Audio Asylum Thread Printer
Get a view of an entire thread on one page
|For Sale Ads|
Hi, I am expecting an Erhard Audio Aretha Preamp to arrive this week... It uses 4 - 6SL7 Tubes. This is a new tube type for me. It was shipped with 4 Tung-Sol 6SL7GT's. I would like some recommendations for good Sounding Old Stock to be on the look out for. I do have some untested RCA 6SL7 GT's and RCA 5691 Red Base Tubes in my possession. Any Information is appreciated! Including any comparisons between 6SN7 and 6SL7 Tubes Sound Wise...Thanks! Chuck
I have this same preamp. I've tried a number of 6SL7 types, but the ones that stand out are older (1940's-50) Tung Sol JAN 6SU7 (brown base, black glass, round plates). If you find some, grab them. I have a few NOS quads that'll I'll keep unless I move away from this preamp.
I had that preamp. The included Tung-Sols were not a good match in my rig but they may be in yours. I found them to be too bright. RCA and Tung-Sol
round plates were the cure. Sylvanias did not work either, they were similar to the new Tung-Sols.
Thanks For the Info... Will be trying some of my RCA's Soon. It came with a pair of Sophia Electric and Sylvania GT's.
RCA 5691 are highly regarded by some. Not to be a wet blanket, but I have found them to be rather unremarkable, and not as clear sounding as many other makes/variants. They're constructed like the Swedish Standard 33S29B, which is another very rare and expensive 6SL7GT type that I find ho-hum. But you have the 5691 already, so give it a try.
I tend to favor tubes that allow sonic detail to emerge. There are many others to try, and some gems from the less expensive end of the pool including:
Ken-Rad (USA) nickel-plate or black-plate 6SL7GT
Rogers/Majestic (Canada) 6SL7GT
CBS (USA) long gray-plate/black-glass 6SL7GT
CBS (USA) gray rounded-plate 6SL7GT
I confess that some of my favorites are hard to come by, and are very expensive:
Valvo (Hamburg Germany) 6SL7GT look similar to Ken-Rad
Valvo (Hamburg Germany) '50s ECC35
Mullard (Blackburn UK) '60s ECC35
I had an amp that used 6SL7's as input tubes, and have enjoyed the sound from Sylvania VT-229's from the 40's.
At least the 6SL7 types are much more reasonable price-wise for NOS compared to the 6SN7's.
When you find some NOS 6SL7's, buy a few extra. You might have to reject some of them due to excessive microphonics.
As it was intended for mobile service, the Loktal 7F7 is less prone to vibration sensitivity.
The rigid individual pins of Loktal types through the glass base is a plus over the common central stem found in Octal stuff.
Thanks for the Savvy Advice!
If you are familiar with NOS 6SN7s, I've found their 6SL7s cousins to have a similar sound. I don't know about current production.
Good point! This has been true in my experience as well.
Thank You Jack! I am familiar with 6SN7 Tubes..
Octal 6SL7 is very close to 9 pin mini 5751. μ = 70. Good OS 6SL7s are NOT easy to come by. The RCA tubes you have easily could be outstanding.
A possibility is building/buying Loktal to Octal adapters and using Loktal 7F7s, which are electrically equivalent to 6SL7s. You can count on Sylvania using the same "cages" in both 6SL7s and 7N7s. They were in business to turn a profit. ;> )
Post a Message!
This post is made possible by the generous support of people like you and our sponsors: