Tubes in your system?

[BruceRPA]

I listen to my Fisher KX-200 Amplifier ( 4 X 7591 + 6 X 12AX7/ECC83) that I built as a kit when I was in High School back in 1968. I listen to it all day long in my office using XM radio and a pair of Braun L-810A speakers that are from the same era, I think. It is a sweet sounding system. The amplifier still has the original tubes and has remained untouched all these years other than having to replace a 1/2 watt resistor a couple of times for some unknown reason. To be fair, it was stored in my basement for about 15 of those years along with a Dynaco SCA-35. They came out when I discovered AK less than a year ago. Since then I have been absolutely snake-bitten by this vintage audio thing, and it's all good! I can't begin to describe how much I enjoy it. Thanks all AK and all Y'All!

(For our southern members, please feel free to correct my grammar and spelling of "All Y'All" Someone once mentioned to me that 'Y'All" is singular and "All Y'All is plural", but I am still not so sure, especially about the spelling Now if you want some help interpreting "Pittsburgh-ese, that I can help yun's with! )

 

[jaymanaa]

Very cool, Hog. Your the first person I've seen mention the KX200. I just finished a recap on mine. I think these amps get overlooked a bit, and don't know why. They sound great, and have some damn nice output iron. I still have the Fisher branded output tubes for mine, but am running RCAs so I can save them (I'm not sure why). I'm not a big Tele fan, but in this amp they really seem to work well in the 12AX7 spots. Is there any chance you still have your schematic. I haven't been able to find one anywhere. Funny thing is I have an X200 also (factory built) and whoever built the KX did a much nicer job. :yes: You could tell they really put some attention to detail in it. Glad to hear your enjoying yours as much as I am mine, Jay

 

[L'wood]

Kegger, there aren't enough 6FW8's left for all of us...mum's the word!! A friend turned me onto these after he rolled them in an Eastern Electric CDP, and it made a marvelous transformation sonically.

L'wood

 

[PakProtector]

Kegger, there aren't enough 6FW8's left for all of us...mum's the word!! A friend turned me onto these after he rolled them in an Eastern Electric CDP, and it made a marvelous transformation sonically.

L'wood

Awwww...c'mon, nobody is charging an arm+leg for these things. Mater of fact, everybody is quite reasonable. Going to have to get a few of these. Thanks for the notice!
cheers,
Douglas

 

[jaymanaa]

Thanks Kegger, you covered my Q's with your last paragraph. I haven't needed any new 6DJ8/6922 examples in a long time and I just wasn't up to speed on the other #'s
being mentioned. Early Amperex examples make my setup sing.

I'm curious about the Amperexs. How would you rate their bass performance? Also, what type (or #) output tube are you using them with? Thanks, Jay

 

[jon_s]

Awwww...c'mon, nobody is charging an arm+leg for these things. Mater of fact, everybody is quite reasonable. Going to have to get a few of these. Thanks for the notice!
cheers,
Douglas

So, it seems I just bought the only 6FW8 on ebay for $2.25 :butt2:




Sorry It was a pretty sketchy auction though.

Tubesandmore.com has some for $6.10, and I'm sure they aren't the only ones with 'em in stock.

 

[BruceRPA]

Is there any chance you still have your schematic. I haven't been able to find one anywhere. Glad to hear your enjoying yours as much as I am mine, Jay

Yes, I still have the original assembly manual. I can scan it at work next week and post it on www.sendspace.com so that you can download it. I will need your email address so that I or sendspace can send a notification that the files are ready to be downloaded. Just send me a PM with your email address and I will scan the manual as soon as I can.

 

[Kegger]

So, it seems I just bought the only 6FW8 on ebay for $2.25 :butt2:




Sorry It was a pretty sketchy auction though.

Tubesandmore.com has some for $6.10, and I'm sure they aren't the only ones with 'em in stock.

Yes not to many on ebay these day's, I did a google search and found a few in
stock at tube sellars though, but yes it is best to try an not build them up all to
much, at least not till we all get a good stash of them!

 

[jon_s]

Yes not to many on ebay these day's, I did a google search and found a few in
stock at tube sellars though, but yes it is best to try an not build them up all to
much, at least not till we all get a good stash of them!

Welp my 6FW8 arrived... sketchy auction = sketchy packing! Two pieces of cardboard taped together forming a makeshift envelope with the tube wrapped in a WalMart bag inside. It was fine, but I was a bit nervous when I saw it.

The tube looks like a 6DJ8, similar plate structure. There appear to be 3 layers of mica at the top and 2 at the bottom. Looks to be of high quality construction. I think the tube is new since the glass is very clear at the bottom, even though the getter is a bit dark in spots. Will find out tonight how it sounds

 

[Kegger]

Do let us know, secretly though Jon!

