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Item #649403172
Info: Vintage 6AN8A / 7199 Tubes

Payment method: Cash, Money Order, Money Wire, Interac/EMT
Condition: N/A (?)
Date Posted: Dec 30, 17 10:16pm (PST)
Edited: Jan 19, 18 6:18pm* Updated!
About Seller: David Dov
David Dov is a premium user
North York,Toronto, ON
Canada
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I have a few original rare hard to find vintage 1950 - 70's 7199 tubes
As well as many 6AN8A tubes to offer to CAM members!
7199 tubes are a high end upgraded low noise type replacing the standard 6AN8 tubes which are used in Dynaco/Eico and other triode pentode amps.
All made in USA
Some of these were never used, the rest hardly used,and if used they were used for less then 30-40 hours per tube

Includes:
Vintage 1960's 7199 Dynaco and RCA Black Plate Tubes
These 7199 tubes are getting hard to find
Tested very strong with a calibrated B&K tube tester
These tubes have most quiet, low noise distinct sonic characteristics!
-No gas or shorts (not even the 7199's which usually show shorts when tested)!!!
All tubes have been tested on my calibrated B+K tester
Many singles,pairs,quads.
Priced to sell:
Please email for available brands + prices
I also have many other tubes to sell,so let me know what you need.
All tubes have tested very good on my Calibrated B+K Tester with good readings of min. 80
All without any gas shorts
I'm now selling off from my collection.
as I have much more then I need, given I'm downsizing (seems to happen with us seniors....)
Many are the much harder to find rare Triple mica Black plates....
All tubes have tested like new and very good on my Calibrated B+K Tester with good readings of min. 80 - 100
All without any gas shorts

Matching pairs of 6AN8A tubes for $50.00
Matching pairs of 7199 tubes for $100.00
Price is firm
Local GTA pickup is welcomed
Shipping is by Canada Post regular parcel,
Usually shipping cost is usually up to $20.00 per shipment of (1-4 tubes) depending on where in Canada.
Keep in mind that 1 - 4 tubes being shipped is the same cost as shipping only a single tube.
*FREE shipping on me on all orders of $160.00 or more!
All tubes will be properly well wrapped,packed and bubble-wrapped boxed.
I have much more then I need, given I'm now downsizing (seems to happen with us seniors....)


Additional Information:

Jan 04, 18 12:04pm

Is anyone else finding (non existent) shorts on their vintage 7199 tubes???

I put away (8) RCA Black plate 7199's some 20+ years ago.
Some of these 7199's now show shorts on my B+K 707 tube tester when I went to test them.
Yet all these tubes play and sound fine, I don't believe it's my tester!
So I took all of these tubes over to my friends testers and guess what.... they tested the same, with imaginary shorts?????
It's not hurting the amp by running these tubes as nothing is wrong with them!
So there does not appear to be any risk of damage to the amp from running these 7199's
All these tubes are not compromised.
There is no strange noises such as a hum or a howling coming from the channel that has the tube under test. or a blueish glow inside the tube which means the tube is gassy.
If you don't have access to a reliable tube tester, then plug one tube into your amp at a time and listen for strange noises such as a hum or a howl coming from the channel that has the tube under test. or a blueish glow inside the tube which means the tube is gassy.
What I find disturbing about this is that several of the 7199's that tested with shorts were taken from working gear.
I am just finishing up a Stereo ST-70 project and of the (8) 7199's I currently have on hand only (3) do NOT show any shorts.
I am extremely frustrated and DO NOT want to spend more $$$$ on any more 7199's!
And also, this seems to be a common problem with the 7199 tube in general
You see all kinds of modded boards for the Stereo ST-70 and not many use the 7199 tube any more.

Could this be why?
Is the 7199 just a finicky tube that people don't want to deal with
The 7199's are for Dynaco Stereo ST-70.
They make the tubes drive.
I ran the amp with the 7199's that came with the amp for quite some time.
I decided to recap the amp because I wasn't very impressed with the sound of the unit.
I bought some better caps and installed them all.
Again I figured I'd test the 7199's and found that (1) of them still showed a short.
And as I stated, all the others I could track down test with shorts as well.
One was pulled from a working amp that sounds great!!
If these tubes are coming out of ST-70s, then you should indeed expect to see some failure rate.
The ST-70 is very hard on 7199's.
The RCA receiving tube manual lists a maximum heater to cathode voltage of 100 volts for the 7199, and in the ST-70 you will typically find 100-130 volts on the cathode of the triode section
I would consider the voltage divider an essential mod.
Mounting a terminal strip along the left side of the power transformer and at a right angle to the 7 lug terminal strip where the filament wiring is connected.
Run a wire from lug 3 of the quad cap to a 1 watt 360K resistor attached to the new terminal strip.
From the other end of the 360K resistor, run a 120K, 1/2 watt resistor to ground (lug 6 of the existing terminal strip). Also from this end of the 360K resistor, run two 330K, 1/2 watt resistors to the filament center taps (one to lug 5 and one to lug 7 of the existing terminal strip).
When you fire up the amp, you should have 70-75 volts DC measured at lug 5 and 7 of the existing terminal strip.
Also, the dual 0.1 ceramic cap remains in place.
If these tubes are coming out of ST-70s, then you should indeed expect to see some failure rate.
The ST-70 is very hard on 7199's.
The RCA receiving tube manual lists a maximum heater to cathode voltage of 100 volts for the 7199,
and in the ST-70 you will typically find 100-130 volts on the cathode of the triode section
Upon further testing, the heater-cathode leakage, which is in parallel to the 47K cathode resistor, lowered the resistance to that side of the phase splitter.
This resulted in a loss of output power and a 25 dB increase in 2nd harmonic distortion.
I use my B&K 707 for testing small signal tubes
as I believe it is better at finding shorts and gas than some other testers.
The thing about 7199s… even if you have tube tester, what do the results mean?
As stated I have (8) 1960's made for Dynaco 7199's.
I put them all in my tube tester – and all of them without exception test shorted.
This seemed very strange, because I knew most of them were [supposedly] NOS, and I used some of them in my Stereo ST-70 with no problems whatsoever.

It is no surprise to me that the 7199's have this problem. they were constructed the same way as the 6GH8s were. They were also most likely produced on the same production line as the 6GH8s were. heater to cathode shorts were very common on both of these tube types.
The 6GH8s were used in just about every color TV that used the RCA designed / licensed chassis from the early sixties on until the last of the tube type sets were produced.
If you took a side by side look at the construction of both of the tubes (providing that they are both made by the same manufacturer), you will see that they are exactly alike in every detail (except for the pin connections). some of these were the worst tubes ever produced & the cause of a lot of problems in the circuits that they were used in. they also had short lives too.
There was an article in a 1996 issue of Sound Practices that detailed this problem, along with a recommended voltage divider circuit for the ST-70 to elevate the filaments to about +75 volts DC, thus extending the life of the 7199.
Upon further testing, the heater-cathode leakage, which is in parallel to the 47K cathode resistor, lowered the resistance to that side of the phase splitter.
This resulted in a loss of output power and a 25 dB increase in 2nd harmonic distortion.
Since reading this article, I have converted my ST-70 amp to using 6U8A's/6GH8A's with converters.
Basically, a 7199 is nothing more then a 6GH8 with a different pinout.
I'm mostly using now 6U8A / 6GH8A's with adapters instead of using 7199 tubes
DD
Dynaco Dave



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