Pap C1 crossover at 500 hz. PAP-C1, Custom Active Analog Crossover for Open Baffle - PureAudioProject LM 508 500hz up Rogue Cronus Magnum II 500hz down If you want biamping, you had better use active croosvoer. Another thing is Class D does not mix well with LM 508. I enjoy unlimeted dynamics out of Altec A7 and two 18 inch Scaena subwoofer added on 56 hz down.
I recommend you to get Altec A7 in Argentina if possible. It works well with LM 508 even with original passive network.
Hi guys There's noise on the right channel of my LM-508. It has been since a while and I think it may be the reason the 300B Golden Lion on that channel blow up. I've tried swaping tubes, but the noise remained. It's like high frequency buzz, like static on vinil, but a bit louder and there's also randomly some low frequency pops. It also seems to be affected somehow by the meters when I turn the light on or I set bias. Eventhough I don't hear it when the music is playing and the sound is very good as usual, it's a little bit annoying and I don't want to risk another tube or the amp itself. I will take next week the LM-508 to a tech guy here, but he's not a tube amp specialist and I can't find one in town. Any thoughts on what could that be? Should I run some test before taking it to the tech? Any suggestion for him?
Same symptoms I experienced with my amp. Read my thread and get it modified but someone who works with tube amps. Drive to neighboring towns if you need to. It needs to be done right. Design flaw for Line Magnetic's LM-508IA.
Hi Scott Thank you for the answer. I've done that change, two years ago, exactly as you mentioned in that thread and it worked perfectly, we measure it. It shouldn't be that, but I will ask the tech to control it again as he did it last time. If he can't solve it, I think I can find one to do it 100 miles from here, but if I can, I would like to avoid the trip.
I'm not Scott. You're welcome. I experienced those same symptoms which were linked to that cap eventually blowing up. Once it was replaced, everything was fine. The only other thing I could think of would be a defective tube but since the issue doesn't change channels when you reverse the tubes, it's very likely the cap. If your tech followed the advice in my thread to add the diode, even if the new cap fails, the diode would protect the amp/rest of the circuitry. However, it'd be best to get that taken care proactively. Keep us informed!
Yes, and I've tried another tubes also. I thought that it was the Amerty Mullard 6C8G, but then I tried the Ken Rad 6C8G, wich I can confirm is the same tube as the Amerty, and the noise was still there. I've also tried changing the tubes on the 6SN7 spots and swaping the 300B and 805.
I've read that some out there have replaced the stock feet with isoAcoustics Bordeaux's. Has anybody tried using GAIA's. Looks like the GAIA II's are in the correct weight range, but I haven't removed the feet yet to see how they are screwed in to see if they would work. Also, am I correct that there is just a screw under the felt on the stock feet?
As a suggestion, try some tube dampeners first. That could accomplish a similar feat at a much lower price.
Thanks! I do have a set of Bourdeax's from an old set of speakers that I don't have any longer so I figure I'll give them a shot. Was just curious to see if anybody had tried GAIA's. Seems like a nice and clean option. I also want to confirm that it's just a matter of removing a screw from the stock feet before I go ripping off the felt
Hmmm. Still got a gentle yet noticeable hum through the speakers. I've done a pretty thorough overhaul of the electrics and think I have a handle on the potential issues there. Is there a chance that it's a tube running out of life? If so, is it more likely to be the smaller tubes, or the 300B etc? I've replaced the 6Sl7 but could it be perhaps the two 6SN7s? Or is this just not what tubes do when they start to run wide of spec?
Any of you LM owners know what to do when the unit will not come out of mute at startup? I have a LM211IA. Thanks.
Is this for one or both channels? If the former, switch tubes around to see if the issue changes channels. Otherwise, switch the 6SL7 to see if the issue goes away. If the answer is "no" in either case, the problem is with the electronics and not tube-related.
Hi guys, I finally found what's causing the noise on the right channel of my LM-508. As I mentioned, it's like a big mosquito on the tweeter that's not audible when music is playing, but annoying when not. There's seems to be an electric compatibility/leak problem with the 6C8G to 6SL7 adapters and the amp as I have three adapters (same model) and three diferent 6C8G tubes and all of the combinations make noise. Also, as soon as I place a regular 6SL7, or the Mullard ECC35, without adapter of course, the noise ends. The adapters are like this ones: 9.64US $ |Asiento de conversión de tubo, accesorios de sonido de, asiento grande de conversión de ocho pies 6F8G a 6SN7/6H8C/6N8P|Transformadores| - AliExpress I've tried cleaning the contacts, but nothing happens. If I slowly move the upper connector of the adapter, when the amp is on, the noise changes a little bit, but remains, so I think it could related to the cable and plug the adapters have, but I have not a clue. I really want to solve it because my favourite tubes on that slot are, by far, the Amerty-Mullard and the Ken Rad 6C8G. Has anyone have any similar issue? What can it be? What could I try to solve it?
It's possibly the adapter. Buy some made by other sellers and try those. I've tried those and have not experienced the issue you describe. Tube adapter 6F8G to 6SN7 - 1 pair | eBay
But if there was a problem with the adapters I should experience a similar problem on both channels and something when I used the adapters with 6F8G tubes also. It's weird. Could it be anything related with ground loops or an electric leak considering the 6SL7 tube works as rectifier in the LM-508? What's the function of the top connectors in 6C8G tubes?
I replaced Synergistic blue fuse (which I had used for 3 years) with purple one in Line Magnetic 508 amp. It seems to make substantial improvement without break in. It make sound faster with sharper focus but not overdone. 200$ well spent
Hi guys, I've just received a pair of EML 300B XLS last week for my LM-508. I wasn't expecting a big change. Oh boy, I was wrong. What a nice pair of tubes. Even cold from the box, they are better on "everything" than my Shuguangs 300B WE Replica. Improved 3D soundstage, detail, tone, transients, realism, etc. I bought them as they offer 5 year warranty, but even without it, they are worthwile for me. I also had the Golden Lions 300B and I also prefered them over the Shugangs, but not by much as I do with the EML. As the GL lasted about a year and a half, EML will cost me about the same per year considering their 5 year warranty. I can say for sure that every valve in this amp has an impact in sound quality, but I'm not sure wich one matter the most. I would advice to upgrade all the tubes, of course experimenting more with low signal tubes as they are cheaper.
You're welcome. It sucks but if you spend the money, you can get some really nice tubes. I don't like spending money on tubes but all of the best tubes have cost me a lot of money. Cheap & best tubes for this amp aren't a combination that exists in my experience. There's good, great, and best; to get "best", you need to spend, spend, spend... unfortunately. Glad you like the EMLs as much as I do.
I had been using EML 300B XLS for last 15 months. Since I got lazy , I had not done comparison of it with either Psvane Acme or WE 300b made in 50's. But EML 300B XLS sounds nice enough overall.
