solid state driven p-p ultralinear

Tube Noob · 14th November 2011, 08:57 PM

Good afternoon Gentlemen,

I am just getting started in electronics, so I think that there are a lot of things I may be overlooking. I have built a few tube amps/preamps/ and a bottlehead kit before, but this is my first try at changing a circuit up. I'd like to try a solid state driven push pull ultra linear. (rev1 schematic attached-which is currently mostly stages that I cut and paste) But that leaves me with a lot of questions...

In regards to global negative feedback, if this were a tube input stage, I would make a connection from the positive speaker output to the cathode of the driver stage (through a Rf). In this case would I tie it to the inverting input of the first stage? Through a feedback resistor? Will that interfere with the R1/R2 gain setting?

With a push/pull topology like this, how do I know/control what class of operation I am biasing the amplifier for? Any areas for improvement on the circuit?

Thank you in advance for the help!

Tube Noob · 14th November 2011, 08:58 PM

sorry, forgot to attach schematic

DF96 · 15th November 2011, 10:19 AM

You could send feedback as you suggested. It would change the gain - that is what it is supposed to do!

The class of operation depends on bias, but the class and anode load impedance interact so you can't just change them independently. Best option is to read the datasheet.

Tube Noob · 15th November 2011, 05:46 PM

Thanks for the response.

On another note, I have yet to decide on an OPT for this design, but I have noticed that common primary impedances for this type of output circuit range from 3k3 to 5k for standard transformers and 1k2 to 1k8 for toroidal xfmer designs.

Why the difference?

DF96 · 15th November 2011, 09:04 PM

Supply voltage, grid bias, Class AB vs B, distortion vs. max power, PA vs. h-fi. Lots of variables, which interact.

ChrisA · 15th November 2011, 09:40 PM

Quote:

Originally Posted by Tube Noob

In regards to global negative feedback, if this were a tube input stage, I would make a connection from the positive speaker output to the cathode of the driver stage (through a Rf). In this case would I tie it to the inverting input of the first stage? Through a feedback resistor? Will that interfere with the R1/R2 gain setting?

I'd send the positive speaker terminal to the inverting amp's positive input. After a suitable RC compensation and scaling step.

14th November 2011, 08:57 PM	#1
Tube Noob diyAudio Member Join Date: Feb 2008 Location: Cleveland, Ohio	solid state driven p-p ultralinear Good afternoon Gentlemen, I am just getting started in electronics, so I think that there are a lot of things I may be overlooking. I have built a few tube amps/preamps/ and a bottlehead kit before, but this is my first try at changing a circuit up. I'd like to try a solid state driven push pull ultra linear. (rev1 schematic attached-which is currently mostly stages that I cut and paste) But that leaves me with a lot of questions... In regards to global negative feedback, if this were a tube input stage, I would make a connection from the positive speaker output to the cathode of the driver stage (through a Rf). In this case would I tie it to the inverting input of the first stage? Through a feedback resistor? Will that interfere with the R1/R2 gain setting? With a push/pull topology like this, how do I know/control what class of operation I am biasing the amplifier for? Any areas for improvement on the circuit? Thank you in advance for the help!

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Solid Solid State Power Amplifier	PMA	Solid State	265	30th August 2011 08:04 PM
solid state just isn't doing it for me!!	bonsai171	Tubes / Valves	9	13th July 2004 11:25 AM
The Solid State Wiki - Your solid state reference guide	Jason	Solid State	0	25th June 2002 05:26 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read

15th November 2011, 10:19 AM	#3
DF96 diyAudio Member Join Date: May 2007	You could send feedback as you suggested. It would change the gain - that is what it is supposed to do! The class of operation depends on bias, but the class and anode load impedance interact so you can't just change them independently. Best option is to read the datasheet.

15th November 2011, 05:46 PM	#4
Tube Noob diyAudio Member Join Date: Feb 2008 Location: Cleveland, Ohio	Thanks for the response. On another note, I have yet to decide on an OPT for this design, but I have noticed that common primary impedances for this type of output circuit range from 3k3 to 5k for standard transformers and 1k2 to 1k8 for toroidal xfmer designs. Why the difference?

15th November 2011, 09:04 PM	#5
DF96 diyAudio Member Join Date: May 2007	Supply voltage, grid bias, Class AB vs B, distortion vs. max power, PA vs. h-fi. Lots of variables, which interact.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)