10 watt 5f2 ideas?

[chrislathan]

I want to design a 10-watt handmade amp to accompany my guitars. Considering a 10-watt that would be between a 5f2 Princeton and the fender pro junior. Same layout, with volume, tone and 2 inputs.

Some will say the low cost of the Pro Junior would negate the marketability, but I have several of the guys that play my guitars that are interested.

I have already started on grill logo and cab ideas, and I've been looking at several schematics. I considered going to 15watts, as the cost involved wouldn't go up a ridiculous amount. But 10 watts is just a number that sticks in my head.

I will start with a blank chassis, and drill/cut to fit whatever needs to be there.

General specs:

10 watts
2 inputs
1 volume
1tone
Power and possibly standby switch
4 and 8 ohm outs
Likely a 10" speaker, but possibly a 12.
Most of my players are blues and classic rock guys, and use minimal pedals.

What circuit(s) would be ideal? Vox? Detuned tweed deluxe?

Open to any and all opinions, and though I'm well-versed in electrical and electronics, I'm new to this branch of the tree.

And... GO!

[eleventeen]

It's not really my type of amp, so my suggestion is not from experience. But a 5F2 Princeton is a single ended 6V6 amp (~~~5 watts) and a Pro-Jr is a push pull 6BQ5 (essentially a 6V6) = ~~15-20 watts.


I kind of like the idea of making a single ended amp using a 6L6 instead of a 6V6. Just tossing out the idea.   

[pompeiisneaks]

The ideas sound good, and shaping tone can be fun, I've got the bug for sure.  The only part I'm unsure of here, is that you're new to building tube amps. 

I think you may want to build a standard amp first, that already exists, and get it working, then try some common mods and tweaks to it as well.  Then you'll start getting ideas about how it all works together.

I've been building amps for a year now and my first attempt at a custom build was a few months back and didn't work so well, even after quite a few builds under my belt. 

There are just so many things about tube amps that are different from other electronics, that it can be weird to wrap your head around them.

As for a small wattage amp, a Fender Champ or Fender Princeton Reverb etc would not be nightmarishly hard as a fairly new build, and can then be tweaked quite a bit with different caps for tone values etc. 

The champ is pretty light, SE amp that I think has about 10 watts no? 

The Princeton I think is about 20.

~Phil

[chrislathan]

I guess I was vague, as usual. Sorry, my brain rarely functions in a linear fashion. I wasn't actually asking about a scratch-built proprietary design.

The only reason I made the "10w 5f2" reference is more in relation to the simplistic approach. A simpler, streamlined circuit. That's why I was asking about the vox and the tweed deluxe.

I am definitely looking at existing amps, mainly due to the resources available here and on the web to answer questions and get good info. The tweed deluxe, possibly with one each of the regular and bright inputs deleted kinda peaks my interest, for the moment

[sluckey]

I'm hoping to add a 10-15w head or combo to my guitar business. Years of cabinet building experience, and I want to build a limited-run amp only available as part of a set with a guitar.

Show us some of your work. Maybe that will give us some ideas about which amp to suggest.

[chrislathan]

If you meant guitars, then I have those pics on my phone in spades..

***EDIT*** I realized after about 15 seconds that you probably didn't mean guitars

[chrislathan]

Amp and cab pics are at home on my desktop, but will get them up too

[tubenit]

I got an idea for you if you're wanting a 10 watt amp.  The HoSo56 using 6BM8 tubes & a 5879 V1 gives about 7-9 watts.  It's a VERY touch sensitive amp and one of the favorites of all I've built.  I played it mic'd with a band for a few yrs and it cut thru the mix great.  I originally built it with reverb but hope to build another one with FX instead.

There are layouts for each of these schematics.

