[Punnisher]

Received the kit on Saturday and had it built four hours later. I've been listening and doing initial break-in for the last day or two.
 
Initial impressions are extremely positive. Really love the way this amp sounds with every headphone I own. The soundstage seems to be quite large and airy with this amplifier. With my other gear there seems to be a "gap" in the middle making imaging seem unnatural. With this amp though, imaging is more seamless and really helps place you in the performance. Another positive difference I've noticed is with bass and kick-drum. Huge bass transients are no match for this amp. I've never heard the kick drum sound so punchy and pronounced.
 
The impedance switch seems to do well with under 200ohm on low and over 200ohm on high. That's my initial impression anyway with the varying impedances I've tried. My dt880 250ohm really sings on the high impedance setting with a flat yet full-bodied sound throughout all frequencies. The same can be said for my 120ohm k601 on the low impedance setting. Headphones that fall in the middle between 120 and 250 ohm could go either way. It's a great feature for a headphone collector who can't be tied down to one impedance range.
 
There's only a couple issues I have found with my amp, and these are very very minor.
 
1. A tiny bit of hum is audible for me during silence. It mostly shows up with very sensitive headphones (Grado) or headphones that are middle-of-the-road impedance on the high setting (dt880 250ohm). It should be noted that I have not tried the numerous tweaks available and that I have an older house which does not have grounds on any of its outlets. Once I attach the amp to a properly grounded outlet the hum may disappear completely. Combined with the tweaks, I am confident I can get the amp to be dead silent. With that said, it doesn't take away from enjoyment at all and should not be a deterrent from buying this awesome kit.
 
2. I only found 3 short black screws in my kit. It would be useful to have 6 short screws for the standoff mounting. I ended up stacking washers with the long screws inside the amp which gets very close to the output transformer leads. I'll be shortening those screws and reinstalling them soon.
 
Thanks to everyone involved with designing and distributing this kit. It's absolutely fantastic.

 

[perrew]

Wanted to try and ecp l-2 but they were all sold out so I got the next best thing instead....a torpedo. I really like this amp!

 

[HiGHFLYiN9]

Very cool vent holes! How did you pull that off? 

 

[Punnisher]

Yes we must hear what you did for that project. Paint? Powdercoat?
 
I have been enjoying my amp very much. My latest pairing is the K702 with 6J6 tubes using low impedance setting. This combo sounds very nice, natural, spacious. I also made a few tweaks including stainless machine screws, clear anodized aluminum knob and tube guards. I like the way it turned out.
 

 

[tomb]

Very nice, Punnisher!
 
That blue one was one of the first prototypes.  It was custom machined/powder-coated by user luvdunhill.

 

[tomb]

<snip>  
2. I only found 3 short black screws in my kit. It would be useful to have 6 short screws for the standoff mounting. I ended up stacking washers with the long screws inside the amp which gets very close to the output transformer leads. I'll be shortening those screws and reinstalling them soon.
 
Thanks to everyone involved with designing and distributing this kit. It's absolutely fantastic.

The short screws are only for one side of the standoffs - they're only supposed to be 3 of those in the kit.  The rest of the screws will fit on the other side.  All screws are selected for a minimum of one washer under the screw.  On the top of the PCB, you should use one washer and a lock-washer.  This cuts down on the possibility of loosening the PCB screw, first.  It should stay tight when you loosen the screw on the bottom of the case.  This is the same for all three standoffs.
 
I suppose I should write another web-page just on hardware, since the screws and washers/etc. included with the kit are extensive.

 

[perrew]

Very nice, Punnisher!

That blue one was one of the first prototypes.  It was custom machined/powder-coated by user luvdunhill.

Yeah I got it from luvdunhill and it is an amazing build with beautiful sound.
Ive been running it with a Pico Dac and it sounds great with the HD800s.
A really nice amp! Tks Dsavitsk/Beezar!

 

[tomb]

  Received the kit on Saturday and had it built four hours later. I've been listening and doing initial break-in for the last day or two.
 
