Willsenton's R8 KT88/EL34 Tube Amplifier

[Jon S]

I have a question. Can the Willsenton R8 accomodate KT77 tubes? I know they can use the EL34. 6050 and KT88 tubes. I read that the KT77 can be used in place of the EL34 on other amps. If you drop in the KT77, how would one adjust the bias? Do you still center the bias meter like the other tubes or does the KT77 require a different voltage?

 

[opnly bafld]

I have a question. Can the Willsenton R8 accomodate KT77 tubes? I know they can use the EL34. 6050 and KT88 tubes. I read that the KT77 can be used in place of the EL34 on other amps. If you drop in the KT77, how would one adjust the bias? Do you still center the bias meter like the other tubes or does the KT77 require a different voltage?

https://audiokarma.org/forums/index.php?threads/can-i-swap-el34-for-kt77.935428/

Starts out talking about another amp, but has some comments on the Willsenton.

 

[Jon S]

OOC, if any of you are an upgraded Willsenton R8 owner, what tubes did you upgrade to? How much of an improvement did it make over the stock OEM tubes? Were there any tubes that was a downgrade?

One YouTuber said that the 6SL7 makes the biggest improvement in sound while another said the 6SN7 made the biggest change for him. What is your experience? Apparently, the KT88/EL34 upgrades did not make as much of an impact when they are upgraded. Is this correct?

I noticed that 6SL7 tubes are pretty scarce, with JJ and Tung-Sol being the only new production tubes available. As for the 6SN7, PSVane, Tung-Sol, Electro-Harmonix and Linlai being the most common makers out there.

 

[markmcmuz]

I would look for some NOS Sylvania 6sn7s and 6sl7s or something along those lines. It seemed to me to be a big improvement although I did not do any A/B testing. I did get the upgraded KT88s when I ordered the amp. Was about $200 more than the stock ones.

 

[Jon S]

I just got a pair of Tung-Sol 6SL7 reissues (I ordered them yesterday from the Tubestore in Canada and got it today, even though I did not pay for expedited shipping) and that made a big difference in the soundstage, it was wider as well as with better focus and more air between instruments and vocals. I ordered a set of PSVane KT88-T MK II and CV-181-T MK II and am still awaiting delivery. It was stuck in customs in San Diego for a few days and left a few days ago.

I also just ordered a set PSVane's EL34PH and 6SN7UKs and still awaiting delivery on that as well. Does anyone have any comments on those tubes?

I tried changing the power tubes to a set of vintage British Gold Monarch KT88s, as well as a set of vintage GE EL34s and Neotron 6SN7s. TBH, I did not notice much of a difference from the stock Willsenton tubes (I have both the EL34s and the KT88s) other than a slight improvement in smoothness. Right now I am leaning towards the EL34 over the KT88 for its warmth as well as running in triode mode.

I read somewhere that the bias trim pots on the R8 are not that durable and they get a bit loose with tube changes. Has anyone encountered this issue?

Another item I read is that the bias meter on the R8 reads low, e.g. it is actually under biasing the tube. What effect does this have on the tubes? Does it mean the tubes will have a longer life span? Most users of El34s say that the tubes generally will last about 2500 hours, but that the PSVane EL34PH seem to have a shorter life span. Thanks in advance.

 

[peterh]

I just got a pair of Tung-Sol 6SL7 reissues (I ordered them yesterday from the Tubestore in Canada and got it today, even though I did not pay for expedited shipping) and that made a big difference in the soundstage, it was wider as well as with better focus and more air between instruments and vocals. I ordered a set of PSVane KT88-T MK II and CV-181-T MK II and am still awaiting delivery. It was stuck in customs in San Diego for a few days and left a few days ago.

I also just ordered a set PSVane's EL34PH and 6SN7UKs and still awaiting delivery on that as well. Does anyone have any comments on those tubes?

I tried changing the power tubes to a set of vintage British Gold Monarch KT88s, as well as a set of vintage GE EL34s and Neotron 6SN7s. TBH, I did not notice much of a difference from the stock Willsenton tubes (I have both the EL34s and the KT88s) other than a slight improvement in smoothness. Right now I am leaning towards the EL34 over the KT88 for its warmth as well as running in triode mode.

