Of traynors and CRIPLINGLY HIGH B+

[guittech]

Hey Guys,

So as I age, and approach 40 (OMG!) I am finding that I am leaning towards some vintagey amps, with less bells and whistles. I have been posting about my Bassmate, which I am in the process of finishing the little tweaks, and I have a Bassmaster that will be the next project, once the Bassmate is buttoned up so to speak.

SO, since i am a Canuck, and Traynors tend to be in pretty steady supply, I don't mind modding them up to be my favourite vintage circuits, Good chassis, Good iron... BUT

THE B+! DAMN THEY ARE HIGH!

My Bassmate is running at about 430v B+. I am sure it will mean a short unhappy life for the groove tube el84's I had laying around to go in it. I DO have the original Phillips tubes, which may end up returning to their home.

The YBA-1 I haven't measure yet, But I am seeing 525v+ listed on the schematic. Which is not only VERY high, but way over the Marshall voltages I will be leaning for (1987 circuit)

WHAT TO DO?! I could add an extra filter stage i guess and dumb down the voltage, but i don't think that is a full solution. What about the big ass Zener Diodes that Weber VST sells? Anyone try them on the CT to drop voltage? And does anybody make a zener diode to drop 80 volts lol? The 39V model might make my Bassmate run a little closer to happy, but it won't do much to take the 525v YBA-1

What about a different solid state rectifier design? Different diodes with less efficiency?

Any ideas?

[martin manning]

Alternative to a big Zener:
http://www.blueguitar.org/new/text/tech ... er_sub.pdf

[xtian]

+1. Here is my build log. I had great luck dropping up to 100v.

https://tubeamparchive.com/viewtopic.php?p=334692

[martin manning]

More specifically, here: https://tubeamparchive.com/viewtopic.ph ... 710#323710

[Leo_Gnardo]

That's why I mentioned 6CA7 for your YBA1, also dropping screen grid voltage with a big resistor (now you see why you can spare the choke?), plus arranging the power supply in a series rather than branch style circuit as Fusionbear mentioned, which will also help pull down the SG voltage. I've also used KT88 successfully in YBA1.

Yes I get the willies putting over 400V on EL84 but tough ones like new JJ's seem to work OK as long as you dial down the bias current & keep plate dissipation within reasonable limits say 12 or 11 watts. Or you can do what was done a long time ago to our local jazz meister's 1970-ish Traynor 1x12 combo, swap out those EL84 sockets for octals & use 6L6. I worked on that amp for him @ 5 years back (swapped out the James tone stack for a 5F6A one), saw him play a couple weeks ago, still sounded terrific. 6L6's are loafing in there - "when you gonna put us to work?" Save your $$ collector item el84's for amps that won't be putting the hi voltage hammer on 'em. I got a couple Motorola labeled Mullards myself. JJ's are, shall we say, expendable. Mullies, Amperexes, Telefunkens, not so much.

Although many have had success with the big zener I just haven't tried it yet. Who's afraid of the big bad Zener? Not me, just lazy I guess. Something to look forward to.

Also not to worry about running a hi voltage 1987. I've had a couple local ones show up with replacement PT's that let them run up 55-60 watts as opposed to the usual 30W or so. They do sound brighter & tighter with that extra voltage, but not bad, not bad a'tall. You can always dial down the preamp hi voltage in the power supply string to help relax the tone.

[guittech]

Thanks Leo,

I am ready and willing to do all the stuff mentioned on the other thread, series PS, Big ass resistor to drop screen grid voltage.... just not sure about the 6ca7's I really like EL34's. I've tried kt66's and kt88's but for me the way the 34 compresses and the midrange characteristics are just part of that Marshall type sound.

Knowing the crazy high voltage I am starting with, vs what The Marshall type circuit I want to end with... I would just like to do a little bit to drop things down a bit.... And to me at least, the Big Zener Diode is preferable, because I suck at making little cleanly wired circuits.... I have enough trouble keeping things organized in a big chassis!

