Picture of my first project 300B

Tomatito · 30th October 2002, 03:27 PM

Hi all,

I'm new to the forum so go easy on me. I thougt I'd share a picture of one of my monoblocks with you. It's my first project and I'm pretty proud. It sounds terrific although I'm not too happy about the hum (5mV)

Bas Horneman · 30th October 2002, 03:42 PM

Very..very nice..never mind for a first time project..it is a fine example of diy ..period.

Did you use star earthing?

Tomatito · 30th October 2002, 03:45 PM

yes I did. I'm trying to rewire the whole thing now so it uses different nodes for the different stages but it doesn't seem to make much difference.

Bas Horneman · 30th October 2002, 03:51 PM

Mmm..looks like you know what you are doing...so I can hardly give any advice.. ;-(

Do you have a hum-pot on the filament of 300b? (AC/DC)..

Did you ground the outside of transformers/chokes/caps etc?

I use indirectly heated triodes..so I have very little hum even with AC filaments..

Tomatito · 30th October 2002, 04:33 PM

Yes, there's a hum-balance pot on the 300B heaters.
Grounding the outsides of the trannies ? Do you mean the steel cases they're in or the transformer itself ? I use a powertransformer with a static shield and that's grounded but maybe it's a good idea to ground the cases as well... Where's my soldering iron....The cases of the capacitors share a groundplane (see picture)

Tomatito · 30th October 2002, 04:39 PM

BTW, nice website...

fdegrove · 30th October 2002, 06:42 PM

Hi Tomatito,

Lovely job!

Hup!Hup!Holland!

I see a handful of tantalum resistors (I think),GZ37,300B and what tube did you use as input?

BTW,I would leave the grounding as it is now.

Cheers,

Tomatito · 30th October 2002, 06:46 PM

Thanks, you're making me blush.

The resistors are Riken Ohm. The input tube is a 6SN7GTB, but tomorrow my 5692 red bases arrive. Can't wait to hear !

FrankDIY · 30th October 2002, 07:00 PM

Very nice job

fdegrove · 30th October 2002, 07:28 PM

Tomatito,

Quote:

5692 red bases arrive. Can't wait to hear !

You're spoiling yourself rotten.

Doei,

30th October 2002, 06:42 PM	#7
fdegrove diyAudio Senior Member Join Date: Aug 2002 Location: Belgium	300B Hi Tomatito, Lovely job! Hup!Hup!Holland! I see a handful of tantalum resistors (I think),GZ37,300B and what tube did you use as input? BTW,I would leave the grounding as it is now. Cheers, __________________ Frank

30th October 2002, 07:00 PM	#9
FrankDIY diyAudio Member Join Date: Mar 2001 Location: Quebec City	Very nice job __________________ Imagination is more important than knowledge. knowledge is limited, imagination encircles the world. Albert Einstein FrankDIY's Audio Corner

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30th October 2002, 03:42 PM	#2
Bas Horneman diyAudio Moderator Emeritus Join Date: Apr 2002 Location: The Netherlands Blog Entries: 18	Very..very nice..never mind for a first time project..it is a fine example of diy ..period. Did you use star earthing?

30th October 2002, 03:45 PM	#3
Tomatito diyAudio Member Join Date: Oct 2002 Location: Amsterdam	yes I did. I'm trying to rewire the whole thing now so it uses different nodes for the different stages but it doesn't seem to make much difference.

30th October 2002, 03:51 PM	#4
Bas Horneman diyAudio Moderator Emeritus Join Date: Apr 2002 Location: The Netherlands Blog Entries: 18	Mmm..looks like you know what you are doing...so I can hardly give any advice.. ;-( Do you have a hum-pot on the filament of 300b? (AC/DC).. Did you ground the outside of transformers/chokes/caps etc? I use indirectly heated triodes..so I have very little hum even with AC filaments..

30th October 2002, 04:39 PM	#6
Tomatito diyAudio Member Join Date: Oct 2002 Location: Amsterdam	BTW, nice website...

30th October 2002, 06:46 PM	#8
Tomatito diyAudio Member Join Date: Oct 2002 Location: Amsterdam	Thanks, you're making me blush. The resistors are Riken Ohm. The input tube is a 6SN7GTB, but tomorrow my 5692 red bases arrive. Can't wait to hear !