Tweed Bassman 5b6 50w head started

[rp]

Waiting for a full report, especially about the fixed bias. I was thinking of doing a fixed/cathode switch to not waste the 50V tap on the planned Hammond. Also thinking about using a 5AR4 (and using a 650V PT) as I'm not sure I want an other soft early '50s tweed clone. Was thinking of using it as a home bass head w/ an old EMC Jensen 15", could be real sweet, round sounding like an early B15. Mark, have you tried a 5AR4 in either your old or the new one?

So, really curious if fixed bias and the 5AR4 might ruin the original mojo?

BTW nice layout, I like yours here much better than TZ ptp one. Nice and tight, the ptp prolly has more wiring than your board

[M Fowler]

I did try a 5AR4 in the cage amp 5b6 but went back to using the 5U4 which added that nice sag. The octal preamp tubes have this sweet compression about them.

An original 5b6 is eyelet board so I figured I would go that route rather then PTP and the real reason was I wanted the tubes on the back rail so they can cool better and easier to replace.

Fixed bias will probably result in trying different value bias resistor pairs such as 270k, 250k, or 220k, etc.

I have no idea what the tone is going to be like but I have seen a few builders are using SS recto with KT88 power tubes and the tone is fantastic so I figure it has to be the octal preamp that is providing the tone people are liking. There are other circuits I want to try that use 6SL7 or 6SN7 tubes.

[M Fowler]

A little more work done on the amp.

[telentubes]

Lookin' good!

[Toppscore]

Hi! Looks like a cool project.

Question: Why 50w instead of 25w-30w?

Will your amp sound like a 1952-1954 5B6? Just amplified louder?
Will it lose that 5B6 "charm" ~ tone?

Just wondering. Thanks.

[M Fowler]

Thanks guys.

I'm building a 50w because steel players want more wattage and I don't know what affect the changes will have on the 5b6 original tone.

After this one I'm going 70w with KT88's and if no one wants them I'm done trying to satisfy musicians

I know what I like and I'm beginning to understand that only I count.

Mark

[Toppscore]

Thanks guys.

I'm building a 50w because steel players want more wattage and I don't know what affect the changes will have on the 5b6 original tone.

After this one I'm going 70w with KT88's and if no one wants them I'm done trying to satisfy musicians

I know what I like and I'm beginning to understand that only I count. Mark

Haha! If others like your product(s), then there's potential
boutique amp shoppe in your future

[telentubes]

Any more progress on this one?

[M Fowler]

Nope I've been busy with family and only work on amps on my good days

[M Fowler]

Almost finished need to connect line out and put into cab.

Played it some tonight but babies sleeping so tomorrow is the work out.

[rp]

Are you talking about the KT88 one? If so please talk more. Seeing the two nice cabs obviously you are having success w/ this and enjoying the sound as must be the clients. This quote from a old post by Lefty still has me going:

The 5b6 was the one that George Fullerton called "possibly the greatest guitar amp we ever made."

Still, I can't imaging what steel players get form it, especially the Little Walter straight-up clones. Those octal tweeds had no head room, not that the later ones had much either. Steel and no headroom???

[M Fowler]

The next one will be the KT88 version and I'll go with LTP PI on that. Dual recto tubes.

The amp is slaved to a SS power amp and 15 inch Speaker for more stage volume if needed.

Mark

[Toppscore]

Almost finished need to connect line out and put into cab. Played it some tonight but babies sleeping so tomorrow is the work out.

MFowler ~ Just wondering . . . .

The two photos above are with out a grill to pass air through
the front to backside, after that amp chassis is installed.

Did you think about the heat, or heat reduction with an open
grill air-flow? Or, you feel the heat is no problem?

Toppscore

[M Fowler]

The heat is no problem and many amp cabinets are designed the same as what I have. They cool from the back.

Look at the Trainwreck cabinet design same way.

[ChrisM]

Looks good Mark!

Do you also use JustRadios for caps?