Glen builds a 700B

[Gepetto]

Two questions, my curiosity

first - would using a bypolar electrolytic cap in place be ok then

second - using a cap of this size make sense size wise but will it be missed? It got in there to begin with for a reason right?

A bipolar of suitable voltage rating will do no harm Glen but it will also not improve anything. Was a just in case location put in for good measure during the design phase. A later change to move to larger 1.5uF Polyester caps (which you have on your backplanes) was made which helps the high frequency decoupling and the inductive effects of the lead wires connecting the backplane boards to the bulk supply.

Happy Thanksgiving.

Joe

 

[grapplesaw]

A bipolar of suitable voltage rating will do no harm Glen but it will also not improve anything. Was a just in case location put in for good measure during the design phase. A later change to move to larger 1.5uF Polyester caps (which you have on your backplanes) was made which helps the high frequency decoupling and the inductive effects of the lead wires connecting the backplane boards to the bulk supply.

Happy Thanksgiving.

Joe

Hope you had a great thanksgiving day Joe and everyone on the Forums m as well.
Thanks for the reply

 

[WOPL Sniffer]

Hope you had a great thanksgiving day Joe and everyone on the Amorim as well.
Thanks for the reply

RIM WHAT???

Huh?

 

[grapplesaw]

So I had to play with my 700b I built and posted in this thread for the past few days.





I Put in revC back plane and revG control board with warm white meter lights.

Also wanted to see what the residual noise was without the shielding on the 120AC wires. I had used twisted #14 just for the overkill of it. So with the AP all hooked up I got with 1k across the inputs

.395 mv on the right
.363 mv on the left
Dc offset was only .0008mv

I got an other B starting next week so will use the shielded AC wire I have and see what it produces.

She’s looking good tonight

 

[laatsch55]

Millivolts or micro volts?

 

[62vauxhall]

So I had to play with my 700b I built and posted in this thread for the past few days.


View attachment 40390 View attachment 40391


I Put in revC back plane and revG control board with warm white meter lights.

Also wanted to see what the residual noise was without the shielding on the 120AC wires. I had used twisted #14 just for the overkill of it. So with the AP all hooked up I got with 1k across the inputs

.395 mv on the right
.363 mv on the left
Dc offset was only .0008mv

I got an other B starting next week so will use the shielded AC wire I have and see what it produces.

She’s looking good tonight

Nice work Glen. Are the level controls still active or did you disable them?

 

[grapplesaw]

Nice work Glen. Are the level controls still active or did you disable them?

Clever catch there Gary.
I have both options available via the slide switch by the inputs. Instead of the stock setup which connects or bypasses the high pass filter I use the switch to connect or bypass the volume pots. There is no longer a high pass filter on the amp.

 

[grapplesaw]

Millivolts or micro volts?

Well the reading was 395uV and 363 uV From which I believe converts to .395mV and .363mV. Lee Please let me know if you think this is not right

 

[laatsch55]

Correct justmaling sure the decimal point was in the right place.

 

[FredR]

Clever catch there Gary.
I have both options available via the slide switch by the inputs. Instead of the stock setup which connects or bypasses the high pass filter I use the switch to connect or bypass the volume pots. There is no longer a high pass filter on the amp.

Excellent idea!

 

[grapplesaw]

Alive and doing fine

I would post the numbers but I am not. They are amazing and I do not have the time to run full power output from 5-20,000hz today and probably never will.

 

[62vauxhall]

Clever catch there Gary.
I have both options available via the slide switch by the inputs. Instead of the stock setup which connects or bypasses the high pass filter I use the switch to connect or bypass the volume pots. There is no longer a high pass filter on the amp.

I like that. The level controls on my amp were left in place for cosmetics but not reconnected. Since it has as much power as it does, the meters barely twitch at volumes I can play it at. Even at -20dB. I feel sometimes that seeing the needles move more would be nice.

When it was stock, I was convinced it sounded better running wide open. But since the controls are benign now, my thought is that I was imagining things. But, I had the same perception about the Kenwood Model 600 I used for oh so many years.

If it's something you think I can do, maybe you can clue me in. A simple diagram would be ideal. The amp is at the other end of my move but I'd like to tackle that when I'm settled in.

 

[grapplesaw]

I like that. The level controls on my amp were left in place for cosmetics but not reconnected. Since it has as much power as it does, the meters barely twitch at volumes I can play it at. Even at -20dB. I feel sometimes that seeing the needles move more would be nice.

When it was stock, I was convinced it sounded better running wide open. But since the controls are benign now, my thought is that I was imagining things. But, I had the same perception about the Kenwood Model 600 I used for oh so many years.

If it's something you think I can do, maybe you can clue me in. A simple diagram would be ideal. The amp is at the other end of my move but I'd like to tackle that when I'm settled in.

Gary lets get a coffee soon. I can guide you easily through this. I also added a six position meter switch which I can give you so you can get better use of the meters at lower volumes.

 

[62vauxhall]

Gary lets get a coffee soon. I can guide you easily through this. I also added a six position meter switch which I can give you so you can get better use of the meters at lower volumes.

Roger that. I'll be around at the end of next week and will call/text you.

 

[J!m]

My KA-9100 has a meter range switch, so you get the show when the volume is less than deafening. That rear switch (or another) could be used for meter range.