Basic Simple 50 watt Bass Head

[gui_tarzan]

That's what this one says on the front and back Mick, "Bass Master Mark II".

Here's the top of my chassis. The PT (on the right) is MASSIVE. I wonder what they were thinking when they put this in there?

[loudthud]

The power transformer in the YBA-1A is the same as in the 130W YBA-3. The output transformer got smaller over the years.

[g1]

The PT (on the right) is MASSIVE. I wonder what they were thinking when they put this in there?

Maybe "how can we get way more than 50W out of a pair of EL34's?"
Or maybe to be sure it would stand up to the "2 years even if you break it" warranty. Not sure if it included tubes back then, kind of doubt it.

[Leo_Gnardo]

I have a Traynor YBA-1A MK II, it makes more than 50w (claimed 90w) but it could be tamed down to 50w. Or build the earlier MK 1. Local bassist Chris Cliff dropped by with his favourite SS Eden WT800 rig and we A/B-d both amps through a couple of Eden cabs using his Wilkes 5-string 'Precision' Surprisingly, the Traynor has a profound depth and richness that the Eden doesn't have, but soon runs out of clean headroom.

Pretty large OT in the Traynor compared to most amps, though.

Some have a small OT and deliver @ 45 watts with EL34/6CA7. I had one of those in college. I fixed up one a couple years ago with the big OT and got 90W with a pair of KT88's, biased appropriately.

[big_teee]

I have a Traynor YCS-50 Custom Special Combo 50 watt with 6L6s and a 1x12 Vintage 30 Ceslestion speaker.
It has Toroid Transformers, both PT, and OT, and DC Heaters.
I bought it in summer of 08.
It has been a marvelous amp.
It is my so-called Bedroom Amp! :<)
I've put a few tubes in it, and I have played it nearly everyday of its life here.
I paid 7 bejamins delivered to my door, and they threw in a nice plastic cover with it.
It is well over $1k now.
So Moral of the Story the Canuck Traynor folks do make some nice stuff.
T

[big_teee]

I found this Schematic for a 2 preamp tube marshall 4150 bass amp.
Anyone got any experience with it.
http://saintgermainmusique.perso.sfr...-bass-100w.pdf
Minus the compression circuit.
I'm just looking at the preamp portion.
T

[loudthud]

That Marshall 4150 looks interesting, I've never seen it before. It's not in Michael Doyle's book.

[pdf64]

I remember the bassist with a pub band I was in for a couple of years in the mid 80s had a 50W version of that.
I don't recall the tone being anything special; he went for the 'Andy Fraser' mid-rangy type of thing.
Actually I was hoping to mp3 some old cassettes including recordings of that band yesterday, but after a decade of inactivity, my tape deck is not inclined to operate - doh!
Pete

[Passinwind]

I agree with the B15N suggestions. Good, modern 6SL7's are commonly available.

Yep, as are great NOS ones. My first couple of goes with NOS ones yielded too much noise and microphonic behavior, but I eventually found a couple of better vendors and never looked back.

For me, at least one band of effective midrange control is mandatory. An Ampeg-based circuit using an inductor or three would be pretty simple and fit nicely with the B-15 theme, IMHO. In my last few rack bass preamps I've been using an active Bax bass/mid stack, with a passive treble one after the second gain stage. Always good to start with tried-and-true though...

[big_teee]

I'm going to stick with the 12xx family of preamp tubes.
I don't want any more variety of tubes, I want to stick to the types I already have.
I need to buckle down and get my design nailed down and get to building it.
I have a lot of the parts already, I need to take inventory and order the rest.
T

[big_teee]

I'm Done, Going to the work bench to build it.

[pdf64]

The benefit of the regular 5F6A topology over the Java is the amp's volume control can be used to set how hard the CF stage is pushed (due to the CF being the final stage of the pre-amp); then a master vol used to set the desired output level (or without a master, then the tone controls all set low - best with the mid wired as a variable resistor).
I find that works well to compress and fatten up the tone from a bass without overdrive being apparent, and, with suitable adjustment, can accommodate both hot and weak pickups.
Pete

[big_teee]

I'm done, Going to the work bench to build it.

[pdf64]

'If that is the case, then why did Leo and team redesign the 5F6 and come up with the blonde and blackface bassman series?'

Well, if eg an accordant and string bass needed to share an amp, then 2 channels with independent tone controls are beneficial; and getting rid of a CF stage in each, whilst retaining a good tone, is a good move in keeping purchase and maintenance costs down.

So their motivation and objectives may not be relevant to this project.

We can't assume that they fully understood what the CF was doing, and if they did, that they would consider it beneficial.
Pete

[big_teee]

I'm done, Going to the work bench to build it.