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wayne 15th January 2019 11:19 PM


Originally Posted by Hook (
That worked, thanks so much 6L6. Project done, and it sounds great. I increased the gain by substituting 10k for 4.75k resistors at R4 and R8 (or was it R10). Now it really works like I would expect a preamp to work.

Thanks Wayne, 6L6 and all the contributors to the thread. Without assistance from the DIYaudio community I'd wouldn't have a working project.

Always good to see another successful build and happy DIYer.

henryve 16th January 2019 12:46 PM


Originally Posted by nano35 (
Ok thanks.
I am planning to try a cap-less version.
I will check the DC offset every time I turn on the system.

Put a dial on the front for DC offset. :D

AllanMarcus 19th January 2019 03:30 AM

Hey there. I just got the PCB and the parts kit from The diyaudiostore. The IEC receptacle they shipped is huge! Including the solder lugs, it will intrude 2 1/8 inch into the enclosure. If I put the IEC in the middle of the rear of the enclosure, the rca inputs will be way over one side. Not pretty at all. Anyone know what diyaudiostore was thinking when they selected this ginormous receptacle?

RafaPolit 19th January 2019 04:10 AM

They were thinking about the quality of the input. They are also actually preparing a case from the DIY store that will fit nicely with the kit parts (hence the 1" stands for the PCB).

I'm really happy with the kit! I think it's top notch, and the space sacrifices are well offset by the grade of the input block.

It just my opinion, obviously.

RafaPolit 19th January 2019 04:12 AM

Ok, so... with everyone talking about DC offset... I have 12mV in one channel and 63mV on the other.

The value is not that high (i hope?), but will the difference between one channel and the other (4x higher on one) have any impact with sound?

More importantly, with this scenario, is there actually any way to change and level the offset?

Thanks for any feedback,

cubicincher 19th January 2019 09:21 AM

Answer to RAFA
Hello Rafa,

63mV offset in one channel seems a little bit high to me?
I am not an electronic engineer.
What I know is that it should not be higher than 50mV.
Perhaps one of the profis can answer this.

In my Whammy I have offsets of 1.2mV and 0.8mV.
I think it can also depend on the Opamp you are using. But I am not sure.


cubicincher 19th January 2019 09:48 AM

And I have spent a lot of time on matching the parts from one chennel to the other. :D

Zen Mod 19th January 2019 11:32 AM

practically ..... no need to match anything

maybe , just to confirm voltage drop of LEDs (in reg circuit) , but nothing else

Wayne did all the thinking , so we Greedy Boyz can chill :clown:

cubicincher 19th January 2019 02:23 PM

Yes, Zen Mod!
And I am one of the most greedy but by darkness in the brain surrounded
students here....:yikes:

6L6 19th January 2019 02:54 PM


Originally Posted by AllanMarcus (
Anyone know what diyaudiostore was thinking when they selected this ginormous receptacle?

Yes, I do.

It’s internally wired, has only one fuse drawer, is switched, filtered, and, the most important, has 3 clearly labeled tabs on the exterior for Live, Neutral and Earth. It covers all the requirements for most countries mains wiring, and happens to be a really nice IEC. :D

Of course, if it doesn’t fit the enclosure, save it for another project and use something that works better for your build. This is DIY after all.

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