i agree. but i would like to add that generally the 508 is a highly detailed and dynamic amp but it is not considered as a warm sounding by definition, which might get some people dissapointed with the sound. didn't hear the 518 but i know that the 210 or 217 for example are warmer and have more tubey sound to them. i think it is more of a speaker matching than a tube rolling that counts in the end.
Yes. My experience with the 518 is pretty much in step with adamaley's above. It is the total tube combination that is important with such a transparent amp. And the Line Magnetic amps each use several different types of tubes for different duties, giving them an even higher degree of customization to one's tastes. For instance, say you have a particular NOS preamp tube that is a favorite. It has been the best option in a number of other tube components through the years. Obviously a great spot to start your tube rolling in this case too. BUT, once you have identified your favorite output tube, driver tube, or rectifier, your favorite preamp tube may not be the best choice in combination with all your other choices. It is all a balancing act. If you change out one set of tubes to start, it may lead you to want to make a change elsewhere too. I try to keep several different tube options available for each type, so that I can try the different combos. When I was using the stock 845s in my amp, I was very happy with RCA black plate 6L6GCs as driver tubes. But once I switched to the WE845s, I preferred GE 6L6GC. Likewise, I started out with Telefunken smooth plate 12AX7s, but after some other tube changes, I MUCH preferred a pair of Mullard 10M in that spot. All of these are highly regarded tubes, but the combination was what made them shine in each case. I was able to make my amp sound very neutral with a lot of slam. And I was able to switch up the tubes and get incredibly vivid tonal colors. And I was able to get a very balanced sound with lots of texture and smoothness. Right now I have been enjoying the last of these options for quite a while. I expect the 508 responds to tube rolling in much the same way as the 518...
only from a "warm" point of view: yes. you can add some warmth as i did but still i think the 508 is not what you can call a warm/laid back/romantic amp. i asked James from lm-audio about the 210 and 217 models and he confirmed that these 300b amps are warmer sounding by comprasion. i wish i could compare the 210 or 219 in my system. just out of curiosity.
There also needs to be some type of balance or else it wouldn't sound great. For instance, if you just have warm components, the end result will sound muddy and plain terrible. If it's just crystal clear-sounding gear, it'll sound aggressive and brittle.
This was exactly my experience with the 518ia as well. It was truly about balancing the various tube options together and then with ones broader system as a whole. I've been wondering lately about how a 518 with an optimized tube complement would compare to the 508. Probably no use speculating... Having owned the 518, it's still hard to wrap my head around the notion of an amp being so clearly superior to the 518 (not that I'm doubting it). I've heard the 219. I loved it. It was better than the 518 for sure, but we're talking the last few iotas of resolution and texture. I've been really attracted to the idea of an integrated with the small signal tube ---> 300b ----> 845/211/805 for a while. The only integrated I'm aware of (other than the 219 and 508) that has this arrangement and is plausibly in my budget is the Coincident Turbo.
Dear LM 508 user, I need your help. I received the 508. It was playing beautiful music using stock tubes. However, I bought a United Electron NOS 805 tubes and after putting them in, there's no music. The stock tubes are biased by setting the current (ma?) 120 on the VU meter. When I put the NOS 805, the bias meter won't move past 60 on the meter. This is after turning the bias knob all the way towards right. Also, the nos 805 pins are a bit smaller than the stock 805 pins. Not sure if this is relevant. The nos tubes are properly lighting up. But no sound as max biasing is 60ma instead of the 120ma recommended on the manual. Please help!
Sounds like those tubes are either incompatible in some way or just plain bad. If it were me, I'd scrap the idea of using them, send them back and go for a new tube. There are good options from reliable distributors like Grant Fidelity. They distribute Psvane 805A-T which I really love. Or find some TJ Full Music 805's. To me, they sound the best, but can be pretty expensive.
Hello Radiohead99, This is probably a silly question, but are you using lead wires with top cap receptacles with the United Electron tubes? These older tubes have metal caps on top and most of the new production 805s don't. In order to run these older tubes, I think that you need to use a lead wire that you plug one end of into the small hole behind each 805 tube on the LM 508IA, otherwise the tube won't work. The older 805 tubes are fed through the metal cap on top of the tube (something the stock tubes don't have) and the other side of the lead wire ends in a ceramic receptacle for the metal cap. Sorry if I'm stating the obvious.
@JeffC Thank you so much. You weren't stating the obvious. It didn't come with the lead wire. There's a metal cap at the top of the tubes. Where do I get the lead wire and is tgere instruction on how to connect them? @J.D.80 I thought NOS tube should of equal if not better than modern tubes. I heard the psvane are very detailed. My system is already very detailed and extended. Hence wanted to try some NOS, hoping it would be warmer/romantic to balance it out. How'd you describe TJ Fullmusic compare to Psvane? Thank you guys! Very helpful
The Psvane tubes just needed around 100 hours to mellow out. They sound a little cold, and shrill at first. The Full Music tubes I have offer a more dynamic, impactful sound. They actually sound a little more detailed to me than the Psvane tubes so maybe you wouldn't like them after all. The bass I get out of my amp when using the Full Music tubes is considerably deeper and tighter.
Dynamic impactful sound is heavenly for rock/indie music that i primarily listen to. However, most of them are of average sound quality. I actually don't mind the details. But as long as the sound is not bright/thin and don't exacerbate an average quality recording by sounding harsh - I can see myself using TJ Fullmusic. Ideally, I'd want impactful tight bass, lush and smooth midrange with extended high. Any idea, where to purchase lead wire for 805 tubes?
For photos of what these lead wires look like, please have a look at post #440 on page 18 of this thread. Until recently, Rachel at Grant Fidelity was providing the lead wires with purchase of Psvane 805 top-capped tubes but I see now that the website no longer offers these tubes. 2 or 3 months ago I reached out to her about purchasing only the lead wires but she said she only had enough pairs of lead wire to match the pairs of tubes she had to sell. Once I'd discovered (from a note on the Grant Fidelity website regarding the compatibility of the new production top-capped 805 tubes with the LM amp) that the two small nubs behind each 805 tube on the LM 508ia chassis are actually insertion points for one end of the lead wire that allows use of the older style tube, I wanted to source the wires because I was intrigued by the possibility of trying out NOS. I reached out to the shop where I purchased the amp and they were surprised to learn what those small holes were for. I directed them to the statement on the Grant Fidelity site that made clear the newer Psvane tubes with the metal top caps could in fact be used with the 508ia and they got in touch with the importer of LM about this. The importer was adamant in his response that the LM 508ia was not compatible with these older style tubes, which left me confused. So I reached out to James at LM and he confirmed the information on the Grant Fidelity site--that the old style tubes with top meal caps were in fact usable on the LM 508ia. I would think that you could have lead wires made for you by a place like partsconnexion. You might want to reach out to them.
why going for the capped version? i purchased my 805A-T from here: Psvane 805A-T/2 Gematchtes Paar - Vorstufenröhren: Doppeltrioden Tube they packed them really well and they also test the tubes before shipping.
Because there are still NOS (new old stock) 805 tubes available--not made by Psvane-- and some of us are curious about what NOS 805 tubes (these all have the metal cap on top) might add to the sound, since, in my experience at least, upgrading other new production tubes with carefully chosen NOS tubes has always made for better sound.
i'm curious too, i was referring to the psvane only, regular vs capped. i also searched a little bit for a nos 805 tubes when i was rolling mine. it seemed to me they have a shorter pins, at least from the pictures.
@bugo403 Yes, the NOS 805 has shorter pins. Not sure if that is going to be an issue. I'm in the process of getting some lead wires. Lets see if thats going to sort things out. It seems no one here used NOS 805 with their LM 508.
I do have a matched pair of NOS 805 tubes but I'm in the process of auditioning a passive preamplifier and upgrading speaker cabinets for my Tannoy HPD 385s, so there are too many variables at play for me to swap in the NOS tubes just yet. I've had the upgraded non-top-capped Psvanes installed for the last 10 months and have no complaints. If you look at some older reviews of other 805 amps (like the Wavac), you'll see that the enhancement achieved by swapping in NOS tubes is always appreciated.
I rolled an RCA 5691 6SL7 Red Base in the 508ia and I'm really enjoying it's pairing with the Psvane 805ATs. They add body and a 3D sense to everything. This tube really brings the midrange to the fore, and voices are exactly how I expect a SET amp to portray them. As a bonus, they extend the soundstage wider; I'm not sure about deeper, and they are extremely quiet, it's uncanny how black the background is. A plus for me is that they have less gain than the Tung-Sols I was using, and they are much cheaper ($75 eBay auction).
Richard, I, too am intrigued by this preamp. In fact, that’s how I ended up on this thread! ‘Looks like’ 2 x 12A?7, 2 x 205, 5U4 tube complement. SHEER SPECULATION! Always been a sucker for the look of the 205. I’ll report back if I dig up any actual, factual info....
Hello All. Quick Question: Bought a pair of 805A-T from Grand Fidelity and put them in on Monday 2-19-18. Everything was sounding good and was looking forward to getting them broken in, but today the most curious thing happened. I turned on my amp and IMMEDIATELY there was a VERY LOUD humming coming from the amplifier. Not the speakers, but the middle of the amplifier. I am worried to say the least and i'm pretty sure my amplifier needs repair at this point as i've done some trouble shooting and come up with the same results. Just curious if anyone else has experience something like this. Please weigh in with questions or comments. Thanks
The middle of the amplifier is the input voltage transformer isn't it? It shouldn't really have much to do with the output power tubes I'd think but I'm far from being a qualified amplifier technician. There was a day when my amp hummed a bit at that middle transformer, but turns out, they were doing work in my building and whatever tools they were using were making a lot of noise in the line. The hum disappeared as soon as the work stopped. I'm assuming you've moved it to different voltage sources to see if the hum is still there. Or swapping the original tubes back in, or even changing 300b drivers? I always thought the output transformers were susceptible to damage from mishaps like accidentally unplugging a speaker cable while the amplifier was turned on, but didn't think the input voltage transformer would be so delicate a thing that tubes could cause it to break.
Is the bias on each new tube holding steady? Have you tried adjusting the hum balancer? I would definitely follow J.D.80's recommendation and swap back in the stock 805s (re-bias) to see if the hum persists. I'm not sure how loud the hum you are hearing is (can you hear it from the listening position even though it isn't coming through the speakers?), but I definitely noticed changes in the sound of that power transformer during the first 4 months or so or use, and if I recall correctly this was associated with swapping out tubes. Sometimes I'd hear a hum through speakers and then sometimes I'd hear it coming from the power transformer. But that hum was definitely not audible across the room and it eventually subsided. I do still hear a tiny hum coming from the amp and if I put my ear right up to my 15 inch Tannoy driver (the one closer to the amp) I can also hear it faintly in the background. The biggest change I noticed with regard to bringing hum down to a very low level happened when I replaced the stock 300Bs with the Psvane WE replicas.
