Construction Practices

[Ned]

I've been around audio since the 50s and built, not copied, a few amps but now, due to a friends interest I am now looking at guitar Amps. I'd like to ask why it seems there is every attempt to leave component leads as long as possible and not use any shielded cable even when a control grid lead is extended 6 inches from the tube. Also in the picture at the top left; why are the leads so long on those orange drops. It would seem that, to prevent lead fatigue and breakage due to the rough life of a guitar amp, they should be right down on the board and secured wth some glue. Just wondering

[martin manning]

Because a guitar amp is to a Hi-Fi amp like moonshine is to single-malt. Welcome to TAG, BTW!

[Phil_S]

Amateur answering here. Mind what Martin says...unless it is a high gain amp, a guitar amp can be rather forgiving. There are plenty of builders who are knowledgeable about good/better/best practices. You should feel free to tighten things up in your build, but there are some compromises that are inevitable. In particular, the long, narrow chassis, head or combo, placement inside the cabinet, these dictate or force choices for control, tube, and transformer placement. As for 6" grid inputs, particularly to V1, that is fairly common and if dressed OK, it is not a problem -- except maybe for high gain amps. Some of us don't like shielded cable because the added capacitance can affect tone on some circuits -- make an amp dead instead of alive. Guitar amp builders tend to use it very sparingly.

I suggest browsing the forum. You'll see all sorts of builds that work, even sloppy ones. You'll also see some that are really quite tidy, and lots in between.

Welcome to TAG!

[Structo]

Some of us don't like shielded cable because the added capacitance can affect tone

You have to be careful what shielded cable you use.

The cheaper stuff is usually pretty high pf/ ft.
Which can dull high frequencies.

Sometimes that is not a bad thing, depending on the amp circuit.

[The New Steve H]

I worried about that stuff until I made a few amps, and then I realized people were right when they told me to forget about it. An amp can have really low noise without the aggravation of shielding. I was concerned about a problem that didn't exist.

It's probably not that important in hi-fi amps either. The hiss in recordings is pretty bad, and no one worries about it.

[matt h]

(deleted)

[Structo]

Man, Matt
That is a sig worthy quote.
Unless of course it is copyrighted or something.
But, sometimes the lines blur between laziness, idiocy, and genius.

[martin manning]

David St. Hubbins: It's such a fine line between stupid, and uh...
Nigel Tufnel: Clever.
David St. Hubbins: Yeah, and clever.

[Structo]

hehehehehehe

[Ned]

Very interesting responses (thanks all) yet the application is not uniform accross the industry. I have seen everything from shielded to a length of grounded wire wrapped around a signal wire to no shielding at all. It appears that more of the expensive ones use proper shielding than not

. Now what about the caps in the picture at the top left.

I am also wondering why there is very little use of drivers between the phase inverter and output pairs or quads in higher power versions using 6550s or similar.

Oh well ..back to my roots in the malt whiskey.

[M Fowler]

Where is the picture you keep referring to?

[Reeltarded]

The ampgarage logo pic ^^^^ <<<<<

Long legs? If they were any shorter they wouldn't reach the caps!

[M Fowler]

Oh for F**k sakes post real pictures if your going to comment, damn it.

I just saw the eye doc today and eye ball was in good health wise just need new prescription eyeglasses on their way so I'll be waiting on that poor wiring photo to be posted.

[Reeltarded]

+1

If i am going to win i have to start double posting.

[M Fowler]

Yup your way behind.