I am back to Syl vt231 from Bad boy playing "Trinity Sessionn " by Cowboy Junkies . It is much more transparent with deeper stage and nuanced and spooky details. That is why I had used it in Line Magnetic 508 amp for two years. The only downside of it is that its bass sound too controlled (not bad but it would be nice if it sounds full as Kenrad or Bad boy). I guess TS bgrp will sound similar to Syl vt231. Let us see whether TS is worth 4 times of cost of RCA , Syl or KR.
@thomaskong I'm glad you're finding the 5691 as having the most transparency among your lot as I did mine. Beyond transparency, for me it is its speed that thrills me the most. Hearing extra hidden notes in guitar riffs, more articulation of lyrics I never knew were there - a greater sense of flutter and nuance. Such an amazing tube for $80, I also have an extra pair but it's GE branded and looks exactly the same. Combining this tube with the TSBGRPs takes these traits into overdrive. They are the most holographic 6SN7s, transparency and see-throughness in spades. They also have an overall sense of neutrality, which sounds true to the source because they don't sound the same on every song.
@Pedro Guillemain You can reach out to The Sound of Tao on WBF. I believe he had his LM 508ia modded by the same person ( I may be mistaken). Check out the Psvane Acme thread over there.
I really like Rca 5691. I had done shootout of 6sn7 tubes. Although I agree that TS bgrp is the best tube with see through transparency but it is overpriced compared with KR, RCA, Syl, RT vt 231s. I was blown away by the performance of Raytheon vt231 which I paid 80$. It is 90% as good as TS bgrp. Shootout of Nos 6sn7 tubes
Anyone have a small amount of background hum on their LM-508IA that can't be reduced completely with the hum cancel pots? I am helping a friend minimize it on his system. He has a 230v version with a 120v-240v step-up transformer. It appears the ground is lifted. We used a real-time spectrum analyzer app on an Ipad to minimize the 120Hz peaks, but he can still hear some hum. Does this design inherently have slightly more hum because of the 300B cathode follower driving the 805 grid?
after correcting with the hum adjustment pots on my 805ia, i have to put my ears within inches of the speakers to be able to hear hum. likewise with a very small mechanical hum from the right side of the amp itself. the speaker hum might in fact be lower than with my previous SS amp.
Hi all. I got a 508IA, 230v (local voltage is also 230v). I like it a lot and have no issues, except for one: When using the IR remote, I hear a buzz from left speaker. It continues as long as I press and hold any button. It happens with any IR remote (TV, AC...). Any idea what's going on and how to solve it? Thanks
Hello guys My ACMEs 805 are delayed on transit due to this Covid-19 problem. I can't wait! During this waiting time, I've just changed the Psvane 805 A-TII I had on my LM-508IA with a new pair of the exact same valves I had for spare because one of the valves wasn't able to reach 120V on bias, even setting bias at their max position. It reached about 110/115V. So I decided to change the pair for a new one, the exact same valves and bought from the same seller (www.china-hifi-audio.com). Well, to my surprise, the sound got better, sweeter, more detailed and controlled. Eventhough, I changed the lay out of the gear, adding more space between them, wich helps with noise and vibrations, I believe the bigger difference in sound was due to the valve change. The downside of this event is that, according to my calculations, these 805 valves replaced were about 8 to 10 months old and I think with about 800 to 1.000 hours of use at low to medium volume levels (I only crank the volume up once in a while and during few seconds as I care about my ears). I use a preamp, but I guess it must be around 8 to 10 on the dial using the LM-508 as integrated. What I mean with all of that is that the I believe the 805 valves lifespan is quite short (about a year or so) and, if the ACMEs really raise the amp to another level, it will be hard for me to go down again to cheaper valves and it will require an considerable expense. I would like to know about your experiences with the 805 or 845 valves on LM amps. By the way, the "old" valves worked fine, just one of them couldnt hold bias. I guess they can last longer, but not sounding as good as new (by a considerable margin), that's for sure. On the other hand, I know preamp valves last longer and they are not too expensive, so I don't worry about them, but I have the Shuguang WE300B Replica, wich are also not cheap, and I much prefer them over the less expensive Gold Lions 300B I also have. I believe 300B valves should last longer, isn't it? I hope so! It will be too expensive to also have to change them once a year!
Had you got parts from Robert Lai? I may need to try that since popping noise upon turn off from left channel is not from defective tubes. It is really cumbersome to disconnect left side speaker cable before turning off the amp.
