6aq5 to el84 converter

[billyoung]

I see these for sale on flea bay,

anyone know schematic for them ?

I have a JCA22 and not thrilled with the tone of it.

would be cool to use the 6aq5s in place of el84 s

thanks

bill

[billyoung]

heres the item on flea bay

http://www.ebay.com/itm/1piece-Gold-pla ... 2c90ba5d4f

[Phil_S]

Funny you should mention this. I saw them, too, and I keep thinking the price is excessive. I know others may disagree. I just completed a tube tester project and want an adapter for 6AQ5's, too. I scouted around for parts and I'm not finding bargains.

Here's the deal with a schematic. Find the tube diagrams here: http://tubedata.itchurch.org/index.html Then make yourself a to/from chart.

Then you'll need an appropriate base that plugs into your noval socket, some sort of non-conductive tube appropriate for electrical use that will fit both the base and the 7 pin socket. Do the internal wiring and figure out how to fix the tube at both ends so it doesn't come apart.

When you come down to it, if you are unable to source the parts from one place, you will get killed on postage/shipping. All of a sudden, those ready made adapters don't seem quite as high priced as they did initially. In any case, I'm not going to pay as much as those cost and I am determined to figure this out.

In my case, I can go from octal to 7-pin, which may actually be easier in the end. I'm thinking I can use PVC pipe for the tube and there must be some sort of end cap that is close enough in diameter. I figure I can drill and mount the 7-pin socket at the closed end of the cap and then somehow epoxy the octal base to the open end of the tube.

[matt h]

(deleted)

[The Ballzz]

3 Points,

A) My friend, Terry Shaffer of http://www.gramplifiers.com has a pretty good source for those 7 pin sockets mentioned by matt h. Whether or not there is a large supply and if he's willing to share that source could only be answered by Terry. I'm fairly sure they are NOS, so available quantities may be limited.

B) I would also love to find a source for 9-pin/noval sockets that would properly fit in a standard 8-pin octal hole! Any adapters I've seen are ugly at best!

C) Those 6AQ5/EL90 adapters, while a little pricey, are certainly more attractive (price wise) than the Yellow Jackets! The Yellow Jackets have generally developed a less than stellar reputation, however I believe that has been perpetuated by improper use and/or understanding of "HOW" they need to be used. This type of device is not always as simply "plug & play" as many assume. A little research and knowledge is necessary for successful use.

All that said, the 6AQ5, when used properly, seems to impart a particular quality that sort of "mimics" or makes up for the sound that is lost by the reduced air movement by speakers in lower wattage situations. Terry's "nominally" 10 watt 6AQ5 amps certainly sound amazingly like their "BIG BOY" relatives! Although I must say that the 10 watt rating can be a little misleading, as these amps put out the "LOUDEST" 10 watts you're likely to ever hear!

My $.02,
Gene

[martin manning]

A standard octal hole? I've seen 1", 1-1/8", and 1-3/16".

[Phil_S]

A standard octal hole? I've seen 1", 1-1/8", and 1-3/16".

No 1 1/4"? LOL!

[The Ballzz]

A standard octal hole? I've seen 1", 1-1/8", and 1-3/16".

Yes indeed, although most kit/project, pre-punched chassis that are currently out there seem to accommodate the Belton sockets that are listed as 1 3/16" to 1 1/4" with 1 1/2" mounting centers. That is what I generally consider as "standard" of course there are many exceptions! I have a 1 7/32" radio chassis punch, so in my part of the universe, that is my "standard" for octals!
YMMV,
Gene

[billyoung]

I bought novel socket savers you can unbolt and pcb mount 7 pins.

I was not too concerned with mechanics, more concerned with the electronic

aspect, are resistors needed or other parts to adapt it ?

