Gainclone building thread based on BrianGT's boards

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#221
I "think" it metioned b4, but I will suggest u to connect or disconnect the amp when the power is off. It is safer than u disconnet it alive...... for the sake of protecting ur speaker.

For ur quote, I will suggest u follow brian's manuel to check the connectivity. SG-> Signal Ground to RCA Jack gound , OG-> Output Ground to Binding post negitive, PG +/- -> Power Gound +/-. So connect ur volume pot ground to RCA jack is correct.
 
#222
tpenguin said:
Ok, a little more info about my problem. It seems that whenever I connect input cables to a source, whether my DVD player or my HT receiver's output, regardless of whether or not the source is turned on, I get the hum. Neither of these as a 3-prong grounded plug. However, when I connect it to a preamp with a grounded plug, I have no noise at all regardless of whether it's on or off. The obvious solution, then, would be to connect my preamp between the source and amp, but I'd prefer to keep from putting anything else in the signal path if I can help it. Does this mean the buzz is coming from the source? If it were, I would assume that I should also hear it through my HT receiver, but I don't, so the question remains how do I get rid of it?
Click to expand...

make sure that your amp is really grounded, like take a resistance measurement between ground pin on plug and your ground on the amp. once you are sure of that try lifting(disconnecting) the ground betwee the input > a switch is good for that because you never know what situation you might use it in.
 
#223
neutron7 said:


make sure that your amp is really grounded, like take a resistance measurement between ground pin on plug and your ground on the amp. once you are sure of that try lifting(disconnecting) the ground betwee the input > a switch is good for that because you never know what situation you might use it in.
Click to expand...

Well, the star ground is definitely connected to the AC ground pin. I actually said something incorrect earlier. I do still get the hum even when I connect it to the preamp. I don't know why I didn't hear it the first time. Maybe I had the volume turned all the way down, or maybe I actually had the power off, but it definitely hums regardless. I'm afraid I don't quite understand what you mean by disconnecting the grounds between the inputs. Do you mean I should remove the sgnd wire from the rca jacks? All the power grounds seem to be wired correctly. Did anybody else using the center tap configuration have this trouble?
 
#224
Your Preamp is probably not grounded to Earth Ground and you have a PD between the three devices. Try connecting a 14 gauge wire to the three devices by connecting to a screw on the chassis and take them all back to an electrical outlet Ground Pin. I suggest you buy a 3 prong plug you can wire yourself and connect the three wires to the ground pin only and plug it in the wall. The other end of each wire attach to the chassis with a screw on lug (ring connector)

And again for Pity Sake, make sure it is the ground pin on the electrical outlet you connect to!!!!

Regards

Anthony
 
#225
neutron7 said:
Coulomb thats nice. is it a class a or something to be just one channel and be that large (and not have PSU inside). I bet its got a lot more inside than a couple of tiny 'clones.

did you make the other matching one? or is it for a sub amp or speaker test amp or something like that.

sorry for the OT everyone 🙂
Click to expand...


300 watt Class A/B for my one of my Subs. 🙂
 
#226
Coulomb said:
Your Preamp is probably not grounded to Earth Ground and you have a PD between the three devices. Try connecting a 14 gauge wire to the three devices by connecting to a screw on the chassis and take them all back to an electrical outlet Ground Pin. I suggest you buy a 3 prong plug you can wire yourself and connect the three wires to the ground pin only and plug it in the wall. The other end of each wire attach to the chassis with a screw on lug (ring connector)

And again for the Pity Sake, make sure it is the grounf pin on the electrical outlet you connect to!!!!

Regards

Anthony
Click to expand...

Well, I'll give it a try, but if the hum is being caused by those devices not being earth-grounded, then why don't I hear it from my HT receiver?
 
#227
tpenguin said:


Well, I'll give it a try, but if the hum is being caused by those devices not being earth-grounded, then why don't I hear it from my HT receiver?
Click to expand...

They may indeed be grounded, but at different PD (Potential Difference) this will cause current flow in the ground circuits. My solution should bring all your equipment to the same PD. Don't forget to wire your HT Receiver directly to ground on the same setup.

Regards

Anthony
 
#229
Coulomb said:


They may indeed be grounded, but at different PD (Potential Difference) this will cause current flow in the ground circuits. My solution should bring all your equipment to the same PD. Don't forget to wire your HT Receiver directly to ground on the same setup.

Regards

Anthony
Click to expand...

Well, Coulomb, you were indeed correct. Grounding the chassis of my source decreased the intensity of the hum by about 75%. However, It's still there, even though I can only hear it when the CD is paused. The improvement is tremendous, but I would prefer that it not hum at all. Any more ideas?

-Logan
 
#230
its a bit of a cheat but you may be able to get rid of the hum by reversing the primaries of your power transformer.

I dont even know why it works but in a certain studio which i will not mention they have a lot of effects units, and sometimes can get rid of hum problems with certain combinations of effects by turning around the power plug on one of them 🙂. (most of them are 2 prong plugs)

this is probably a bad thing to do!
 
#231
GC heatsink

Do anyone know of anywhere in the UK where I could obtain brass/bronze of a size (approx 5cm x 2cm x 15cm ) to make a heatsink for a GC, similar the one the illustrious PD uses in his latest submission to Brians GC gallery?

All of the places I have tried only do bar upto 7mm thick.

Peter
For that amp I noticed that the one this forum does not have the metal in the Zebrawood, what benefit does that give? What kind of tolerance fit to the caps do you usually go for?

TIA

Simon
 
#232
Re: GC heatsink

SineEra said:

For that amp I noticed that the one this forum does not have the metal in the Zebrawood, what benefit does that give?
Click to expand...

What exactly do you mean here?

I drill the opening for the caps 7/8, as cut out tool I have has this particular dimention. It fits perfectly for BG with jacket on, when you skin them, you have a biy loose fit, but it's still OK.
 
#234
Back by popular demand:

I have started taking orders again for NIGC (non-inverted gainclone) basic kits and pcbs. I put a new order page up on my website at:
http://www.BrianGT.com/order
Be sure to add the appropiate shipping to your cart before checking out.

I am only offering Basic kits and PCB sets at this time. I have ordered the parts for the premium kits, and am expecting them in a few weeks. Basic kits are selling for $35, and pcb sets are selling for $15. I am keeping the prices at a reasonable level, and a portion of the profits will be donated to diyAudio.

I will start shipping out the new orders out at the end of next week.

The premium kits will be offered again in the near future, as soon as I receive the parts for them. I won't be accepting any payment for the premium kits until then. (expecting 2-5 weeks, according to manufacturer's lead-times)

Here is a link to my gallery of projects using my kits/pcbs:
http://www.briangt.com/gallery/nigc
and build pictures from my amplifier using the kit:
http://www.briangt.com/gallery/nigc-kit

The Wiki here also has information on the kits:
http://www.diyaudio.com/wiki/index.php?page=NI+GC+PCB+Group+Order+Phase+II

Drop me an e-mail, or make a post here if you have any questions.

--
Brian
 
#235
Peter
Apologies for my lack of clarity in the question. Trying to do things from memory and not checking ones facts can make you look an ***.
In comparing patek3.jpg and patek11.jpg in Brian's gallery, it looks as if in 11 the lefthand piece of zebrawood has piece of silver metal of triangular cross section running along it, with the holes for the caps in.

Perhaps I am mistaken and it is just a trick of the light.


Simon
 
#238
OK... here's a few of the "BrianGT billet clone"...
 

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