My Acme 805 and 300B had been working fine for 2k hours so far without sign of any detrioration. I hope that they last 5K hous or more . But who knows! If Acme 805 die in the future, I may try United Nos 805 that I had kept for almost 2 years. The only reason that I had not tried United Nos 805 is that I need to use cap to supply voltage. Regarding 300b, there are many options, thus I will not think about it until Acme 300B fails.
No, I still have to close it with Robert. I think I will do it this week. Then he has to send me the parts and I have to put them on the amp. I will post my impressions ASAP, but I think it will take about a month or so.
Welcome to LM508 club! Lot of work on tube rolling. It could be fun or hassle. I never had problem with IR remote. You had better contact seller about the problem. He may send new remote to you.
No. I'd suggest switching tubes if you have spares. If the hum is occurring in both channels, I'd start with the 6SL7 as it's the only tube affecting both. No but I'd suggest recording a video so we can hear the noise when the remote is in use. In the meantime, I'd suggest turning off all the breakers in your electrical panel to test it again. If it doesn't make noise any longer, something else is interfering to create the noise. If you have a universal remote like the Logitech Harmony, you could configure it to produce the same signal as the Line Magnetic remote if only to see whether the same behavior is heard. Personally, I very much doubt the issue is caused by the remote and believe the problem is due to either a defective component within the amp or something else causing interference. I bought some NOS RCA 805s which will last far longer than most new power amp tubes. If you ever find yourself in the position of needing to change your power tubes again, I'd suggest looking into that avenue so as to avoid the need to change as often as you've had.
The source of buzz is definitely not the remote itself, because I get the same buzz with any other remote. I will try to catch it on video and uploaded Thanks
I'd also be curious to know if you switch the speaker outputs so the channels are reversed (L speaker is now plugged into R output of the amp and R speaker is plugged in L output of the amp) if the noise would occur in the speaker that is physically on the left side.
On close inspections I realize that there is a lower buzz from right speaker. Later on I will try to switch between speaker cables.
Tube rolling tips to new comer. The best improvement for the value is 5691 Rca red base(6sl7) recommended by @Adamaley. There are many nice 6sn7 tubes. 6SN7 VT I recommend vt231(militry version made in 1940's). All vt231 (Sylvania, Kenrad, Rca, Raytheon and Tung sol) are excellent. Bass Kr, Rca, Rt, TS , Syl in the order Transparency TS, Syl, Kr, RT, RCA Details Syl, TS, Kr, RT, RCA Tonal balance Kr, RCA, TS, RT, Syl Soundstage width RCA, Syl, TS, Kr, RT Soundstage Depth TS, Kr, Syl, RT, RCA Thus overall they are close in SQ. Unless you want see-through transparency, you do not need to pay 500$ for TS bgrp. Kr is attractive due to best bass and sweet tonality. Syl is attractive due to excellent details and transparency RCA give warm and lush sound which make one comfortable with nice bass. RT is not far behind other ones. maybe best value as available around 100$ at Ebay TS’s bass is close to Syl with tight but not full impact compared with KR. It could be hit and miss to get Nos tube from Ebay. But you can minimize the risk by ordering tubes from dealers with good rating and return offer. Psavne Acme 805 and 300B will make Lm 508 or 805 shine but they are costly around 900$ per pair. Psvane Vacuum tube & Amplifiers Acme 805 is on sale from dealer that I had bought. He is fast with shipping and replaced faulty ones quick. I can recommend him.
After you close the deal, please let me know his contact email or details of deal. It will be better if you PM me. thanks Thomas
That confirms the issue is a component in the amp and not a problem with the remote. My guess is the motor that spins the volume bleeds interference into that channel. If your amp's under warranty, contact your dealer. Otherwise, you can bring it to a tech to have it looked into.
Thing is, it's happening with remotes of all other components, such as TV, AC, that doesn't activate the volume motor
Ah, that's important info that wasn't mentioned. What you're experiencing is likely RFI. You'll have to do some research on the different troubleshooting steps and potential solutions to address the problem. The only other possibility is there is in fact an issue with the RF "eye" of the LM that is causing this problem and a tech would need to look into it for you. I'm afraid there is no direct easy solution that I can provide for this issue.
I just covered the IR "eye" of the LM and no buzzing when using any remote. Since I use the Pre in function (PS Audio is my pre amp), this is a good solution. Thank you!
