[PFKMan23]

You can run the 6414 at either 6V or 12V, depending on how your amp is configured and how the adapter is wired (an ecc adapter will be wired for either 6V or 12V). You do not need to have the 12V option to use this tube.

 

[Frihed89]

A bias adjustment to run the 6414? Say what? My unit will have a high-bias adjustment. Is that what we are tlaking about here.

 

[sacd lover]

Quote:

Originally Posted by Frihed89 /img/forum/go_quote.gif A bias adjustment to run the 6414? Say what? My unit will have a high-bias adjustment. Is that what we are tlaking about here.

No .... the bias adjustment is for the output tubes only. If your amp can use the 5751, the 6414 will work fine; possibly better.

 

[adolphe]

Ugh...my brand new MPX3 is waiting for me at my apartment, but I'm out of state on work this morning...I can't wait to get home tonight!!!!!

 

[Inter]

Quote:

Originally Posted by guzziguy /img/forum/go_quote.gif My advice, which I originally got from Earl and now whole heartedly agree with, is to order a loctal adaptor (7n7) from SP and get a Sylvania tall bottle 7n7 to replace the EH6sn7 tube currently in the gain position. The improvement is very large. Next, tell us about the 5687's in the outputs. SP sent mine with two Tung Sol D-gettors. I haven't felt the need yet to try something else. Depending on what you have it may or may not be worthwhile to roll something else in. My main advice is, don't worry too much about it and enjoy the music with your amp.

Thanks! How much would the adaptor and the tube cost me approx? Also, the 5687's doesn't seem to have any markings on them, so I am not sure.

 

[adhoc]

If anyone could give me a little more information about these 14N7s I picked up, I would be most grateful. They are unlike anything else mentioned so far in this thread.

- short bottle
- grey glass
- marked Sylvania
- black T-plates (like Syl VT-231s)

I've placed it next to a tall bottle 7N7 grey glass, which is also a mystery in itself to me.

 

[guzziguy]

Quote:

Originally Posted by Inter /img/forum/go_quote.gif Thanks! How much would the adaptor and the tube cost me approx? Also, the 5687's doesn't seem to have any markings on them, so I am not sure.

The cost of an SP adaptor is $99. There are cheaper adaptors out there, but they have a spotty reliability record. 7n7 tubes currently cost anywhere from $5 to $12, the tall bottle being the most expensive. Even so, $111 is less than the cost of a lot of comparable (sound quality wise) 6sn7 tubes. When you have to buy the second tube, you are way ahead and you also get a lot of the money back if you later sell the amp and adaptor. Please note that all prices are USD.

My 5687's didn't have any markings either. I think that they are Tung Sol D-gettors because their structure matches a pair that I have. You can try asking Mikhail, but you'll probably need to do it via telephone and it may not be worth it to you.

 

[augustwest]

That 7n7 looks different from the ones in my collection. The difference is the sharply delinated silver flashing. Does it have any ID markings of any kind? My grey glass versions don't have any top silver flashing, and all the other versions of my 7n7's look like the 14n7 you have.

- augustwest

 

[Frihed89]

Some of the tubes that cab be used as the input are:
6SN7, 6CG7, 6414, 12AX7, 5751, 7N7 and others...

Some of the tubes that can be used for the 2 outputs are:
6SN7, 6BL7, 5687, and others......

Now, on this list only the 6SN7 can share all 3 positions? Is that right?

Earlier in this thread there's a list of tubes that can be used, but it doesn't always say in which position. It sure would be nice to know that.

It would also be nice to see everyone's top three favourite tube combinations (and which model they apply to), and why.

 

[PFKMan23]

Quote:

Originally Posted by Frihed89 /img/forum/go_quote.gif Some of the tubes that cab be used as the input are: 6SN7, 6CG7, 6414, 12AX7, 5751, 7N7 and others... Some of the tubes that can be used for the 2 outputs are: 6SN7, 6BL7, 5687, and others...... Now, on this list only the 6SN7 can share all 3 positions? Is that right? Earlier in this thread there's a list of tubes that can be used, but it doesn't always say in which position. It sure would be nice to know that. It would also be nice to see everyone's top three favourite tube combinations (and which model they apply to), and why.

That's not really that accurate. The 6BL7 and the 5687s can also be used as gain, although some people do prefer them as outputs. You can also use the 6cg7/6fq7 and 6gu7 as output tubes as well. Keep in mind that the 7n7s are basically electrically identical to the 6sn7s so you can also use those as outputs. I also wouldn't use the 12ax7 as the gain is too high for our headphones.

 

[sacd lover]

Quote:

Originally Posted by Frihed89 /img/forum/go_quote.gif Some of the tubes that cab be used as the input are: 6SN7, 6CG7, 6414, 12AX7, 5751, 7N7 and others... Some of the tubes that can be used for the 2 outputs are: 6SN7, 6BL7, 5687, and others...... Now, on this list only the 6SN7 can share all 3 positions? Is that right? Earlier in this thread there's a list of tubes that can be used, but it doesn't always say in which position. It sure would be nice to know that. It would also be nice to see everyone's top three favourite tube combinations (and which model they apply to), and why.

