[Frihed89]

The used triple micah black plates (Raytheons and Sylvanias) that i recently got sound much better in the Mapletree head amp than the other RCA and GE tubes i tried. I know they are hard to find, but 5751 prices are coming down and people are now selling from their private stocks of these tubes for less than they paid.

I have a fairly serious hearing disease by the way!

 

[3x331m]

Quote:

Originally Posted by sacd lover /img/forum/go_quote.gif No .... the 6414 series of tubes nor the 12au7/5814a will not work in the Mapletree amp.

Do you mean the 12au7/5814a is not compatible with MAD amps ?

 

[Voodoochile]

I have maybe five different 5751, and also a half dozen different 12AX7/a, and so far, a Sylvania 5751 and GE 5751 both seem to be the best of the lot. The Sovtek 5751 is not that bad, though. In fact, it's better than many NOS tubes. Rather remarkable for a current-production tube, I think. I guess my thought on it is that unless you can get your hands on a pretty nice NOS tube, the Sovtek may well do you better than some more widely available NOS tubes.

The Sovtek spiral filament 12AX7, while not my favorite 12AX7, is also easily nicer in this amp than the gold-pinned Electro-Harmonix, which seems to be fairly well-regarded for a current-production tube. I don't care for the EH in my phono stage, either. Interesting for sure. I'd also like to try the "new soviet" mullard just for kicks.

 

[Hi-Finthen]

Quote:

Originally Posted by tuatara /img/forum/go_quote.gif I purchased quite a few 5751s when I obtained my Mapletree amp and have tried several of them including Sylvania Gold Pins, 50s GE black plate triple micas, RCA Commands etc. To be honest I dont have golden ears and haven't noticed huge differences between the various valves..there are changes but to my ears not something that grabs you by the throat. Probably the best would be the GEs but I've had a Command in now for several months and it sounds fine. I have also tried a few new production types and have found none horrificly poor, some a little less full or complete than the nos items. Since Lloyd sent my amp with some 12AT7s fitted(out of 5751s at the time) I have also tried a couple of these, again the nos ones work fine. From my own experience I dont think the Purist design is one where you'll notice big sonic variations with different tubes..maybe that's a good thing and saves money chasing those expensive items. A friend also running a Purist plus finds the Grove Tube Mullard copy works well for him. I think its impossible to be dogmatic about this subject as personal preferences, hearing,phones, the recordings we play, the source we use all have a bearing on the final sound.

Thanks tuatara for your summations, as I will keep this all in mind tempering my choices.

Quote:

Originally Posted by Frihed89 /img/forum/go_quote.gif The used triple micah black plates (Raytheons and Sylvanias) that i recently got sound much better in the Mapletree head amp than the other RCA and GE tubes i tried. I know they are hard to find, but 5751 prices are coming down and people are now selling from their private stocks of these tubes for less than they paid. I have a fairly serious hearing disease by the way!

Thank you Frihed89 for further confirmation on these two (Raytheons and Sylvanias) also referanced in the audiogon link provided, and helping me fine tune my shopping list.

Quote:

Originally Posted by Voodoochile /img/forum/go_quote.gif I have maybe five different 5751, and also a half dozen different 12AX7/a, and so far, a Sylvania 5751 and GE 5751 both seem to be the best of the lot. The Sovtek 5751 is not that bad, though. In fact, it's better than many NOS tubes. Rather remarkable for a current-production tube, I think. I guess my thought on it is that unless you can get your hands on a pretty nice NOS tube, the Sovtek may well do you better than some more widely available NOS tubes. The Sovtek spiral filament 12AX7, while not my favorite 12AX7, is also easily nicer in this amp than the gold-pinned Electro-Harmonix, which seems to be fairly well-regarded for a current-production tube. I don't care for the EH in my phono stage, either. Interesting for sure. I'd also like to try the "new soviet" mullard just for kicks.

Thanks for your input Voodoochile; Again, the Sylvania and GE brand 5751 gets mentioned with high regard. Of course, new production tubes are to be looked into also I suppose, as a referance point of sonic interest cost/benefit reality check and to have reliable spares.

I can now followup with my refined search for perhaps 5 tube buys to outfit my stash with some degree of confidence; Realizing the potential sonic differences maybe so subtle or even less desirable in terms of NOS vs Newstock will help to temper my inventory to perhaps three. Good advice all, for this budget concious one ;-}


Quote:

Originally Posted by 3x331m /img/forum/go_quote.gif Do you mean the 12au7/5814a is not compatible with MAD amps ?

In any circuit designed for 12AX7 the gain of 12au7 is proportionally 80% less making them undesirable in this position on the MAD. Whereas I believe, the others mentioned above may be only a loss of 20% gain vs the 12AX7s... However, the benifits become more choices of subtle differences and long life duribility with less chance of microphonics with some specific specimin of tube chosen. And perhaps the tube with 20% less gain may draw less upon the power supply keeping it from softly clipping on transiants would be a supposition of mine that perhaps as a theory others may want to comment on.

Good stuff headfellow~
As always thanx for sharring~

 

[Voodoochile]

Review, finally.

 

[mrarroyo]

I started an impression thread at: http://www6.head-fi.org/forums/showthread.php?t=210509