I read somewhere that the bias trim pots on the R8 are not that durable and they get a bit loose with tube changes. Has anyone encountered this issue?

Another item I read is that the bias meter on the R8 reads low, e.g. it is actually under biasing the tube. What effect does this have on the tubes? Does it mean the tubes will have a longer life span? Most users of El34s say that the tubes generally will last about 2500 hours, but that the PSVane EL34PH seem to have a shorter life span. Thanks in advance.

If the bias meter reads low it will actually mean that the tubes draws MORE current. Better check with an DVDM and
if possible calibrate the bias meter.

Normal lifetime for EL34 is 3000-5000h

 

[Jon S]

I just received and installed the Psvane KT88-T MK II and CV181-T MK II. At first it did not appear to make much of a difference in the sound but after listening to diifferent music, I can say that the soundfield has expanded with certain music. Orchestral music now seems to fill the wall more behind the speakers. Vocals are richer and more expansive. The image is a tad wider but depth has not really improved. I can hardly wait for the tubes to break in. My speakers are now invisible. With solid state amps (I had Acurus DIA-100, a Pioneer SC-97 AVR, a class A Marantz PM7200 and a SoundArtist Sa200ia) I definitely noted that the music came from the speakers. I no longer have the sense that the sound is coming from the speakers.

These tubes were almost $700, was it worth it? To me, it reached the point of diminishing returns. You pay a premium just to get an incremental improvement in sound.

On a side note, the KT88 seems more brash than the EL34s. The EL34s definitely has smoother sound. I can hardly wait for the Psvane EL34-PH (Philips-Holland design) and 6SN7-UK tubes to come in. The EL34-PH is supposedly arguably the best of its type of current tubes.

I am now trying to convince my wife to let me buy some new speakers. I am looking at the Polk R700. I was considering getting the Klipsch RP8000F II but I have read that they are more suited for rock and pop and my current taste is for classical and vocals. Also, I understand that the Klipsch speakers are cheaper because of its use of less expensive components. My big concern is that the Klipsch are all two-way speakers. With both woofers going in to the mid-range, there is less cohesion at the crossover point. The Polk's are 3-way speakers with better cohesion.

 

[Jon S]

I just could not take it any more. The Psvane KT88-T MK II tubes was just too "hard". The soundstage was a tad wider but it lost that holographic edge and air between sources that the EL34s had. I removed the Psvane and replaced them with a set of reissued Mullard EL34 instead of the GE EL34s I was using earlier. TBH, I could not tell any differences between the two EL34s. The EL34 lost some of the sizzling highs of the KT88 and the bass got a little looser.

I strongly recommend any R8 owners to try the EL34 over the KT88s. It is more musical, but definitely warmer than the KT88. One point I liked about the KT88 is that it had a larger soundfield than the EL34 which seems a bit more closed.

I am now awaiting for my final purchases, the Psvane EL34-PH and 6SN7-UK along with a pair of Sylavnia 6SL7WGT Golds.

 

[Jon S]

Just discovered something interesting. The Psvane KT88-T MK II and CV181-T MK II comes in two flavors. They have the Classic series and the Collection series. The Collection Series are more expensive and have tighter tolerances over the Classics. Most vendors sell the Classic series and some do sell the Collections. The problem is that the vendors who sell the Classic series sell it at the same price as the Collection series thinking that the average buyer does not know there are two variants. Some vendors list as premium series but Psvane does not list that, so it may just be the Classic series as well.

I am not certain but I believe the Classic series come in a plain white box imprinted with Psvane while the collection series comes in a boxed set. Unfortunately, the sets I got were the Classic series.

 

[Jon S]

I was thinking that all those reviewers using the Psvane KT88-t MK II and CV181-T MK II in the Willsenton R8 amps cannot be wrong. Something must be wrong on my side. So I installed both the KT88s and CV181 back into my R8 along with the Tung-Sol 6SL7 tubes. I decided to change speakers. I took out the Polk LSi15s and moved in the Sony SS-M9. These are massive 120lb monsters from 1995, designed by Dan Anagnos. formerly of Polk Audio. They were rated highly by Stereophile magazine in Sept 1996.

