7 hours ago, carusoracer said:

Hello,

1st time posting. I have had my stock R8 since March 2033, hard to believe.

Question for EL34 owners. Any issues switching from KT88? I tend to think I prefer the warmth of the EL34, however I’m leary of changing over. I lost 2 of the 4 Shuguang Treasure Z series from China HiFi. late last year.

I’m back to the stock KT 88 and it’s just not my cup of tea.

I have several sets of EL34’s in the main system and hate to lose a quad.

2nd, what have others done to improve the performance with the upper end glare. If I could just get that under control I would luv the amp.more. It has been a solid performer other than losing 2 tubes.

Appreciate the feedback, thanks!

Should be no issues switching to EL34's, just lower the bias settings for each tube before inserting the EL34's then once installed adjust to correct settings for them, re-check after a couple of hours then every 2 to 3 months.

1 minute ago, muon* said:

Should be no issues switching to EL34's, just lower the bias settings for each tube before inserting the EL34's then once installed adjust to correct settings for them, re-check after a couple of hours then every 2 to 3 months.

Don't forget the tube type switch on the rear panel of the amplifier! Make sure it is for the correct type of tube you are using.

12 hours ago, jon96789 said:

Not sure how many hours you put on the amp but power tubes do not last long. If you get over 1,000 hours on a set you are doing well. Vintage EL34 tubes can last a couple thousand hours but it is impossible to find NOS vintage tubes at a reasonable price. A quad of Mullard EL34 XF2 British-made tubes can easily fetch way over $1,000. But generally vintage tubes do sound better than what is currently being sold.

Chinese tubes are not known for their reliability. I have read users who say the tubes fail after about 600 hours. The Russian-made New Sensor EL34-type tubes usually last two-three times longer. The New Sensor tubes are the Electro Harmonix (EL34 and 6CA7EH), Mullards, Sovtek, Svetlana, Telefunken, Tung-Sol and the Gold Lion KT77s. They vary in price from about $130-300/quad. Buy tubes from a vendor that matches the tubes before shipping, such as VivaTubes, The Tube Store and TubeDepot.

IMHO, the only decent Chinese EL34-type tube is the Psvane Legend EL34PH tubes, but they are pricey, ~$400/quad. The problem is that I find that Psvane do not match their tubes that well as they do not measure what they claim that they are labeled. I bought a quad of "measured" 45mA tubes and they really measured between 34-40mA. Be aware that these tubes are very picky on the front tubes. Some pairings sound really flat and dull. Newer Psvane tubes such as the ART or Summit series have a clean detailed sound (but IMHO lack warmth) but are priced quite high. On a side note, don't buy the Psvane Horizon tubes from Amazon. Buyers report issues with these tubes, some being DOA, noisy or what is boxed is not what is labeled (my guess is some buyers may be swapping out tubes after purchase and returning them although I hope I am wrong).

If you are still using the OEM stock 6SN7/6SL7 tubes, that is the cause of the high end glare. Replace them with RCA smoked glass 5SN7/6SL7 tubes to get a warmer sound... You can find them on eBay for about $25-100 tube. Just be careful when buying them. Look for matched pairs/triplets. Sylvanias will reduce the glare but not as much as the RCAs.

Sylvania prices are all over the map. You can find good values on eBay as well. Look for the earlier

tubes with the silver getters near the bottom and manufactured in the 1950s. They are usually

labeled as VT231s and VT229s which are the military grade tubes. Avoid tubes that show scorching

on the very top as as it shows as a well used tube.

The tube on the right shows heavy scorching, indicating possible high usage.

Luckily, the front end tubes last a long time because of their lower voltage demands. They can last

from 4,000 to 10,000 hours, unlike power tubes which can fail in about 1,000 to 2,000 hours.

I always enjoy your thorough and knowledgeable posts Jon.

Have you compared the Grey Glass RCA 6SN7 to a Tung Sol Black Glass VT229 ?

I have the latter but pondering the Grey Glass . I have a 1944 pair of Grey Glass in the 6SN7 and they beat everything else I’ve got

The RCAs are warmer but the Tung-Sols are a smidgen cleaner with a bit better clarity. I wish i could afford a set of black glass Tung-Sol VT231s but they are too expensive for me. I also like the Ken-Rad black glass 6SN7/6SL7 tubes. They sound between the RCAs and the Tung-Sols.

Another combo I like is the Sylvania 6SN7W with the metal base, matched with the Sylvania 6SL7WGT Gold with the brown micanol base or the RCA 5691s which are very clean sounding tubes but are a bit lacking in warmth.

