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Socket for 6AQ5

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Hi all,

I'm new to tubes/valves and am in the process of collecting all the bits to build a Moebius line stage using 6AQ5's.

I see a current thread where a guy had trouble with his octal sockets, so I thought I'd ask - how do I identify the correct sockets for the 6AQ5? I know them as seven pin miniature sockets, but I've variously seen them described as B7G, and on the GE datasheet, E7-1.

Can you help?

Cheers

Stuey
 
Geez Douglas, I'm not QUITE that thick! ;)

Yes, I know the octal has eight pins. I was just referring to another thread where the poster got sockets that his valves wouldn't fit, and I don't want to end up in that situation. Given that much of my stuff comes from o/seas.

I know also that it's a small seven pin socket that I need...

Can I put it another way? Is there more than one type of 'small seven pin' socket configuration?

Cheers for the info.

Stuey
 
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Hi Stuey,
It's just a simple 7-pin tube socket. You need to specify whether you want PCB mount or chassis mount. Some chassis sockets may come with supports or hold downs. I have even seen shielded 7-pin sockets. Some PCB sockets may have different circumference for the pins, but that should be about it.

Note too that sockets may be phenolic, mica filled molded, ceramic or molded. The ceramic ones can deal with heat better, but many tube radios used phenolic sockets.

On to contacts. Forget gold plated, that disappears quickly. Cadmium plated (I think) were standard and preferred. Someone may even come out with a nickel or brass type.

So there you have it. Larger sockets are made with various pin configurations. Some really old types are large like octal, but with 7 contacts. These are special and should be noted as such.

-Chris
 
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Hi Douglas,
You mean that your 813s are morbidly obese? :angel:

Anyway, I thought that all Tnuctipun were extinct after that one unified command. But then again, "food that talks" might fear that return for all time.

I don't know anything of the story, but I just had to investigate your tag line a little bit. Of course, this also revealed the meaning of your "handle". However, I had never thought of you as livestock. Cow, pig or sheep?

Hi Steve,
Geez, I should have been buying my sockets from you! The 7-pin you show there are pretty much garden variety and would work fine. I haven't looked further into your site, because I got a "page load error" [network timeout] trying to load http://www.apexjr.com/.

Ahhhh, now I'm in. Hey, I like those right angle 9-pin ceramic sockets you have. I have to say that your place is a wonderland for guys like me. It's a good thing you're located in CA and I didn't know about your place when I went to the first Burning Amp.

Some day I'm going to have to find out if there is an inexpensive way to ship to the Toronto, Ontario area. Will you accept Credit cards or PayPal at some point in the future?

-Chris
 
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Joined 2002
Paid Member
Anatech...
I'm a one man operation and try to compete with the
big guys... I've been doing the surplus stuff all my life
Well, since I was 8 years old....( worked for my DaD)
I know what people are looking for and it's getting harder
and harder to find stuff. But I keep trying.

I do have a warehouse that is open to look at, but by
appointment only and am located by the 2 and 210 freeways
in Southern California.

There are a few ways to ship to Canada, all depending
on the weight. Least expensive is the USPS priority mail
international flat rate envelope... Only up 3 lbs 15 oz.....
Then the Flat rate small box... TODAY they yet rasied
the price, and lastly the large flat rate box also just today
raising the price. I have learned my lesson with UPS
and do NOT use UPS to ship to Canada.

And now lastly...
I do accept Visa, M/C and AmEx with a 3% processing fee
and PayPal with a 5% fee...

Steve @ Apex Jr.
 
Administrator
Joined 2004
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Hi Steve,
All the more reason to support you, right? ;)

I did read the "by appointment" thing. Same as me. One man (okay, 0.65 % of a man) operation, by appointment. I am normally here and my basement only looks like a messy warehouse. :)

Your credit card terms are fair and freedom from UPS is wonderful. No one can change what USPS does, so that's okay. I fully understand the 5% PayPal surcharge.

Thank you Steve, now I just have to become solvent again.

Best, Chris
 
Stuey,

Don't use the 6AQ5.  Although otherwise cool, they are (depending on example) somewhere between moderately and fabulously microphonic.  I'm now using an otherwise almost identical (in characteristics) but completely nonmicrophonic tube, the 6T4.  Same socket, BTW.

An externally hosted image should be here but it was not working when we last tested it.


Almost same circuit, but a little lower voltage due to the very restrictive Vh-k rating of the 6T4.  This is definitely the ne plus ultra Mœbius.

Aloha,

Poinz
 
6T4s are very available.  You're just not going to find them at boutique vendors (at least not yet :^).  You got to ask your bulk vendors, those guys with warehouses full of old orphan teevee tubes.  They'll tell you, 'Heck yah, how many you want?'.  Get at least a dozen; twenty or thirty is better (if they want over a couple bucks each for quantity, tell 'em to be reasonable), so you can test up and match.  You'll have enough for the rest of your natural life for the price of a good NOS 6SN7. I got 170 of them from Jack at The Tube Center, all RCAs in clean boxes, for $2.50 each.

Aloha,

Poinz
 
Poindexter said:
Don't use the 6AQ5 ... I'm now using an otherwise almost identical (in characteristics) but completely nonmicrophonic tube, the 6T4.

Triode connected, the 6AQ5 has a similar mu and rp, but it also has 3x the plate dissipation and double the heater current. It is basically a EL84 with a slightly lower dissipation and max voltage.

Poinz, why the 18K resistor on the output? Seems a little low.

Oh, also, I called Amveco and the primaries are would bifilar, meaning that the only insulation from your primary to your secondary is the enamel on the wire.
 
All that you say is true.  I enjoy the lesser heater current, and the plate dissipation rating is not germane, since I'm burning 1.5 - 1.6 watts per device.  The salient characteristic for me is microphony. The 6AQ5 has those big cylindrical plates, and most of them ring like a bell.  I wonder if it's a problem in power amp service, they never were a very popular device.

Hm, maybe I should find another transformer solution, given what you discovered.  I've never had any problem, but two coats of varnish ain't a 230v insulation.  I would assume that, being bifilar, the induced voltage in the 'secondary' primary would be in inverse polarity.  I have in the past advised those who are nervous about the unconventional connection to just get a 120V Hammond, since 65V/device still yields plenty of swing.

Mahalo,

Poinz
 
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Hi Poindexter,
The Heathkit EA-2 used these output tubes (6AQ5A). The 6BQ5A offered greater output power in the specs war.

Keep in mind they were intended to be in the output where there is low gain. As far as cylindrical plates tending to be microphonic, I'm not so sure of that. There are tubes built similar to that used in signal positions. Besides, a cylinder should be very stiff. There are mica supports to damp each end to some degree.

Want to see microphonic? Nuvistors can really pick up mechanical noise.

What you need is a garden variety, low mu triode. Time to go hunting in your favorite tube manual. You probably want something other than a power output tube. Capacitance may become a problem with the larger tubes.

-Chris
 
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