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Odd, I am positive mine follows. Which did you use for semiconductors?

For the Heater? Or the b+ red one? How could it work with no ct?

I have actually done that already. I appreciate the ideas though!

They are indeed

I apologize for the late reply! I hope that you guys had a good Easter Weekend. I have finally got a really nice choke and a better filter cap in place.. the low level hum is now gone very quiet, but I am left with an annoying quiet buzz from the speakers I have moved the choke around to make...

They should be connected with only one ground point so I can't see how there is a ground loop There could be something in the bias supply. Though with both boards acting up it seems odd

Update.. I swapped boards and the other board is identical with the hum. This I think leaves it up to the power transformer/grounding/wiring. Unless I made the same mistake on two boards The hum is directly affected by the bias I give the output tubes. As I biased them up on the second...

Thank you very much for such an in depth reply! I want to say that it is something to do with grounding, or a noisy supply. One of the two. I checked and noticed that the filaments for the 300bs have about 300mv ac on them as well suddenly. Even when the bench supply is in place, yet the amp...

http://tubelab.com/designs/tubelab-se/schematic/

I will link a schematic right away! Around the rectifier I actually tried a few things. I set the rect half way in the socket and with test leads, made sure everything was contacting as it should. I also tried two different tubes in place. After that, I powered the amp up with a seperate...

Hey, So I am finally back st my tubelab project. The amp is in a chassis and the power transformer is on a seperate chassis with an umbilical The amp has a power supply related Hum issue and is pretty loud getting into the output stage somewhere. I have quadruple checked the wiring to make...

Thanks guys, I won't pretend that I know more about electronics than I do because how else do I learn. The layout of the board has the transistors directly under it, and it would be very easy to add one more set of outputs without a messy layout or long leads etc The heat sink would have...

hey, got a quick question for those with more expertise than I have Say I have a lateral mosfet amp that uses 2x n channel and 2x p channel mosfets. I want to increase power output, speaker control, or simply be able to spread heat of a higher bias or higher rail voltage more evenly.. can I...

hey guys, I have been hunting for a really good near no compromise design for a fully balanced kt 88/120/150 monoblock amp using between 4 and 8 output tubes, preferably more. I understand the work and cost that will go into this and have experience to put something like this together, I...

Thanks guys I already know the differences in classes, how they work, how they sound, efficiency and heat etc and what makes an amp a certain class. I can easily hear the difference. What I would like to know is how to mathematically figure out using a multimeter, oscilloscope or other piece...

Haha well that's one way for sure :D It's a class ab lateral mosfet amp that I biased into what I think is class a for at least a watt or two. The heatsinks are large enough to keep the devices well under their max temp as well as any internal components, the power supply is built strong...

Hey guys, This one has been bugging me. I know the difference between class A and class AB etc and how they work. How do I actually know if an amp is running class a or when it is running class ab? Thanks!

I will grab some pics shortly. I can scope along the B+ and see what I get. All my ac and signal wiring outside the board is twisted together and hum isn't affected by moving wires/transformer placement etc. It's also not affected by removing the signal tubes or shorting the input. Next step...

Hey all, I just built my first tubelab SE amp very carefully and I. The process of testing the amp sounds really good, but has quite a bad 120hz hum coming somewhere from the output stage. I am at a slight loss of what to look into now and would appreciate some help. Thank you in advance!

Thanks for the help Time to order some parts

You sir have solved my problem! I had 220 by mistake

Without a load it looks clean, with any sort of load it clips the top half pretty quick

so all the transistors are installed properly for sure i noticed that the driver transistors get pretty hot

Anyone got anything?

hey, I have a marantz 2216 that had a blown channel. I replaced all transistors on the board with proper replacements as well as any damaged out of spec resistors I could find. New caps all around as well I can't figure out this distortion issue. At anything above very low volumes, it cuts the...