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Willsenton R300B SE Integrated Amp

CohibaJoe

AK Subscriber
Subscriber
I have been reevaluating my gear and will be adding "2" 300B units into my rotation. I have been watching and reading about the Willsenton R300B Amp and have purchased this 12/30/22. Unit has shipped with ETA 1/10/23. All in at $1281 and compiling a parts list to upgrade the Films, Resistors, etc. From what I have research and asked, this brand is made in the same factory that makes Cayin and PrimaLuna. I have also ordered DECWARE - The Zen Sarah Amp Model SEWE300B with ETA ...2yrs?? My PrimaLuna was sent to Upscale Audio to be traded in for 2 pairs of WE300B tubes.

Once the R300B is delivered I will be posting pictures and a parts list to start this journey.

Features:
Single-ended pure Class A tube Integrated amplifier
The body of Willsenton R300B use classic blue piano paint.
• Pure hand-made, Point to point manual welding.
• Two 5U4G vacuum tubes are used for high-voltage rectification. 1pcs of 6SL7 and 2pcs of 6SN7 vacuum tubes are used for the voltage amplifier and preamp stage.
The power amplifier stage uses two Willsenton custom-made 300B vacuum tubes for single-end Class A power amplification.
• Reasonable internal structure, with fever circuit, high frequency is clear and detailed, full frequency is full, low frequency dynamic is loose and powerful
• Use a square power transformer specially developed for this R300B tube amplifier
• Two wide frequency high-end EI type single-ended output transformers with high-end special
• Provide professional equipment input ports, R300B is equipped with multiple signal input ports, which can facilitate you to connect a variety of audio source signals, so that you can have different audio sources and different experiences
• Brushed aluminum alloy panel, using brushed panel, exquisite workmanship, comfortable feel, high-grade and elegant.
• Gold-plated port, a design that integrates quality and beauty, reduces signal loss, and has good conduction performance; the metal mesh cover can protect the beauty of the electronic tube, making it safer for users.
• Power on mute delay function, soft-start feature to prolong tube life (about 30 seconds).
• Infrared function remote control
• Use Japanese ALPS high-end potentiometer
• Peripheral power tube bias current adjustment function and power output level meter sensitivity switch
• Negative feedback circuit design
• Use thick silver-plated signal leads
• Headphones output 6.5mm jack

Product specification
Rated output power: 8W + 8W
Machine frequency response: 15Hz-45KHz(±0.5dB)
Total harmonic distortion: 1%
Signal to noise ratio: 90dB
Input sensitivity: 210mv (when be an integrated amp)
620mV (when be a Power amplifier)
Input impedance: 100k ohms
Output impedance: 4Ω, 8Ω, 16Ω
Headphone output for impedance: 8 ohms - 32 ohms
Power supply voltage: AC 100V - 240V 60Hz/50Hz (100V, 110V, 115V, 120V, 230V,240V version will take 7-14 business days to order). 220v is in stock.
Volume: (W × D × H): 405 * 355 * 200 mm
Vacuum tube: 300B x2, 5U4G x2, 6SN7 x2, 6SL7x1
Net weight: 50lbs
Gross weight: 59lbs
Power consumption: 280W
 
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Eagerly following. I've had my eye on this for a few months, the reviews have been positive, i'm curious to see an unfiltered appraisal.
 
In to follow this closely. I've been considering doing the exact same thing this year.
 
I have not heard any, but the Willsenton gear appears to be pretty well made. Appears to be similar to another decent Chinese brand the RFTLYS. Very similar build quality.
 
A day earlier, nice. Will be unboxing tonight (pics) and will start an Upgrade parts list (Films and Resistors). I also received today NOS tubes (waiting on Linlai™ Global WE300B).
The plan is to start a 200hr burn-in then replace 3 Films.

WillR300a.png
 
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Here we go. They have upgraded the Resistors "same as in the PrimaLuna" but will be upgrading the Power Board 450V 220UF cap (UUcap??) and "2" Willsenton .22uf/650v, "1" Willsenton .33uf/630v.

Films: Mundorf Supreme Silver/Oil "2" .22uf/1000V, "1" .33uf/1000V
Caps: Vishay/BC Components MAL215947221E3 220UF/450V, UCC KWB 10000uf/16V

Will300a.png Will300b.png Will300c.pngWill300d.png
 
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Parts are in and I have replaced the UUcap HE 220uf/450V with Vishay/BC Components MAL215947221E3 and
Changxin 10000uf/16v with UCC KWB. Going to put on 150hrs before I replace the Willsenton Films (.22/.33uf) with Mundorf Supreme Silver/Oil.
Unit has been BIAS and what JUMPS out to me is the Mid-Range, Bass and Spatial Depth.

