[yuujin]

Thanks tom for the invaluable kits that are close to effortless to build.

 

[dustinsterk]

Hello all,
A little off topic but does anyone have any comparisons on the Torpedo vs Bottlehead crack.  I am torn what to build next but am leaning toward the Torpedo.  I have not heard either but will be driving my HD600s with one of these two amps and am looking for a recommendation.
 
Thanks in advance.
 
--Dustin

 

[RustA]

Quote:

Hello all,
A little off topic but does anyone have any comparisons on the Torpedo vs Bottlehead crack.  I am torn what to build next but am leaning toward the Torpedo.  I have not heard either but will be driving my HD600s with one of these two amps and am looking for a recommendation.
 
Thanks in advance.
 
--Dustin

 
PMed you about the question...

 

[catfish]

Can anyone recommend a cinema are similar transformer for the input of this to take a balanced connection (my DAC has balanced out and is quite a distance from the amp.)

 

[nikongod]

Quote:

Can anyone recommend a cinema are similar transformer for the input of this to take a balanced connection (my DAC has balanced out and is quite a distance from the amp.)

 
Did you mean Cinemag? 
CMLI-15/15B

 

[RustA]

Quick report:
 
The amp arrived and my friend helped me to assemble it, including several tweaks mentioned here... I don't have an idea how significant the hum is without them, but it is unhearable on low impedance/gain setting and gets noticable only at 75 - 100 % volume on high setting with Sennheiser HD800. Since I use StageDAC with 2.2vrms output and have no need for replaygain, it's absolutely a non-issue (I don't get past 25% actually). Therefore, this amp is practically dead-silent even with HD800! My friend offered me to tweak the amp even more but I have no need for that right now.
 
The Torpedo looks very very very nice, way better than on the promo photos... It's actually cute and compact, not much heavy. The casing gets covered by dust quite easily but it's not really an issue for me.
 
As for the SQ, I would say more or less on par with O2... It's not the same sound and the results with Torpedo also depend on tubes but I don't see any of those two as superior (just significantly different). However, I have to state that I don't subscribe to audiophoolery and really didn¨t manage to hear a BETTER amplifier than O2 in category up to 1000USD (didn't bother to try anything more expensive). I don't really understand all that talk about how one amplifier KILLS the other one... Maybe imagination and placebo are not strong enough with me.

 
TomB told me that this amp has zero harshness... I feel this is significantly dependent on tubes you use ( = it's not true everytime). I've tried six different pairs and while they sound all similar, there are differences that become obvious especially when you are searching for the right "synergy" with your DAC and headphones to finalise the chain.
 
I must say that I really enjoy the amp in combination with StageDAC (hardware crossfeed FTW!). I have tweaked the crossfeed and the other settings to offer the best sound for me, and then chose the right set of tubes to balance the signature. I don't find the Torpedo to be mind-blowing but it works very well with HD800 - doesn't exaggerate the soundstage and works as a little EQ as well (tubes!). I would say that I knew why to purchase this amplifier and got exactly what I was expecting - a quality and versatile tube amplifier -  nothing more, nothing less.

 

[tomb]

Many thanks for such a fine review, RustA!!  I'm glad we sent all those tubes.  It's very nice to know that it can pair well with HD800's. 

 
 
P.S. Dust is a sometime nuisance on mine, too.  I thought it was just me, but I wouldn't want to change back to silver.

 

[DingoSmuggler]

Quote:

TomB told me that this amp has zero harshness... I feel this is significantly dependent on tubes you use ( = it's not true everytime). I've tried six different pairs and while they sound all similar, there are differences that become obvious especially when you are searching for the right "synergy" with your DAC and headphones to finalise the chain.

Because torpedo tubes are all about 50 - 60 years old, when first using a set of tubes they won't perform so well for the first few hours. They need a bit of time for the getters to do their thing and restore the vacuum inside. So don't judge any tube on initial impressions. But even after all that, some of my torpedo tubes are a bit crappy sounding.
I think my best overall performers would be dumont 5964s i got from tomb.

 

[RustA]

Quote:

Because torpedo tubes are all about 50 - 60 years old, when first using a set of tubes they won't perform so well for the first few hours. They need a bit of time for the getters to do their thing and restore the vacuum inside. So don't judge any tube on initial impressions. But even after all that, some of my torpedo tubes are a bit crappy sounding.
I think my best overall performers would be dumont 5964s i got from tomb.

 
I understand, thank you! I am not really a fan of pink-noise burn-in or similar - just listening and enjoying I chose one of the sets TomB shipped to me that works well with the rest of my chain from the start, we will see how it develops with time... I will most probably try all the sets once again today since it is always better to decide through several listening sessions (to avoid wrong judgement due to fatigue or placebo).
 
