@Tube Lab, Thank you for your video, I appreciate your time to find and locate replacements pots. How did your repair work out, is your R8 and the pots you installed operating correctly ? My R8 burned the V2 KT88 10 ohm and 1K ohm resistors and I saw some sparks flying, heard loud static, but the sound came back on in seconds. I turned it off before I could tell if it red plated or listening if the left channel was dead. Skunky also thinks that the pots may have been faulty or the bias too high. I had previously checked the bias and it seems the V2 may have been getting wonky.
The pot replacement is working fine, they have the same footprint (standard) and range as well as stem height. The only issue is the shaft rotates with very little resistance so it takes time to learn how to co-ordinate the movement. There's a special slot screw driver that captures the shaft, which would make adjusting the pots much easier. And yes the first sign of trouble with any pot is they often start to get noisy - that's when you should replace them, especially in a bias circuit.
@@vnnguyen132 I would need to flip our R8 over to have a look at how we installed the bias fail safe resistor and with Charles on vacation that's not going to happen any time soon. In January we plan on developing an upgrade pcb for the R8 that will fix a couple of problems. The board will be a simple job even for technically inexperienced owners.
Re solder suckers, I recently got three different types to try. One was like yours and it has the best ergonomics but the tip tends to melt. A similar looking one but with a completely metal housing has a better tip but tends to stick. The best is a larger all plastic one (light-blue colour with yellow buttons) as tip doesn't melt and its larger size sucks more solder in one go.
Thanks for chiming in about the solder sucker, I've got an all metal housing one on the chopping block now. We'll see how long that one lasts. But the first one I've been using fairly heavily for about two years now so it really doesn't owe me anything. Cheers!
There is a lot more wrong with the R8 than this. I followed another well known TH-camr's rebuild of my R8. (Oh, you mentioned her) All the resistors were rubbish, the wiring was absolutely made to enhance noise.The grounding was silly. If you have an R8, you need to have all that work done. And the fail-safe was a big oversight
We've used our R8 commercially for 2.5 years and in all that time the amp has been stock. The only problems we've had are with high wear items like the bias pots, which we put probably the equivalent of 100 years of service on in 2.5 years. Otherwise the amp has performed perfectly in stock form and sounded great! The resistors are fine as built (Skunky said the same thing in her own video). The fail safe is easy enough to add and remember we ran the amp for 2.5 years without a fail safe in place without a problem. Given our hours of operation, I stand behind my original statement that the R8 is a great amp at a bargain price - even in stock form.
She got and kept your attention. Perhaps if she was only able to do one video saying the amp was great, she wouldn't have been able to hold her largest audience for any product to date? My R8 has and is running perfectly, perhaps it could benefit from a few upgrades, but most equipment can.
@@pnichols6500 Of course most gear can be upgraded. I suggest you have a look at her comparison between the R8 and a Muzishare she was asked to work on. I know which one I would buy now. (I might add that my R8 took control of itself and powered up spontaneously. China Hifi sent me a new on/off switch but that could have been a real issue if, say, I had been away from home) Her latest on the Willsenton 300 is proving to be a real eye opener. It seems to have issues well beyond the R8
Nice work
@Tube Lab, Thank you for your video, I appreciate your time to find and locate replacements pots.
How did your repair work out, is your R8 and the pots you installed operating correctly ?
My R8 burned the V2 KT88 10 ohm and 1K ohm resistors and I saw some sparks flying, heard loud static, but the sound came back on in seconds. I turned it off before I could tell if it red plated or listening if the left channel was dead.
Skunky also thinks that the pots may have been faulty or the bias too high. I had previously checked the bias and it seems the V2 may have been getting wonky.
The pot replacement is working fine, they have the same footprint (standard) and range as well as stem height. The only issue is the shaft rotates with very little resistance so it takes time to learn how to co-ordinate the movement. There's a special slot screw driver that captures the shaft, which would make adjusting the pots much easier.
And yes the first sign of trouble with any pot is they often start to get noisy - that's when you should replace them, especially in a bias circuit.
@@tubelab194 Thanks for the fast reply, glad yours is working.
Is it easier to solder the "false safe" to 1.2K and the pot's leg (that connects to the 100K resistor) ?
@@vnnguyen132 I would need to flip our R8 over to have a look at how we installed the bias fail safe resistor and with Charles on vacation that's not going to happen any time soon. In January we plan on developing an upgrade pcb for the R8 that will fix a couple of problems. The board will be a simple job even for technically inexperienced owners.
@ Thanks for your prompt response. I love and appreciate your informative videos.
Re solder suckers, I recently got three different types to try. One was like yours and it has the best ergonomics but the tip tends to melt. A similar looking one but with a completely metal housing has a better tip but tends to stick. The best is a larger all plastic one (light-blue colour with yellow buttons) as tip doesn't melt and its larger size sucks more solder in one go.
Thanks for chiming in about the solder sucker, I've got an all metal housing one on the chopping block now. We'll see how long that one lasts. But the first one I've been using fairly heavily for about two years now so it really doesn't owe me anything. Cheers!
Skunkie has done this
Actually as far as I'm aware Skunky has not replaced the bias pots.
There is a lot more wrong with the R8 than this.
I followed another well known TH-camr's rebuild of my R8. (Oh, you mentioned her)
All the resistors were rubbish, the wiring was absolutely made to enhance noise.The grounding was silly. If you have an R8, you need to have all that work done. And the fail-safe was a big oversight
We've used our R8 commercially for 2.5 years and in all that time the amp has been stock. The only problems we've had are with high wear items like the bias pots, which we put probably the equivalent of 100 years of service on in 2.5 years. Otherwise the amp has performed perfectly in stock form and sounded great! The resistors are fine as built (Skunky said the same thing in her own video). The fail safe is easy enough to add and remember we ran the amp for 2.5 years without a fail safe in place without a problem. Given our hours of operation, I stand behind my original statement that the R8 is a great amp at a bargain price - even in stock form.
She got and kept your attention.
Perhaps if she was only able to do one video saying the amp was great, she wouldn't have been able to hold her largest audience for any product to date?
My R8 has and is running perfectly, perhaps it could benefit from a few upgrades, but most equipment can.
@@pnichols6500 Of course most gear can be upgraded. I suggest you have a look at her comparison between the R8 and a Muzishare she was asked to work on. I know which one I would buy now. (I might add that my R8 took control of itself and powered up spontaneously. China Hifi sent me a new on/off switch but that could have been a real issue if, say, I had been away from home)
Her latest on the Willsenton 300 is proving to be a real eye opener. It seems to have issues well beyond the R8