BTW: No buzz from the transformers and/or Hum from the Speakers. This is dead quiet which I somewhat expended from Cayin and PrimaLuna factory...time will tell.
See you at 150hrs.

Will300h.png Will300i.png Will300j.png
 
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What's your reasoning behind changing out those capacitors?

Are you doing any before and after measurements of the differences these parts make? If yes I'd love to see them posted.

Thanks.
 
What's your reasoning behind changing out those capacitors?

Are you doing any before and after measurements of the differences these parts make? If yes I'd love to see them posted.

Thanks.
The one's that I removed and replaced...Cheap crappy Caps (Changxin), with my C22 Clone Recap 1/2 of the Changxin Caps was off by +25%. Based
on this I replaced with UCC(Mouser) and the UUcap (no idea who makes this) with Vishay/BC. As to the Willsenton Films (not bad so far), after 150hrs I will replace with
Mundorf Supreme Silver/Oil as I use this in past upgrades, and the MS S/O sounds fantastic after 150hrs+.
 
I understand now. I wouldn't worry too much about the tolerance, +/25% for large lytic isn't a big deal in a power supply. I do understand your reasoning of not trusting those caps for long term use, probably 1000 hour rated at only 85°C. I've built some cheap Chinese kit amps that didn't come assembled and so I used Nichicon long life rated for 10,000 hours with max ripple current at 105°C to replace the off brand caps that came with the kit.

I'm still not completely sold on coupling capacitors making much of any difference sound-wise but to each their own. The fact there isn't a signal across them means they really can't do much in the way of negatively effecting the sound. I've done lots of measurements and blind testing and came to the conclusion they don't really matter, even electrolytic. The thing with electyrolytic caps is the hysteresis distortion but in a coupling cap situation, especially valve amps there is a DC bias which removes the hysteresis. The Chinese kits I got had what looked like WIMA caps but they were fakes, so I don't blame you for replacing the film caps also in the amp for reliability purposes also.

Funny there is another thread discussing this amplifier except not about the parts brands, we are more technically discussing the design. You might want to read that thread as it could give you some ideas to make some improvements with the design.
 
At 50hrs and still sounding really nice (the Bass and Mid-Range jump out as this Amp kicks butt). Once at 100hrs I will be rolling in the following then at 150hrs will be upgrading the
Films to Mundorf Supreme Silver/Oil.

"2" Tung-Sol 5U4G Tubes 1954 Black Plate
"1" Ken Rad JAN VT-229 6SL7
"2" CBS Hytron 6SN7GT "Bad Boy"
Ordered Linlai™ Global WE300B and Western Electric 300B

WillR300Tubes.png
 
Hi, looking forward to your experiences with the Willsenton R300 amp. Where did you purchase it? Amazon?? thanks
 
At 70hrs and I noticed a change in overall sound quality. Opening up with a wider, deeper and cleaner sound tone. This Amp is a Mid-Range and Bass titian, and I cannot wait until I
start to tube roll. I never have posted my test speakers that I use are Pinnacle Classic Gold Tower (1984).

PinnacleGT.png
 
Started the burn-in of Mundorf Supreme Silver/Oil films. Using my spear Marantz 7T and will leave on until Saturday (144hrs streaming).

WillR300a.png
 
Since you are not adverse into digging in and making changes I would recommend you check out AK member StepheK's youtube channel. She recently opened up a Willsenton R8 and made a bunch of improvements. Not just upgrading coupling caps but PS, wiring improvements ect. There might be some manufacturing similarities between the two units that you can correct.
 
Since you are not adverse into digging in and making changes I would recommend you check out AK member StepheK's youtube channel. She recently opened up a Willsenton R8 and made a bunch of improvements. Not just upgrading coupling caps but PS, wiring improvements ect. There might be some manufacturing similarities between the two units that you can correct.
That R8 has a bunch of design issues that have been reported with owners and it's nice to see StepheK sort these out with mods to improve the reliably, noise and sound. I have been following the series and have noticed the construction is night and day as the wiring is a bird's nest in the R8 (StepheK's R8, upgraded a mess and the scope confirmed this). The R300B in my unit had questionable Caps as I listed (2 Changxin, 1 UUcap) and was replaced with
UCC btw..used through the unit and 1 Vishay/BC Power Board Cap. The resistors are the same as used in the PrimaLuna (which I confirmed with my unit) as well as the Speaker connecters, wiring and relays. The Films are good to what I am hearing but, I will be replacing with Mundorf Supreme Silver/Oil. As I reported the R300B is dead silent and sounds wonderful so making design modifications do not make sense unless an issue surfaces. Maybe StepheK will get one in to review?
 
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