With respect, Tubenit

[sluckey]

I was wanting to see your guitars since your goal is to pair an amp with a guitar. They look good. I think you should build some unique amp that hasn't been "built to death". Something that would have a good sound and command a good price. That HoSo56 would be a good choice. Also, maybe consider the little 10 watt Magnatone M2 that I built last year...

     http://sluckeyamps.com/lil_maggie/lil_maggie.htm

[chrislathan]

[shooter]

here's a sort - kinda 5F2ish amp I built, PSE EL84's, loves pedal, wants to be abused near max, anyway, fwiw

[pompeiisneaks]

I agree with the consensus here, your guitars look great, and very unique, I think they deserve a unique amplifier as a counterpoint. 

:)

~Phil

[dude]

here's a sort - kinda 5F2ish amp I built, PSE EL84's, loves pedal, wants to be abused near max, anyway, fwiw

Two EL84's with separate cathode bias rather than together...? I guess this amp is considered a SE...? And not push/pull...?


That amp looks inviting, what's the B+ and does it have clean sparkling highs along with grit. The gain is the basically a volume with grit added...?

How do you think 6V6's or 6L6's would sound?


al

[pompeiisneaks]

Yup its parallel SE if I'm reading that right.  just splitting the input to both tubes and linking their output to the one side of the transformer. 

Switching power tubes of that kind means changing the output transformer, and you'll get an increased output wattage as well.  As I recall, in P-P, the two EL84's are about 15 watts, the 6v6 are like 22 or 25 watts and the 6L6's are about 30 or is it 40?  just increases your output power, and since the plate impedance changes you need different output transformer.  (They may also like different voltages, I don't know what this specific amp uses per that schematic, but you did ask, and hopefully shooter will have that. )

EDIT: part of why I mentioned P-P output is because I think the output wattage would be less in SE no?  That's something I still haven't wrapped my head around.  I know that SE is way less efficient than P-P, but I don't know if that also correlates to output wattage? 

~Phil

[chrislathan]

i am currently building under the HalfBreed Guitars name. everything i do is a mix of different brands or guitars. taking the best qualities of each.. i want the amp to emulate that, maybe doing a fender type circuit in a gibson-style cabinet or something like that. the black guitar is an esquire tele with the cocked wah wiring. here's a couple more. will post a ton more in hobbies.

[chrislathan]

But back to the original subject. I think whatever I decide will be built in a head-type chassis, with the controls flipped to mount it upside down in a combo cab. I know that would necessitate venting the top of the combo cab, but I have some perforated brass sheet I've been looking for an excuse to use. Spent some time last night looking at Hammond aluminum enclosures on Mouser, and I think there are a few in the $20-ish price range that would offer plenty of room to lay things out with a pleasing aesthetic.

[sluckey]

There are plenty of head style cabs out there that don't have top vents and don't have heat problems either. I've used 4 Hammond aluminum chassis. They are only .04" thick. You can literally hold one in your hands and twist it like a pretzel. I don't use them anymore.

[shooter]

I guess this amp is considered a SE...?

It is, PSE actually, IIRC, B+ is around 260 -280.  I sorta like low power, easy to build, odd.
for sparkle clean, this is my last build, doesn't like to create it's own grit, but has no problem amplifying pedal induced grit.

EDIT:  It's sorta kinda a champish amp, same iron from the 5E3 I believe, only X 2.  The TS is good, but only over a short range, so expect tweaking there.

[chrislathan]

Also, the black guitar is called the Preston (as in Bill S. Preston, Esquire)
Another is called The Logan (Theodore Logan)

If the eventual amp is based off a fender schematic, it shall be called "Apollo Tweed" 

[kagliostro]

Shooter

What about your Le Gourmet ?

http://el34world.com/Forum/index.php?topic=18394.msg187753;topicseen#msg187753



Franco

[tubenit]

Chrislathan,

Very nice guitars!  Thanks for sharing the pictures. 

With respect, Tubenit

[kagliostro]

I apolologize, forgot to say I like your guitars

I like this one a lot 





Franco

[chrislathan]

The back. It started as a solid walnut blank, and I completely hollowed it out before gluing the top .

