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12ax7 12AU7 EL34 / KT 88/ 6550 upgrades for PL2

I acquired a used primaluna prologue two a month or so ago. This is my first experience with tube amp. Coming from rotel amplification I am just wowed with the tubes. The PL2 had upgraded tung sol 6550s. Nice sound. But I changed to new issue Electro Harmonix H EL34EH. Ran-in the tubes two days straight with music. Was simply blown away with soundstage and tone! Guitar riffs and blues sound gorgeous! Bass isn't too shabby either. Quite enjoyable.

Then found a little more improvement by switching 12ax7s from stock to Electro Harmonix ($10 bucks each).

The tried changing out 12AU7 with some old used tunsol 5963/12au7 (made in the USA) and was not happy. Changed back to stock.

Does anybody have any good experiences with upgrading the 12ax7/12au7 and power tubes on the PL2. I would appreciate the advise. Tube rolling is so much fun!

My speakers are quad 22L2, cd player oppo bdp 83se and analog source is MMF5 w/ MMshure ML140E.
rohitdev
rohitdev OP
18 posts
 
yes jwglista, i am getting skeptical of the value we can find sonically in upgrading the 12au7 tubes. I have always been thinking of the reissue gold lion KT88s in favor of the shuguang kt88 z since the price is nearly half!

evilfij - I have the tungsol 6550 reissues and like them. The Electro-harmonix EL34s though are more exciting in the mids than the tungsol 6550 reissues in the primaluna prologue 2.

Currently running in the new mullard 12ax7s. They sang for an hour or so last night and already sound promising...
rohitdev OP
18 posts
 
I am loving the new mullard 12ax7s. Kevin's advice was right on. Smooth organic sound yet the bass is full and less bloated than before. Seems like the noise floor went down and there is more detail. I bet the NOS mullard cv4004 may have been better. But am satisfied for the $ / sonics value of the new mullard.
rohitdev OP
18 posts
 
I just got my Shuguang KT88z treasures Grade A. Thanks Horchai for the suggestion. They sound so well balanced and full bodied right out of the box! I have read that it just gets better. But recommended burn in is 300 hours?!! I bought these from the tubestore. The guys are awesome. Such a pleasure to deal with the people there. Tried to buy these treasures from grant fidelity initially but they said it wouldnt be here by Xmas. That was just ridiculuous. I ordered mine on 12/13 and I got it on 12/14. Oh well not my loss. I am just going to enjoy the music.
david12
1,398 posts
 
Any views on the Shuangung Psvanne tubes the 12AUX7 , imported by Grant Fidelity? I have been thinking about them for my amp, thanks
knghifi
1,667 posts
 
Love the Telefunken 12au7 ribbed plate in my VAC Sig MKIIa. It's high resolution, detailed, clear, high end extension ... just awesome. The smooth plate is too warm for me.

Also have success with Telefunken 12ax7 ribbed plate in a McIntosh MC2200. The stock Chinese tubes are JUNK and can't believe the improvements with the Tele.

Love the Shuangung BT CV181-Z in my MW Transporter so also curious about the Shuangung Psvanne 12au7.
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