Since you are doing 805 tryout, try to get a pair of amperex 805 with the metal frame. For the few minutes that I had it running before one of them loss bias, they sounded quite good. I returned the bad one but not able to find matching one for the other.
Amperex also have a house sound of round midrange. I enjoy Amperex 12au7 in Rogue Cronus Magnum II which is used to drive my Raal SR1a headphone. Amperex 6sn7 sound rather dull despite nice midrange. Thus Amperex 805 may also sound dull in my system. After trying National Union, I may give tryout of Amperex 805 if it is available in good condition.
Melz 1578 made in 72 (6sn7) and Acme 300b stays in my LM 508 all the time. It is hard to bump them in my system. But I take turns on 6sl7 tubes depending on 805 to be used. Brimar or Mullard ECC35 work well with RCA 805 made in 60's. Russian 6n9s or RCA 5691 work well with Acme 805, United 805 and RCA vt 143 made in 1943.
What's the logic for that? Only thing I could think of would be that fewer vibrations would benefit the tubes themselves but then again, there are tube dampeners which can be purchased and accomplish that feat.
I'm also expecting an Amperex 805 pair tomorrow, which I believe is a rebranded National Union (I may be wrong here). All the same, it'll be another datapoint for the group.
Both internal and external vibrations impact the sound. Getting rid of them improved imaging and presentation of detail and clarity in my system. It's definitely worth experimenting before settling on a solution. I had a Sistrum Apprentice platform initially underneath my amp but it sucked out my midrange. Moving to the Isoacoustics brought benefits without downsides. I combined the Sistrum with the Oreas as seen in the image below, but eventually preferred the sound with just the Isoacoustics Orea Bordeauxs.
I have a set of three Isoacoustics Orea Bordeauxs that I don't use. I can send them to whomever is willing to pay for shipping to try them out for a couple of weeks or so. If other members want to ascertain whether it's useful in their system we can have them travel around. I preferred using three rather than four under my amp. One in front and two in the back, but of course, experimentation is in order.
Mine are already on the way - they are returnable - otherwise I would have taken you up on your offer! Thanks.
Followup on that post from September. I have been using a pair of Jupiter Copper between 6SL7 and 6SN7 and a pair of Miflex KCPU between 6SN7 and 300B. I actually acquired another pair of Jupiter but I ended up putting them in my DAC instead as it worked out really well there. Recently I made another capacitor purchase and I managed to swap out that pair of Jupiter from my DAC. So today I replaced the Miflex. These Jupiters are worth every penny. While the Miflex has great bass definition it sounded dark at the top, the Jupiter opened up the top end with great clarity without sacrificing much at the bottom end. Everything image better now and the tonal balance is better. As to compare to the Wavac. The Wavac is still better in detail. The 508IA with the Jupiter also can reproduce the same sound, but the Wavac reproduces it with smoothness and naturalness while the 508IA is a bit too aggressive and forceful, the excessive amount of dynamics makes the sound less real. I will try to tune some of the power supply capacitor to see if that can be fixed. So if anyone want to do some quick (but not cheap) upgrades, I highly recommend the Jupiter Copper.
Thanks for that! Which cap numbers would need to be replaced to perform the same mod and which specific caps would need to be bought?
I notice that Line Magnetic Australia really promotes use of the German ELROG 300B tubes (they make 3 types of 300B's) for highest performance. Has anyone here tried them?
I'm buying this amp this spring. Been trying to find reviews or anything on it. So far nothing but sound test videos on youtube.
I'd love a pair as I've read they're terrific but the price is really high; about twice what I paid for my EML 300B-XLS. I believe @adamaley tried them.
C102 and C103. Replace with the following (you need 4 of them): Jupiter Copper 0.1uF - Jupiter Capacitor 0.1uF 600Vdc Copper Foil The caveat is that this cap need 200+ hours to burn in. I left mine in my DAC and ran it 24/7 for 1.5 weeks. If done in the 508IA, it will take months of music listening. or if you don't mind leaving 0.5kW running 24/7 for that long for burn in purpose only. It might end up burning a hole in the wallet too.
Over the weekend I did some more tuning. I removed one of the large Mundorf power cap that I had on before. I thought that the 22uF would be beneficial, it does make things dynamic but perhaps too much of a good thing. I replaced it with the small Miflex that I took out earlier and now the overall is smoother. There is enough dynamics without being too aggressive. I understand that Mundorf has good reputation, but I ended up removing more Mundorf cap than putting on. Perhaps they just don't agree with my ears. The amp is sounding really good now. I think soon I will be able to come with a complete upgrade recommendation list.
lol. Don't expect any ground breaking research. It will mostly be consolidating what I have posted so far in this thread.
Hi guys I've tried some 6SL7 valves I had at hand and some I bought. Here is the picture and my thoughts: From left to right: - I have a couple of Tung Sol black glass. I'm not an expert, but I believe the second one is round plate. I really don't know if it's THE round plate all rave about, but it has it. Both are nice valves, but the worse from the pack. Not too engaging. - Brimar 6SL7 GT. Very nice. Very balanced and good soundstage. Better than the TS. - Sylvania 6SL7 WGT Brown Base. WOW, what a nice one. Dynamic, smooth, good bass, 3D soundstage, realism, ambience, etc. Beautiful valve. The only caveat, "maybe" is that is "a little" too forward sounding and "maybe" it lacks some little depth in the soundstage, but it could be my perception. - Melz 6N9S. Very nice valve. Balanced and sweet, but not as 3D and engaging as the Sylvania BB. Nevertheless, I could live very happy with this one. - Sylvania Vt-229. To be honest, I tried this one days ago and I'm writing on what I recall. Very nice one too. I guess quite similar as Sylvania BB, but not as good. Not as smooth and holographic. I have a Raytheon Vt-229 in stock. I will try it next year. I guess I'm done with 6SL7 rolling for now. Hope it helps. Happy listening!
That's because they're not the round plate ones. I've owned a couple of pairs. These are not it. The round plate ones are very expensive so if you see an inexpensive Tung-Sol, it's not the round plate one, guaranteed.
Ok, agree. But as they also have round plates and black glass, how do you know wich one is the real deal TS BG RP? Could you share some pictures with us? Just for the record
No, the ones you have do not have round plates. The round plates one do have black glass, however. These are the real deal. You can see the huge pictures there and compare to what you have. 2, NEW, Tung Sol JAN-CTL-6SN7GT, VT-231, wartime, black round plate, match pair | eBay
I bought a pair of vintage Tung-Sol 6SN7GT's from a guy who had purchased through Vintage Tube Services. They are the real deal and are the best sounding 6SN7's I've rolled so far into the LM805ia. Thankfully I paid less than half what that guy on eBay is charging
Hi guys One question. I've found here un my country a very famous 6SN7 (single valve) almost free and with warranty of good working condition. I buy it and I would like to test it on the LM-508. To do that I need to try it with a different 6SN7 on the other channel of the amp. I believe I wouldn't harm the amp even they are different 6SN7 valves. Am I correct? If it works fine, I can buy the other one somewhere abroad and finally get a pair at a very very reasonable total price.
