Line Magnetic 508ia and the Elusive 805 Tube

@slaw3 

After doing a lot of reading on the excellent and very informative discussion on the Steve Hoffman website regarding tube rolling in the LM 508, I tried the EML XLS 300B tubes, which are excellent and definitely a step up from the stock tube. I replaced the 6SN7 tubes with some 1940s vintage Sylvanias from Brent Jesse, which were also terrific. 

I have tried a two or three 6SL7 tubes, settling for now on a Mullard ECC35--it is a bit on the pricey side, but sounds great. I think the finesse of this tube is a nice complement to the robust dynamics of the EML 300Bs.

So far, I have stuck with the stock 805 tubes. I may roll in some others at some point, though what I would really like to try would be some Elrog 300Bs. These are REALLY pricey, so it may be a while before I can experiment with these.

I am not sure I can say which change would result in the biggest difference, but I would certainly suggest trying some different 300Bs. Before you do anything, spend some time reading the Steve Hoffman thread. There are several 508 owners there who have done a lot more tube rolling than I have in their amps. You might benefit from their experiences, as I did.

The 508 is a good amp even with the stock tubes, but you can definitely take it higher by finding a combination of tubes that suits your particular tastes.

Happy listening!

Hello Waltersalas 
Im from Argentina and I bought my 508 from china directly from an authorized dealer because there's no Line Magnetic dealer here and the price difference was huge. 
China-hifi-audio.com https://www.china-hifi-audio.com › ... Its a very profesional dealer and you can trust him. I bought a lot of items from him with out problem. 
One of the things I bought were the Psvane 805A-TII tubes and they were a noticeable upgrade from the stock tubes: especially with more detail and stronger and fuller bass. 
Those Psvane are not too expensive (about USD 150 plus shippment). 
The only thing is that on my second pair, one I bought as a back up, I got one broken. I only had to send it back for a replacement and it cost me about USD 30 for the return shippment. 
I hope it helps. 
Kind regards 
Pedro

PS: I have not tried Mullards, but for 6SN7 and 6SL7 tubes in the 508, I like Tungsol the best, by far. I have tried Sylvania, RCA, GE, Ken Rad, Westinghouse, National and Shuguang Treasure and WE Replica. 

@plga Thanks for responding, Pedro. I appreciate your thoughtful input on my thread.

I hope you enjoy your 508 for a long time to come!

You are welcome Waltersalas. 
I hope one day I can hear your LM-508 with your Tektons DI. I bet they sound GREAT! 
With my Q Acoustics Concept 500 the LM508 sounds BEAUTIFUL!
Specially with upgraded tubes, Power Cord (DH Labs) and Fuse (Hifi Tuning Supreme). 
Kind regards 

Are there any measurements published for this amp when it is driven to peak i.e close to 48 Watts?. 

Anyone here have noticed problems when driven with speakers that are 92 dB efficient?.