Initial impressions are extremely positive. Really love the way this amp sounds with every headphone I own. The soundstage seems to be quite large and airy with this amplifier. With my other gear there seems to be a "gap" in the middle making imaging seem unnatural. With this amp though, imaging is more seamless and really helps place you in the performance. Another positive difference I've noticed is with bass and kick-drum. Huge bass transients are no match for this amp. I've never heard the kick drum sound so punchy and pronounced.
 
The impedance switch seems to do well with under 200ohm on low and over 200ohm on high. That's my initial impression anyway with the varying impedances I've tried. My dt880 250ohm really sings on the high impedance setting with a flat yet full-bodied sound throughout all frequencies. The same can be said for my 120ohm k601 on the low impedance setting. Headphones that fall in the middle between 120 and 250 ohm could go either way. It's a great feature for a headphone collector who can't be tied down to one impedance range.
 
There's only a couple issues I have found with my amp, and these are very very minor.
 
1. A tiny bit of hum is audible for me during silence. It mostly shows up with very sensitive headphones (Grado) or headphones that are middle-of-the-road impedance on the high setting (dt880 250ohm). It should be noted that I have not tried the numerous tweaks available and that I have an older house which does not have grounds on any of its outlets. Once I attach the amp to a properly grounded outlet the hum may disappear completely. Combined with the tweaks, I am confident I can get the amp to be dead silent. With that said, it doesn't take away from enjoyment at all and should not be a deterrent from buying this awesome kit.
 
2. I only found 3 short black screws in my kit. It would be useful to have 6 short screws for the standoff mounting. I ended up stacking washers with the long screws inside the amp which gets very close to the output transformer leads. I'll be shortening those screws and reinstalling them soon.
 
Thanks to everyone involved with designing and distributing this kit. It's absolutely fantastic.

 
OK - I blew it.  You are absolutely correct about the screws/washers.  I just built two recently and I must've messed up when originally coming up with the hardware pack.  The standoffs work best with 1/4" screws on both sides:

1. On top of the PCB - 1/4" socket head, lock washer, washer
2. Underneath the PCB - Washer, standoff
3. Bottom of case - washer, 1/4" socket head screw.

 
I've also noticed some quality-control issues on the Hammond choke.  Not that it hurts anything about the circuit, but the metal tabs and frame of the choke have some variances that require more hardware - specifically, a washer under the tabs.  So, for the choke you have this for each mounting tab (2 of them):

1. On top of mounting tab - 1/4" socket head, washer
2. Underneath mounting tab, on top of PCB - washer
3. Underneath PCB - washer, lock washer, nut

 
As someone also pointed out, the back stand off (closest to the PT) is also too close to the 200V B+ trace that cuts across the width of the PCB.  A regular washer touches the trace and if you clamp down too hard or scratch the mask, you'll have a short.  I will supply a nylon washer with all hardware in the future.  We'll fix that with the next revision of PCB's.
 
Speaking of which, I'm pretty excited about a tweak that I've been supplying with the last few kits.  It reduces any trace of the ripple with my Grados and further improves the sound quality of the amp.  Dsavitsk told me that Kevin Gilmore suggested that the heater power supply was oscillating at the rectifiers.  This makes sense, because it's never "hum" (60 Hz).  It's a 180 Hz artifact that only presented itself when the case is buttoned up.  None of that made sense with typical 60Hz hum.  By default, however, we used very fast Schottky rectifiers for the heater supply and those appear to be causing oscillation.  The noise (as small as it was) has always seemed to favor the left channel, too, which is where the heater supply rectifiers are located.
 
Anyway, we went to general purpose diodes and small snubber capacitors for the last couple of kits.  There is really no need for super-speed rectifiers to power just the tube heaters.  The DC requirement is only there to prevent any 60Hz hum, which has never been a problem.  The two Torpedoes that I just built recently used this combination of rectifiers and snubber capacitors and the amp has never sounded better or more quiet.  As I said, I can no longer detect any noise at all with my Grado HF-2's.
 
