Willsenton R8 vs the classics

[33RPMThorens]

Is this true?

Philosophically, I have read a ton of books and listened to a ton of you tube philosophers about the idea of Objective Truth. I am just some dude from Columbus Ohio, have nothing to add in terms of what "true" means. It's true (the R8 sounds magical) in the moment for folks that like it.

On the other hand....

Even if the R8/Muzishare X7 or the like sounded better, I like the idea of the ST70 better from a long term sustainability standpoint.

 

[Lavane]

Philosophically, I have read a ton of books and listened to a ton of you tube philosophers about the idea of Objective Truth. I am just some dude from Columbus Ohio, have nothing to add in terms of what "true" means. It's true (the R8 sounds magical) in the moment for folks that like it.

On the other hand....

Even if the R8/Muzishare X7 or the like sounded better, I like the idea of the ST70 better from a long term sustainability standpoint.

Thats another thing to think about. The ST-70 should be easier to work on if needed, and there are plenty of options and parts readily available for the ST-70.

 

[33RPMThorens]

Thats a other thing to think about. The ST-70 should be easier to work on if needed, and there are plenty of options and parts readily available for the ST-70.

Exactly.

 

[Aerobat]

Exactly.

These things don't have a lot of "parts". There's nothing in the R8 that can't be replaced, as opposed to a silicon chipped or transistorized device that's one and done.

 

[Jon S]

With the right tube complement, the R8 can sound fantastic. I have a ton of tubes, old and new... Right now, I think the Ken-Rad VT229/VT231 front-end tubes sound awesome with either the Matsushita 6CA7, Mullard XF2 EL34. Groove Tubes EL34M or the Psvane EL34PH. The Ken-Rad front tubes presents a more 3D image than any other front tubes I have, beating the Sylvania 6SN7W/6SL7W, the MELZ 6N9S/6N8S, Tung-Sol 6SN7/6SL7 or the RCA 6SN7/6SL7 gray glass tubes (or any combination there of).

The Psvane EL34PH is a puzzler though, on some tubes they sound flat with no bass. With the Ken-Rads they sound excellent and with others very good. I also have some old and new KT88s. TBH, I prefer the warmth of the EL34 over the dynamics of the KT88.

The R8 has two modes, ultralinear or triode. With in the ultralinear mode, the mid-range is more pronounced and upfront with a more dynamic presentation (this excels in pop, vocals and rock music). In triode mode, the center focus is more laid back which sounmds better for classical and instrumentals.

But like I mentioned earlier, the R8 is very sensitive to noisy pre-amp tubes. With noisy tubes, the volume control exhibits a scratchy sound when adjusted. And the control is too sensitive, a tap on the remote will jump the volume by a three-four dB. At the 9:00 position, the volume is quite loud on my 87dB sensitive Polk R700s.

 

[gadget73]

FWIW, the ST-70 has the same concern with bias pots going open causing output tubes to run away. Fix is the same though, resistor from pot wiper to the most negative end to force it full negative if anything loses contact.

Honestly most old amps with bias adjust pots have this same design, and the fix is also usually the same.

 

[Aerobat]

With the right tube complement, the R8 can sound fantastic. I have a ton of tubes, old and new... Right now, I think the Ken-Rad VT229/VT231 front-end tubes sound awesome with either the Matsushita 6CA7, Mullard XF2 EL34. Groove Tubes EL34M or the Psvane EL34PH. The Ken-Rad front tubes presents a more 3D image than any other front tubes I have, beating the Sylvania 6SN7W/6SL7W, the MELZ 6N9S/6N8S, Tung-Sol 6SN7/6SL7 or the RCA 6SN7/6SL7 gray glass tubes (or any combination there of).

The Psvane EL34PH is a puzzler though, on some tubes they sound flat with no bass. With the Ken-Rads they sound excellent and with others very good. I also have some old and new KT88s. TBH, I prefer the warmth of the EL34 over the dynamics of the KT88.

The R8 has two modes, ultralinear or triode. With in the ultralinear mode, the mid-range is more pronounced and upfront with a more dynamic presentation (this excels in pop, vocals and rock music). In triode mode, the center focus is more laid back which sounmds better for classical and instrumentals.

But like I mentioned earlier, the R8 is very sensitive to noisy pre-amp tubes. With noisy tubes, the volume control exhibits a scratchy sound when adjusted. And the control is too sensitive, a tap on the remote will jump the volume by a three-four dB. At the 9:00 position, the volume is quite loud on my 87dB sensitive Polk R700s.

I bought Psvane 6550s and find they are bright and light on bass. I'm running new production Mullard EL34s at the moment, with Sylvania 6SN7s and National 6SL7s. I agree the remote volume pot is way too aggressive so I end up getting up to adjust the volume (need the exercise anyway). I use triode mode exclusively and to my ears ultralinear is too much in my face. It's a nice amp with a nice look and has given me no issues.

 

[gadget73]

Could always add a resistor upstream of the volume pot to make it less touchy. If it hits max power before full travel on the pot you can throw away some signal with no issues. Just add the resistance between the top of the pot and the input jack. Maybe if you want to get more scientific with it, bypass the resistor with a small value cap so there is no HF loss. Kinda need to measure to figure out the proper value for that.

