trinityamps.com

I'm a little confused reading the site. On the opening 18 watt page, it mentions three versions, but then on the specs page, it lists four. I assume that the three was a typo.

Going further, I'm trying to nail down the differences between the four versions. I'm particularly confused with regard to identifying both channels on all four amps.

As I understand it, going right to left, the Marshall 18 watters had a normal channel (two inputs, volume, tone) and then a tremolo channel (two inputs, volume, tone, rate, depth). My understanding is that all four of the Trinity amps replace the tone control and both tremolo controls on the "tremolo channel" with treble, midrange and bass. Is this correct? If so, for sake of clarity, I suppose this is the "TMB channel" in the Trinity literature on the site.

The sIII and the TMB are both said to be TMB amps. That part I get.

The TMB channel of the sIII is supposed to be lower gain (JTMM-45 style) than the TMB channel of the TMB (Marshall 2203 of the late '70s). I get that too.

It's the other channel (Normal) that confuses me. For the sIII, it says it "is the same design as the original Marshall 18 Watt Tremolo channel". OK, I suppose this means that the sIII Normal is like the Marshall Tremolo.
1) Does that mean that neither of teh sIII channels are the same as the Marshall "Normal" (i.e. not Tremolo)?
2) Are the two channels on the Marshall the same anyway (not counting the tremolo feature)?
3) What about the Normal Channel on the TMB? Is it also voiced like the Normal Channel on the sIII, or is it different entirely? I know their TMB channels are different, but what about their "Normal" channels?

The Plexi has me a bit more stumped.
1) Which channel is the Plexi channel and which one isn't? Or, in different terms, which channel has the TMB controls: Plexi or Normal?
2) It says the Normal channel "provides way more overdrive than most 18 watt normal channels". Is that more than the Marshall 18 watt, or also more than the Trinity sIII and Trinity TMB?
3) Does that clean boost apply to both channels, or just one? If one, which?
4) Is the clean boost footswitchable for this amp, or only the v6? The literature doesn't really say.

Is the v6 basically a Plexi with footswitchable output tubes, or are there other differences not listed on the site?

Finally, I see in the Gallery that a few of the amps actually have a Gain knob where one of the two inputs would be. Which amp is that?


I know there are a lot of questions in one post, but I really want to understand before ordering. Besides, it seems to make more sense to put them in one than to spread them out in a bunch of posts.

Robert

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Oops, a few more questions.

1) The Gallery showsa photo of a green amp titled "Trinity_sIIIV6front". It has two toggles on the back. One is to the left. The other is just to the right of the impedance selector. What do they do?
2) Is that amp an sIII or a v6?


3) The next amp pictured is red and it's titled "anderson_sIII". I'm guessing this one is a Trinity 18 sIII. It's rearview shot only shows one toggle. What's that toggle for?

4) Further down the line, there's a black one with a couple pictures labeled "neonfront" and "neonrear". This one has no toggles in back. Why? Which model is this?

5) The one even further down that has a Gain in place of an input seems to lose a knob spot to a standby switch. Which model is that?

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I hope I can help clear it up.

All 4 amps have the same front plate. On the TMB channel, there is a Gain & Volume now (used to be Volume &Master)and real earl versions used an input jack hole for a MV control for a very short time.

The sIII - Has a 'low' gain TMB channel. The normal channel is the original 18 watt tremolo channel with Tone control only. Serious Boost switch on TMB channel only.

The plexi - Has a 'med' gain TMB channel (a bit more presence/crunch). The normal channel is the original plexi lead channel with Tone control only. Huge balls OD. Clean boost for a bit more volume not OD so much on TMB channel only

The TMB - Has a 'high' gain TMB channel. The normal channel is the original 18 watt non-tremolo channel with Tone control only. No boost required.

The v6 is any one of these but add the option to switch in 6V6 output tubes for a creamier sound. It has a switch for boost (as applicable) and another one for the power tubes.