solder it up put inside a perscription bottle and cast epoxy into it

then cut off the bottle. They are soft easy to cut. i got the pcb type 7 pins

coming and have the 9 pin socket savers ....I dont like the EL84s in the

JCA22 at all and low watts seems more of my modus operandi,

its easier to solder a structure say using buss wire. Like i said electrically

are there parts required ? will the 6aq5 run at same electrical parameters

as the 6aq5 ? I listened to terrys amp samples sounds fab to me......more to

my likings than the el84. I also been considering a downsized version of

randy aikens attenuator for small amps, they still scream. I am working

on a two output types with classic jtm45 style front end complete with

mustard caps and lemco tone caps, and a couple of caps from 50's era I

like. The one I built 10 or more years ago got ghost notes at the octave,

It took forever to rid them, but it was a 5 watt plexi that shook the windows

in my house driving a v-30 4x12. I made it at someones request, at the time

I wanted to pursue less watts. I was pleased with tone, and joe hardy tried

it out and liked it he had some suggestions, at the time I did not agree with,

but now I think he was right on. I got several ideas I want to try with my

luck it wont be straight forward lol. I want to go back ten years and

pursue my original ideas. This forum is wonderful. There seems to be alot

of interest in lower powered amps which is cool as far as I am concerned.

I have heard some great clips of amps. I think my tone still awaits me.

Like the greek sirens lured the sailor to shipwreck on the rocks lol.

I bought a pair of 6aq5 s, but later i found tubes fancy gourmet tubes i

like alot more, so the 6aq5 are now orphan children with no home.

I got the socket savers and more 7 pin sockets on way. I got a monster

hammond m100 amp that lives upside down and has some of every socket.

I use it to try out crazy ideas. Was cheaper to buy it, than a hammond

power transformer They are so big seems noone wants them. I got two but only use one at moment.
still curious of schematic for the china converters.

thanks for responses guys !!!!!!!!!!!!!!

[davent]

3 Points,



B) I would also love to find a source for 9-pin/noval sockets that would properly fit in a standard 8-pin octal hole! Any adapters I've seen are ugly at best!

Gene

Not sure whether this are one of the uglies but... an option.
[img:250:188]http://www.tubeface.com/sites/tubeface. ... dapter.jpg[/img]

http://www.tubeface.com/chassis/octal-noval-adapter

Not sure about the voltages in that particular el84 amp but the 6aq5 is spec'd at relatively low voltages so there may be more involved then just physically adapting the tube in getting it to play nice in that amp.

[Phil_S]

I think I found the stuff for octal to 7 pin. CPVC pipe parts, 1" straight through coupling is a little tight on an octal plug. Sandpaper on the inside will fix that. 3/4" cap goes nicely inside the 1" coupling and should have enough real estate on top for a 7 pin socket. Mounting the socket may be a little tricky. Epoxy or CPVC cement may be needed to stablize the cap when inserted into the coupling, but I'm inclined to try a screw so I can take it apart, just in case.

PVC parts are a different size and don't work.

Now, to find a second octal plug. Do I attempt to booger a useless tube with the right kind of base, or do I try to buy one or two?

[davent]

Hoffman has the octal bases if you are looking to purchase. last item on the page.

http://hoffmanamps.com/MyStore/perlshop ... ubeSockets

[The Ballzz]

davent,
Thanks for that link. That adapter ain't half bad and that's a forum I've not seen before.

billyoung,
the 6AQ5 would like to see a bit lower plate and screen voltage than an EL84. I think many keep the plates in the 280v to 300v range, but I've been having pretty good luck up around 317v with all tubes loaded, at idle in a cathode biased configuration. Not sure if your amp is cathode or fixed bias. That may make a difference in the acceptable voltages.

From several comments I've read/heard, the real voltage limiting factor is the compact size of the the tube. It is supposedly a "mini" 6V6 but the small size can lead to internal shorting/arcing due to close proximity of the internal parts. They do, however, sound fantastic when they are right. In my builds, I use a 550v (275v/275v) center tapped PT like this:

http://www.classictone.net/40-18085.html

or similar from MPS. Do you happen to know the specs of your current PT and OT?

I'd love to see the JCA22 schematic if you have one! If you don't feel right posting it, we could PM real email addresses to share.
Thanks,
Gene

[Leo_Gnardo]

Now, to find a second octal plug. Do I attempt to booger a useless tube with the right kind of base, or do I try to buy one or two?

Antique/CE also have octal headers. You don't have to pick glass bits out of some smashed tube.

[Phil_S]

Thanks fellas. I'm looking for one of these, but not at this price:
http://www.ebay.com/itm/370638994599?_t ... EBIDX%3AIT

Leo: I was thinking of cutting open a metal 6AC7 (no 6CA7). Cracked glass and I don't get along well. Don't ask me how I know this, but let's say I learned the hard way some 40+ years ago and never forgot. It was months before I could play guitar again. So, thanks for the pointer.