Wana's_makin'_a_guitar said:
mayfly said:
Hey Wanna,
I had a quick look at the Aus kit. Er, perhaps you should consider Ceriatone... :glasses10:
Why is that? It sounded like a pretty good review.
hokay, Here's my opinion:
1 - the layout is confused, clustered and not well thought out. Check out that eyelet board that extends 3/4 the length of the chassis with almost nothing connected to it. Also check out the length of the leads on some of the components - they are quite long and need to be bent at odd angles to make it fit. That's a recipe for unreliability, especially when a lot of those long lead components have no insulation on the leads. It also makes for a difficult to repair amp since you have to unsolder a bunch of stuff to get at the bad component.
2 - Everything is lug mounted where the ceriatone uses an eyelet board - much easier to deal with both in original construction and in repairs. More reliable too.
3 - The chassis is punched for a bunch of knobs - but the kit only uses three. Again not well thought out. Perhaps they were thinking of future features - but if that's the case then where is the front label plate to cover up those unused holes?
4 - no bottom plate - I'm assuming that they won't add one (I admit this might be incorrect, but given the other issues with the amp I'm betting that it's not). It's not going to pass a safety certification unless it's steel on the bottom - wood won't do when there is something arcing inside there.
5 - the front end tube stage is the middle one necessitating a long run of shielded cable to the tube. To make matters worse, the grid blocking resistor for the front end is mounted to the input jacks - which is ok as long as the run of cable in the amp is short. As it is, it's a recipe for picking up the Aus police radio. Now granted, this could be fun - but not in the middle of a show.
6 - the wire for the heaters for the preamp tubes looks like it is much to high a gauge for carrying the current load.
7 - doesn't look like there is much power supply decoupling. There's no choke and the multi-section cap only looks like a 20uf/20uf/20uf. That first stage should be at least 50uf even with a tube rectifier.
8 - er - why is the power switch on the back and the standby switch on the front?
9 - no grommets on the leads from the output transformer. This will eventually lead to shorting out the transformer - one of the most expensive parts in the amp. It will also give you a good solid jolt through your guitar when that happens.
10 - is this a cathode bias amp? If so the cathode bypass caps look a little on the small side for good tone - but that could just be the angle of the photo.
Overall, this looks like the first amp that someone designed. There are a bunch of fundamental mistakes. You can do better with a Ceriatone.
BTW, here's the insides of an amp that I designed:
Note the board with easy access to all components, and the short runs on the grid inputs. Note that the knob and tube positions are well lined up to the components on the board. Also note the choke, the proper decoupling, the proper wire gauge, the proper cathode bypass caps, the flameproof metal oxide resistors, the grommets on all wires going through the chassis, and blah blah blah.
I'm going to build one. Probably out of walnut instead of Koa, though.
