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Hi to all
I,m fairly new here, I built a 5e3 from a kit assembled by a local amp guru here in Adelaide South Australia with chassis from Modulus and a Tasmanian Oak head cabinet that I built with a friend.
The result was a pretty good amp but I caught the bug of building.
I purchased an incomplete 18 watt amp from a bloke in Melbourne who designed and built the circuit himself, I found it was pretty well complete, however he has added a bunch of pre-amp switching,s and a resonance knob that unfortunately don't really do much to better the sound of the amp, in fact they seem to add a bit of a frying bacon and farting noises, it is also point to point wired with some long cables running around.
I have had a play with the thing by tidying up the cabling and disconnecting the resonance and replacing a couple of dodgy looking caps and resistors as well as tidying up the soldering. But the result is I still have an amp that is OK but not great it has been a good learning experience and a bit of fun project.
I have decided that I am going to strip it down to components and build an sIII the transformers are GDS and at the right current settings sound great I am hoping that by building an sIII I will have an amp with more versatility over both channels and throughout the range of knob settings.
I am going all in here! I am building the turret board myself I am still debating with myself about whether I will add extra turrets to allow additional switching for different voicing,s, I have bent up a chassis and been mucking around with a panel layout to laser engrave once I have settled on what to include and leave etc.
The main question that is pulsing through what is left of my brain is, what wattage potentiometers do I get the ones I have are alpha and I am considering upgrading to CTS or Bournes to try and quieten the project down, Mouser, Digikey etc all have watt ratings on their pots whereas amp suppliers don,t how important is this as I have not seen it on any schematics either
Tim

Hi Tim. Welcome to the forum.

Sounds like an interesting project. Good luck with the rebuild.

Volume, gain and tone pots in a guitar amp are low wattage. Alphas are 1/2 watt. You can go a higher wattage if you want, but unless the quality is much better there isn't any real reason to do so.

Have you tried just using some contact cleaner on your noisy pots?

Thank you Mitch if the general consensus it that Alpha pots are Ok I will re-use the ones I have. I,m not sure how price relates to quality with pots I just figured that being the bit that is fiddled with the most having the best quality you can put in would be beneficial. I know that some kit suppliers are in the business of selling "magic" as opposed to a swag of electrical components, all the trawling on the subject I have done suggests that the Trinity guys are not like that which is why I settled on their design. If I did not have this project basically fall into my lap I was going to buy a Trinity kit, who knows down the track I may still buy an OSD kit as that interests me also.

Alpha pots are good ones. They get the job done and are quite reliable. Most amp builders and kits use them, including Trinity. CTS and Bourns are higher quality, so if you want to use them go ahead. CTS pots are used a lot in guitars. Bourns show up in high-end test equipment.

Ok so here goes a couple of silly questions I am toying with the V6 option has anyone tried it? and how beneficial is it? does it really add much more or does it affect the original and just make a compromise? The other thing I have noticed is there are only a couple of capacitors difference between the sIII and the plexi has anyone tried switching between the two versions of the amp? I am conscious that the biggest rookie mistake is adding too many bells and whistles and ending up with a noisy mess with useless switching which I want to avoid just curious as to what is possible and practicable.
Thanks
Tim

v6 is a cool addition that has bo impact on the EL84s. you need space for the tubes and they do run all the time. Imthink the GDS transformers will be ok iwht that. Use the Trinity v6 design to connect up the extra power tubes.

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

Thank you Stephen the blank chassis Ive bent up is 610mm wide so I will have plenty of room for the V6
I would still like to know if switching between sIII and plexi is a practicable idea
The next point I am pondering is how far apart to space the transformers, I have read to go as far apart as practicable to avoid noisy interactions between them, is there a limit, most amps Ive seen have the transformers only about 50mm apart
Im still planning the layout, when I start marking it out and drilling holes I start posting some photos
Tim

To find the positions and orientation for the transformers on a blank chassis so they have minimum interaction, look up "transformer headphone trick" on the Internet. Here's a link to start you off.
https://www.thegearpage.net/board/index ... ck.733998/

I see there is a post that mentions the headphone trick on this forum, too.
viewtopic.php?f=1&t=2121

Hi Guys Ive made my turret board but I made a basic mistake. I mucked around and got the image to print the right size for the material (G10 fiberglass 3mm thick) which was 300mm square. Once I manipulated the image to 300x75 mm I stuck it onto the board and drilled it out. The problem is that I made the board too wide and the four resisters that go all the way across the board. I could just use two smaller value resistors in series or extend the legs or add extra turrets or I could slice one side off the turret board and re-drill the holes closer in. Any suggestions of which way would be the best solution.
How can I post photos

I would probably cut the board and redrill the holes closer in. Or add extra turrets spaced for the resistors. Hard to say without seeing it, though.

To post images, there are two ways to do it. If the image is hosted on an external site, just add the url inside img tags. Like this: [img]YourImageURL[/img]. You can either type the tags yourself or click the Img button on the toolbar above the message window.

Or if the image is on your computer you can scroll down to the "Upload attachment" section below the message window. There you can browse for the image on your computer and add it to the file.

Best is to reinstall just those turrets. Dont add wire to the components, it adds another point of possible failure.

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

Hi all Ive been caught up in working for a living lately and consequentially haven't had time to spend on my hobbies. I have decided to add the 6v6 dual power tube option, so my question is what should the tube cathode switch be rated at? am I reading the layout correctly that it is switching between 12 and 22 volts

I am still curious to hear if anyone has created switching between different preamp options eg between sIII and plexi
Thank you
Tim

Yes, that sounds about right. It's low voltage at around 80 mA so you don't need a huge switch. Looks like the layouts show a DPDT mini toggle switch. I'd use a high quality one, though.

Thank you Mitch I,m building a combo so I want to put all the switching on the front panel Im thinking Carling
Tim

Carling are very goodquality. We use them a lot.

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

Hi Guys
Another question that's probably been asked a million times before. How much space should be between tubes Im building the Trinity sIII V6 version in a combo which has 3X 12ax7,s 2X EL 84,s 2X 6v6 and an EZ81
The other things to fit is power lead, fuse, speaker plug and impedance switch. I have about 460mm to squeeze it into about 18.25 inches
It is going to be tight with about 16mm between the smaller tubes and about 25 between the 6v6,s. so I,m wondering if I should put the speaker jacks and or the power cable on the inside face instead or should I just put them all on the face Ive got and hope for the best?
I solved my turret board problem by adding additional turrets on the ground bus and dog-legging the bus

The layout looks OK. It would be best to give the output tubes as much space as you can, though. It helps with heat dissipation and makes the wiring easier. Heat dissipation isn't the greatest, anyway, when the tubes are mounted upside down.

Hi Guys
Starting to assemble my turret board and found I don't have a couple of resistors that I need. The question is can I substitute 1 watt resistors for .5 watt ones how important is the wattage?

Resistor wattage is important. It's calculated based on the voltage drop and the current. Then whatever wattage you get is usually doubled to make sure the resistor isn't working near its limits.

So while it's not good to go lower, you can always go higher. The resistor will run cooler and quieter.

Same with capacitor voltage ratings. You can go higher there, too.