The soundfield sounded congested with everything in the middle. I then swapped the Audioquest interconnects and Rocket 33 speaker cables with Morrow Audio speaker and interconnect cables. That made a significant change in sound. The soundfield was no longer congested, it was smaller in width but more focused. The image still retained that wall of sound feeling behind the speakers. The Psvanes sounded more dynamic with better transients over the EL34. The EL34 still had an edge in depth and image over the KT88. The KT88 had tighter bass and not as warm as the EL34. The KT88s made the amp sound more like an excellent solid state amplifier.

I think I will leave the Psvanes in for a while and let them break in.

 

[Hajidub]

I just could not take it any more. The Psvane KT88-T MK II tubes was just too "hard". The soundstage was a tad wider but it lost that holographic edge and air between sources that the EL34s had. I removed the Psvane and replaced them with a set of reissued Mullard EL34 instead of the GE EL34s I was using earlier. TBH, I could not tell any differences between the two EL34s. The EL34 lost some of the sizzling highs of the KT88 and the bass got a little looser.

I strongly recommend any R8 owners to try the EL34 over the KT88s. It is more musical, but definitely warmer than the KT88. One point I liked about the KT88 is that it had a larger soundfield than the EL34 which seems a bit more closed.

I am now awaiting for my final purchases, the Psvane EL34-PH and 6SN7-UK along with a pair of Sylavnia 6SL7WGT Golds.

Pretty sure in my earlier post I told this was going to be the result. EL's for what you're listening to, calmer for the genre.

 

[Jon S]

So this is a partial inventory of tubes that I have gotten since I bought the Willsenton R8 in November.
On the left are the Psvane KT88-T MK II Classic with the CV181-T MK II Classic right below it.
The next column are the Mullard and GE EL34s
The next column are the Tung-Sol 6SL7, the Neotron 6SL7, two of the Genalex Gold monarch KT88 with the Willsenton OEM 6SN7, below that are the Willsenton EL34s
On the end are the Willsenton KT88
Missing is a set of Genalex KT88 Gold Lions.

Still waiting for my Sylvania 6SL7WGT which are mil-spec 6SL7. According to Jim @ Valvesandmore.com, they are quieter than the 6SL7s from the 50-80s but are not as musical as other Sylvanias.

Also waiting for the Psvane EL34-PH and 6SN7-UKs along with the Electro Harmonix 6CA7s. I think that should be enough for a while.

Does anyone know who makes the Willsenton tubes? Jim @ Valvesandmore.com said they were so bad sounding and mismatched that he tossed his OEM tubes.

 

[Jon S]

I just got the Sylvania 6SL7WGT and replaced the Tung-Sol 6SL7 that replaced the stock Willsenton 6SL7. The Sylvania improved the focus in the soundfeld over the Tung-Sol but I cannot really say if it improved the sonics over the Tung-Sol. Jim mentioned that the reissue Tung-Sols are not that musical and are a bit "hard" in sound.

 

[Jon S]

I experimented a bit after discussing the R8 with Thomas & Stereo as well as Tarun from the British Audiophile... They commented that the R8 is more sensitive to the pre-amp tubes changes than the power tubes.

I put all the stock Willsenton tubes back in the R8 (I was using the EL34s, not the KT88s) and the sound was definitely on the harsh side. I replaced the 6SL7s with Sylvania 6SL7WGTs and the 6SN7s with a set of Neotron 6SN7s. To my surprise, the amp sounded a lot smoother, the bite from before vanished completely. The stock Willsenton EL34 actually performed nicely, not as good as expensive tubes but it could hold its own to current Mullard or Tung-Sol tubes.

I just got my Psvane EL34PH and Psvane 6SN7-UK tubes and am starting the break-in process. Straight out of the box the tubes sounded pretty good. I am more impressed with the EL34PH more than the 6SN7-UK. I am trying to see if there is a difference between them and the Psvane KT88-T MK II and CV181-T MK II since they both cost about the same.