The model with a knob where the standby switch was, was a custom amp with power level (VVR/VRM) and the ability to cascade the TMB channel into the normal channel for more gain.

Hope that helps a bit.

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

Thanks, that did clear things up a whole lot.

The only area where I'm not 100% clear is the boost. Apparently, the TMB model has no boost at all, while the sIII has a "serious" boost on the TMB channel and the Plexi has a clean boost on the TMB channel.

1) By "serious", I'm guessing you mean a gain (i.e. more distortion) type of boost as opposed to a clean type of boost. Even though it's said to have the lowest gain TMB channel of the three, the sIII appears to sort of make up for it with the gain boost. Is that a reasonable description?

2) Are the boosts the sIII or Plexi footswitchable, or is it only a rear panel switch? The only reason I ask is that the website text only really mentions FOOTSWITCHABLE in describing the v6.



Your v6 description is very interesting. I take it that one could have a v6 version of either the sIII, Plexi or TMB. That really opens up the possibilities.

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Yes, it does allow the amp to cover a lot of ground.



Yes & No. All kits have a toggle switch only.
We have a special slow on - slow off opto switch we use on our production builds to keep the 'pop' under control. We don't sell that as a kit. You would have to figure out a way to do it quietly or put up with the switching pop.

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

Thanks again for the very quick response.

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I haven't built any of these amps, but hope to soon. I too had similar questions about the voicing of the channels and found the documentation a little confusing. My understanding of the schematics is that the changes between sIII, TMB and Plexi are only fairly straightforward resistor and capacitor swaps in the pre-amp section of the circuit (coco please correct me if I am wrong). I think the best option is to choose the build you think will most likely suit and then alter a few components later to suit voicing/gain requirements.

EDIT: with regards to the footswitchable query I believe that is an option for switching between 6v6 and el84 power tubes on the v6 builds only.

They all use the same board. On top of the preamp mods as suggested, the TMB has a different volume pot (1M); the plexi a different cathode resistor of 470. They all have different tone controls for the Normal channel. TMB channel coupling caps are different on the plexi as well.

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

Does that answer apply to ONLY the three basic versions (sIII, Plexi and TMB), or does that include the v6 modified versions of those three as well?

The reason I ask is this blurb from the site text:
"v6 - The v6 adds foot switchable output tubes and foot switchable boost. In this design, you can switch in 6V6 or the EL84 output tubes. The sound is close to a Fender Deluxe and an 18 watt grafted together."

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If we build a v6 amp for a customer, the foot switching applies. If you build it, it doesn't.

see this post about our Soft Boost: viewtopic.php?f=12&t=1093

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

Thanks for clarifying yet again!

It looks like I'll have to do a little learning to pursue a footswitch.

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Hey, you get the easy part. It took a lot of research to get that cricuit to do what we wanted it to do!!

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

Hi there guys!

Hope you don't mind bringing up the old thread...
I'm planning on making a single (TMB) channel amp with 4 el84s so a 36w basically, but i'm still thinking which preamp to go with...

Here's the deal - reading topics and posts by many people there seems to be a somewhat big difference in the TMB channels of the sIII, Plexi and TMB 18watters. To be perfectly honest i can't quite work out why...

As far as i can work out here are the differences between these 3 in their TMB channels:

1) V1-a cathode resistor/capacitor: [sIII] 820r/.68uf / [Plexi] 820r/.68uf / [TMB] 820r/22uf
-from my experience, on first 2 amps less lower frequencies are being pushed by the 1st gain stage compared to the TMB, something like a JMP lead/bass thing, making sIII and Plexi a bit more "middly" in the first stage and TMB more "round" as the 22uf bypass cap boosts pretty much all frequencies to the maximum unlike 0.68uf. Some avoid higher values than 2uf as it can lead to a flabby bass

2) V1a Coupling capacitor: [sIII] 0.0047uf / [Plexi] 0.022uf / [TMB] 0.0047uf
-again, most to do with the frequency range, the higher the value, the more bass goes through, higher values makes for a flabbier bass, lower values for a more focused tone and tighter bass.

