trinityamps.com

This will be the forum for the new Tramp. A Single Ended, Simple design that goes from Clean to Dirty with only two tubes and 5 controls. So it's perfect for a beginner and with a VRM included, your perfect bedroom amp!!

Specs to be posted soon.

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

I thought the tramp had stowed away on a train and had left the area, glad to hear it's close

Can I pick up a kit next weekend when I come and see you ???

AJC

Very cool!

Only two tubes, does that include the output tube?

Can't wait to see the design ideas behind this one.

TRAMP SPECIFICATION

1. Controls: Power, Gain, Bass, Treble, Volume, 1 input
2. VRM incorporated into design
3. Amp to be able to go from Clean to Dirty.
4. Drive octal tubes with OT & bias changes
5. Cathode Bias
6. Solid State rectifier
7. 2 tubes (3 max)
8. Beginner build
9. 1 additional Noval sockets (power or pre-amp)
10. Power Indicator
11. Tweed/'tude switch for clean/dirty preamp
12. Headphone output

Possible options: line out, drive EL84 tubes

Power / Level control – Rotary ON-OFF switch with 1M control for VRM*.
Actions: Off – On (low level is standby. Turning control further effects the VRM control.

*VRM– components mounted on eyelet board. MOSFET mounted immediately beside board & leads soldered in directly.

Gain control – to adjust amount of overdrive. Note: Amp has to be able to go from Clean to Dirty.

Tone Controls:
Bass – approx 10 db Cut/Boost @ 100 Hz fixed (still TBD)
Treble - approx 10 db Cut/Boost @ 4 KHz fixed (still TBD)
Ability to scoop midrange 10 db.

Volume control – overall volume level control.

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

So I guess I can pick up the kit next Saturday then??

AJC

(I love being a pest - just ask my wife!)

When do the kits ship, I want one

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Fantasy Noise is what my shop of dreams is called and was the only way to beat my addiction, like many here I suffer from G.A.S.


Tele's make the best noise

Sounds cool!!! I'm still jonesin' for a Triwatt too....

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Deric®

Anyone who followed the TRIWATT design , prototype build will know it takes a while to perfect, finalize the design and tool up for it. Maybe by the end of the year or sooner. Prototype by Halloween.

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

Excellent...a new area to explore!

Sounds very interesting. Timing will be spot on...I should have my multi-arcade project done by the end of the month & I'll be looking for another adventure.

Besides...6 amps isn't enough, right? RIGHT?!?

So, when you say "octal tubes with OT & bias changes", could that be something along the lines of the THD concept? Basically any Octal tube (within reason) with a beefy OT? I've always been curious about how they make that work considering different tubes like different OT impedances.

One thing I've noticed about the plethora of low-cost single-ended amps on the market, the EL84 units at least, is that the tone of all of them has a fizzy & somewaht "nasal" character - kind of an AM radio thing (but not that extreme). My VJr is still like that even after major modifications through several designs. I haven't changed the OT though, and that may be the key. I realize the fizziness is just part of the EL84 character when you push them hard, but the nasal thing isn't apparrent in the EL84 push-pull amps I've built/played.

With that said, I haven't tried any of the boutique (pricey) single-ended units.

The Tramp's OT will certainly be beefy. However, the THD Univalve has compromise bias resistor and OT load impedance values, so that almost none of the tubes it runs actually work optimally. Some run cold, some too hot. What I prefer to do is to have one or two cathode resistors on a switch, plus a couple of different selectable OT taps.

You're also not the first person to notice that EL84s sound a lot better in PP amps than SE ones. However, that POS little OT is the first thing that needs to be changed in your VJ, and also its many derivatives that are out there at the moment. That will take out a lot of the fizz and nasal characteristic. Having said that, I still prefer 6V6s to EL84s in SE amps.

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Great tones come in small glass jars!

Yeah - I've been planning on dropping a Hammond 125 ESE or maybe a DSE in there. Just haven't gotten around to it. I've also considered a 6V6 mod, or even a switchable output stage (both very common VJ mods). Truth be known the amp is basically a hot-rodded 18w lite pre-amp with a SE output stage at this point. It's also biased a little hot and that probably isn't helping things. Gotta change that bias resistor to a 250 or 280...and maybe beef up the first filter cap, and maybe add a switchable NFB...

