GC SuperSymmetry

[qusp]

not completely true, the dgn package does allow slightly higher real world current output, but requires a pcb cheat to allow soldering by hand in the form of a via under the pad that you fill with solder from underneath to connect to copper pour. the regular soic8 package gets pretty toasty, but still works very well

 

[BrianDonegan]

not completely true, the dgn package does allow slightly higher real world current output, but requires a pcb cheat to allow soldering by hand in the form of a via under the pad that you fill with solder from underneath to connect to copper pour. the regular soic8 package gets pretty toasty, but still works very well

Not exactly a high-current application for the chip, however.

 

[buzzforb]

As Brian said, THS4131 in the SOIC package is a good choice. It's bigger, easier to manipulate.

Have you tried a discrete input buffer or just op amps in keeping with the theme.

 

[juma]

Have you tried a discrete input buffer or just op amps in keeping with the theme.

Of course, see post #682

 

[buzzforb]

Very nice. The B1 was exactly what i was thinking of using. What if any difference was there in the sound over the fully op amp version?

 

[juma]

... What if any difference was there in the sound over the fully op amp version?

Less than nuances - it's just that a couple of BF862 are a lot more cheaper than AD797...

 

[buzzforb]

2pcs AD AD797 AD797AR on SOIC DIP adapter | eBay

DO i have to worry about fakes with these kind of parts. I know it is a problem with the Jfets floating around on EBAY

 

[juma]

...DO i have to worry about fakes...

Yes you do - chips are easiest to rebrand/ remark. Ebay is known for fake chips (especially if the price is very low and seller is from China)...

 

[BrianDonegan]

Buy from DigiKey/Mouser and avoid the risks.

 

[buzzforb]

juma,
Do you still have the little BF862 boards you had made? I know its been a while based on the post.

 

[juma]

Do you mean adapter PCBs (SMD to TH) from the BF862 preamp thread ?
If so, yes I have a couple more.

 

[buzzforb]

After looking at the thread again, I think i can make the bf862 boards myself. Am i correct in thinking that you use the version with the BF862 buffer, driven by your bf862 preamp?

 

[juma]

After looking at the thread again, I think i can make the bf862 boards myself.

That's the way

Am i correct in thinking that you use the version with the BF862 buffer, driven by your bf862 preamp?

Generally, yes. Right now, the main amp is this one

 

[buzzforb]

THis is very similar to the F5, correct. The oonly difference i see is tha you have dropped the protection circuit and the feedback circuit on the front end is different. I understand why you have droppped the protection circuit, since you know enough to not have to worry with them. I don't know that I see an advantage to the different feeback setup on the front end, but I may be missing something. Also, you have dropped the thermistors, which Pass says help with drift. Other than the different fets, am I missing something.

 

[juma]

... am I missing something.

Just the whole thread ....

 

[buzzforb]

I have been known to do that.

 

[buzzforb]

I have boards for two F4 amps and was wandering if it possible to drive them with just opa1632. From datasheet it appears that its output voltage will swing to within 4-5V of the rails, so 15V rails should yield 20V swing, correct.

 

[sek]

According to it's datasheet specification OPA1632 swings to within (V-)+1.9V and (V+)-1.9V, respectively, when loaded by 2kOhm. Into 600Ohm this drops to 4.5V within the supply voltage levels.

For a +/-15V supply this would yeld +/-13.1V into 2kOhm and +/-10.5V into 600Ohm. That's 21Vpp into 600Ohm already.

I've attached the diagram showing output voltage vs. load resistance from the datasheet in order to better explain what I mean.

Cheers,
Sebastian.

 

[buzzforb]

Does anyone have a copy of wensans post and explanation about common mode feedback? apparently the host is no longre carrying the pics.

 

[Zen Mod]

which post , exactly ?