300B schematic recommendations

[Bill Coltrane]

Triode / Pentode Loadline Simulator v.1.0 (20161216 www.trioda.com)

This is a great tool to play with.

And with a bit of tweeking you can get totally different distortion characteristics.
The 300b can go from inaudible distortion to quite audible, just by changing the values of the surrounding components.

Some people think a certain tube has a certain sound, but tubes themselves don't make a sound. It's the whole circuit that has a specific transfer function. (You can substitute tube for technology to make this statement general.)

 

[euro21]

c3g should be a good driver for 300b?

Yes.

 

[RajkoM]

c3g should be a good driver for 300b?

Best, IMO

 

[Sunwontrise]

Yes.

And using my transformers with 2,5k or 3,4k - in your schematic its 5k 8 Ohm?

 

[mbrennwa]

These are nice driver tubes -- but these designs also don't have a buffer to provide drive the current to the 300B grid. Not my piece of cake.

 

[Sunwontrise]

Also a good one?

 

[euro21]

And using my transformers with 2,5k or 3,4k - in your schematic its 5k 8 Ohm?

With altered B+, and 300B operating point it's usable.

 

[Ketje]

No, it's over compensating.
Simpel bypassing the Rk gives gain 80x and with the feedback you get about 115x.
Mona

Kokoriantz is right, the gain of the first tube is only 80x if the cathode is decoupled.Without the gain is less and restored by the feedback.
Mona

 

[Sunwontrise]

Ok,

I've found some cheap D3A tubes - so I can focus on the Little Ceasar mk4 schematic

I would like to build an stereo amplifier with just only one power transformer - I need a bit of help for this:

GZ34 should give me enough power, but where can I take the voltages for the second channel?

Greetings,

Felix

 

[Ketje]

A bit confusing, 463v and 426v becomes 455v and 420v at the power supply. 463v goes to B+, 426v to B++ With two amps on one supply, change the choke to 200mA, use B+ for the two and give the second chanel it's own R1 and C3. The 2x380v from the transformer has to be good for at least 2x150mA. And each 300B needs its own heater supply (also separate windings)
Mona

 

[U130421]

Excellent choice , an elaborated circuit . As Eli said the u of 6N30 is too low , get informed from Triode Dick what is the input sensitivity. Probably you will need a preamplifier.

If D3a you have it cheap , why not replace 6N30 by D3a wired in triode.

 

[Sunwontrise]

If D3a you have it cheap , why not replace 6N30 by D3a wired in triode.

Do you have a schematic?

 

[Soundhappy]

MJ1208_(08)300B-single-power-amp_MatsunamiK.pdf - Google Drive
MJ1408_(8)WE300B-A1-single-power-IVC[prequel]_KanedaA.pdf - Google Drive
MJ1409_(5)WE300B-A1-single-power-IVC[sequel]_KanedaA.pdf - Google Drive

 

[Soundhappy]

MJ1305_(05)300B-single-power-amp_MatsunamiK.pdf - Google Drive
MJ1407_(3)300B-single-non-NFB-amp_IwamuraY.pdf - Google Drive

 

[fred76]

MJ1208_(08)300B-single-power-amp_MatsunamiK.pdf - Google Drive
MJ1408_(8)WE300B-A1-single-power-IVC[prequel]_KanedaA.pdf - Google Drive
MJ1409_(5)WE300B-A1-single-power-IVC[sequel]_KanedaA.pdf - Google Drive

That’s cool, Soundhappy.. I like the one with the paralleled 12AU7 input, maybe that could be replaced with an SN7 and with the cathodes unbypassed, then the 6V6 driver with IT looks cool to me.. What primary impedance was chosen for the universal Tango X-20S? What is the inductance and resistance values of the S-2062 PSU choke in the schema? Thank you.

Do you have more Japanese 300B articles with a 10Y or 801A driver using an IT too? Thanks!

 

[Soundhappy]

Find what You need about 300B from this link HOME
Enjoy DIY

Japanese DIY Electronics Sites

 

[U130421]

Do you have a schematic?

This circuit is very similar architecture to the one you chose. Just replace the 6N30 circuit by the D3a.They both function at the same current .R9 33k in yours pass to 39k, R1 27k becomes 22k

 

[fred76]

Find what You need about 300B from this link HOME
Enjoy DIY

Thank you for the choke and OPT photos that shows the info and details.. The hookup wiring uses the 3.5k pri on the OPT.. Thanks again.

 

[Soundhappy]

ISO Tango are still in business and have distributors all around the world
販売店 – ISO TRANSFORMERS
MJ1901_(07)appendix_transformer-handbook.pdf - Google Drive

 

[Sunwontrise]

This circuit is very similar architecture to the one you chose. Just replace the 6N30 circuit by the D3a.They both function at the same current .R9 33k in yours pass to 39k, R1 27k becomes 22k

Thanks man! I'll do this, ordered another two D3a's.

I found a power transformer with 370V @ 320ma - would this be enough? And how much ma should my choke be capable off?

Felix