6C33C-B. PP or SE ?

[felixx]

Romy.

 

[felixx]

Romy

 

[rdf]

Yesterday I saw this schematic :

http://www.bonavolta.ch/hobby/en/audio/6c33c_3.htm

Yuck. Most OPT secondary windings have in the range of 0.2 ohms DC resistance. If I read that schematic correctly the design puts roughly 30mV of DC across the speaker best case.

 

[45]

Re: Re: 6C33C-B. PP or SE ?

Yuck. Most OPT secondary windings have in the range of 0.2 ohms DC resistance. If I read that schematic correctly the design puts roughly 30mV of DC across the speaker best case.

The anode current of the 6C33 is 160mA. There is no DC across the speaker.

45

 

[rdf]

Isn't that 160 ma passing through the the OPT secondary? 160ma X 0.2 ohm = 32 mV.

 

[inertial]

From my memory I believe to remember there is a little "offset" sort of.
🙄

Cheers,
Paolo

 

[45]

Your loop is not the correct one.
There is no DC current through the secondary, its two ends are at the same voltage.
The output transformer has no gap for such unbalance and the choice for para-feed operation would questionable. This is not the case, Aloia is an excellent and well established professional designer and not a diy'er....

45

 

[rdf]

Your loop is not the correct one.
There is no DC current through the secondary, its two ends are at the same voltage.

45

As shown in the excerpt the 6C33 anode current appears to return to PS ground through the secondary winding, wired as cathode feedback. Simply saying 'no it doesn't' isn't a rebuttal.

 

[45]

There are two kinds of DC feedback.

Without in-out DC Fb the connection is in fig.a.

http://www.audiodesignguide.com/ba/msb_output.jpg

Cathode follower output is another option. Basically you have 4 options in total.

45

 

[rdf]

Isn't Aloia's circuit using configuration 'B'? How does the final's bias current return to the power supply ground? I don't see any DC feedback in it.

 

[gabrielbecheanu]

Hi Predator864
Any news about your project? Witch diagram you chose for your amp? I would like to build one for my self
Keep us in touch with your project. .
Best regard
Gabriel

 

[Akita]

Romy, Melquiades look great to me.

But why need to use 3 transformer?

 

[piero7]

I have the Aloia 6C33 SE. You can configure in many ways.

It is a great SE amp with 30 watt output with only one tube...

 

[trondareo]

Do you have a diagram? pics?
I am thinking of building a 6c33c myself.

I have the Aloia 6C33 SE. You can configure in many ways.

It is a great SE amp with 30 watt output with only one tube...

 

[Jeb-D.]

I have the Aloia 6C33 SE. You can configure in many ways.

It is a great SE amp with 30 watt output with only one tube...

I take it you are referring to peak power, not RMS?

 

[45]

I take it you are referring to peak power, not RMS?

No Jeb it's rms power with less than 5% THD! It's a class A2 amp.

Cheers,
45

 

[Jeb-D.]

No Jeb it's rms power with less than 5% THD! It's a class A2 amp.

Cheers,
45

I'm sorry; I just noticed the driver is an EL34!

 

[piero7]

Do you have a diagram? pics?
I am thinking of building a 6c33c myself.

I'm gonna rebuild it, I have all infos and explanations from aloia (in italian of course)

 

[trondareo]

piero7,
Is it based on the same schematic that predator864 introduces in the first post here?

 

[piero7]

piero7,
Is it based on the same schematic that predator864 introduces in the first post here?

Yup, I'm talking about it 😉 It is a great ampli desined by a master