I should post a pic in the dressing room section I guess. Too lazy to drag the thing out of the cab right now though!

Meanwhile, back on topic!

I was looking at the Univalve schem earlier. I see what you're talking about. They don't mess with the bias supply or plate voltages at all. It does look like they have switchable OT impedence though.

(without looking at the schem) that's probably for the OT's secondaries.

Correct me if I'm wrong but you can affect the primaries Z by altering the secondary Z. Like I think setting the secondary to 4R and running a 8R load halves the primary Z.

I think Dave Hunter's Two Stroke kinda works like that. He doesn't alter bias resistor's but changes the impedance according to what tubes are in the output section. Always liked that design. Might be cool to have an extra octal socket in the Tramp. It's real simple, the other tube is in parallel, literally. Add the second tube and halve the primary impedance.

Pardon me, could you repeat that a little slower and louder please?! (or maybe in English) lol..

I need to learn more tube amp lingo and theory...

AJC

That's what I get for not paying attention! You're right of course. It also shows that I'm a bit of an invalid reading schems sometimes!

I know how you feel Andrew. When I do try to sound intelligent I often sound like I don't have a clue (see my post above!). That's why I usually leave the technical stuff to all our far more knowledgable friends!

Colder bias will tend to make the EL84 more buzzy. You would probably do better to reduce the B+ voltage with a zener or two, and put a huge cap (1000uF to 2200uF) on the EL84 cathodes to reduce bias voltage transients which cause the EL84 to starve. There's a lot more information on VJr modding on SEwatt.com,and look for the Marshall, Fender, Vox and Bad Cat Mini Cat mods - all of which I had some involvement in. Unfortunately Roger's customers in Canada may have problems getting through to that site.

I had forgotten they had switchable OT load impedance. My bad.

Sure. Although some OTs don't handle the different current and voltage levels well. In the past I've used the Hammond 125ESE, which gives a few different ratios, and can handle just about anything you throw at it. Then it's a matter of changing the impedance tapping and/or speaker to get the load impedance you want - see http://hammondmfg.com/125SEsch.gif

Just you need a PT and OT that are twice as big.


In non-EE-speak if you put an 8 ohm speaker, for example, on a 4 ohm output tap, you double the load impedance seen on the primary. Or say if you put an 8 ohm speaker on the 16 ohm output tap, you halve the load impedance at the OT primary. And so on, etc....

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Great tones come in small glass jars!

I'm not a Rogers customer (and never will be...I wouldn't even let them run cable to my house when I built it. No offence to any Rogers affiliates on here!) so that won't be an issue. I've been poking around SEwatt on many occasions. Actually, it was the inspiration for my working on a Mini-Cat layout - yet another project I haven't gotten back to!

I do plan on bumping up the cap on the EL84 cathodes. I think I currently have the stock value in there.

As for the bias & buzziness, I have no doubt you're right. The stock bias is a little hot though so I would like to bring it down a bit to help with tube life if nothing else. I have thought about adding zeners to drop the B+ a little. I can't remember what the B+ is off hand. Should be pretty close to stock though. I haven't messed with that at all.

This is all assuming I don't re-build the thing again of course...



Actually Phil it was probably my bad. I think I read the schematic incorrectly (or misinterpreted it). As kurtlives pointed out it's more likely a switch for the output impedance that I was looking at, although as you note regarding the Hammond transformers one could vary the impedance with different taps if the OT has the option.



This is exactly where my head was when I was reading the THD schem, and also probably because I was looking at Toneslut trannies for a potential 'Wreck clone project that also have multiple taps for different load impedances.

Has anyone tried switchable OTs? If you had a big beefy tranny for louder situations and then switched to a champ sized transformer for bedroom levels,is it even possible?It would be neat to quickly switch over for recording and such.

I can't wait for the Tramp. I told myself "no more amps" but I'll make an exception for this one. Looking forward to seeing the prototype and hearing some sound clips.