So I bought the Willsenton R-800i


After I bought the Klipsch Cornwall IVs recently it became apparent quite quickly that to make it really shine it needs a tube amp to drive it. (For me at least.) After doing some (=endless) research, considering the options (budget, shops nearby carrying models I´m interested in, etc.) and also asking around on this very forum I decided to go for the Willsenton R-800i. None of my friends here shares my excitement for audio stuff or even has a comparable system, so what´s now in my living room is the one tube amp I know. And I´m delighted. Together with the speakers it gives the music the presence and glow that I so desired.

Of course I can tell that there´s more potential in this amp and I already exchanged some of the stock tubes. There are more on the way and I can´t wait to test them. For now my financial means are a bit limited so I´m not ordering Western Electric and Takatsuki 300Bs just for the sake of comparing them. In fact I´m waiting with those a bit and go for the others first.

Searching online I find a lot of information on English language forums. Somehow tube rolling is not discussed as much on the German forums I checked though – and out of curiosity (and because they were pretty cheap) I went for both West- and East-German ECC83s and a fairly random mix of other tubes from the US and the Soviet Union. I´m waiting for them to arrive and not being able to read about some of them it raises my curiosity how they will sound. Maybe crappy, maybe not so bad, maybe even very good. I´ll see. Tube rolling will take some time and I don´t mind. The amp is there to stay for quite a while.

There´s an exhaustive thread on the Willsenton amps and fitting tubes here but since I found people´s comments on this forum so helpful I´m looking forward to hear from you. I´m open for tube recommendations and would like to hear anyone´s experience with the Willsenton R-800i. Or maybe someone has questions?

As for the tubes:

805 – stock replaced for Cossor
300B – stock
6SN7 – stock replaced for Sylvania GTBs, waiting for Fonon NOS (Soviet, 1979, a bargain for 10€)
12AX7 – stock replaced with current Mullard model, waiting for West German ones from AEG and Telefunken, East German ones from RSD and Funkwerk Erfurt (both used) and also Sylvania JAN 5751 NOS (a military model)
5U4G – stock, waiting for RCA NOS black plate and Svetlana NOS „Coke Bottle“

chmaiwald

I'm so done with my R800i.  China Hifi no longer responds to me. 

They shipped me two new bias boards as my right side pot was going nuts.  I opened the unit up to install them. Guess what?  The one on the left is a relatively painless surgery. The one on the right?  I simply cannot figure out how to do it without taking the amp apart. I mean significant deconstruction.  

What's more, the through holes on the PCB are only big enough for like 28 gauge wire. It looks like they just (somehow) soldered the wire to the top of the through hole.  

There are some good quality components in there, but when I looked at the big 1000v electrolytics, they are no-name junk that I cannot even locate online.  

This amp is far from a piece of junk. But I question parts quality now and design layout.  Further, I question having and amp 1000 v on the plates of the 805s if (a) customer service stinks; (b) design choices are wonky; etc. 

I hate having to write this. Your mileage may vary. For me, this feels like a 100lb paperweight now.  I'm not sure I want to even take it in and put money into it.  

Oh, China Hifi refuses to give me a name of their authorized US repair vendor(s).  Terrible. 

@jbhiller ​​@chmaiwald you guys still use tube amps with Cornwalls?

How did you placed those speakers in your room?

(distance from front wall,between them and from your chair)

@gregoriomtb16 I still use the Willsenton with Cornwalls. It´s a very good combination I´d say.

The speakers are about 8ft. apart and just a few inches from the wall, maybe 8. They are in our combined kitchen/living room and the best listening position is actually behind the family sofa the middle of which is also about 8ft from each speaker, maybe even less. The best listening position is a few more feet to the back, there´s our kitchen table we spend a lot of time at. Sure, the furniture interferes probably but the sound there is still great in my book. Realities of having a family...

When they were still new I built platforms with tiny weels to easily move them. While in the beginning I toed them in from time to time and found the more direct sound more pleasing I stopped doing so after a while. And when I toed them in again recently, pointing straight at me on the sofa, I found that the stage and depth suffered. So now they are pointing into the room again.

I posted this on StereoNet, so I figured I’d post it here too.

My personal R800i blew a 300B tube (Gold Lion) and wouldn’t bias correctly (no matter how far I turned the adjustment down for either channel, it wouldn’t get within the proper range on the blue VU meters). So I sent it off to Scott Frankland.

When Scott got to the amp (he’s very busy) he noticed a few design issues. The biggest was that both channels share plate voltage nodes, but that there are no bypass caps for this. He added 18 "critical" resistors and 4 bypass caps to address this issue.

A smaller issue was that there wasn’t enough filtration to account for all the hum, so we’ve added more.

He also mentioned this was a curious design for audio, but it wasn’t unheard of:

"The Willsenton R800i operates the 805 as a power grid tube, which is allowed for rf transmitting tubes but not often seen in audio amps. This means that the operating point is below the diode line on the plate curves, in the area of positive grid bias. This causes the grid to draw a certain amount of current continuously. It’s a technique in rf that allows the tube to be pushed to deliver more power. Of course, that grid current has to be supplied by the driver stage, which in this case is the 300B. The R800i operates the 300B as a cathode follower direct coupled to the 805 grid. This is certainly unusual in audio, but not unheard of. I recall that the early Wavac amps used this (or a similar technique)."

I also had Scott modify/upgrade the amp. The mods Scott performed were (in addition to the design issues):

• Upgraded caps (VCap ODAM)
• Upgraded resistors to 1% values (from ~3% with stock)

The amp was burned in and then I got a follow-up email from Scott:

"Clearly the Willsenton 300B’s and 805’s were designed to work together, and clearly other brands don’t. I set the bias range to be just below 100mA so that the full range of bias would be available as the tubes age, but I’m concerned that the Gold Lion’s may not bias down with the current adjustment. I recommend that you send me the Gold Lion 300B’s (or have them shipped here) in case a further adjustment is needed."

So, I have had a set of PSVane 300B’s and 805’s shipped to Scott so he can swap those in and see how the bias needs to be adjusted. Right now the amp has the stock Willsenton 300B’s and a set of LinLai 805 DG’s in it (the original Willsenton 805’s were not included with the amp when I bought it from the previous owner).

Perhaps some of this info will help other R800i owners. I like the sound of the R800i enough that I’ve sold my R8 (even though I like the R8). I am hoping these mods deliver the performance and reliability I’m looking for.