B1 with Korg Triode

[der_yeti]

Very lucky! I tried two different Nutubes and both showed the ringing issue. Nevertheless I stopped it in both cases with two big pencil erasers stacked one upon the other on the Nutube, screwing the pcb to the chassis with the rubber screws for the drones and plugging every hole of the chassis.

Could you show a picture with the rubber screws, please?

 

[Marra]

These work well.

Male Female Bobbin Mounts: AV Mounts Online

 

[RainfallSky]

Updated list:

Lately I am obsessed to try Takman REY metal film resistors.
Also like their "green moss" color. 🙂
They have limited values but mostly all we usually need.
Judging by PCB photo even RN60 or Takman REY 0.5W resistors should fit.

Check length of alternate 3W resistor from your list.
5W Mundorf is 24x8mm and Kiwame 5W is 24x9mm.
May not fit.

 

[rikiheck]

For power supply mouser 709-RS25-24 worked really well for me. No transformer needed (although I've used isolation trans) and the voltage can be adjusted.

Added to my local copy. Will include it when I update.

For 10 uf caps, I used polyprop/film caps. So far no complain. You are building a great sounding preamp. Have fun!


It depends on where you want to place them. They won't fit into the board as they are much bigger than Elna silmics. So, you would have to find ways to place them in the chassis.

I've used them in an original B1, so you can do vertical or various options. It seems it doesn't matter: Electrolytics are cheaper per uF, especially at large values; but that's it.

 

[Yaho]

Hum noticed Please help

I've connected the B1 and F6. They sound beautiful. They are definietely keepers. I loved them.

I noticed hum on both channels. Not too loud but I can hear it from 8 feet away. First, I thought it was the F6. But it is dead quiet when the B1 is off.

It seems like the hum is higher than 60hz (don't have a scope). Any suggestion? Please help. Thanks

 

[Nelson Pass]

What are you using for the power supply?

 

[6L6]

I noticed hum on both channels.

It seems like the hum is higher than 60hz (don't have a scope). Any suggestion? Please help.

Please post a series of well-lit, in-focus photos.

 

[Yaho]

Mr. Nelson Pass!

What are you using for the power supply?

Mean Well RS-25-24

RS-25-MEAN WELL Switching Power Supply Manufacturer

Please post a series of well-lit, in-focus photos.

Please teach me how. I've tried. It seems like I need to upload to certain sites first?

I am trying.

In the mean time, the B1 and the F6 are singing so beautifully.

 

[Ben Mah]

To post pictures, do not use the "Quick Reply". Hit "Post Reply" and then click on the "paper clip" (attachments) to upload pictures from your computer to the diyAudio website.

 

[Yaho]

Ben Mah,

Thanks!

 

[Ben Mah]

Your signal grounds should be paired with the signal wires. Each channel of the signal output should be twisted with its own ground wire from the board to the output jacks. Likewise, each input signal should be twisted with its own ground wire from the input jacks to the selector and volume control. The output from the volume control should also be twisted with its ground wire to the preamp board.

I see what looks like a wire from the output ground to the safety ground. That is probably not necessary and may also cause hum.

 

[Yaho]

Ben Mah,

I will rewire and see what happens.

And I will disconnect the safety ground wire.

thanks

 

[Ben Mah]

I also see that you doubled all of the signal wires. That is probably overkill, and not necessary. Many builders actually go for the thinnest possible wires for low level signals.

Your signal out jacks are very close to the AC jack. That is also not ideal.

 

[Yaho]

doubled

Good eyes! wow. I am thinking about replacing them with shielded wires tomorrow.

 

[Eric]

Grounding issues (missing a ground point on the PCB) for me led to some hum that I could hear a few feet away from the speaker. When the grounding was fixed, my hum disappeared.

 

[Yaho]

Hi Thanks for the reply.

missing a ground point on the PCB

please explain.

thanks

 

[2 picoDumbs]

Yaho
Can you please make the change we discussed.

That is your PROBLEM.

At least one of them and most likely No More. Touch Wood.

 

[Yaho]

will do, tomorrow. i walked away from my amps. thanks

 

[MagnusHH]

Yikes, 500 pages is a little to much to read. Does this DIY preamp support balanced (XLR) input and output? And is there a good quality complete kit, or shopping list (lets say in the $400 area)?

 

[Tuberoller]

Hey Ben,
Can you explain or provide reference on why "... thinnest possible wires for low level signals."

Just a curious newbie🙂