The rectifiers are BY228GP-E3 - Mouser Part #625-BY228GP-E3.  The snubber caps can be numerous possibilities - just look on the Millett MAX, MiniMAX, or MOSFET-MAX BOM's for suggested equivalents.  I used SA102A101JAR, again at Mouser Part #581-SA102A101JAR.  All you need do is to solder a snubber cap in parallel across a rectifier.  This is best done on the bottom of the PCB.  Don't solder the snubber caps across two rectifiers, or you'll cause a short - just piggyback each snubber cap across each rectifier.
 
I'll detail all of this on the Torpedo website when I get a chance.
 

 

[jdkJake]

Speaking of which, I'm pretty excited about a tweak that I've been supplying with the last few kits.  It reduces any trace of the ripple with my Grados and further improves the sound quality of the amp.  Dsavitsk told me that Kevin Gilmore suggested that the heater power supply was oscillating at the rectifiers.  This makes sense, because it's never "hum" (60 Hz).  It's a 180 Hz artifact that only presented itself when the case is buttoned up.  None of that made sense with typical 60Hz hum.  By default, however, we used very fast Schottky rectifiers for the heater supply and those appear to be causing oscillation.  The noise (as small as it was) has always seemed to favor the left channel, too, which is where the heater supply rectifiers are located.

Anyway, we went to general purpose diodes and small snubber capacitors for the last couple of kits.  There is really no need for super-speed rectifiers to power just the tube heaters.  The DC requirement is only there to prevent any 60Hz hum, which has never been a problem.  The two Torpedoes that I just built recently used this combination of rectifiers and snubber capacitors and the amp has never sounded better or more quiet.  As I said, I can no longer detect any noise at all with my Grado HF-2's.

The rectifiers are BY228GP-E3 - Mouser Part #625-BY228GP-E3.  The snubber caps can be numerous possibilities - just look on the Millett MAX, MiniMAX, or MOSFET-MAX BOM's for suggested equivalents.  I used [COLOR=0066CC]SA102A101JAR,[/COLOR] again at Mouser Part #[COLOR=0066CC]581-SA102A101JAR[/COLOR].  All you need do is to solder a snubber cap in parallel across a rectifier.  This is best done on the bottom of the PCB.  Don't solder the snubber caps across two rectifiers, or you'll cause a short - just piggyback each snubber cap across each rectifier.

That sounds quite promising TomB!

Placed my Mouser order earlier today...

 

[cubeasic]

Hallo,

when will the torpedo kits be available again on beezar?
Or did I miss them?

Florian

 

[tomb]

Hallo,

when will the torpedo kits be available again on beezar?
Or did I miss them?

Florian

They're only temporarily out of stock.  Edcor is fabricating new transformers, but it may be another week or two.  When I receive them, the Torpedo kits will go right back on sale.

 

[Gijs]

Hey guys (and gals),
 
I'm the one who ordered the last Torpedo before Tom ran out of transformers, sorry about that... 
 
I finished building the Torpedo last Sunday, and spent the last few days building a pupDAC as well. It was my first move into what you would call the "audiophile" world, and for me it was one of those small steps for a man but giant leaps for, err, a man... Until last week I listenend to vinyl, CD's and MP3's through a pair of AKG k271's and k702'd and an Oatley Electronica k272 portable tube amp. Listening to music is different now, to say the least. But, first things first. 
 
Before ordering both kits, I exchanged some pm's with Tom, asked some "newbie"-questions, and he proved very helpful and patient. For me, it would the first time building both something wall-powered and an  SMD-kit, speaking of challanges... So, I placed my order. The kist came very nicely packaged, everything was clearly marked and explained. Both the BOM's with both kits, as well as the "build-threads" for both kits inspired a lot of confidence. When I had questions, Tom replied within a day. 
 