[size=x-large]GROUP 1[/size]

Almost all SP amps will work with these tubes .....

Input: 6 volt = 6CG7/ 6GU7/ 6SN7GT-A-B/ 7AF7/ 7N7

Input: 12 volt = 12AU7/ 12FQ7/ 12SN7GT-A/ 14AF7/ 14N7

Input: number tubes = 5687 (no with PPX3)/ 5841A/ 6350/ 6463/ 7119

Output tubes: 5687/ 6350/ 6463/ 7044/ 7119/ 6BL7GT-A/ 6BX7GT/ 6CG7/ 6SN7GT-A-B.

**** The stock PPX3 will not work with the 6BL7GT-A/6BX7GT ouput tubes. Why? Because the PPX3 does not have a power transformer that is capable of supplying the heater current demands for these tubes. For this same reason you cant use three 5687's in the PPX3. The amp will work with these tubes with an upgraded power transformer.

[size=x-large]GROUP 2[/size]

On specific SP amps these tubes will work. These INPUT tubes have high gain and may cause hum or distortion in some cases. You need to consult with Mikhail to determine if these will work in your specific amp. I get hum in the older, new chassis p2p models I have using high gain tubes.

Input tube: 6 volt = 6SL7GT/ 6SU7GTY/ 7F7/ (12AV7 * 6 or 12 volt)

Input tube: 12 volt = 12AV7/ 12SL7GT/ 14F7

Input tube: number tubes = 5751/6414/6829/7062

**** The 6SL7GT/ 6SU7GTY/ 7F7 /14F7/ 5751 are very high gain (Amplification Factor of 70) and will only work in very specific SP amps.

[size=x-large]GROUP 3[/size]

Tubes that can be run in all three positions in MPX3 level amps or above are ....

6CG7/ 6SN7GT-A-B/ 7N7/ 12FQ7/ 12SN7GT-A/ 14N7/ 5687/ 6350/ 7119. I left out the 6463 and 7044 because these tubes are microphonic and will give you trouble in the gain / input position, most of the time .... but not all the time. I have had a few tubes that worked adequately. But with so many others I dont bother with them much.

I am sure I probably missed a few but as a beginner you have more than enough to keep you busy.

 

[Inter]

Quote:

Originally Posted by guzziguy /img/forum/go_quote.gif The cost of an SP adaptor is $99. There are cheaper adaptors out there, but they have a spotty reliability record. 7n7 tubes currently cost anywhere from $5 to $12, the tall bottle being the most expensive. Even so, $111 is less than the cost of a lot of comparable (sound quality wise) 6sn7 tubes. When you have to buy the second tube, you are way ahead and you also get a lot of the money back if you later sell the amp and adaptor. Please note that all prices are USD. My 5687's didn't have any markings either. I think that they are Tung Sol D-gettors because their structure matches a pair that I have. You can try asking Mikhail, but you'll probably need to do it via telephone and it may not be worth it to you.

Ok thanks.

I'll mail Mikhail when I find the money for it.

 

[augustwest]

"the 5965 has even higher gain of 48. This tube will work fine with the 6bl7gta but I had the plates of some 5687's cherry red using the 6414w."

Earl -
I found this comment earlier in the thread, and I am somewhat confused by it. Are you saying the 5965 & the 5687's shouldn't be use together? could you please clarify?

- augustwest

 

[sacd lover]

Quote:

Originally Posted by augustwest /img/forum/go_quote.gif "the 5965 has even higher gain of 48. This tube will work fine with the 6bl7gta but I had the plates of some 5687's cherry red using the 6414w." Earl - I found this comment earlier in the thread, and I am somewhat confused by it. Are you saying the 5965 & the 5687's shouldn't be use together? could you please clarify? - augustwest

The 5965 is a very similar tube to the 6414 .... but with even higher gain. The 5965 is going to overdrive the 5687 tube in amps like the SLAM SE that are running the 5687 near its limits .... and the high gain is going to cause hum in the older amps designed specifically for a low gain input tube. The 5965 will work with the PPX3 SLAM because you can manipulate = lower the gain with the texture control. The tube works with the SLAM SE with 6bl7gta's @ 300 volts in my SLAM SE. This is mostly a case of synergy between a given tube and the specific amp.

Does that make sense?

 

[PhilS]

I am assuming that I can try the 12AU7 and the 12AV7 in the gain position in my Supra in place of the 6414 (I believe I have the 6-volt ECC adapter). Your post 221 above, Earl, suggests I can't do this, at least with the 12AU7. Am I missing something? I just ordered some 12AV7 and 12AU7's off of ebay.

See posts 172, 173 and 174 for the source of my confusion.