Contemplating a 5b6 build. I'm looking for power, and advice

[KellyBass]

Greetings!,

A country guitar (tele) player approached me recently, and is looking for a custom built amp.

His criteria is: (his words)
50-60 watts...enough to compete with super's
Steel guitar type cleans and a bit of fur when he needs it
Strong low end
A beautiful, warm full bodied tone
Something different. Not the typical Fender tone.
Simplicity!!! Volume and tone knobs

Well, the 5b6 came to mind very quickly. Besides, I can't wait to build one!

I've been researching them quite a bit lately...especially learned a lot reading about Mark's builds. From what I've read, it's fairly critical to build point to point and, in general, not stray too far from Fender's layout...or overall approach. I've ordered Tino's book, and will follow his layout advice.

My main concern is the power. The original spec is for 2 6L6's...cathode biased. How much power can I really expect from this configuration? Would it be wise to consider a 2 KT88 arrangement? If I'm not mistaken, one of Mr. Fowler's builds was a 2 KT88 amp. I can't seem to find any info on how the amp turned out...and was it worth the trouble?

Any other advice would definitely be appreciated!!

Thanks!

[M Fowler]

This is a very good amp in my opinion and from those that own the one's I built.

The Tino version is the way to build it but space the tubes out more there is plenty of space even in a 12 x 8 x 2 chassis. I like the smaller chassis to keep wiring short on PTP basis.

The stock circuit is around 30w not 50w as Little Water Amps states. Go with larger transformers and you can run whatever tube you like, I have run 6550, KT88 and KT120.

I also use the .1 coupling caps but others seem to deviate.

Tonemerc did a large wattage version too.

[M Fowler]

The two 5b6 amps I built using turret board/eyelet board gave me problems but the PTP versions have all been great.

The high powered version your talking about was built using a tone board and after having problems I changed it over to more of a modified Ampeg B15N running two 6LS7's no 6SC7 preamp tube and pair of KT88's it is loud and sounds good. I need to take that one to my bud's guitar shop and get some feed back from others.

Mark

[M Fowler]

Sorry to keep going on and on about the 5b6 but I'm not done with this circuit yet.

I need Martin Manning and others to help with technical aspects for getting the most out of this circuit. Choice of 6SC7 plate resistor and cathode resistor/bypass cap choice. Go to 12AX7 LTP PI. Go with pair of KT88's and plate resistor choices there as well.

80w to 100w iron.

Lots of things to mess with. Change up the tone circuit as well.

[telentubes]

I messed with my 5b6 for months and shelved it. Started out with a board, ended up PTP. Rewired 3 times. Ended up building 2 50 Watt Small Specials instead, which are out of this world.
I would try again, with different iron, and more of Tino's layout, but I got to the point where I couldn't work on the 5b6 any more.
Consider a Small Special.

[M Fowler]

I messed with my 5b6 for months and shelved it. Started out with a board, ended up PTP. Rewired 3 times. Ended up building 2 50 Watt Small Specials instead, which are out of this world.
I would try again, with different iron, and more of Tino's layout, but I got to the point where I couldn't work on the 5b6 any more. Tweeds can also be a bit of a one trick pony in my opinion (sour grapes syndrome).
Consider a Small Special.

Yeah the Small Special is a good amp but totally different animal.

The Tweed Bassman 5b6 is for noodling at home, blues, jazz, country licks but put a pedal board in front of it through 1x12 or 2x12 cabinet and it flat rocks out. Tone shaping is done from the guitar and/or effects pedals. My favorite is EH Soul Food (Klon Clone) with Resonant Pedals Small Hadron Collider (booster).

[ToneMerc]

I worked up an eyelet board layout that worked fine, I believe david root copied my eyelet board layout and had some success as well. The tailing distortion artifact I was chasing was not the amp at all, but my test speaker.

Overall, while it worked and sounded fine it didn't really knock my socks off as a guitar amp. I'm thinking as built stock it would make a better pedal steel or harp amp.

I would like to do another version with maybe a pair of fat bottle 6CA7's and Twin output iron or the octal preamp section followed by a 700/350V MusicMan style power amp section, but it's not on my immediate radar.

TM

[M Fowler]

I worked up an eyelet board layout that worked fine, I believe david root copied my eyelet board layout and had some success as well. The tailing distortion artifact I was chasing was not the amp at all, but my test speaker.