[Leo_Gnardo]

And does anybody make a zener diode to drop 80 volts lol? The 39V model might make my Bassmate run a little closer to happy, but it won't do much to take the 525v YBA-1

You could run two 39V Z's in series, and you'll have to provide a "floating" heat sink for the one that's not at ground. 78V, close enough to 80. Plenty of space inside that YBA, use some up.

Yes I dig the '34 tone too. It's all what the customer wants, some are willing to experiment, some don't mind the change in tone with other tubes, some just gotta have EL34's. Courses for horses, innit?

"Less efficient" rectifiers come in glass cylinders. They're nice too but you would have to add a 5V filament transformer, more octal sockets, what a hassle compared to a couple big zeners. But you would get compression at volume for sure.

You may be able to xave a couple loonies buying from Mouser or DigiKey, I think both have Canada warehouses then you can skip customs hassles & charges. If Active Electronics is still around IIRC they're Canada based, should have zeners & heatsinks to fill the bill too. Shop til you drop.

[guittech]

Bwahahahahahahahaha!!!!

http://www.ntepartsdirect.com/ENG/PRODUCT/NTE5283AK

[vibratoking]

That's one pricey zener

[LOUDthud]

There is a YBA-1 and a YBA-1A. Not the same amp, don't confuse them. The YBA-1 has a bridge rectifier and a B+ around 450V. The YBA-1A has a Full Wave Center Tap and a B+ around 540V. The YBA-1A is the Bassmaster Mark II or just the Mark II in later versions. All versions I've seen have a fan. Very early YBA-1s (66 or 67) have a little higher B+ (500V?) with a FWCT supply and originally, 7027s.

[gui_tarzan]

I've got a YBA-1A (with the fan) and you're right, I never expected to see well over 500v on the plates but it's there. The PT is massive.

[LOUDthud]

I've got a YBA-1A (with the fan) and you're right, I never expected to see well over 500v on the plates but it's there. The PT is massive.

Yes, the same PT is used on the YBA-3. They run about 160W on four EL34s. It's basically an OEM version of the Hammond 278CX.

[C Moore]

+1. Here is my build log. I had great luck dropping up to 100v.

https://tubeamparchive.com/viewtopic.php?p=334692

Always enjoy looking at your Work/Builds.
What are the little boards you use.? Are they conductive on one side, or are you wiring them.?
Thank You

[guittech]

There is a YBA-1 and a YBA-1A. Not the same amp, don't confuse them. The YBA-1 has a bridge rectifier and a B+ around 450V. The YBA-1A has a Full Wave Center Tap and a B+ around 540V. The YBA-1A is the Bassmaster Mark II or just the Mark II in later versions. All versions I've seen have a fan. Very early YBA-1s (66 or 67) have a little higher B+ (500V?) with a FWCT supply and originally, 7027s.

Oh, there are alot more than 2 variants of this amp lol! Pete Traynor was a tinkerer, and all traynor amps got subtly tweaked (or sometimes not so subtly) over the years.

yes, mine is the 1a, SUPER high voltage, thus the whole "how to get it low" idea. BUT it isn't labeled 1a. The tube chart is labeled yba-1, it has no fan. But it does have GIANT iron! Would the zener still work? I'll be honest, I understand the mosfet will work, but I am not the best with electronics theory. I find pedals a COMPLETE mystery! I can rebuild a Marshall, but give me a fuzz pedal and i scratch my head and go googly eyed. I've tried to expand my knowedge,but its an uphill battle. Thats why i like the Zener idea, despite cost, it's one wire, one hole in the chassis and one big goofy looking zener!

[Phil_S]

Bwahahahahahahahaha!!!!
http://www.ntepartsdirect.com/ENG/PRODUCT/NTE5283AK

At that price, it would be cheaper and not generate so much heat to just add a choke and modify it to a FW rectifier. Maybe something from the Hammond 159 series?