THD yellow jacket clone "socket adaptor"

[Mat Cortex]

hi i'm Mat and i'm new to this forum.
i'm messing with the idea to make a DIY "yellow jacket" to replace the 6v6 in my 1965 gibson falcon, but with 5902 sub-mini tube instead of EL84. Can it be done ?

Here's my amp actual schematic (with a few mod).

5902 tube info:
http://frank.pocnet.net/sheets/137/5/5902.pdf

the goal is to make the amp quieter without a tone sucking attenuator.

[Phil_S]

IMO, that tube won't work in that amp. The adapter isn't the issue. It's the overall specs of the 5902. The voltage supplied by the circuit to the 6V6's is well above what is possible to use with a 5902.

The amp might be a candidate for VVR. Search the forum for VVR.

...and welcome to TAG!

[10thTx]

You could also look at just using the pentode of a 6MB8 tube (7-9w) OR just the pentode on an ECL84 (3-4w) or a 6K6 (7-8w) if voltages would work.

You can also look at a VVR to lower voltages.

Just some options to consider. With respect, 10thtx

[Mat Cortex]

thanks for the info...
i Dont want to drill new holes in the chassis so i don't think the VVR or power scaling is an option ....

i tought that i could put a zeener to drop the plate voltage and use the 5902 without major surgery !

other options or opinion ?

what about 5902wa ? peak plate voltage = 360V see attached PDF

[ampfab]

I vote VVR

[Phil_S]

Convert a tone control to a fixed value and use that hole for the VVR. There are always choices if you are willing. Inside, you can use non-invasive fixatives (silicone, epoxy, cement, double sided tape, etc.) if something needs to be attached.

[armillary]

Does an appropriate resistor across the speaker terminals qualify as a tone sucking attenuator? Have you tried one yet to see how it sounds?

10thTx, I think your 6K6 idea is worth looking into. I might try it myself.

[ampgeek]

Welcome Mat!

Coincidently, I came across a handful of NOS 5902 WA tubes in a dusty old box of electronic gear at an estate sale just before your post. It also had some of the sub-mini tubes commonly used in our pre-amp designs (6112 and 6021 IIRC).

So...I started fantasizing about a 2'ish watt mini-screamer amp design in my "spare time".

I, too, wondered if the WA's higher peak plate voltage could be used to our advantage. I did a lot of searching but never found anything at all regarding the use of the WA in guitar amp applications (plenty of documentation for the straight 5902 version). Not to mention anything regarding operation of the WA up at the high, peak plate voltages.

My end (and potentially flawed!) assessment is that the WA can be used interchangably with the 5902 at plate voltages no higher than ~250 VDC.

Hopefully someone more experienced with these little beauties can confirm that.

Cheers,
Dave O.

[Mat Cortex]

thanks all for your reply.

Convert a tone control to a fixed value and use that hole for the VVR.
not possible, there's juste one tone knob on the panel. But a great idea!!!

i only tried a friend's diy attenuator (l-pad only) and on heavy attenuation the sound was farty, muddy and fuzzy.

For those who already saw a crestline falcon (62-66) chassis, i could bend a sheet metal and replace the "inner cover" of the chassis, drill it and install the VVR circuit. look at this picture and there a kind of cover that close the chassis to form a kind of triangle. Weird looking i know, but they sound awsome with a few little mod.

thanks for your tips.

EDIT: photo deleted

[Mat Cortex]

hi Dave
i saw that Dana Hall from Hall Amplification use the 5902 in his Lil'Devil but doesn't say nothing about the WA version.

http://www.hallamplification.com/main.html?src=%2F#2,1

it would be great if it works ! But i'm not enough skilled to tell if it's possible or not.

[matt h]

(deleted)

[EtherealWidow]

Made a couple of these for the guys at my church. They like em. Little bit of tone suck, but that goes for any resistor-only attenuator. I built the bottom left one. Super simple.

https://taweber.powweb.com/store/attensch.jpg

[Mat Cortex]

So, i think i'd go for the layered approach as Matt H said.
the 5902wa wasn't a bad idea, buy way out of my skill.
Maybe it's time for a new amp and my first build ! ( out off my skill too.... keep on reading and learnig before)

topic closed.

[ampgeek]

Mat,

Yep...I have to agree that the 5902 wasn't a bad idea...but...could turn into a real snake-in-the-grass trying to implement them on an existing amp.

And..yes again....persuing them in a new build would be a great first project to wet your feet with this hobby.

I intend on doing something with my 5902s so feel free to TAG along (pun intended ) !

Be forewarned though....building a single amp is NEVER enough!!

Cheers,
Dave O.

[Phil_S]

Convert a tone control to a fixed value and use that hole for the VVR. not possible, there's juste one tone knob on the panel. But a great idea!!!

Thanks. Of course you can do this. What is the problem here? If you are like many players, you leave the Tone knob at the same spot and hardly ever change it. Pull the pot and build a resistive divider that mimics the pot. If you really use the Tone control, then, no, I wouldn't. I have a GA17-RVT from the same era -- no tone knob included.

I think I would not go to the trouble of bending a new chassis. It is my belief that some of the mojo comes from the layout, the parts, and how it all hangs together. Your new amp might turn out to be something else, or it might not. Not worth finding out.