square wave of Zen4

wish · 24th August 2004, 10:35 AM

What is usual square wave of Zen4 amplifier?

I looked at 1KHz square wave at output and notice 10 peaks on top of square. There was also noticable fall before first peak.

I increased fallback capacitor c12 value approx. 2 times and number of notable peaks decreased to 4.

I can't deside if it really helps to improve sound.

What are usual and desired square wave forms?

Should I increase c12 value more to see no peaks and falls?

Prune · 24th August 2004, 12:17 PM

Quote:

What are usual and desired square wave forms?

Squarish.

Blues · 25th August 2004, 01:42 AM

Hi wish! Are you looking at an actual zv4 circuit or in simulation? I saw the peaks on the leading corner of a square wave using simulation with c12 at 5pF. Increasing c12 to about 11pF rounded it off up to 10khz. In Nelson's zv4 article he described how he watched the square wave as he trimmed a couple of twisted wire he used for c12...he most probably got 5pF to work well with the stock zv4 circuit board. Other values might work well with other DIY boards. Tell me more on what you find out...I don't have an oscilloscope. Looking at the amplified square wave tells us how close it resembles what you feed it...it certainly affects the sound...how much you like it subjectively? Look at amplified sq. w of tube circuits!

wish · 25th August 2004, 06:48 AM

Hi!

I'm looking with oscilloscope at actual built circuit. Q4 is replaced with IRF9610, R2 and R3 lowered to 10K and 47K, C12 initially increased to 22pF. PCB is reworked. Now C12 is increased twice, to 40pF.

I'm confused with the fact of multiple small ringing peaks even after doubling C12 and suspect some flaw in my design. Any advice?

Quote:

Look at amplified sq. w of tube circuits!

I've found some wave samples:
http://www.icl.co.jp/audio/english/2a3/2a3amp.htm
http://www.hometheaterhifi.com/volum...mp-1-2001.html
I see that form isn't ideal, with single or multiple peaks, did you mean that?

Thanks.

Blues · 26th August 2004, 12:02 AM

my advice is to sit down with every change you make and then let your ears be the judge (subjective). then you'll come to the conclusion which values and measurements (objective) sounds best. make sure you take note and let me know

...I don't have the luxury of test equipment and time right now. I lot of tube designs have far from ideal bench test results but sound good to many.

GRollins · 26th August 2004, 03:52 AM

Those little ripples indicate that the amplifier isn't quite as tame as it should be. When in doubt, roll things off a bit. It's better to have a slightly rounded leading edge than one that looks like a pond where a fish has jumped.

Grey

Nelson Pass · 28th August 2004, 06:57 PM

I have a stock Z4 here, and I'll fire it up and look, and
report back.

Later:

No overshoot. Source impedance (and that resistance in series
with the input that sets the gain) have an effect here. Are you
using less than stock value for input resistor?

jarek · 28th August 2004, 08:19 PM

Quote:

I looked at 1KHz square wave at output and notice 10 peaks on top of square. There was also noticable fall before first peak.

Silly question. Have you tested signal itself? I mean your source of the square walve.

Blues · 29th August 2004, 07:34 PM

I noticed in simulation that lower values of R2 and R3 tend to require a higher value of C12 to tame the overshoots.

Nelson, in your experience does a lower value of feedback resistor and higher cap across it robs the output of some microdetails (treble extension)? And does the ckt board layout have an effect on c12 value? Thanks!

Nelson Pass · 30th August 2004, 02:58 AM

My wanders over the value terrain does not seem to have
covered that plot of ground, but probably it is the case. I chose
the input impedance to satisfy the whining of preamp owners
who think that only 47 Kohms is compatible with their tubes.

24th August 2004, 10:35 AM	#1
wish diyAudio Member Join Date: Jul 2004 Location: Perm	square wave of Zen4 What is usual square wave of Zen4 amplifier? I looked at 1KHz square wave at output and notice 10 peaks on top of square. There was also noticable fall before first peak. I increased fallback capacitor c12 value approx. 2 times and number of notable peaks decreased to 4. I can't deside if it really helps to improve sound. What are usual and desired square wave forms? Should I increase c12 value more to see no peaks and falls?

26th August 2004, 12:02 AM	#5
Blues Lightning In A Bottle diyAudio Member Join Date: Sep 2003 Location: Bremerton, WA	my advice is to sit down with every change you make and then let your ears be the judge (subjective). then you'll come to the conclusion which values and measurements (objective) sounds best. make sure you take note and let me know...I don't have the luxury of test equipment and time right now. I lot of tube designs have far from ideal bench test results but sound good to many.

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
Sine wave - Square & Triangle wave generator using Transistors / OP-Amps	lineup	Solid State	20	9th October 2006 12:15 AM
square wave in = square wave out	rick57	Solid State	19	15th April 2003 11:45 AM
Microphone turns triangle wave into square wave?	Circlotron	Analogue Source	18	25th January 2003 06:44 AM

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


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

25th August 2004, 01:42 AM	#3
Blues Lightning In A Bottle diyAudio Member Join Date: Sep 2003 Location: Bremerton, WA	Hi wish! Are you looking at an actual zv4 circuit or in simulation? I saw the peaks on the leading corner of a square wave using simulation with c12 at 5pF. Increasing c12 to about 11pF rounded it off up to 10khz. In Nelson's zv4 article he described how he watched the square wave as he trimmed a couple of twisted wire he used for c12...he most probably got 5pF to work well with the stock zv4 circuit board. Other values might work well with other DIY boards. Tell me more on what you find out...I don't have an oscilloscope. Looking at the amplified square wave tells us how close it resembles what you feed it...it certainly affects the sound...how much you like it subjectively? Look at amplified sq. w of tube circuits!

26th August 2004, 03:52 AM	#6
GRollins diyAudio Member Join Date: Feb 2001 Location: Columbia, SC	Those little ripples indicate that the amplifier isn't quite as tame as it should be. When in doubt, roll things off a bit. It's better to have a slightly rounded leading edge than one that looks like a pond where a fish has jumped. Grey

28th August 2004, 06:57 PM	#7
Nelson Pass The one and only Join Date: Mar 2001	I have a stock Z4 here, and I'll fire it up and look, and report back. Later: No overshoot. Source impedance (and that resistance in series with the input that sets the gain) have an effect here. Are you using less than stock value for input resistor?

29th August 2004, 07:34 PM	#9
Blues Lightning In A Bottle diyAudio Member Join Date: Sep 2003 Location: Bremerton, WA	I noticed in simulation that lower values of R2 and R3 tend to require a higher value of C12 to tame the overshoots. Nelson, in your experience does a lower value of feedback resistor and higher cap across it robs the output of some microdetails (treble extension)? And does the ckt board layout have an effect on c12 value? Thanks!

30th August 2004, 02:58 AM	#10
Nelson Pass The one and only Join Date: Mar 2001	My wanders over the value terrain does not seem to have covered that plot of ground, but probably it is the case. I chose the input impedance to satisfy the whining of preamp owners who think that only 47 Kohms is compatible with their tubes.

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