Tubes for VAC PA 100/100

Just got this beauty yesterday and I am pretty impressed so far. Any owners have thoughts on replacement KT-88s or other feedback regarding this amp?


A couple of months ago I purchased a used VAC PA 100/ 100 and it arrived with some Electro Harmonix tubes that sound good.

The amp did arrive with a non stock power cord. According to VAC the PA 100/100 sound varies more than most of their amps, depending on power cord used. I ordered the original stock cord from VAC for $20 or so and it sounds a bit better than an old Aragon cord I was using.

Last week I had listened to some rental cords from The Cable Company including an Elrod which definetly made it sound better, (fuller base and better soundstaging) though my bias is towards testing one of Michael Wolff's cords.

A couple of weeks ago I added some Argent Audio Pursang interconnects and in conjunction with the VAC the quality of the sound and the soundstage benefited.
I use Kt-88 tubes from VAC and Chinese tubes from The Tube Store. They are both good tubes that retain the sound of the original tubes that came with the amp. The E-H tubes are suppose to be very dark sounding and will make the amp sound very different than the factory sound.
I just completely retubed mine in the past few weeks.

I just got the EH K88s and I think they are smoother and more nuanced with bigger/better range top to bottom.

Previously had Valve Art and the original stock (Golden Dragons relabled?). EH much better than stock. Stock slightly better for some mucic than Valve Art IMHO.

I have been playing with the 12AU7's as well. Just put in a quad of NOS RCA clear tops this week. Jury is still out vs. stock and NOS Mullard. Not that impressed with the Mullard and they had a funny static sound while warming up (but would be fine after a minute). May go back to stock.
Svetlana KT88's,(Winged "C") branded now, are more neutral than the VAC supplied tube. They are not as fat and bloomy through the bottom end with more definition on top. The quality of the driver tube will make a big difference also. I prefer NOS RTC's for their harmonic richness and smoothness. Sylvania 6189's will give more slam for rock and classical. I have tried new EH and JJ in this position and they both suck, bright, hard, thin compared to the other NOS tubes.
Just wanted to add a comment here as I have now had enough time to break-in all the new tubes.

After about 40=50 hours on the RCA clear tops, along with additional time on the new EH KT88 I have to say that the amp is just positively singing now.

Soundstage is wall to wall, seperation, dynamics, detail, are wonderful. Nice tube mid-sweetness but with lots more of low end and clear highs than before.

This is the amp I was hoping for when I got it. Prior to these upgrades I could hear the potential but had not felt the amp had reached it. I think this combo is a vast improvement on stock, or the various combos I mentioned in my previous post.

Good luck and happy rolling.