 

[Jon S]

I find the Psvane 6SN7-UK to be a big let down in the R8. The soundstage is down by half in size compared to the French vintage Neotron 6SN7 tubes. The Psvane CT181-T MK II is a LOT better than their 6SN7-UK tubes. I find the Neotron 6SN7 and the Psvane CV181-T MK II very similar in sound and soundstage.

 

[Jon S]

Here are a couple of new videos on the Willsenton R8 that is really interesting and owners should note...
Stephe describes the good points as well as some parts of the amp that she considers troubling. Primarily the power supply caps are very under the minimum capacity needed and the poor quality resistors in the circuitry.

 

[Jon S]

Stephe from Skunkie Works also noted that the 6SL7s have a bigger impact on the sonics than the 6SN7 tubes. I am finding that to be quite true. I tried using Tung-Sol and Mullard 6SN7s as well as the Psvane 6SN7-PH and the CV181-T MK II and did some improvements but nothing earth-shaking.

After replacing the Willsenton 6SL7 with a pair of Tung-Sol reissued 6SL7s there was notable improvements, primarily a drop in the harshness in the midrange. I then tried a NOS Sylvania 6SL7-WGT and the sonics improved a tad more (primarily because the 6SL7-WGTs are military spec and were built for reliability which made the tube less musical.

I also just got a pair of British-made NOS Maganvox 6SL7GT for only $25 and am stunned at how much of a difference it made in the sound. The noise floor was considerably lowered and there was improved sonics, clarity and sweetness. The vocals are more natural and image is more focused. I contacted the seller and bought the last pair of 6SL7-GTs he had. Even with the stock Willsenton KT88 or El34 and the stock 6SN7s, the amplifier sounded pretty sweet. Popping in a set of vintage British Genalex Gold Monarchs and Psvane 6SN7-UK tubes was nirvana.

 

[Jon S]

I found out the Magnavox 6SL7s are actually Russian-made Foton tubes. Matched with the Psvane EL34-PH and Psvane 6SN7-UK was probably the worst combination I have ever heard. The highs were shrill and the mids were pronounced with no bass. The Psvane EL34-PH and Psvane 6SN7-UK sounds a lot better with the Sylvania 6SL7WGTs.

With the Gold Monarch KT88 and the stock 6SN7s was a lot better than the Psvanes with the Magnavox as well.. Using the Neotron 6SN7s made it even better. It's really odd how some combinations can be so much better or worse.

On a side note, i tried getting the 0.1uF 500v K42Y-2 capacitors for the modifications done on the StereoNet site. These are Russian caps and are now unobtanium. The only sellers are either in Russia or Ukraine. I have recently ordered some tubes from Ukraine and it is taking a long time to ship (expect 6-8 weeks) because of the war. I tried to find other similar caps and they are ridiculously expensive. As an example, Arizona Capacitors Red Cactus 0.10uF 600VDC costs $35 each or a total $140!

 

[StepheK]

Here are a couple of new videos on the Willsenton R8 that is really interesting and owners should note...
Stephe describes the good points as well as some parts of the amp that she considers troubling. Primarily the power supply caps are very under the minimum capacity needed and the poor quality resistors in the circuitry.

Thanks for the mention. I do want to add: I am VERY impressed with the build quality, especially the chassis, and the output transformers seem up to the task. This amp delivers a real 45W of power, unlike many of the other Made in China tube amps I have tested. It sounds good out of the box and I think for a DIYer, this can be fairly easily improved quite a bit. I do see some grounding issues and I plan to deal with some of that later in my exploration of this amp.

On tube rolling, I liked what I heard from some short bottle GE 6SL7's and a set of Gold Lion KT88's. I have a lot more tube rolling to do

 

[Jon S]

Yes, I really like the amp and love your YT videos that you posted. I would wish that you would list the component specs that you are replacing, e,g, 0.1uf resistor, 2 watt or 0.22 cap, film, 600v etc. That way i could order the parts myself to upgrade the amp. I went to Mouser and they do not list the 30mm 550v 330uf cap you mentioned in your video. I could only find the Kemet Aluminum Electrolytic Capacitors - Snap In 500V 330uF 20% (13k Hrs AEC-Q200) and had to order that. I hope it will be okay. I wanted to order the resistors for the power tubes but was not certain which ones you ordered.