5F2-A Super SE

[chrislathan]

i was scouring the sch files index page, and found this:

http://el34world.com/charts/SchFiles/5F2A_Super_SE_V1.sch

has anyone built/had experience with this circuit?the schematic calls for a 125gse OT, and the majority (possibly outdated) of the info I've found says that this won't live long with 2 6l6 tubes

[shooter]

I built something very similar, called it "copperhead" was built on a power company, sub-station buss-bar.  solid, lightning annealed, copper!  the guitar guys liked it, went into their world, I was new at the game so my PT was under-sized and smoked after switching from 6V6 to 6L6, got re-built by someone else and far as I know still being used.  Hook it up to a 4X12 cab with 100+ spl's and you'll think it was a 30Watter.  look up Gibson GA-8SE, that where I stole/plagiarized my design from.

trem was weak, but it interacted with the signal in ways the players liked.

[Willabe]

A problem with SE amps compared with PP amps is the OT, size, weight and there for more $$.

Lets say you can get a full ~10W's out of each 6L6GB/GC with that SE amp, so a total of ~20w's.

Now you can get ~22w's out of a pair of 6V6's in PP, Fender Deluxe Reverb. BUT, the DR OT will be much smaller than the OT for the 2x6L6GB/GC SE amp.

Also you probably will need an extra stage of B+ filtering before the OT B+ node. SE amps output stage doesn't have the built in noise canceling that a PP amp has. So you have to add another filter cap then either a choke or a R before the stock B+ 1st filter node. Not a big deal if you plan for it and have the space.

[chrislathan]

I was actually looking at something more in the 10-12watt range. Just saw it in the schematic files, and thought that the circuit looks similar to the regular 5f2. Upon closer inspection, there are some differences of course, but it didn't look like too challenging a build

[shooter]

You should fall right in at 10-12W at speaker.  I like the dual volume feature, never done that but might steal it

[chrislathan]

how would a harvard 5f10 or 6g10 stack up for what i'm looking for?

could use a 5f2 chassis, simple layout..

[Willabe]

You should print out ALL the SE (single ended, ONLY 1 power tube) Fender Champ, Vibro Champ, Princeton and Harvard amps schematics and spend some time comparing them with each other. That will help you decide what you want to build.

They are very similar, most of the main differences are no tone control, single tone control, 2 knob tone stack, vibrato, different value B+ dcv dropping R's, choke/no choke and I think that 1 Harvard 6G10 had a 10" speaker where all the others had an 8"?

1. None of them sound drastically different from each other.

2. At the heart of them ALL is still a single cascaded 12AX7 (the later 1's, early 1's had an octal preamp tube) going into a single cathode bias 6V6 with a 5Y3 rectifier tube.   

The 5F10 is a PP (push/pull 2 x 6V6 amp) different animal. I think it would be pretty/very difficult to get that in a 5F2A chassis as it has 2 extra tubes. I'm wiring up a 5F2A and that chassis is tight. If it were a blank chassis that you could move the placement of the tube sockets then maybe it would work.       

[chrislathan]

I'll likely do them with a blank chassis, as I want a same/similar layout for both head and combo versions, albeit with inverted and reversed control panels. I meant I could build the first in the Princeton 5f2 chassis I already have if I went with the 6g10

[Willabe]

Ok, but;

1. Why a 6G10 instead of a 5F2A? What's the difference?

2. Why a combo and a head?

[sluckey]

The only difference between the 6G10 and the 5F2A is the speaker. Harvard has 10", Princeton has 8".

The 5F10 Harvard is a fixed bias PP amp.

[Willabe]

I was actually looking at something more in the 10-12watt range.

Why? (I'm not trying to be rude.)

There's not a lot of perceived difference to the human ear between a 5w/10w/12w/15w amp through the same speaker(s). Looking at wattage output #'s on a schematic and/or reading post's online is different than actually hearing it for your self.

A plain old regular Champ (and it's brothers, Vibro Champ, Princeton 5F2A.....) will give ~5w/~6w, get a SE 10w OT for a 6L6GB/GC and ~8w/~10w, get a SE 15w OT for a 6550/KT88 and a PT with enough B+ current/ heater current, get ~12w/~15w. (Hammond, Allen Amps and others sell the OT/Pt's for the larger w SE amps.) BUT those OT's and PT will cost more. Or you could build a Princeton reverb and get ~15w 2 x 6V6's in PP.

SE amps do sound/feel different than PP amps. It's not always just about ouput volume. Some guys really don't like SE amps, some love them.   

I've been running my Champ/Princeton 5F2A that's on my BB (bread board) through a WGS 15" speaker and it's pretty loud for a 5w/6w amp when compared to a Champ 8" speaker. Way louder, fuller, with much more bass bottom end and mids.     

Edit;  ^^^^ I should say that it's STILL a Champ, no magic power increase in clean volume.  But any speaker change from the little 8" stock Fender speaker will be noticeable. And going to a single 15" is a pretty extreme up grade with a Champ.        

[chrislathan]

6g10 is a 10watt amplifier, based off the 5f2a with different transformers. Only time fender ever paired the two together.

I just want to be able to do either a combo or head based on demand, in response to the question of why.

