Hi everyone,
I received Glenn's OTL amplifier a few weeks ago (see picture below) and I have been enjoying it very much... so much that I didn't have time to write much lately
I posted some preliminary impressions on my blog (tweak-fi), but here is a copy of what I wrote using the ALO recabled Beyer T1s :
"Power tubes :
- With the two RCA 6AS7s, the sound is reminiscent of a bigger more complete LD MKIII - it is very appealing, and simple to like
- With the six RCA 6BL7s, the sound was very different : much more refined, more extended in the frequency extremes, more delicate ... but it took me some time to "get it"
Driver tubes (6SN7) :
- The sound with the stock 6SN7 RCA Glenn provided with the amp was neutral and dead quiet (no noticeable noise floor with my Beyer T1s)
- The sound with Sylvania 6SN7W was very nice : more refined, richer and warmer than the "stock" RCA. However, the noise floor is higher than the stock one, though once the music is playing, it goes slightly unnoticed
- The sound with the VT231 6SN7 Sylvania was fantastic : great timber, great soundstage and excellent resolution but there is a annoying buzzing on the right channel --> I hope it can disappear with burn-in
Rectifier :
- I personally didn't like much the sound of the 3DG4 tube (Westinghouse and Zenith). The sound was very "strong"/powerful but at the expense of the soundstage layering and spaciounsness
- The 5AW4 RCA worked better, especially in the soundstage department
I wrote those impressions after listening for only a few hours. I will post some more detailed impressions/review later on.
But the more I have listened to this amp, the more I came to appreciate what Glenn has done. It is a dynamic, fast, accurate and "rich sounding" amplifier. I was fearing that a tube amp might be too warm or not enough detailed, but the resolution of Glenn's amplifier is as good or better than anything I have had the pleasure to listen to."
Since then, I acquire the HD800s and they worked perfectly with the amplifier.
I am wondering about a few things though :
- Can one use six 6SN7s on the amplifier instead of six 6BL7s?
- Would the gain of 6SN7s be higher or lower than that of the 6BL7s (in the output stage)?
- Has anyone tried anything than the 3DG4/5AW4s as rectifiers for Glenn OTL amps?
- I looked around for "modern" 6SN7s to try - and I came across the Sophia ones. Did any one try that brand? Is it really low noise?
I will write a detailed review of Glenn's amplifier in the coming weeks as I get a better hold/understanding on the sound with both the Beyer T1s and HD800s.
Happy tunes everyone!
