Group order of non-inverted LM4780 pc boards? Anyone interested?

[BrianGT]

Good one Brian How does it sound BTW?

What will you be bringing to ATL DIY this year?
Still not 100% if I'm going or not... My girl gets 4 wisdom teeth out that Thursday so depending on how she feels Friday night I may or may not make it

Chris,

I will finish it and bring it with me.

If you make the trip this year, try not to get arrested for excessive speeding again.

--
Brian

 

[cdoggy81]

Thanks Brian.... funny you should mention.....
I was making a left hand turn Friday (the 22nd) on to 7th street. Got in the turn lane just before 6th street, drove past it & made my turn on 7th. Got pulled over & given a ticket for $118 for not turning on to 6th street B/C I drove in the center lane. I CAN'T GET A BREAK!!!


$118

 

[Peter Daniel]

At least I listened to my one channel, instead of spending a bunch of time taking pictures of it

I made those pictures to have a proof that I'm actually doing something about those boards

I read somwhere that Florida drives are the worst in America.

 

[Ed LaFontaine]

BPA 200 in the works?

Peter said: "I will be experimenting with bridged configuration soon."
Peter, are we likely to find one day that we can combine boards into a BPA 200 arrangement?
Regards,

 

[BrianGT]

Re: BPA 200 in the works?

Peter said: "I will be experimenting with bridged configuration soon."
Peter, are we likely to find one day that we can combine boards into a BPA 200 arrangement?
Regards,

This is part of the master plan

--
Brian

 

[BrianGT]

I made those pictures to have a proof that I'm actually doing something about those boards

I read somwhere that Florida drives are the worst in America.

Florida drivers do suck, as they are mostly old people who shouldn't be allowed to drive.

Georgia drivers are ok. While they tend to drive rather fast, they are usually courteous.

--
Brian

 

[DWong]

Brain and Peter,

Good to see that the kits are ready. When will you send out the kits for international orders?



Dennis

 

[BrianGT]

Brain and Peter,

Good to see that the kits are ready. When will you send out the kits for international orders?

Dennis

I am shipping out the US orders now, and I shipped all the parts for the international orders up to Peter last week, and they should arrive by the end of this week, meaning that the international orders should start shipping out at the end of this week, or early next week, depending on the shipment.

--
Brian

 

[wigginjs]

Could I use a 70VCT@625VA transformer (35-0-35) to power 6 LM4780 amps, or would I need a larger transformer? How would I calculate the current draw for the 6 LM4780 amps all driving 8ohm loads?

 

[Ed LaFontaine]

2 X trouble

m0tion,
With 70 VCT you would provide about +/- 50 V to the chips. This, we are told by the app. note would lead to serious heat problems.

Each Lm4780 is about equal to 2 Lm3886. We have seen that an LM3886 needs a minimum of 80 VA, and more is better. So, 6 LM4780 should have at least 960 VA...and more is better.

 

[lgreen]

Boards Received

I received my boards today. Thank you! they look very nice. Can't get a project out right away but its good to have one in the hopper.

 

[motherone]

Got my boards today. Thanks Brian & Peter.. They look great!

 

[JimD]

Brian,

Received my LM 4780 pc boards yesterday. They look great!

Is there a schematic I can use to determine which components go where on the pcb?

Thank you

Jim

 

[Peter Daniel]

I'm sure Brian is coming up with something. In a meantime you can use this schematic from National's site.

 

[Peter Daniel]

When looking an that pic, two power resistors are from the outputs (0.1R). Two horizontal resistors, closest to the chip, are 20k(or22k) feedback. Between power resistors, from left to right: 20k (input to ground), 2 x 1K (or 680 for more gain), and 2 x 1k (or 220R) series input resistors.

 

[JimD]

Peter

Thank you. That should get me started.

OFF TOPIC
Have you constructed any gaineclones utilizing all Riken Resistors?
If so what is your impression in relation to the sound of the premium component combination with Caddocks and Riken?

Jim

 

[Peter Daniel]

I never built an amp using all Rikens. I don't think it will work well. I tried Rikens at feedback position, but to me, Caddocks works the best there.

Today I replaced Dales (in gain seting position) in my ML preamp with Rikens and they didn't even last an hour there. I switched back to Dales as they sound better there.

Everything is circuit dependant and only you can tell what sounds best for you .

 

[JimD]

Understood.

Thank you.

Jim

 

[cdoggy81]

Has anyone tried the HOLCO's? I've heard a few good things on the Asylum forum. Nothing about chip amp applications though Peter, any usage???

 

[Peter Daniel]

Holcos are OK, but not the best. They don't posses the clarity of Rikens and Caddocks and can sound a bit veiled/mellow. However they are usually better than Dales, for instance.

There is no simple answer which is really better, for as my previous post shows, everything is circuit (and system) dependant.

Whenever I build more complicated circuits, with more resistors, Holcos are my first choice because of the relatively low price.

My first GC had Holcos at feedback location, and it sounded fine.... untill I tried Caddocks

Good carbon resistors might work well here, but I still didn't find the right ones.