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The amp is NOT a single ended triode amp it is a PENTODE amp. Maynard answered all your questions and I agree with him 100% but I will still add my two pennies. If tubes are purchased from a reputable dealer they have already been burned in to weed out the duds. Like Maynard said failure is usually early in the tubes life. Second when myself of anyone else knows what they are doing and builds an amp it goes through rigorous testing and then it should be listened to for several hours, by the time it gets to the customer he shouldn't worry about doing anything besides turning it on and enjoying the music. ToolshedMatt uses a Zener Diode to drop voltage to the screen for pentode operation, for those of you that don't know here is a graph of thier characteristics. Depending on it's conduction is how much voltage is dropped. The screen doesn not pull a constant current. If the conduction region falls near the "knee" then you can clearly see during operation the screen voltage will vary. Not a very accurate way of running pentode operation. In this Class A amp it probably isn't as big of a deal as it would be for a Class AB push pull amp. After all that I am glad that Matt the buyer has had a great first experience with a tube amp as we all knew he would. I am certain with all of Maynards efforts of adding this tube section for education purposes more and more people will find their way to hollow state technology. It is truly magical. Merry Crimbus.

I got you covered

I just read the other thread where this all went down............it's raining amps over in Fords, NJ!!!!!!!!!!!!!!! He's got all flavors now, Triode, Pentode, soon to be Push Pull next. This must be how women feel about their attire.

I am happy that Jim is happy!!!!

Not the greatest of environments for gear. Unless of course you have a finished garage that cars dont' go in and out of. Just pull in the bike when I'm not working on something. My Pioneer SX-780 has been out here for years without a problem, there is space heaters i use out there when I'm working so its not too bad. Just some saw dust i blow off with compressed air is the routine. Have not listened to my records for years. It should be fine then. Good luck I hope you get it then!! My garage is opened and closed multiple times a day and wet cars sit in there......it's not pretty.

Not the greatest of environments for gear. Unless of course you have a finished garage that cars dont' go in and out of.

I hope someone that doesn't have a rig and wants to jump into vinyl or has a vinyl collection and wants to get back into listening to it gets this. I was going to upgrade from what I have now but I really like the fully automatic feature it has. I usually listen to music while I work, my workshop is in the next room over so I sometimes can't run to the player to lift the needle. I have a Denon DP-300F with an Ortofon 2M red Cartridge, it sounds really balanced to me. I have heard a lot of expensive turntables and I can't justify the cost.

Great eye Jim!!! In all seriousness if any forum member in the NJ area doesn't jump on this amp they are nuts!!

Don't be fooled, Maynard has a bunch of Chinese kids in his sweatshop pumping those amps out around the clock!!!

I would say start by getting some junk electrical devices and rip the printed circuit boards from them. Get yourself a decent soldering station and a multimeter. You will also need a desolder pump, desolder braid, solder, and some flux. Then practice removing and resoldering components on and off the printed circuit boards you salvaged from junk electronics. In the meantime learn to read schematics. I haven't looked at this whole link but it looks informative: http://www.instructables.com/id/HOW-TO-READ-CIRCUIT-DIAGRAMS/ Also read up on some common safety practices when working on electronics. After you feel comfortable you can start to build stuff. If you really want to have a good grasp on things get something like "The Art of Electronics" and work your way through that. The first chapter has some complicated maths but take your time and learn the fundamentals. If you want to specialize on tube circuits then there are several great books on tube amplifier circuits. But cross that bridge when you get to it. Start small and practice soldering, good soldering skills is really important.

Hello Mike, it looks like the input is the yellow wire to pin 3? If so I don't see a grid stop resistor. Maybe throw a big fat grid stop resistor as close to the pin as possible, 10k will do. Or maybe try grounding pin 1, the shell like you said. I would probably do both, easy enough to try. As far as the cap value it's 1 nanofarad or 1000 picofarads or .001 microfarads. I see now the James is versatile with all it's tap options. I have never used them but they look great and I bet they sound great too!! NWA through the Scott? You are cray cray!!!!! I haven't listened to them in years LOL. Actually you are kinda taking me by surprise with that musical selection. I don't judge because I listen to everything myself......I am all over the place. Anyway that Scott looks like it's in great shape I love it!!!