I've only been into tube audio since 2023. I was surprised at how many tubes I bought over the years. I have about 80 6SL7s, 90 6SNs, 120 EL34s and 40 KT88s. A good 70+ were given to me by my brother who switched to different tubes (from octal to 9-pins and EL34s to KT88s). He has been into tube audio for about 20 years and some of the tubes he gave me are worth some big bucks, such as the Genalex Gold Monarch KT88s. He bought a case of 24 tubes and he gave me six. Those six tubes are worth about $1500, as well as a quad of vintage Mullard EL34 XF2 tubes which are the best sounding tubes I have ever listened too.

I also have a couple of quads of Matsushita 6CA7s which were tooled using Mullard machines. I think they are the second best sounding tubes I got but the Matsushita seems to be notorious for early failures. The NOS ones measure well but the tubes go downhill pretty fast. I think I'd be lucky to get more than a thousand hours on them.

I also have a couple of dozen Groove Tubes EL34M Mullard clone tubes, 16 being NOS (note, only the EL34M tubes are worth buying. GT made several different variants from China and Russia). These tubes sound better than the New Sensor EL34/6CA7 tubes IMHO, but they need a hundred hours or so to break in. They sound rather mediocre otherwise. They are unavailable in the US but can be bought at Watford Valves in England. Brent Jessee of AudioTubes says that the EL34M are the only tubes that rivaled the original Mullards. Apparently they bought a huge amount when the GTs were still being manufactured. They sell for $50/tube which is very reasonable. They pretest, match and screen every tube before shipping. All of the tubes I got were very tightly matched, being within 1 mA of each other. Watford has been in business since the 1990s. I think they are a small operation as they close down during the holidays and the summer for a couple of weeks at a time.

On a side note, Brent Jessee has just announced his retirement after 30 years in business and will be closing on March 5, 2026.

On 08/02/2026 at 8:36 PM, carusoracer said:

Hello,

1st time posting. I have had my stock R8 since March 2033, hard to believe.

Question for EL34 owners. Any issues switching from KT88? I tend to think I prefer the warmth of the EL34, however I’m leary of changing over. I lost 2 of the 4 Shuguang Treasure Z series from China HiFi. late last year.

I’m back to the stock KT 88 and it’s just not my cup of tea.

I have several sets of EL34’s in the main system and hate to lose a quad.

2nd, what have others done to improve the performance with the upper end glare. If I could just get that under control I would luv the amp.more. It has been a solid performer other than losing 2 tubes.

Appreciate the feedback, thanks!

For powertubes I can recommend https://www.ebay.com/itm/196627649881?_skw=6P3S-E&itmmeta=01KH4M4SMM1VNP3SA18QJYBWCZ&hash=item2dc7ebd559%3Ag%3ACLsAAOSwFCxm8983&itmprp=enc%3AAQALAAAAwGfYFPkwiKCW4ZNSs2u11xDjkA6WmqGcukd131ZrwJgIRFiG31Qa6bwnq7g31vjaPjpGoGzfk7vhJkIqbfHCD1yhKpbRh5tle68MurNUtuUQQIuyRnde0flco3h2fT%2F1yjJY6AbrU1tsFlOdhQ3czE%2FUe2Urae%2Bm3cLEk4w1tAdzj7Z1BBpxlnNvuCN%2FUKY3fFdwkR5T7NBwoPrl6hp4ToiEkk1WzopXrqsU3IxIOOfYS3ziBxdzwAnGbpvp7dROmw%3D%3D%7Ctkp%3ABk9SR7iak5SJZw&keyword=6P3S-E&sacat=0&relatedSearch=true

On 08/02/2026 at 8:36 PM, carusoracer said:

Hello,

1st time posting. I have had my stock R8 since March 2033, hard to believe.

Question for EL34 owners. Any issues switching from KT88? I tend to think I prefer the warmth of the EL34, however I’m leary of changing over. I lost 2 of the 4 Shuguang Treasure Z series from China HiFi. late last year.

I’m back to the stock KT 88 and it’s just not my cup of tea.

I have several sets of EL34’s in the main system and hate to lose a quad.

2nd, what have others done to improve the performance with the upper end glare. If I could just get that under control I would luv the amp.more. It has been a solid performer other than losing 2 tubes.

Appreciate the feedback, thanks!

