trinityamps.com

Hi All

I am starting a 18 watt sIII combo build, I have rebuilt many amplifiers before however never built one off a kit or from scratch.

Deciding to go the trinity route, I read the manual and I was wondering the tube locations on the backside of the chasis?

Do I skip the first hole then go 1/2/3/4/5 imp switch and jack then rectifier tube?

I am trying to find a pic on the site however, all there is posted is the head pictures which are very helpful

Thanks in advance

Dan

Yes.
But you can start there if you want. Its an extra for TC15.

Combo build pictures hmmm, let me look. We did build a combo recently so there may be pictures of it. Most seem to build heads, which explains the docs!

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

Not the best pictures at all but they might help. This customer is located in Berwick, NS.

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

Yes

That is perfect!

Many Thanks!

One last question.

Can I make the boost footswitchable with a SPST footswitch?

Use a 1/4 mono jack and run a cable to the jack from the switch like a marshall PD801 single footswitch?

I know I've got to drill a larger hole in the rear

The kit is solid!

THANKS

Yes you can use a footswitch but it may pop so you will need to make some Modes to eliminate them. we can probably help. Go for it!

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

So wire it standard to the output then and then try it to see if it pops?

It's a boost for the TMB channel correct (sIII)

Thanks in advance

Dan

Check out this post re: pop

viewtopic.php?f=7&t=3044&p=24138&hilit=pop#p24138

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

Well I got the trannies in, pots on, tube sockets etc.

I am wiring the main Can Cap The wiring diagram calls for cement resistor 1K5 5W the colour diagram is very helpful. 95% of it for me has been me going by that and reading the manual, however the colour diagram seems to be the ticket.

I have two cement resistors 150 ohm 5 W and a 5W 2K4

Please tell me if I am about to install the incorrect resistor across the cap

Thanks in advance

As well, the neutral wire and the indicator lamp. There is a plain wire side and a resistor side of the LED indicator lamp.

Does the Neutral wire solder to the resistor side of the indicator LED?

Thanks again

Dan

lastly, I am creating a twisted pair from the IEC to the LED There is white wire however there is no black.

Can I use some of the other wire? The only black I received was the shield wire

Thanks again

You should have a 1K5, so the 2K4 is an error. But use it and if B+ is too low, we'll send you s 1K5.



It doesn't matter, it is an AC device, so no polarity.



Yes, any convenient wire will do. Solid is probably easiest to use.

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

OK 22 guage solid OK? I have lots of solid core wire here

I'll go to RAE and buy a resistor, the local electronics shop.

In assembling the board, the jumpers across the turrets, do you solder them from the backside ? The BUSS bar? do you run that underneath the board?

RAE didn't have the resistor, Because I didn't have black 22 wire for the power to LED I can't test it yet, I don't want to cut another color and run short.

I'll try Jentronics for a 1K5 cement resistor.

ROHS solder? How important is it to have that for the turrets? Will it not stick at all?

Reason being, all the electronics shops only sell it in a $50 roll

Rosin core lead free 97/3 tin/copper solder

Will any ROHS compliant solder work?

I am hoping to get parts today, SLEEP tonight and start fresh tomorrow as I've got the day off
Thanks Please advise

Dan

You can use a 1K5 2W resistor, that is if you can't find the 5W part.

Use any wire you like to wire the pilot lamp. I wouldn't use too low a guage as it will make the wiring difficult.

Jumpers on the board that go from resistor to resistor go on the turrets above the board. Looks at pics here on the forum as to how it's done. Coco has lots of pics of his finished production amps here.

RoHS solder works just fine. Some don't like it as it's a pain in the ass to work with compared to regular lead solder. I like leaded solder myself.

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I got the resistor at jentronic today I have the trannies wired, the IEC and fuse wired plus the power switches.

I'll look tomorrow for PHOS solder, leaded will flow but its a crappy looking joint, I am using a professional WELLER 25 WATT

I think ROHS solder flows at a higher temp

One more question, I've mostly used the colour schematic to follow to date with great success.

The turret board I am getting into that tomorrow after I reload on solder.

The hot side of the board (tube side) there are circles with numbers in spots. On the track

1.0, 1.0 155, 1.5, 217 etc If you look at the schematic it is clearly there.

Any ideas>

Thanks in advance

Dan

Those are DC voltages

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THANK YOU!!!

I just did the forst 1/4 of the build and all my voltages are 110% solid and bang on

Turret board time today

This is an awesome project but very mentally and time consuming.

I just want to get it 110% correct as I want to show off the "guts" of this amp.

THANKS AGAIN

DT

Last question The pF caps.... diagram specifies 500 pF I put my fluke on them and they are 1 nF

1000 pF double the spec I have two of them the outside says 500 +- 5% 500 v however when I check it with my fluke I get different.

What will that cap affect in the circuit. It runs on the TB and between the pots (2)

Thanks in advance
Dan

The turret board pic is very helpful for assembling the TB (what you posted here steven) however on my board only 2 resistors are metal

is this correct for a sIII


THANKS

I kinda have my doubts those caps are actually measuring double their specified value. You sure your meter is accurate and calibrated? Is the battery fresh?

The circuit will work fine with the caps. Replace them latter when the amp is working with 500pF.

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I got the amp finished today

It makes sounds no problem, no excessive hiss, (It is very quiet) The boost really is a signal booster I don't get the "pop" but it definitely gives the channel more volume. More bright.

my question, Is there a hard fire way to figure out where on the switch the impedances are? I used the colour flow chart and I believe orange is 16 ohms The centre is 8 which I will be running when I get my combo box (running 2 x G12M 25 watt speakers)

The amp sounds farty and bassy I hooked it up to my 4 x 12 G12T 75 cab. I am impressed it works, (its got a lot of gain) however I am wondering if I have the impedance selector on 4 as opposed to 16 I play Gibsons with H/B and P90's.

It's like when it's at 4-5 and the gain on 7-8 it almost sounds like a fuzz pedal from the speakers there is some noise there

Will the amp sound like this when first played? I had a buddy who built JMP 50 he said his amp sounded awful for the first bit, Like crap until everything seated in. I am wondering if that is the case here.

The EL84 cathode biased? so the tubes self bias themselves? Do they settle at a 70% diaspation? Is there a way to check this?

I have all JJ in the amp 1-5 are ECC803s (high gain low noise) JJECC803s, ECC803s, JJ EL 84/EL84 and a JJ EZ 81 rectifier

They were all tested and are all excellent matched powertubes and the preamp tubes were checked on a maxi preamp tester

Any opinions please submit

Thanks in Advance

Dan

Cathode biased the tubes at idle at 100% plate dissapation, this is normal. When playing the NFB in the cathode circuit of the output tubes biases the tubes lower.

With the amp flat on a surface (tubes pointing up), looking at the back of the amp the impedance selector switch goes 4-8-16.

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