 

[Aerobat]

Could always add a resistor upstream of the volume pot to make it less touchy. If it hits max power before full travel on the pot you can throw away some signal with no issues. Just add the resistance between the top of the pot and the input jack. Maybe if you want to get more scientific with it, bypass the resistor with a small value cap so there is no HF loss. Kinda need to measure to figure out the proper value for that.

OK need to have a gig at my place lol

 

[McMack]

I bought Psvane 6550s and find they are bright and light on bass. I'm running new production Mullard EL34s at the moment, with Sylvania 6SN7s and National 6SL7s. I agree the remote volume pot is way too aggressive so I end up getting up to adjust the volume (need the exercise anyway). I use triode mode exclusively and to my ears ultralinear is too much in my face. It's a nice amp with a nice look and has given me no issues.

How many hours on the 6550's?

 

[Aerobat]

How many hours on the 6550's?

Not many, maybe 50?

 

[McMack]

Not many, maybe 50?

Maybe they need more hours to break in.

 

[Aerobat]

I was looking on Mouser for replacement bias pots for the R8 (mine work fine but it would be nice to have quality Bournes pots in it) and I didn't see much that was close to the ones in there. 20K, triangular pin pattern with pins 5mm apart. I could force a pot in it but if it's not aligned and solidly mounted it could be a problem to adjust through the hole in the chassis. Funny because my 1961 Fisher's bias pot is original and mounted to the top of the chassis and has no issues.

 

[gadget73]

Not all pots are created equally. I have some vintage pots that are fine, but the ones in my Pilot were crap and went in the trash.

 

[Jon S]

I was looking on Mouser for replacement bias pots for the R8 (mine work fine but it would be nice to have quality Bournes pots in it) and I didn't see much that was close to the ones in there. 20K, triangular pin pattern with pins 5mm apart. I could force a pot in it but if it's not aligned and solidly mounted it could be a problem to adjust through the hole in the chassis. Funny because my 1961 Fisher's bias pot is original and mounted to the top of the chassis and has no issues.

You can buy the Bourns 3310Y-001-203L 20K Ohm 1/4W Plastic Linear potentiometer from DigiKey for ~$5/each... They are a drop in replacement for the Willsenton R8 and the Muzishare X7 amplifiers. The pots are plastic and a tad smaller in overall size than the OEM pots (Vishay does not make 20K ohm pots and will require resistors to be installed to properly match the voltages)

You can watch a YT Video from Tube Lab on how to replace the pot. If you are replacing a bad pot, I'd recommend you replace all four iso only the bad pot. The OEM pots are notoriously prone to failure (I had two pots fail, one on the R8 and the other on the X7, taking out a Electro-Harmonix 6CA7 and a Gold Lion KT88). The pots are made of plastic and can easily be damaged if too much heat is applied to the pins so buy a spare or two. Also, when reinstalling the bias board, make sure you test fit the alignment as the board has a bit of play and pot shafts can be too far from the opening on the chassis if the board is misaligned. You want to align the board more to the center of the chassis, not to the sides of the chassis.

 

[Aerobat]

You can buy the Bourns 3310Y-001-203L 20K Ohm 1/4W Plastic Linear potentiometer from DigiKey for ~$5/each... They are a drop in replacement for the Willsenton R8 and the Muzishare X7 amplifiers. The pots are plastic and a tad smaller in overall size than the OEM pots (Vishay does not make 20K ohm pots and will require resistors to be installed to properly match the voltages)

You can watch a YT Video from Tube Lab on how to replace the pot. If you are replacing a bad pot, I'd recommend you replace all four iso only the bad pot. The OEM pots are notoriously prone to failure (I had two pots fail, one on the R8 and the other on the X7, taking out a Electro-Harmonix 6CA7 and a Gold Lion KT88). The pots are made of plastic and can easily be damaged if too much heat is applied to the pins so buy a spare or two. Also, when reinstalling the bias board, make sure you test fit the alignment as the board has a bit of play and pot shafts can be too far from the opening on the chassis if the board is misaligned. You want to align the board more to the center of the chassis, not to the sides of the chassis.

Done and ordered, and thanks for the advice on installation.

 

[Jon S]

If you gave an early Willsenton R8, make sure you install the safety resistors to avoid the amplifier burning up when a pot fails. See Stephe's video. In fact, you should watch the entire play list... I don't recommend you do the pre-amp mods as there is a discussion that this actually can cause issues.

 

[Aerobat]

If you gave an early Willsenton R8, make sure you install the safety resistors to avoid the amplifier burning up when a pot fails. See Stephe's video. In fact, you should watch the entire play list... I don't recommend you do the pre-amp mods as there is a discussion that this actually can cause issues.

It's a V1 and I actually did all of her mods with the exception of the volume control grounding scheme, which I may get to. If you mean the value of the grid leak resistor, I left it stock.

 

[StepheK]

If you gave an early Willsenton R8, make sure you install the safety resistors to avoid the amplifier burning up when a pot fails. See Stephe's video. In fact, you should watch the entire play list... I don't recommend you do the pre-amp mods as there is a discussion that this actually can cause issues.

Which "pre-amp mods" are you talking about?

 

[Jon S]

Do you have the older R8 or the "MK II" version? I gather you have the "MK II"...