Tube Lab #40 - Electro-Harmonix *6550EH + Willsenton R8 Tube Package
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- Опубликовано: 15 июл 2021
- A busy Episode in which we talk about a very affordable KT88 type power tube, progress on the 6P7S Monoblocks and some wonderful and weird tubes that came in.
*Caution: Operating Maximum for Electro-Harmonix 6550eh is 440v plate 440v screen.
Measured operating voltages on my R8 are 446v on the Plate and Screen. I have been operating the 6550eh tubes for a week without a problem. Normally a tube can operate a wee bit over design maximum without an issue.
Link to my online store: valvesnmore.com/ 
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My orders in. Just what I was looking for to start rolling on my R8. Thanks so much for all you do.
I received this set of tubes sooner than expected. The shipment was packed very well and in great shape. I’ve been burning them in and they sound very nice. I can hear the three “C”. Noticeably better than the stock tubes
Great channel. Wealth of knowledge
I imagine you Jim, walking into your tube store.... Like the warehouse house at the end of Indiana Jones where they leave the arc of the covenant lololol xx
Looking forward to viewing the kits . I’m hopeless at soldering but fascinating…..would love a 101 soldering vid. …sadly
Everyone is hopeless at first! Me included! In a 15 minute vid I can get you soldering with the best - after a wee bit of practice! The secrets are: a good temp controlled soldering iron with correct tip, Kester solder, solder paste, clean contact surfaces and Bob's Your Uncle perfect solder joints! First pair of kits are moving forward every day! The preamp will have a mini PCB I've developed with the help of a viewer and now my Son. They're high quality, with huge traces and will make assembling much easier. The kit will be a hybrid of small PCBs and point to point wiring.
i find this brand of 6550 tube you have to carful with the screen voltage 660 volts max on the anode and 440 volts max on the screen , true KT 88 800 volts max on the anode 600 volts max on the screen
Thanks for the heads up! I forget the exact operating voltages of the Willsenton R8, but it's well under that and the setting for my custom power tube tester is set at 400v.
Hi there, thank you for the video. Do you happen to know what the switch setting should be for the 6550's on back of the R8. The settings are either for the 34's or the 88's. Not sure which one to put it on.
Hey! The 6550 is like a slightly lower powered KT88, so you want to have it on the KT88 setting. Make sure you adjust all the bias pots all the way counter clockwise and give them a few minutes to warm up, then do an initial bias, listen to some music for a bit, and then adjust the bias again. If these are new tubes to the amp, make sure you do not leave it unattended and that you stay in the room and periodically check the bias to ensure there is no drift that could eventually cause a red-plate situation. Cheers, and happy listening.
@@tubelab194 thank you. I appreciate the help. Can you tell me more about a red plate situation? I’m fairly new to tube amps and have not heard of this before. I have been running EL 34’s on it and was encouraged to run the 6550 s in order to get better bass out of the system.
@@joshuabriese3525 red plating is when a tube runs away (current) and gets so hot the plate starts to glow a bright orange > hence "red plating". This of course means the tube is destroyed and if left on other components will be fried as well and if the fuse doesn't pop in time, you could possibly have an electrical fire. This is the main reason why we never leave any of our tube gear on unattended.
@@tubelab194thank you for your help. So far so good with the new tubes 😊
@@tubelab194 Well I had my first experience with red plating recently. My Willsenton R8 runs EL34s or KT88s/6550s. I have only ran the EL34s on it but someone said to try out the 6550s for a bit better bass. So I think I have something wrong with my KT88/6550 circuit as I have had two tubes go back in V3 spot. One just stopped working and one red plated. However works just fine on EL34's. Not sure what to do next.