I'm really sorry if I am annoying you guys with my questions. Just trying to sort things out

[Willabe]

The only difference between the 6G10 and the 5F2A is the speaker. Harvard has 10", Princeton has 8".

The 5F10 Harvard is a fixed bias PP amp.

I know that, I posted that a few post's back. 

(I'm trying to get him to think this through by studying the schematics for the similarities/differences of them.) 
 

[sluckey]

I know that, I posted that a few post's back.

I was saying that for Chris' benefit. I should have said the schematics are the same. The Harvard boasts 10 watts compared to the Princeton's 4.5 watts. The different transformers may mean that a Harvard PT won't fit the cutout for a Princeton chassis.

[Willabe]

6g10 is a 10watt amplifier, based off the 5f2a with different transformers. Only time fender ever paired the two together.

Where did you read that, have a link? Can't be 10w with a SE 6V6. Fender probably just changed the name because of the 10" speaker change. 

I'm really sorry if I am annoying you guys with my questions. Just trying to sort things out.

We're trying to help you sort it out. 

If you print out the Champ family schemos and study then you will see that their very much the same as I posted above.

I was actually looking at something more in the 10-12watt range.

You still haven't answered this. You can build any size amp you want/need but it would help us to know the reason(s) your looking for ~10w/~12w's, see questions 1/2/3 below.

Questions to ask yourself to narrow down your choices;

1. Power.

2. Do you need/want a clean or distorted sounding amp? (No matter what you do with a SE Champ type amp there's only so much clean volume you will ever get out of it.)

3.Where will you be using the amp? Home, practice, at a gig?
 
(1/2/3 As I said above not much difference between ~5 to~15w to the human ear. But a 15w amp will give you a little more clean volume before a 5w amp. Speakers apply to this also.)

3. Do you like the sound of a SE amp?

4. What's your budget? (If you like the SE sound will your budget allow for a larger OT?)

5. Do you need tone control(s)?

6. Do you need vibrato?

(It's really tremolo and not vibrato as Fender called it and it's arguably not Fenders best sounding tremolo but not their worst. It will cost you 1 more 12AX7 tube and socket and chassis space for them plus the components cost and space on the eyelet/turret board and in the chassis.)

[chrislathan]

http://ampwares.com/amplifiers/fender-harvard/

I looked up 6g10 Harvard specifications, and everything says 10w. I understand that the 5f10 would be a more likely reason to cause the Harvard name to carry that designation.

I want you guys to believe me when I say I really do appreciate your input. At the OBGYN now (38weeks+ currently). will reply to your queries at length later

[shooter]

and everything says 10w

I have this discussion regularly with musicians, I usually give up n say; "yup that 6V6 is dissipating 10 to 12W"  and they seem to be happy then
That said, if you want a 5F2 at 10W audio, design for PSE, kt88, 6550.

so you doing the delivering or receiving?

[chrislathan]

Our first baby is due 12/1. So receiving 

[Willabe]

Our first baby is due 12/1. So receiving 

Hey, that's great!                     

[Willabe]

http://ampwares.com/amplifiers/fender-harvard/

I looked up 6g10 Harvard specifications, and everything says 10w.

On the link they have the 2 amps listed together as both 10w but they should be listed separately. They are different animals.   

[chrislathan]

Got it.

To answer a couple of the earlier questions.

Power: the reason why "10-12 watts" sticks out to me is that there are a ton of 5w champ/ga5/VJR variants
Readily and cheaply available. The same is somewhat true for mass-produced 15 watters. And as Sluckey' stated in a parallel post, it would be nice to build something as a counterpart for my guitars that hadn't been "built to death".

Enter the 10w amp.. Sluckey's Lil Maggie is a cool build, and there is a nice perceived jump in "value"(cash) by the fact that "twice the output power for a bit more money" is easy for someone to wrap their head around.

I know there are plenty of tried and true 15w designs out there. But the guys that play my guitars are typically not the "just another guy playing a Strat at the Thursday blues jam" type. They love their gear, they love talking gear etc, but they love most the questions the guitars and gear provoke. And they are the ones I was "polling" to get ideas.

As far as use goes, practice, and mic-d at gigs as well as home use.

[PRR]

6G10 Harvard is not 10 Watts clean audio output.

I think this point has been made here, but I gotta prove it to myself.

20V in 470r is 42.5mA cathode current. Foo on screen current. 350V on plate, 20V on cathode, 330V across tube. 14W Pdiss. The Absolute Best sine output is 50%, 7 Watts. Real tubes, well-loaded, lucky to get 40%, 5.6 Watts.

Champ to this Harvard, it's like my Odyssey minivan. Accord sedan guts in a bigger body. A bigger body, or a bigger speaker and cabinet, does haul better. And sells at a higher price.

5F10 is TWO 6V6, a very different beast. Right away twice the potential power. More because push-pull distorts less, you can push further. I'd guess well over 10 Watts. 14W easily, depending on loading.

> They are different animals.

Fender Field Guide is a massive work, so not a shock that errors of cross-reference snuck in.

[VMS]

From the clips I've heard I like the way these gibson ga-8 amps sound:


Single-end:


http://el34world.com/charts/Schematics/files/gibson/Gibson_GA-8_6V6.pdf


Push-pull:


http://el34world.com/charts/Schematics/files/gibson/Gibson_GA-8T.pdf