3) [sIII] 100k resistor Volume wiper to ground, no mixer resistor / [Plexi] 100k resistor Volume wiper to ground, no mixer resistor / [TMB] 470k mixer resistor
- can't really say i know the difference here gain-wise.....

4) Master Volume potentiometer: [sIII] 500kA / [Plexi] 500kA / [TMB] 1MA
- from what i understand, TMB's 1M master volume pot lets less signal to the ground making it more gainy compared to the 500k pot on sIII and Plexi

5) V2a Cathode resistor / capacitor: [sIII] 2k7/no cap (boost on: 1.35k/no cap) / [Plexi] 2k7/no cap (boost on: 1.35k/22uf) / [TMB] 820r
- i guess that this makes the biggest difference in gain within these 3 amps, the higher the value of the cathode resistor, the lower the gain in that stage

I hope i found all the difference from these 3 amps which are pretty similar. TMB stands out the most, but to be honest apart from the V1 coupling cap and a V2a cathode bypass capacitor... I'm asking if there's anything vital i'm missing here?

Thanks a lot guys!!!

Hi Bulotavic. Nice to see you here!

As you probably know from 18watt.com, Richie Hall published the 18W TMB design in a rough and ready form that others could experiment with and tweak to their own tastes. Trinity's TMB is closer to Richies' original TMB design than the other two, although it is tweaked.

1 - The large cathode cap was in the original TMB. Personally I prefer not to use anything bigger than 1uF or possibly 2uF in that position.

2 - The Trinity Plexi deliberately uses cap and resistor values based on common Marshall Plexi preamp values. The Normal channel preamp is similar to a Plexi's dark/bass channel, for Plexi-style use with a patch cable between the two channels.

3 - The 100k resistor to ground reduces preamp gain, for later breakup. With the sIII the idea was to give more of a JTM45ish feel as far as breakup goes. The 470k mixer in the TMB is from a typical Plexi preamp.

4 - Yes, in a subtle way. I would also never refer to that pot as a Master Volume, since it only controls one of the two channels. It's really just a Volume control for the TMB channel.

5 - That is correct. The large cathode cap reduces more gain ,when non-bypassed. The Boost then switches a bypass cap and or parallel resistor across the cathode resistor.

I also really recommend taking a look at Unimind's Brown Plexi variant described in some recent threads, which sounds totally killer!

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Great tones come in small glass jars!

Very informative stuff!

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Hey, Phil!

Yeh, this is a great place!

Many many many thanks for your reply, it's really helpful, especially since i'm planing a build based on 18w amp.

The thing is - i got some great old trannies out of really old Klemt Echolette M40 (PT 290-0-290 with 2 sets of 6.3v heaters -originally it had 5 preamp ecc83 tubes, 4 EL84 output and 2 EZ81 rectifiers) so it's got a lot of power! - OT seems nice and beefy, with 4k taps and UL taps as well and outputs for 4 and 15ohm) - in other words great stuff for a 36w project.

The question is - what to do with the preamp section?
I like the "normal" channel of the 18w, but i think it works best with 18w and that 36w would make it cleaner and not as "raunchy and raw" as it is. It sounds great for early rock tones and stuff like ZZ Top, but for me lacks the versatility that i need for gigging, especially as the setlist contains stuff from ZZ Top, Hendrix (great for normal channel) to gainier stuff like Whitesnake, gainy Gary Moore tones... Plus the other guitarist plays Mesa Boogie MKIII so, it's no match for it's power and chunky bottom end.

Looking at the Brown mod - it just sounds soooo awesome! I'm battling between the sIII One and the Brown... Well, i'd definitely make the TMB regular channel more like the Brown one, the question is only where to put the cascade, or the triode i'll have left after removing the normal channel...

Any opinions on that?