These will remove the upper end glare https://www.ebay.com/itm/206054272391?_skw=Sylvania+6sl7&itmmeta=01KH4MFC89JDXNGV84JRQFZWVM&hash=item2ff9caad87%3Ag%3A7BkAAeSwzotphp-7&itmprp=enc%3AAQALAAAA8GfYFPkwiKCW4ZNSs2u11xCAYB2rLFHHOGOvSW0eR5ZEbeucCOEdItlNzTresL2PP6Z%2BejfBSPw1D5%2BXebM9s38pUkdDOLRgsunzav6MZZIjpUxWBgyxfUFQaEqEllHZowBZq2hqG9g7x7culPvwQPyEggUTYEsbAKfhdaRCXNeJbKWqWrJmvkLXnEIlMUOvJJtkNEuushVoMzFTfB%2Fj7hOTjkRztKkWLxdYwsHsYqRtWUNeYCw%2BZn%2BlAhnPaBf5zSIgkw%2B36VlBZk7ALAexLUWZgvOCZNt4rYhWMC%2FZ2blGskWROTzaGVowW8ATNUggCA%3D%3D%7Ctkp%3ABk9SR6TEvZSJZw&keyword=Sylvania+6sl7&sacat=0&relatedSearch=true

Hello,

Great posts and some valuable insights on the various tubes and sources. I appreciate all of your feedback!

I recall many years ago getting tubes from Brent Jesses. Always loved to browse his website.

The long and short of it, it’s always down to personal taste. I tend to lean towards the British tweed, creamy midrange, with a sweet yet extended top end, and tight but warm botttom end. Sounds a bit like audio erotica, but I do love my tubes.

My favorite house sound is the late 50’s and early sixties GEC, Gold Lion, Gold Monarch, and Mullard, for the exotic.

The workhorse with sublime character, warmth and longevity is the 1st. Edition, Black bottle Shuguang Treasure Series, all variants, KT 88, 6CA7, and 9 pin 12- series.

If anyone has a tested quad or Octet, of the above for sale please contact / pm.

I may not been as helpful in the original post with my dilemma. Better stated, I’m okay to switch over to EL34 from KT88, with proper biasing, and changing the switch setting, without too much cause for concern? I’m hoping that will help relieve some of the upper end glassy, glare.

I’ve had several tubes losses on my highly modded old Jolida 502 EL34 amp, due to the bias pots going south. Hence my switch to the KT88 Willsenton to try something different.

2 sets of original Svetlana Winged T quads lost. Along with some very old early 70’s Shuguang EL34’s. Hence my trepidation.

My favorite tube is the 6SN7, I have come to settle on the early 50’s and 60’s vintage.

Favorite : 53’ GECB65 , layers of warmth, yet detailed with the sweet top end , that is haunting with female voice and saxophone. I’m still chasing the Gold Lion..

2nd early 6CA7-Z Treasurer Series. Lots of variants, but they gathered the best engineers on a team that collaborated to create the best possible product. This was prior to the split of Shuguang and creation of Pvane, then PSVANE or something similar. It’s all bit hazy but, I remember closely following it at the time. Certainly the arms race was on. Many people gave up due to extreme break in time needed for the gold pinned, black bottled Treasure series. Recommended 150 hours or so I recall. Plus the longevity, robust design and competitive pricing was a big factor. Ultimately, poor Quality Control from clones, and splintering off of the engineers led to their demise. The early years are classics. Resin on the bow, deep moving body of the cello, sweet singing of the strings from a Stradivarius, to delicate tinkling of a triangle. Bold yet balanced, IMHO :-)

Yes! I luv tubes and have had many over the years. Nice to know there are still some audiophiles out there keeping the tubes glowing.

Cheers

I'd pressed my R8 back into service about a month ago after using a Jadis Orchestra for the last while. I've changed speakers a couple of times over the last year, newest ones being Spendor Classic 2/3, and I had an itch to see what they were like with a bit more juice. So I pulled the R8 out, switched out the Groovetube EL 34 I had in there for the stock KT88, and what do you know, it really suited the Spendors. So naturally I immediately went shopping for new KT88s, and ordered a set of Gold Lions.

They finally arrived today after a three week delay due to restocking, out with the old, in with the new, turned the amp on* and immediately the tube in V2 went red and things smelled a bit burny. Turned it off and let everything cool down, tried it in V1 to check and same again. I've mailed the supplier to ask for a replacement, waiting to hear from them now, so stock tubes will go back in. The joys of it eh?

1 hour ago, TK77 said:

turned the amp on* and immediately the tube in V2 went red and

That a shame, sorry to hear that. Did you turn the bios all the way down before turning on the amp?

Hey, yes I did, everything turned down (I added the * in my post to add that detail at the bottom and then forgot all about it).

21 minutes ago, TK77 said:

Hey, yes I did, everything turned down (I added the * in my post to add that detail at the bottom and then forgot all about it).

I also have the gold lion kt88 tubes, but I don't use them cause I'm happy with the much cheaper option 6P3S-E. Perhaps you should try them out while waiting for this to be resolved

You might want to consider replacing the bias pots on the R8 if you have not done so... The bias pots on Chinese amps are a weak point and are known to fail... One pot failed in my R8 as well as my Muzishare X7, taking out a Gold Lion KT88 as well.

