Sorry - they are in my profile so I didn't write them here but I will in case anyone wants to know without digging down there. 1x 5R4GYS Philips (rectifer) 2x 12DF7 Westinghouse (preamp) 2x RCA 6L6GC black plate (driver) 2x RCA 845 (power) For the rectifier, I have and love a Mullard 5AR4, and it's a tossup between that and the Philips. I tried the Mullard 10M 12AX7 and RCA black plate 12AX7 in the preamp - there's just something a tiny bit more refined and less edgy about these Westinghouse that I like. I had the original 6P3P Chinese drivers, switched to 1940s RCA 6L6G (smoky bottle) drivers which I really like but I don't think they mated well gain-wise to the 845s like the 6L6GCs do. And the RCA power tubes, I don't know that I want for more in that department. Although I am lately tempted to try the Elrogs… Amazing that we have these options! I'm glad to hear you're hearing what I'm hearing. Anything we can do to encourage each other to extract more tiny percentages of quality out of our gear is always welcome.
Mok, those sound like tubes for the 518ia. I think these guys were looking for recommendations for the 508ia.
In my initial post (in response to the topic of transformer taps) I wrote that I was talking about my 518ia. (see New Line Magnetic 508ia Integrated Amp ). Then someone asked about my tube rolling on that amp, and this post was the response to that. I realize the topic here is 508ia, but I thought my post was germane to the current discussion, and made sure to qualify it with specifics.
Hello guys, Here is my update to three issues with my LM-508. 1- Design flaw and risk of cap blowing under the right transformer. Cap C36 on the squematics someone uploaded on this forum. That cap recieves reverse voltage during the 30 seconds delay on powering up the amp. It starts at -120V and it ends at -80V. It can be solved perfectly following @Strat-Mangler advice about using a diode. Thank you for warning us and for the solution. The cap on my LM-508 was about to blow! 2- Upgrades of internal parts for better sound. I've bought my LM-508 from China, directly from a chinese LM dealer, as I have no LM dealer here in my country (Argentina). Even if I had, I don't know if I would pay almost double for the same amp. Well, recently I got in touch with Robert Lai from Live Acoustics (Singapore) and he agreed on sending me some internal parts and the instructions for upgrading the amp to his model. Well.... WOW WOW WOW. The LM-508 is a GREAT amp directly from factory, but with Robert's upgrades it's a music BEAST. The music is much more refined and real. I couldn't be happier!! This was a one experiment only and I really don't know if Robert is willing on doing it with other LM-508 owners (or other Line Magnetic amps), but if you are thinking about buying this amp, you really should consider buying it from him, with the mods of course. I believe I'm one of the few people that have tried the amp before and after the mods. NOTE: please don't ask me to send you Roberts instructions as I want to respect his will about not doing it. NOTE II: I know someone will say that hearing memory don't last days, but I can asure you that the mods are worthwile. I've heard my favorite tracks sounding like never before. NOTE III: my system is pretty revealing, so the differences were easily detected. 3- Psvane ACME 805. I bought a pair from China-hifi-Audio online store, Yaqin,Meixing Mingda,XiangSheng,Line Magnetic Tube Amplifier, power amp, preamp,hi-fi CD Player high end audio for sale and one came broken!! I was very worried, but kindly, Mr. Yong sent me a replacement. Well, it came a couple weeks ago, just during the work on the internal parts of the amp, and I could only test it yesterday evening for a few hours. Burning the new internal parts of the amp takes time and I should expect some days before trying any other upgrade on the system, but I wanted to test the replacement valve ASAP to make sure it worked ok as I was a little bit worried about it (they are pretty expensive and shipping companies sometimes don't handle them with enough care). Well, after my preliminar test, my impressions are that the Psvane ACMEs 805 are very nice valves. As they need some more burning time, I'm not sure yet that the upgrade in sound quality with the valves resembles the one with Robert upgrades, but they are very good valves for sure. I would descrive the upgrades with the ACMEs like more vivid and 3D sound. Is like the music finally got separated from the speakers in all directions. There are more "sparkle" on the air and better instrument separation. Details are more evident. NOTE: I also tighten up the LM-508 transformer's srews a little bit. There was a very little speaker hum before, byt now there's no hum whatsoever. Next tweak to it's way: Herbie's tube dampers!!