Hey Mike, Yes Maynard did email me the schematic. I do apologize for I thought you were using feedback with the transformer in the loop. The high value resistor and series cap makes sense now, thanks for clarifying. For tube amps 2kHz square wave testing is most important for it usually represents what the performance at the upper limit of our hearing. For real overkill I do like to run 10kHz square waves through for kicks but most people tell me that's overkill. 5kHz is a good compramise. And yes I would think flying leads from breadboarding would create a large parasitic capacitance at the plate of the driver tube. I have used an RC network around the plate load resistor in the past with good results, but I wouldn't worry about that until you get it in it's chassis with the permanent layout. Another thing you could try is shunting a 1nF 1kV cap from the plates of the 6BQ5 to ground and see if the square wave improves a bit. What you have is good so maybe no improvements will be had. Sounds like you only plan to use the James outputs temporarily? Those are nice, I would just build an amp around them.

I am glad my work got his blessing!

I have read some posts from this sloth guy.......I agree with some of his views but he seemed like a jerk about it. He does use the same simulation software as me so he can't be all that bad.

That is after you scrape the white silicone crud off. It took longer to clean that stuff of then it did to de-solder and re-solder.

Here it is, I installed plutonium grade capacitors and Helium 3 resistors that were used in the apollo missions They only cost $1k a piece.........the sound is out of this world!! JK lol!! Since there is no global feedback I replaced the two cathode resistors with just on on the preamp tube. Global feedback switched to "Schade" feedback. Amps was rewired from ultralinear to triode mode. The old GE 5U4G was very weak so that was replaced with a NOS Sylvania, I am now getting 40+ more B+. I rearranged the two stages AC coupling for a smaller time constant and added a big fat grid stopper to help with recovery time. I also added a 1kV 1nF cap shunting the EL34 plate to ground to help response. Cheap Chinese coupling caps were replaced with real Wima MKP10 polypropylene's. The Bypass caps were upgraded from cheap Chinese brands to Elna Silmic II's. There was a safety concern where the output transformer wires were being chaffed against the hole in chassis, you don't want 310V shorting to the chassis so I fixed that. I am probably forgetting some stuff. Impressions: Much better clarity and soundstaging. I know there was talk about splitting the power supply rails but I felt that the -46db channel separation was adequate. Don't let the price tag fool you, this amp is heavy and the output iron is better than expected. Really deep tight bass!! The response will better what most of the Klipsch speakers can go down to. My honest opinion is that Jim hit a home run with this amp! I really can't wait for him to listen to it! One word; WOW!! Here is the grizzly detail.

PM replied.

Really not sure.......I am the third owner. I don't think Craig has serial numbers on these things, if he does I can't find it. And yes the transformers are massive!! This amp is a back breaker.

Hey guys thanks for all the kind words! This amp would make someone a very nice Christmas Present! Get it all hooked up before your New Years eve Party!! As far as specs go it's a push pull class AB power amp good for about 45 watts per channel. It has 4 and 8 ohm speaker connections. It also has bias taps and controls on top for easy bias and tube swapping. Also the unit has a triode/ultralinear switch. I am more than happy to answer any other questions so feel free to PM me.

Amperex 12AX7's x2 Valvo 12AU7's x2 Penta KT88's x4 Sovtek 5AR4's x2 Fully tested as well as biased and AC balanced. I have a fresh Quad of Penta KT88's that I am including and I am also throwing in a Shunyata Venom Power cable for the Holidays. $1200 includes shipping!!! Unit has been SOLD.

Non-inductive?

Hello Creeve welcome to the forum!! Edcor has really good prices but you have to wait for them to be built. https://edcorusa.com/ If you have an electronic background then things will be fairly easy. Also you can ask me any questions if you like I will do my best to answer them.

Yes, I adopted "Stephanie", it's not the same trust me :/

( . Y . ) are awesome...........on real women!!!