I am enjoying a set of Psvane ART Series 6CA7-T3 matched with a set of Sylvania VT229/VT231s... I did not like the Psvanes originally when I paired them with vintage Tung-Sol tubes but they sound pretty darn good with the Sylvanias. I do not care for the Psvane KT-88-T MK IIs in the R8, but they sound decent in the X7 matched with Matsushita 12AU7/12AX7s.

46 minutes ago, EuroPad said:

I also have the gold lion kt88 tubes, but I don't use them cause I'm happy with the much cheaper option 6P3S-E. Perhaps you should try them out while waiting for this to be resolved

I’ve just ordered a set of these on your recommendation. Flipping cheap .

We’ll see how they compare to the Black Treasures or the winged C’s . For the money you can’t really go far wrong

21 minutes ago, jon96789 said:

You might want to consider replacing the bias pots on the R8 if you have not done so... The bias pots on Chinese amps are a weak point and are known to fail... One pot failed in my R8 as well as my Muzishare X7, taking out a Gold Lion KT88 as well.

I am enjoying a set of Psvane ART Series 6CA7-T3 matched with a set of Sylvania VT229/VT231s... I did not like the Psvanes originally when I paired them with vintage Tung-Sol tubes but they sound pretty darn good with the Sylvanias. I do not care for the Psvane KT-88-T MK IIs in the R8, but they sound decent in the X7 matched with Matsushita 12AU7/12AX7s.

Cheers Jon. I did have a bias pot fail on me early on, V4 like a lot of people here, so I changed that and haven't had any issues since. I tried this tube in V1 after initially putting it in V2 and same result. I have the stock Willsenton tubes back in there now and it's all fine again so will wait to hear back from the vendor.

last night, after powering on my R8, i noticed my right channel was silent. I was thinking, not another problem! Switching inputs made no difference, it was still the right channel. I then noticed that the top of the right 6SN7 only had one glowing pin, the other pin was pretty dim. So I switched out the Sylania 6SN7GT and all was well.

I tested the bad tube, it was originally tested with gain of 20.3/19.8 and Mhos of 1905/1935. The tube now measured at 14.4/19.8 and 1000/1895 so the tube went bad. Luckily, i have 10 of these tubes so it was not an issue. It just shows tubes do die at any time.

On 17/02/2026 at 5:57 AM, TK77 said:

Cheers Jon. I did have a bias pot fail on me early on, V4 like a lot of people here, so I changed that and haven't had any issues since. I tried this tube in V1 after initially putting it in V2 and same result. I have the stock Willsenton tubes back in there now and it's all fine again so will wait to hear back from the vendor.

Did you change all the pots or just that one?

Just that one (it was actually someone I'd got to have a look at it for me). I've since done a few of the little jobs on the amp myself, changing caps and so on, so if I do have a pot issue, or I swap it back out to backup amp again, I'll do the other three.

Maybe answered before but what is the reason that there is a loud pop out of the speaker when turning off the R8?

Thanx!

1 hour ago, ThoFi said:

Maybe answered before but what is the reason that there is a loud pop out of the speaker when turning off the R8?

Thanx!

When you switch a tube amp off, the high-voltage rail (the B+) drops away as soon as the power is cut. That happens before everything in the signal path has fully discharged. In that short time the output stage can send a brief voltage spike through the output transformer and into the speakers, which is what you hear as a loud pop/thump. It’s a common characteristic of many tube amps and, on its own, doesn’t usually mean anything is wrong.

Edit: never mind.

Edited February 27Feb 27 by muon*

Loving my R8 and tube rolling, just pulled the trigger on the below

Ray Tube KT88's (Select) matched quad - replacing Tung Sol EL34B's

Ray Tube 6SL7's already had these.

Ray Tube 6NL7 (Reserve) got this dirt cheap

I just need to swap out the two 6NL7's Psvane tubes.

Simply loving this amp!

On 27/2/2026 at 11:51 PM, Barry_72 said:

Loving my R8 and tube rolling, just pulled the trigger on the below

Ray Tube KT88's (Select) matched quad - replacing Tung Sol EL34B's

Ray Tube 6SL7's already had these.

Ray Tube 6NL7 (Reserve) got this dirt cheap

I just need to swap out the two 6NL7's Psvane tubes.

Simply loving this amp!

Since setup.

What Synthesis is that?

On 27/2/2026 at 3:58 AM, muon* said:

Edit: never mind.

…regarding pop noise?

2 hours ago, ThoFi said:

…regarding pop noise?

Was just saying to turn the volume to zero when powering on and off.

But then I don't own an R8 so have no idea if it would help with this amp, so I deleted it.

Edited March 1Mar 1 by muon*

2 hours ago, muon* said:

Was just saying to turn the volume to zero when powering on and off.

But then I don't own an R8 so have no idea if it would help with this amp, so I deleted it.

Thanx.

But, no, didn’t help with the R8