Overall, while it worked and sounded fine it didn't really knock my socks off as a guitar amp. I'm thinking as built stock it would make a better pedal steel or harp amp.

I would like to do another version with maybe a pair of fat bottle 6CA7's and Twin output iron or the octal preamp section followed by a 700/350V MusicMan style power amp section, but it's not on my immediate radar.

TM

If I was heading out the door to a gig I would grab my JCM800 50w combo for sure. But I can't stand having one amp, I enjoy the mellow octal tube tone, or the chime of an EL84 amp and growl of a 4 gain stage Plexi 100w Marshall AFD #39. Good lord I need to build more amps.

[ToneMerc]

Good lord I need to build more amps.

That's my mantra for sure!

TM

[Phil_S]

My 5B6 build worked out great except for the two "extra" holes in the top of the chassis. See it here: http://home.comcast.net/~psymonds/5B6.html
I think I must have got the layout here...thanks to whomever it was, sorry don't remember. The iron is recycled from something else, not sure what, bought used. Ignore the 2nd pic from the bottom...the html is all wrong and makes the OT look like the stack is about 4"! I'm pretty sure I was a bit over $100 for this one, but well under $200. I should keep records. Cab was extra, not shown.

Everyone should have one of these. I think it's pretty loud. Mine is running a pair of Russian 6p3S (6L6 wannabees).

Actually, I plugged it in yesterday and the 2x10 was not liking it with a bunch of bad noise. I think it was too powerful and moved it to the 1x12 Weber Blue Dog (50W) and it behaved fine, but that's the wrong speaker for this amp, IMO. I'll have to see what I can do to ramp up the power handling. I thought that 2x10 was a 50W cab.

[martin manning]

I need Martin Manning and others to help with technical aspects for getting the most out of this circuit. Choice of 6SC7 plate resistor and cathode resistor/bypass cap choice.

Now that you mention it, there is something odd about the values shown in Fender's 5B6 layout. For the voltages shown (300V supply, 160V Plate, 2.1V Cathode), the 250k plate resistor doesn't jive with the 2k5 Rk. If you make it 167k, though, everything falls into place on the 6SC7 plate curves. This suggests that it might actually have been a 180k E24 (10%) resistor in the amp used to fill in the voltages. Curiously, that resistor's value is not listed on the schematic.

[ToneMerc]

I need Martin Manning and others to help with technical aspects for getting the most out of this circuit. Choice of 6SC7 plate resistor and cathode resistor/bypass cap choice.

Now that you mention it, there is something odd about the values shown in Fender's 5B6 layout. For the voltages shown (300V supply, 160V Plate, 2.1V Cathode), the 250k plate resistor doesn't jive with the 2k5 Rk. If you make it 167k, though, everything falls into place on the 6SC7 plate curves. This suggests that it might actually have been a 180k E24 (10%) resistor in the amp used to fill in the voltages.

Martin, my as built matched the stock Fender values with voltages in the 144 range. I swapped the 249K with a 180K and voltages fell right in line at around 162.

https://tubeamparchive.com/viewtopic.php?t=20117




TM

[martin manning]

;^)

[KellyBass]

This is excellent! Mark, I'm glad you found my post!

I really have learned a lot about this circuit by reading about your 5b6 builds. I was feeling a little squeamish about recommending, and then attempting this amp. But seeing such an all star cast discussing it, I'm ready to order some iron!

I fell in love with the sound of this amp the first time I heard some clips. I think Mr. Fullerton may just be right. There's just something about it...

[RWood]

I messed with my 5b6 for months and shelved it. Started out with a board, ended up PTP. Rewired 3 times. Ended up building 2 50 Watt Small Specials instead, which are out of this world.
I would try again, with different iron, and more of Tino's layout, but I got to the point where I couldn't work on the 5b6 any more. Tweeds can also be a bit of a one trick pony in my opinion (sour grapes syndrome).
Consider a Small Special.

After playing bass, guitar, steel, and keys on B-3 patch through 1x15" Weber bass speaker, 1x12 Eminence, and 4x12 Fanes, along with several pedals, I'd say it is definately not a one-trick-pony.
Every different instrument and different cab presented a different response with the only similarity being the octal warmth.