[mingles]

I'm completely unfamiliar with rectifier tubes. How much influence does this tube have on the sound?

I haven't finished building my unit, but I need to buy the rest of my parts. How does the Sovtek 5Y3GT sound compared to others? I'm willing to spend more if there's a better tube to use.

thanks in advance.

[PatOMalley]

They matter a lot.
I swapped in a Bendidx 6106 on my Clarinet and it really quieted the microphonics on the AU7's. then I tried a Japanese made Mullard 5AR4 and same thing but very smooth.

What I have understood in coupling caps is that you want to provide the best power to signal so that damping that power coming in by using well made rectifiers like the overbuilt Bendix get you quiet power for the signal, thus less microphony. The Bendix is a darker sound, while the 'Mullard' is not as dark but buttery smooth.

[amandarae]

I'm completely unfamiliar with rectifier tubes. How much influence does this tube have on the sound?

I haven't finished building my unit, but I need to buy the rest of my parts. How does the Sovtek 5Y3GT sound compared to others? I'm willing to spend more if there's a better tube to use.

thanks in advance.

Hello Mike,

Apologies for butting in like this but here's my understanding on rectifier tubes.

The rectifier tube changes the sound of the preamp because each tube, wether they are identical in brand and construction or different in both, and type, will vary the voltage drop on itself when use in a circuit.  When this things happen, the B+ will change.  A shift in B+ changes the power dissipation of the tubes use in the gain stages (12a**) thus affects their operating points.

For example, a 5V4 will have a 25 volt voltage drop, a 5AR4 about 50v, a 5Y3 have 60 volts, a 6106 have 60 volts and so on.  As you can see, it is possible that the 6106 and 5Y3 will sound the same in the preamp but a 5V4 and a 5AR4 is  unlikely.  

So, in retrospect, yes the rectifier changes the sound of the preamp because it changes the voltage operating parameters of the tubes by changing the B+ and not because they are blackplates, made in England, NOS and rare, etc.

Also, FWIW, a 5U4 with a voltage drop of 40-50 is not recommended to use in this preamp because the filament draws higher(3 amp) current  than the 370BX secondary 5V filament winding spec(2A).

If it was me, I will buy what Jim listed in the parts list (Sovtek 5Y3GT) and enjoy the preamp.  I am using the same tube in my preamp after tube rolling the rectifier considerably.   I tried many (Mullard 5AR4 Metal base, Mullard 5AR4 Fat base, Mullard single O, double O, double DD getters 5AR4, Phillips metal base, Amperex metal and black base, Bendix 6106, RCA-Sylvania-Raytheon-Mazda  5Y3 ST's/GT's, and WGA/WGB, and Sylvania-Raytheon-Zenith-RCA 5V4's) rectifier tubes and spent quite a lot of time and considerable amount of money on them.
  
I always go back to the Sovtek.  My reasoning, it sound good to me and the preamp was designed with this tube in consideration.  Very simple.

But of course, if you want to roll the rectifier to find what you like, then go ahead.  It is your preamp after all.


regards,

Abe

I could be wrong of course.....

[mingles]

This site is amazing.

Abe, thanks for the excellent explanation! I'm sold on the Sovtek.

Pat, I appreciate your reply too.

What are you guys using for AX7 and AU7? Are Telefunkens worth rolling in?

[tanchiro58]

Mingles,

I am using Mullard GZ34 BVA as rectifier and Tungsram 12AU7s in my Clarinet. This combination is best to my sonic taste IMO.

Try Osram 5Y3 if you can find one. It has better resolution than other 5Y3 in my system.

[amandarae]

This site is amazing.

Abe, thanks for the excellent explanation! I'm sold on the Sovtek.

Pat, I appreciate your reply too.

What are you guys using for AX7 and AU7? Are Telefunkens worth rolling in?

Hello Mark,

Right now, I have long plate Mullards for the 12AX7's and Amperex Bugle Boy large halo getter on the 12AU7.  My table are mostly idler drives.  When I use my belt drive (Teres), I prefer the Sovtek 12AXLPS on the 12AX7's and Telefunken smooth plate or RCA 5814 on the 12AU7.

regards,

Abe

[PatOMalley]

Now using RCA 5814A blackplates. my favorites. nicest phat tone with large presence

next:

Amperex Holland bugleboys - slightly dark with less bang in the midrange but with delicacy. nice vocals.
Ratheon 12AU7 - lively midrange nice extension
GE 5963 labelled CONN - nice thick midrange similar to RCA BPs
I also like the new production TAD selected shungyang 12AU7 - rougher, not as much sweet detail but with a nice midrange punch. Must try the new production Tung Sols or Mullards next ...