trinityamps.com

I don't have a Dremel, but I scraped more paint away from the ground points and sanded a bit.

The hum has been cut in half, it's noticeable but not objectionable even with everything all the way up.

I'll spend some time this weekend grinding away some more. I'm sure that was the only problem.

You know I once read "if it's quiet, it's a ground plane, if it's noisy, it's a ground loop."

I still can't get over how loud this "15-Watt" amp is.

P

[quote="Paul G."]I still can't get over how loud this "15-Watt" amp is./quote]

Those are marketing watts. You can always rate an amp lower than what it really is without being guilty of false advertising. I scoped mine and found it to be putting out more like 21 Watts RMS and more than twice that peak. The 18 Watt is the same way. It puts out 18 Watts of clean power, but closer to 45 peak.

_________________
--s2
www.s2amps.com
www.category5amps.com

Use star/lock washers to bite into the metal, and tighen these down as much as you can.

I'm asuming you have lugs on the ends of the ground wires;
you are using two star ground points;
the 68K input resistors are right on the pins of V1;
115V is grounded to the chassis, not the star ground; and
you used shielded wires from input jacks to them

Right??

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Speaking of hardware...

Coco, what do you use for mounting hardware on your chassis? I'm having a custom combo chassis made by Komboking for a customer (in Canada BTW) which I will have to machine myself. I could put cage nuts in it, but cutting square holes is a pain. Do you have a reccommendation as to what I can use for some kind of integrated nut to hole the back on the chassis?

_________________
--s2
www.s2amps.com
www.category5amps.com

Sure,

There are special clips that hold a square nut that are made by Hammond

You simply drill a 17/64" hole, and the clip slips over it and the nut is held in place on the other side. Works like a charm.

If you look hard enough, you might fid some in your local IT server room!

Hammond Part No. 1421N P25.

Mouser Part #: 546-1421NP25
Mfr. Part #: 1421NP25
Mfr.: Hammond
Description: Hammond Electronic Rack Accessories
10-32 CLIPNUT 25PK

25 cost $13 tho. So they're a bit pricey. I can send you 4.

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Why not have the star grounding points masked off during painting?

Coco,

Are you getting those from Mouser? They show being non-stocked. If so, how long does it take them to fill your order? I need 6 if you don't mind sending them to me. We can work out the cost offline.

Kevin,

That would be pretty tough to do. People seem to like to ground at different places... Ceri@tone's chassis are powder coated, so that would entail having their supplier reliably do that before the powder is applied for a small quantity customer. I've found that suppliers barely want to take my orders at all, much less do special things for me.

The gold anodized Trinity chassis also need to be scraped at all ground points since anozided aluminum is a poor conductor compared to bare aluminum. Since anodizing is a dip process, you can't really mask it.

It really isn't a big deal if you have a dremel tool or something similar. It just takes a minute or two.

_________________
--s2
www.s2amps.com
www.category5amps.com

Star washers, yup, tight, yup.

Yup.

yup.

No--I'd have to run two shielded wires to the inputs and add a terminal block. Most amps have the 68K right on the jacks. If I still have any noise at all after grinding everything down this weekend, I'll go there.

Nope--I'll move that too.

Yup.

Thanks, P.

I can't remember who it was, maybe s2, but there was a thread over at 18w that discussed this. The person involved had experimented with the 68K resistor in various positions....at the jack, inline, etc....and the only place where the 68K resistor actually did it's job as intended, was right on the tube socket.

-F

I agree, 100%. that's the best place for it. Yes, you'll need a tage strip there.

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

S2

You should go to quality powdercoating in carrollton tx.
They will give you little dot stickers to put on wherever you want a ground point. Also they are reasonable as long as you want a stock color.

Peace
Travis

Did you star ground your amp? I have had pretty good success with star grounds and ground busses. It seems like the critical thing is to have only one connection to the chassis, which means all ground points would terminate in the same location, right where they meet the chassis.

I just star grounded my Gergory Mark X, and I was astounded at how that killed the hum almost completely. Now there is just a slight amount of hum when the volume is maxed, with no input. This was the first non-DIY amp that I converted to a star ground, the others that I built were that way from the start. My Spitfire ended up being a ground buss, and tht seemed to work very well.

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PJM

http://www.diyguitarist.com