Building both kits, different as they may be, was a matter of painting by numbers. The Torpedo kit came with the Zener diodes, the Hammond 154 choke and the snubber caps to put on the recifiers. The latter two were not shown in this build thread, but were well explained on the packaging and on Wikipedia. I also ordered an extra pair of matched tubes, the 5964's. 
One thing I found: the Torpedo kit it quite sizeable, with a thick PCB and some rather large components. All these drain a  lot of heat from the soldering iron, and I found that my 25 Watt iron could hardly cope. With some components, I really had to take my time and let the heat "sink in", as it were. I did get the job done, but patience was required at times. As for the rest, I just followed this build thread, took my time and all went well. 
As for the pupDAC, that's the other end of the spectrum. 79 components on a surface the size of a credit card (OK, it's two-sided, but still...)! The first two to fit are the trickiest of the whole kit. I really took my time, and spent about an entire morning just fitting just these first two, always checking a double checking. The pupDAC-site refers to a couple of tutorials on SMD-soldering and, as a noob, I found these very helpful. 
 
And then there was the glorious moment of plugging in the pupDAC and seeing the LED coming on, then switching on the Torpedo, and seeing its LED's coming on and the tubes beginning to gently glow... I was high on solder flux fumes drunk on enthousiasm! 
 
Then the journey of re-discovering my entire music collection began. I mainly listen to electronic music, ranging from the older stuff such as Kraftwerk to dubtechno and well produced stuff like the work of someone like Amon Tobin or Kruder & Dorfmeister.  Compared to my previous, now rather rudimentary,  set-up, everything has a lot more presence and detail. I find that the Torpedo does give a lot of detail, especially through the k702's, but presents these details quite gently. These details may not necessarily be found in highs, also mids and lows are presented with a clarity that is at times surprising, even spine-tingling. Also, especially with the k702's, sound stage and headroom are wide, but I haven't found them to be too far off yet (something the k702's are at times been "accused of"). I read on these forums that the k702's lack bass, but I haven't found that to be the case yet, there's also a lot of detail to be found "down below". Everything appears to be presented with "ease". In previous posts in this thread, some people mention the terms "not harsh". I have found this to be a bit of an understatement, I personally would call "musical". Everything I have listened to sofar sounds both precise yet easy on the one hand, but on the other hand, effects such as echo and panning are quite impressive at the same time. 
 
So much for my endeavours with the pupDAC and the Torpedo. Should you be considering ordering either of the two, I would  say: go for it, they're both worth every penny / cent!

 

[tomb]

Many, many thanks for such kind comments!

 
Just to be clear, though, it's Dsavitsk that's designed the wonderful Torpedo and continues to tweak it for the best performance.  It's really reached a point right now that it's very competitive with amps costing much, much more.  Cobaltmute gave us the pupDAC, a really wonderful USB-powered DAC whose performance is stellar with great midrange and bass, along with outstandingly detailed highs.  It pairs well with the Torpedo (and everything else, too!).  My part is in helping with the prototype builds, documentation, case design - and support when it's not above my head.

 
I hope I don't get into trouble with saying this, but I've been quite surprised at the detail that's available through a transformer-coupled tube amp.  I always wondered which was better: good output-coupling capacitors or transformers.  I don't wonder anymore.  If a cymbal crash breaks up, you can rest assured it's in the recording, not the amp or DAC.

 

[Punnisher]

I agree that it's definitely a world-class amplifier. I have absolutely no desire to upgrade from this. The soundstage has a very spacious and 3D feeling.
 
It makes my k702 sound brilliant and musical. It does quite well with the HD800 as well, though I didn't have an extended listen with them.
 
Oh, and I haven't even tried rolling my tubes to the other pairs I have. Just more to look forward to. For the record, my build is stock with 6j6 tubes, though I upgraded to Clarity Caps.

 

[bidoux]

Hi
 
I have been looking at the schematic for the Torpedo (quick link : http://www.diyforums.org/Torpedo/schem/TORPEDOschem.gif)  and there are a few things I can't figure out. First is the bias current : is it only 2 or 3 mA ?  Second is the biasing method : does it serve a purpose to have the same current flowing through D12, D13 and D10 (other than saving a few resistors) ? Actually, why the use of a transistor + led under the cathode ? Wouldn't a string of leds or diodes do the same ?
 
A data I can't find anywhere as well is the B+ voltage. I guess it is in the 200V (and it doesn't matter because of the ccs) but since the bias current seems different than in the other l'espressivo designs ...
 
thanks