Tube Rolling For ASL Hurricanes

Gbmcleod:

It's been sometime since your post. What has been your experience in changing the 6SN7s? Do you prefer the stock tubes?

I would be interested to hear which tubes you've tried.

My experience is the NOS tubes I wrote about (still using the same combination) improved every aspect of the sound while remaining nuetral in terms of the "stock" sound.

I would love to hear your comments

I have had both the older version (MIT caps) moded by Israel Blume and the latest version (new grey green PIO metal can caps). I prefer the newer version, they seem a little smoother in the mid-range.

A word of advice - you must replace the stock tubes to get any where near the capablities of these amps.

I have replaced the power tubes with the new Electo-Harmonix KT-88s. The new version come with the Value Arts which are good. The EHs are vastly superior. I encourge you visit this web site:

www.hometheaterhifi.com/volume_9_2/power-tube-comparison-6-2002.html.

Jason gives a great discription of the various 6550 and KT-88s.

Next, I replaced the driver tubes (the orignals are Chinese copy of the metal based Slyvania 6SN7 Ws). Here I have tried just about every NOS 6SN7 there are (notable exception the NUs)and even a set of Mullard ECC32s. Here is a list: Slyvania 6SN7W (Metal base & black base both short and tall),WGA, WGT, Tall boys , VT-231, 52s, Kenrads VT-231, dark and clear glass, Tung-sols Vt-231 grey glass, RCA VT-231 grey glass.
Hear is the best combination I have herad yet RCA VT-231 Grey Glass in position 1, Sly metal base in position 2 ,and Tung-sol Grey glass in position 3.

The sound improvement is unbelieveable. Same tonal neutrality with major improvements in resolution, imaging depth and width of sound staging, three dementionality. More extended on top, and much more extended in the bottom.

Before you judge these amps you have to hear them with at least a decent set of NOS drivers.

The addition of top gun power chords and a set of richard greys also helped overall, but no where near the NOS and Power tube upgrades.

I have had no reliablity problems. These amps have to come a long ways, it is not surprising some people have had a defective pair or two.

For the $4400 these amps cost, they are a steal. They have beaten amps priced five times as much! I can see why some people who have $20,000 amps are a little testy about some of the positive reviews these amps have recieved.

Enjoy!!!

Ecclectique wrote - "What I found most interesting about rb99's selection of drivers... was the order in which he combined them to "voice" his amps.Oddly enough...I use "exactly" the same tubes, and in "exactly" the same order in my amplifiers as well."

I tried virtually all combinations, including using all the same tube, i.e., three RCA grey glasses. The synergies of having difference tubes kind of surprised me. I alway thought the closer the matching of the drivers tubes the better. The strength of these three tubes combines to keep the tonality fairly neutral, but improved all other aspects of the sound. The biggest improvement is in the bass extention and control.

I have to note the ECC32 where very seductive - if someone prefered a warmer/lush sound these would be a good choice in leau of the Sly W metal bases.

The only 6sn7 I have still to try are the Raytheons and the National Unions. The NU are supposted to sound alot like the Ken-Rad Dark Glass, which I did not care for. The Raytheons could possibly be a good choice. I'll let you know.

Thanks for sharing your experiences with tube rolling in your ASL amp.

Best regards.

Kana813 - I wonder why?

I'll try RCA 5692s. Thanks.