• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

which 300B project? help please


Previously: Kuei Yang Wang
2002-11-10 5:35 pm

Marlowe said:
Therefore, That's only one tube (= two systems) for stereo channel?

Of course.

Marlowe said:
The two systems in ONE 5687 are independent, not connected in parallel?


Marlowe said:
the schematic indeed made me confusing.

I appreciate that it is easiest to ask loads of questions, but all the answers you got so far and plenty past and beyond could have been had had you applied some more research. If someone says: "This schematic is the Kondo/Audio Note Japan M7 Linestage" you have plenty of terms to google, if you want to find out more.

Alex Ceveza,

May be you can help me by providing a rough resistors value in substitute to the 5k 30w ohmite like what wellborne Lab are using for a start. Can't get those ohmite variable resistors with that value and rating here in Singapore even from farnell or RScomponents. I'm using the 6AN4 as driver. Thanks.

Hey Mark,
Are you still in the war zone?
If so, let me know what parts you need and I'll send you whatever I have.

I have about 3000 square feet of vintage audio gear, tubes, parts, etc, and it is stacked to the 10-12 foot high ceilings. I mention this because with so much stuff on hand I probably have all or most of what you need.

As I mentioned above, if you're still in country I'll send you whatever you need (if I have it), on me.

Please consider it a gift and a thank you.


2012-10-28 1:58 am
Does anyone have the wiring diagram for the secondary of the st3kb se transformer?
I don't have a diagram, but it can be configured by interconnecting the 8 tagged leads as follows:

16 ohm
s4 out to red terminal
join s1, f2
join s2, f3
join s3, f4
f1 out

8 ohms
s4 out to red terminal
join s1,f2, f3
join s2, s3, f4
f1 out

4 ohms
join s1, s4 out to red terminal
join s2, s3, f1, f4
join f2, f3 out

2 ohms
join s1, s2, s3, s4 out to red terminal
join f1, f2, f3, f4 out