[chrislathan]

Close up. Also, I posted more pics in "other hobbies"

[chrislathan]

There are plenty of head style cabs out there that don't have top vents and don't have heat problems either. I've used 4 Hammond aluminum chassis. They are only .04" thick. You can literally hold one in your hands and twist it like a pretzel. I don't use them anymore.

Sir Sluckey, the reason I thought venting would be necessary is that if I mount a head-type enclosure upside down, there'd be nowhere for the radiated heat from all the goodies to go except into the wood of the cab. If I did an open-ended chassis, however, it could escape into the cabinet itself, so long as there was internal width in the cab to allow for it

[sean_thornton]

Maybe a "Pushy Croaker"? 2 x 6p1p will give you about 10w, 2 x 6V6 gets you 12 to 14w, 2 x el84 makes 15w. Cathode bias for simplicity, great tone with easy to find tubes. Building one right now with a pair of ecl86's, should make 12 to 15 watts easy. Incorporating a Bitmo single knob tone control (it's not just for EVJ's, it's my favorite single knob tc), master volume between the pentode of the 6U8 and the phase inverter. All the cleans and crunch you will ever need. Very simple to build, great tone, well documented online. Using all russian tubes, Antek toroidal PT, Edcor OT, you could build one for about $150 (that doesn't include the cabinet).

[sluckey]

Sir Sluckey, the reason I thought venting would be necessary is that if I mount a head-type enclosure upside down, there'd be nowhere for the radiated heat from all the goodies to go except into the wood of the cab. If I did an open-ended chassis, however, it could escape into the cabinet itself, so long as there was internal width in the cab to allow for it

Sir chris, there are about a gazillion 10 watt heads with tubes pointing down that don't have top vents.

[Willabe]

And half a gazillion 40w to 80w combo amps with no top vents.

[chrislathan]

I realize that tubes typically do point down. But in a lot of cases, the transformers point forward, toward the driver. I guess I'm reverting back to my car audio days where you didn't mount amplifiers upside down, as the heat radiated back into the chassis/PC board rather than into open air as intended

[tubenit]

 Most Dumble amp heads have NO top vents & tubes and transformers point down.  They are 50-100 watt amps.

With respect, Tubenit

[shooter]

Franco, I was trying to stay close to "fenderish"  Le gourmet is a 1-off, the pa section could be used to get closer to 15W vs 8-10W

[kagliostro]

15W .... I didn't remembered that

Ciao

Franco

[shooter]

nice wood-working!

15W

Franco, I measured 15w clean, 23W near square wave

[kagliostro]

Before or after I want give a try to that circuit with 6Н8С and ГУ50 (I have a few on my stock)

The ГУ50 tube datascheet (Ok not the ГУ50 datasheet, the EL152 datasheet that is the civil version)

say 18W     on 2K load with 300V B+ and 250V G2

Franco

[PRR]

> say 18W     on 2K load with 300V B+ and 250V G2

Probably 30-35W at 800V 8K.

[tubeswell]

...  As I recall, in P-P, the two EL84's are about 15 watts, the 6v6 are like 22 or 25 watts and the 6L6's are about 30 or is it 40?  ...

Depends how you bias the tubes, the strength of the signal going into them, the load resistance, and the size of the output transformer.


e.g.


a PVC30 and PVC50 both use 4 x EL84s in PP.


A PR and DR both use 2 x 6V6s - one puts out about 15W, the other about 22W.

[J Rindt]

FWIW.......i like the sound of The Ampeg M12, and it has Trem.

http://el34world.com/charts/Schematics/files/ampeg/Ampeg_M-12.gif

[kagliostro]

Probably 30-35W at 800V 8K.

I don't know in SE, 18W @ 300V is in SE, at 800V B+ & 300V G2 with 8K load in PP the datasheet say 120W 

Really you think that 30-35W will be reached ?

Franco

attached the EL152 datasheet

[pompeiisneaks]

...  As I recall, in P-P, the two EL84's are about 15 watts, the 6v6 are like 22 or 25 watts and the 6L6's are about 30 or is it 40?  ...