 

[jon_s]

Do let us know, secretly though Jon!

Ha, my public opinion is that these tubes sound like Sh!t

Welp, no, on first impressions I'd say they sound exactly like 6DJ8's. So, no surprises, good or bad. They aren't nearly as bright and colorful as an Amperex A-frame, or PQ. And not "sharp" like a 6N23P. More on the neutral, polite side, without being dull like a GE. A totally livable tube. If someone asked me to do a blind test between my HP made-in-Hollands vs. the 6FW8, I would pass -- no way could I tell the difference. I might buy a few more, but I don't feel the need to hoard a lifetime supply in a safety deposit box :thmbsp:.

 

[jaymanaa]

Well, so far Amperex gets my vote for the 6DJ8 spot. I thought I'd check in and give my thoughts on some 2A3 testing I did today. I tried Sylvania which was far and away the brightest of the ones I tried, but a bit wimpy on the bottom. I also tried Ken-Rads with the top section of the glass smoked and the bottom getter flash. These were pretty much the opposite of the Sylvania in a side by side test. Lot,s of bottom, but had to turn the Lpad up on the high freq. horns. All said, I didn't see anything in either that would make me give up the RCA dual plates. To be fair, the Sylvys were used, but tested strong. Jay

 

[jaymanaa]

I know, I'm wearing this thread out Anyone have any experience with 6CG7s? It's a 9pin twin triode about the size of a 12BH7. I got a little RCA SE 6BQ5 that uses them up front, and was curious about their sound. Thanks, Jay

 

[Kegger]

NO NO JAY keep the thread alive, I think it's a good one!

The 6CG7 is the 9 pin version of the 6SN7, as of yet I have not had a chance to use any.
But I am going to make it a point to do so and build something with them, maybe a rebuild
of this citation 5 I have here using them in the phase splitter and something like a 12b4 or
6s4a as a driver tube since there is (2) 9 pin sockets per channel on the 5.

I believe Douglas has some experience with them though.

 

[jaymanaa]

Ok, one more question. Is there any reason that a 6cG7 couldn't be substitued for a 6N1P? Seems to be a bit less gain, but other than that, I couldn't see anything that would cause a release of magic smoke. :scratch2:

 

[Kegger]

No I believe that should be fine Jay,
I'd be interested in your thoughts on the sound when you try it.

 

[jaymanaa]

Thanks Kegger, I'm sarting to get a little better at cypherin tube specs, but I sure appreciate you double cheking me. :thmbsp: I tested up a couple of RCA tall gray plates from an old RCA console amp, and stuck them in the 6N1P spot on my 2A3 monos. I have really been struggling to find a tube for that spot. The Phillips JAN 6922s were terrible, and so far the best I've found were Russian 6N1Ps (Sovteks I think). I've only listened to a couple CDs with the 6CG7s, but so far I think they are very good, and totally different. I was fighting some harshness on the 511 Bs, and wasn't getting all the bass I felt was possible. These have totally elliminated the harshness, and picked the bass up quite a bit. Reminds me of subbing a 12BH7 in a 12AU7 spot. The music is just "nicer" to listen to. I did have to run the volume up a tad on the pre, but am still not much past high noon. I'm going to listen to them tonight, and spin some "known" vinyl with them. I think there is still room for improvement, but I do beleive these are the best so far. I finally got lucky and swung a deal on some fancier Amperex 6DJ8s that will be the next contestant. All in all, I would say for the money, anyone who runs this type of tube might want to give these a shot. I'm pretty happy right now. Jay

 

[Kegger]

Do you have the schem for the amp or know what the plate load is on those tubes?
Just in case your still not sure how to determine that it's the resistor attached to the
B+ then feeds the anode of the tube your looking at.

Reason I ask is there is a pretty big difference between a 6dj8 plate resistance and a
6cg7, with the 6dj8 being around 2700 and the 6cg7 being around 7500 and the 6n1p
does not have the low plate resistance as some think as it seems to be about what a
6cg7 is. Does not mean they won't work in the same curcuit or even sound good but
you may want to tweak the plate for the specific tube your trying. Using the 5x plate
resistance scale should put yu in the ballpark.

Also I'm curious what the cathode bias resistor value is and while your at it the B+.
If you have the schem how about emailing it to me. :thmbsp:

 

[jaymanaa]

No schematic, but I do need to check all that anyway. I'm going to sit down this weekend and try to draw up a schematic. Should be fairly easy (simple SE circuit). I went to epray and looked around a bit at 6CG7s. Pretty affordable tube. Seems as though everyone makes a "to do" over the RCA cleartops? :scratch2:

 

[Kegger]

YAH if yu do up the schem I'd be interested in taken a peak at it.

Don't know much about the different 6CG7's. Only thing I've read is the american made
ratheons are suppose to be a quite nice tube.