavor yet.

i'm building a 5B6 (most likely as a gift for a family friend) using 6SC7s, 6SL7, EZ81 and 6V6. wanted to scale the original down to 25W or less, using an 8k CT output transformer. would be interested in your schematic too.

is there a way i can use a 6L6GC pair under 25W with the 8kCT tranny? my power transformer gives me 275-0-275 at 150mA on the secondary side. heater winding has 5A on tap, so no worries there.

[Cliff Schecht]

I built the Fender Bassman 5B6 with octal preamp tubes and it has a great tone it it.

I have an updated schematic and data if you choose to go that route as the Fender schematic shows remote face plate.

I would like to take a look at it. I have been considering a Bassman build just have not decided on what flavor yet.

i'm building a 5B6 (most likely as a gift for a family friend) using 6SC7s, 6SL7, EZ81 and 6V6. wanted to scale the original down to 25W or less, using an 8k CT output transformer. would be interested in your schematic too.

is there a way i can use a 6L6GC pair under 25W with the 8kCT tranny? my power transformer gives me 275-0-275 at 150mA on the secondary side. heater winding has 5A on tap, so no worries there.

Yup, you can either used fixed bias or cathode bias to do this, you just have to adjust the bias voltage/cathode resistor accordingly.

So I talked with the local amp guy and while he didn't have anything on hand as far as amps, he had some transformers that I'm thinking about picking up. The power transformer is a Hammond 272BX which would be perfect for either a dual 6L6 amp or a quad 6V6 amp with 3 or 4 12A*7's in the preamp.

The 272BX is rated at 300-0-300 @ 115mA and only has a 3A heater winding and a 2A 5V winding, so it is really only any good for 2 x 6V6s, and 3 or 4 pre-amp tubes (and a 5Y3G or 5AR4 rectifier). I wouldn't run 2 x 6L6s or 4 x 6V6 off that myself.

But could do with the 272FX.

http://www.hammondmfg.com/263.htm

Yeah, I realized that pretty quickly. I scrapped an old 50's hifi project build because it was built terribly and I didn't really have a use for it. The transformer in it is 660V CT (don't know the current but it's a fairly hefty unit) with a 5V and 6.3V heater taps. I'm using it in a tweed Deluxe build right now and am making provisions to be able to use either 6V6 or 6L6's in the output. I just finished wiring up the power supply and used it to reform an old Sprague can cap from 1952. I was quite surprised to find the cap leaked only 200uA before reforming! The build is going very well so far, I will post more when I finish it.

[flood]

I would like to take a look at it. I have been considering a Bassman build just have not decided on what flavor yet.

i'm building a 5B6 (most likely as a gift for a family friend) using 6SC7s, 6SL7, EZ81 and 6V6. wanted to scale the original down to 25W or less, using an 8k CT output transformer. would be interested in your schematic too.

is there a way i can use a 6L6GC pair under 25W with the 8kCT tranny? my power transformer gives me 275-0-275 at 150mA on the secondary side. heater winding has 5A on tap, so no worries there.

Yup, you can either used fixed bias or cathode bias to do this, you just have to adjust the bias voltage/cathode resistor accordingly.

thank you cliff! what would, in your opinion, be the maximum power i could get from a pair of 6L6s with about 350V on the plates and an 8k CT?