Depends how you bias the tubes, the strength of the signal going into them, the load resistance, and the size of the output transformer.


e.g.


a PVC30 and PVC50 both use 4 x EL84s in PP.


A PR and DR both use 2 x 6V6s - one puts out about 15W, the other about 22W.

Oh ok good to know.  that makes sense too, you can adjust a lot of variables to get different output from a specific tube.  The only other part I wasn't sure of is how to know the SE vs PP type output if all other variables are equal, isn't it something like 50% for SE?

I.e. A 15W el34 PP setup ends out more like 7 watts in SE parallel mode for two tubes?  or am I just way off there :P

~Phil

[PRR]

> Really you think

I mis-read the datasheet.

Use it like 6550. ~~17W out in SE.

[kagliostro]

Thanks PRR

Franco

[tubeswell]

...  As I recall, in P-P, the two EL84's are about 15 watts, the 6v6 are like 22 or 25 watts and the 6L6's are about 30 or is it 40?  ...

Depends how you bias the tubes, the strength of the signal going into them, the load resistance, and the size of the output transformer.


e.g.


a PVC30 and PVC50 both use 4 x EL84s in PP.


A PR and DR both use 2 x 6V6s - one puts out about 15W, the other about 22W.

Oh ok good to know.  that makes sense too, you can adjust a lot of variables to get different output from a specific tube.  The only other part I wasn't sure of is how to know the SE vs PP type output if all other variables are equal, isn't it something like 50% for SE?

I.e. A 15W el34 PP setup ends out more like 7 watts in SE parallel mode for two tubes?  or am I just way off there :P

~Phil

Yes the output power is roughly 0.4 to 0.5 of the total plate dissipation for a centre bias Class A amp with an optimal load resistance and the right sized (air-gapped) OT.


If you put two tubes in parallel, and halve the load resistance, and run a bigger (heavier) OT, you can get more power (but you can get more power still with a P-P Class A/B amp using the same number of output tubes and the same PT - but with a P-P OT). But 2 x the power doesn't equate to 2 x the volume. You will possibly notice a 3dB increase in loudness. To be twice as loud, you need 10 X the power.

[Ed_Chambley]

One of our members Jjasilli posted this schematic a while back when I was considering a 10 watt SE build.  I already had a build close to this so I simply converted it.  You can also find the fender "pawn shop" amp for cheap and you will have the cabinet, transformers, chassis and tubes.

Saw one on Craigslist for $200 the other day.

Anyway, I did convert a Vibro Champ circuit because I really like the tremolo of these.  I added a Mojotone SS loop I got from Ebay and a 1 tube reverb and put it into small head box.  I had to do some messing around with the tone stack and made the first bypass cap 6.8uf to shave some bass where JJ has a 3.3uf.  Added a couple of other things like adjustable NFB, switching bypass caps for V1b to add or remove some gain which also will bypass the tone stack using a .02 coupling cap.  I did use different values in the tone stack, but only for the bass.

This amp turned out really useful and would make a great amp to use to show off your guitars, which look like very nice guitars with some unique ideas.

The amp surprisingly has more headroom than I expected.  I did use a nice Edcor 15 SE transformer which is fairly large.  Initially I used one a little too small and it saturated quickly, but after the OT upgrade I got a nice tight bass and this is also where the headroom came from.

Switching between it and my Princeton Reverb (bone stock) it actually has more punch and clarity.

[shooter]

Franco, IIRC, the KT88 was dissipating about 38W.  Funny, I just got off the phone, that amp is looking for it's 3rd home 

[kagliostro]

 

[chrislathan]

I just dug 8 NIB NOS 9x15" alnico speakers out of the hoard. Would make for a funky but cool layout. Keeping the cab shorter than a 12" round

[chrislathan]

I'm intrigued by the vibro-champ, the hoso56 and the magnetometer. Does anyone have a component layout for the vibro-champ and hoso?

[John]

Should be in Archives of Favorite Topics.