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Now for something different...

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That worked, thanks for the tip  :laugh:

 

In other news, I fixed the offset-issue. Didn't have to do anything except realize that the servo op-amp is a dual-OP and not the usual OP27  ::) Note to self, read the schematic properly FFS! :mikey2:

 

 

//UFN

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what value of input pot should be used on squarewave klone? read 10K somewhere before but I can't find it

 

or maybe should use higer value like 50K/100K since it's fet input? thanks

Edited by ang728

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well I do 10k, just because I don't want too many different versions in stock.

 

but 50k or 100k works fine for this

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Thanks !

 

well I do 10k, just because I don't want too many different versions in stock.

 

but 50k or 100k works fine for this

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I like that one a lot!!  :)  I have a pile of these that I need to finish at some point as it is a really good amp. 

 

Any troubles with that feedback switch? 

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I like that one a lot!!  :)  I have a pile of these that I need to finish at some point as it is a really good amp. 

 

Any troubles with that feedback switch? 

Thanks!

 

besides not as "hi gain" as I thought , actually they work well .Love that sound with switch on 

 

btw,I am curious about how does this feedback design work in the circuit , any paper or keywords that I can learn from ? :)

Edited by ang728

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What would the current draw be for a balanced version? Inside or outside GRLV range ( think I saw 1,5 amps somewhere)?

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26 minutes ago, MLA said:

What would the current draw be for a balanced version? Inside or outside GRLV range ( think I saw 1,5 amps somewhere)?

I put them on lab bench psu before,can't remember what's exact number of current draw,but I'm sure under 1.5A

then built a slimmer case version a while ago using orginal GR and works pretty well

Edited by ang728

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On 2 december 2014 at 10:03 PM, kevin gilmore said:

about 120ma, measure across the 10 ohm resistors

Just double checking: 120ma, not mv? Can't get near the ma version, so thought I'd ask before pulling things apart...

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39 minutes ago, MLA said:

Just double checking: 120ma, not mv? Can't get near the ma version, so thought I'd ask before pulling things apart...

YES,it's 120mA,you should have 1.2V reading across 10R

but 100mA-110mA sounds best IMO

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Great, thanks! Can't get more than halfway there, so I've screwed up somewhere... Makes for a nice evening of troubleshooting :)

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Ok, not so long evening, a bad solder joint it was. Nice and steady at 120 ma now. Guess I have to go watch a movie instead. Boring :)

Many thanks for both of your very quick responses!!!

Edited by MLA

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Sorry for refloating this thread.

I'm listening to my "SquareWave KG latest version" in SE configuration. (Thanks Dr. Gilmore)

It works great and is very simple to assemble. I have regulated the BIAS @ 120mA without problems and could even raise it much more.

I have used a 100K resistor to make the servo act as fast as possible and from the beginning the offset is 0 Vdc so I don't need wait for listening music. I matched all the transistors as best as possible but with the MJE200 and MJE201 it was impossible to find an identical pair. 🙄

The next step is to install it in a box but I'm hesitating, Is it worth making a balanced version? Is there much difference between the SE vs. Balanced version?

I have enough material and pcb´s to do this without problems but if this does not make sense, I'll leave it in SE configuration.

Edited by jose

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Yesterday I was listening to the Square Wave with different headphones (hd800, W5000 ....) and I was wondering if the output impedance changes when changing the gain (Low to High)?

I understand that if he does it, I do not know exactly how much or if the change is very radical.

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Just warmed this up, sounds terrific. Think I'll populate the other two boards for a balanced Squarewave.

 

IMG_1396.JPG

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I'm glad to see another Squarewave alive. 

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19 minutes ago, Rossliew said:

Sorry how does this amp sound compared to the dynalo? 

mostly the same

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The Squarewave does not sound bad but IMHO dynalo is superior: More balanced, more musical ...

 

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Thanks. Thought the Squarewave would be a nice complement to the Dynalo.

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