Okay, gotcha. Sorry, I guess I missed the earlier post. Of course, I found your answer interesting, as I use the same amp. Especially interesting to hear you use original RCA 845s, which I have not had the opportunity to hear.
Thanks for your detailed feedback on modification of LM 508. I have to try the same thing in near future. After having shootout of more than 18 6sn7 Nos tubes, I am having break from paying attention to hardware but just enjoying music. I had settled into 1578 Melz and 6n9s(6sl7) Russian tubes which make me happy with wide and deep soundstage, full bass and excellent dynamics, round mid range and clean treble. What can I expect more? The only issue is some Russian tubes are noisy so you have to deal with dealers who will replace faulty tubes. I expect you to enjoy Psavne Acme 805 tubes which had been working fine in my system for more than 2k hours. Good luck Pedro.
1578 Melz https://www.ebay.com/itm/Matched-pair-Extremely-rare-1578-6N8S-audiophile-6H8S-6SN7-Metal-base/273874731266?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649 But choice of tube depends on system and personal taste. With your warm speaker, Sylvania vt 231 could be good choice.. On the other hand, my system is very revealing which works well with Russian tubes. Shootout of Nos 6sn7 tubes
Hello Thomas I've tried several 6SN7 tubes (Sylvania, Tungsol, RCA, GE, Westinghouse, National and Shuguang Black Treasure) and my favorites were the BT. Nevertheless, it's like you say, system and taste dependant. What I can asure is that, in my experience, Robert mods had a bigger impact on sound quality than rolling valves. Happy listening!
Was curious what the Singapore mods are. While no direct parts number, from googling various descriptions, I can get an idea what type of mods were used in either 518IA or 508IA: German Rectifier, Urushi capacitors, Mundorf capacitors. 1. European Components for the power supply (It’s not the same that you can buy directly from China) 2. Vishay Resistor 3. Vishay Capacitors 4. Kiwame Resistors 5. Mundorf Oil Coupling Capacitors etc 6. Mundorf Power Capacitors. So basically: - better bridge rectifiers for power supply - better power supply caps from Mundorf - better coupling cap using Mundorf Silver Gold Oil - and various resistor upgrades.
I also recommend you to try 6n9s(6sl7) Russian tube 2PCS 6N9S (6H9C) / 6SL7 / 1579 MELZ TUBES! NOS! METAL BASE! TESTED! RARE 50'S! | eBay or RCA 5691 red base. I prefer the former to latter with nuanced details and better bass . But the difference is rather small. I used to use Mullard ECC35 which got beat by both 6n9s and RCA 5691.
I finally got the LM805ia ... was the Singapore Edition (upgraded by Robert Lai). Had it for a few days as it was destined for a customer of mine. All I can say is that this baby is impressive. Even with stock tubes, I enjoyed the amp. Had it hooked up to the Denafrips Pontus then streamed Tidal via my lappie. Pontus and 805 is a good match. Pontus to my SS set up was just ok. The feedback selector impressed me. I never realized what feedback does to the sound. That was a very good function added in by Line Magnetic. As I only had NOS 6SN7s, I tube rolled. With the RCA Red Bass 5692 (50’s), things smoothness out, mids were better too. Using the Sylvania 6SN7GTA (50’s) the sound was more crisp, more air and clarity improved. Now when I used the Pope’s that was even better. But the difference is not night and day but rather it really improves the overall listening experience. I now wonder how much better it may get if I were to also swap the 6SL7 and use the ACME 805 tubes. The LM805ia is very good amp. Guess, I’ll be getting one for myself soon.
German Rectifier is probably just Infineon Schottky diodes. They are like <$4 a piece and 4 is needed. Those will replace the rectifier for the tube high voltage supply. Ultrafast and noise free.
Are you talking about these? 2. 805-DG Overhung Filament vacuum tubes by LINLAI (pair) | Psvane, Treasure, & More: Premium Tubes I have not yet touched the stock Psvane 805's and don't want to have to raise the cage to accommodate the Acme's, so interested in other options. The stock 805's are rebadged Psvane 805 A's ($135/pair). The only other 2 upgrade options that fit in the cage are the Psvane 805 A-T's @ $325/pair or Psvane Cossor's at $200/pair. It seems like the A-T's are a small upgrade on the stock A's? No idea about the Cossor's and how they fit in the Psvane lineup.
Yes. Where are you finding the Cossors for $200/pair? I am trying to avoid directly purchasing from China as shipping takes forever these days and any issues will be hard to resolve. Linlai is supposed to be formed by former Psvane engineers. the 805-DG has some similarities with the ACME. At its price, the ACME is tough to swallow. the Linlai might be half the price at some % of the performance.
back to the 6SN7/6SL7 ... For the 6SL7 slot, I have tried a TS 6SU7GTY, RCA Red Base 5691, and Mullard ECC35. At least with the 805, I think that the Mullard softens things up a bit too much, the TS is the most palpable but a little etched/fatiguing, and the RCA is the most balanced and solid. I think that the strong drive of the RCA is a better match to this first stage of the 508/805 than the finesse of the ECC35. For the 6SN7, I have had been using a pair of TS black glass round plate VT231' s with success. Well rounded, good soundstage, and dynamic. I recently got a pair of Melz 1578's from the late 1960's and while they have a great open top-end, I have struggled with their tonal balance - they sound rather thin at times. I am actually not sure if I got a pair of fake stamped 1578's given the production dates and have had multiple emails with the Russian seller. So will likely send them back and try another pair from the mid 70's if I can find some. I would also like to try some TS 6F8G's but waiting on a pair from mid 40's with the oval mica - want to get the right ones and finish off my tube-rolling on the front-end of the amp. Regardless, the combination of the TS BGRP 6SN7's and RCA 5691 works *very* well in the 508/805 in my opinion. Maybe a bit on the euphonic side but I am ok with that
Yes, that $200/pair is a rough price from all of the Chinese sellers. I don't see any on this side of the water. It would be interesting to know why Grant Fidelity doesn't carry the Cossor line and how they fit in against the regular Psvane tubes. Price aside, I am unsure which of Cossor 805 or 805A-T is better.
I had upgraded from stock tube to Cossor and then to Acme. I still keep Cossor as reserve just in case Acme go out. Cossor is a pretty good upgrade from stock with round texture and cleaner treble It is best to upgrade to Acme from stock if you can afford it. But Cossor also could be meaningful upgrade from stock tube. Psvane Vacuum tube & Amplifiers I had got my Acme and Cossor tube from this dealer. Shipping was fast and he replaced faulty Acme in a week.
this is a pretty funny translation about the new Linlai DG series ... it's all about the bile ducts apparently ... Hook installation filament technology, 211-DG / 845-DG / 805-DG tube,hifi tube
I still keep BT tube. It is a good tube with no serious fault. It sound full and round with pretty good bass which will work well with bright system. Thus I respect your choice. I am about to order modification kit from Lai but I will also keep his trade secret not disclosing details of components. But Syl, RCA vt 231 give more details than BT and Russian tubes and Kenrad vt231 give more dynamics sound with fuller bass.
Ah very good question and I should have mentioned that aspect of my tube rolling. I was on NFB 1 for the full low feedback SET experience but have recently found that dialing it back a bit to NFB 2 is more linear, 'in balance', and less fatiguing over time. How NFB interacts with tube choices is huge. When I first got the 5691 I was using NFB1 and didn't think much of it. So I went back to the ECC35. And then I decided to try NFB 2. And enjoyed it with the ECC35. But then I thought I might as well throw in the 5691 with NFB2. And et voila, it just worked. I know you preferred the ECC35 to the 5691 and TS in another thread. Do you use NFB 1? The ECC35's tonal balance might play better with NFB 1, and the 5691 might be a bit too much. But I prefer the NFB2 setting, particularly with the 5691. (Admittedly I have not tried the TS 6SU7GY on NFB2 yet).
maybe you guys can give me some advice on tube rolling. current this is my setup. Syl VT229, Syl VT231, KR VV302B, stock 805 It is driving a pair of old Focal Mezzo Utopia which has a slightly aggressive top end. I find that while the bass is good, the highs are slightly edgy and not refined. esp loud symphonic passages, the trumpets are a bit harsh. Eg. Mravinsky's Tchaikovsky symphony 4 beginning when the trumpet are going at it. It strains my ears. I don't know if the edginess is from the Syl tubes. The KR is marginally more full body than the stock so that not it. My next step would be to upgrade the stock 805. Cossor, ACME, or take the risk and try out Linlai. Maybe the choice of tube will fix the aggressive top end?