Quote:

Many thanks for such a fine review, RustA!!  I'm glad we sent all those tubes.  It's very nice to know that it can pair well with HD800's. 

 
 
P.S. Dust is a sometime nuisance on mine, too.  I thought it was just me, but I wouldn't want to change back to silver.

 
I would like to thank you as well - all the content was packed REALLY well and there were no problems during the building process. My friend likes the amp as well but it's too revealing for him (he is not an audiophile really and only listen to lossy audio files).
 
The report above was really only a report - it is for sure that I couldn't assess the amp properly after only several hours of listening and tweaking my system... I need more time to spend with my favourite music and will post my more developed impressions afterwards here.

 
I must stress that I chose my "endgame" setup having versatility/options as a priority. HD800 are extremely comfortable, have imaging, separation and soundstage like no other headphone I have ever heard and offer very neutral frequency response. Then, the StageDAC has many options how to tweak the signal - crossfeed with several settings, tonal balance, over-sampling, pulse response... Finally, Torpedo offers low/high impedance switch to work well with different headphones + its tube nature is suitable for perfecting the chain with small sound adjustments, to balance the rest. This was my primary goal since I am not a "detail-head" or "ultimate audiophile". I wanted to get a natural sound and combine advantages of both speakers and headphones sound while staying safe in terms of money - and I must say this is definitely possible with HD800, hardware-based crossfeed and this nice tube amplifier.

 

[KimLaroux]

Quote:

Because torpedo tubes are all about 50 - 60 years old, when first using a set of tubes they won't perform so well for the first few hours. They need a bit of time for the getters to do their thing and restore the vacuum inside. So don't judge any tube on initial impressions. But even after all that, some of my torpedo tubes are a bit crappy sounding.
I think my best overall performers would be dumont 5964s i got from tomb.

 
I believe the getters are always active, even when the tubes are in storage and not used. They are just a layer of metal that react with gases inside the tube and "absorbs" them by oxidation. They are independent of the tube being powered or not. If a tube has been infiltrated by gases, powering it won't change much.
 
I do agree that most tubes will change characteristics after a few hours. I haven't learned what may be responsible for this yet, but I'm pretty sure it does not involve the getters.

 

[tomb]

Quote:

 
I believe the getters are always active, even when the tubes are in storage and not used. They are just a layer of metal that react with gases inside the tube and "absorbs" them by oxidation. They are independent of the tube being powered or not. If a tube has been infiltrated by gases, powering it won't change much.
 
I do agree that most tubes will change characteristics after a few hours. I haven't learned what may be responsible for this yet, but I'm pretty sure it does not involve the getters.

I think you are correct in theory, but maybe not in practice.

  The getter "flash" is the silver deposit on the inside of the glass.  It's produced the first time by heating the getter itself, which usually has barium on it (from what I've read).  The high heat will "flash" the barium over to the glass, producing the silver splotch.
 
You are correct that the silver splotch will continue to react with gas in the tube whether the tube is on or not.  This is easy to see if you've ever broken a tube, because the getter flash will turn white almost instantly in the presence of the oxygen in air.  However, heating the tube back up after a few decades of storage may still release additional barium from the getter, aiding the cleansing of the tube from gas.  Plus, heat will speed up almost any non-exothermic reaction, so the removal of residual gas is still aided by having the tube "run-in" for awhile if it's been a NOS tube in storage for a number of years.

 

[vixr]

I read that the use of a tube socket can sometimes shorten the life of a tube by not allowing enough thermal expansion...causing micro cracks around the pins.  

  I will take more care in the future to ensure that no adhesive gets on the tube socket connectors when I remove the rivet for an LED and glue the ceramic back together.

 

[KimLaroux]

Quote:

I think you are correct in theory, but maybe not in practice.

  The getter "flash" is the silver deposit on the inside of the glass.  It's produced the first time by heating the getter itself, which usually has barium on it (from what I've read).  The high heat will "flash" the barium over to the glass, producing the silver splotch.
 
You are correct that the silver splotch will continue to react with gas in the tube whether the tube is on or not.  This is easy to see if you've ever broken a tube, because the getter flash will turn white almost instantly in the presence of the oxygen in air.  However, heating the tube back up after a few decades of storage may still release additional barium from the getter, aiding the cleansing of the tube from gas.  Plus, heat will speed up almost any non-exothermic reaction, so the removal of residual gas is still aided by having the tube "run-in" for awhile if it's been a NOS tube in storage for a number of years.

 
That's a valid argument. Heat may speed up the process. Raising the temperature also means particles which need a higher energy to react have a higher probability of doing so.
 
But honestly, there's no way powering it up again will release more barium. This stuff boils at 1897 °C (3447 °F). I doubt a tube gets that hot. It is originally flashed using radio frequency of the type used in microwave ovens.
 
So, anyone willing to "burn in" a NOS tube using a microwave oven? 

 
(honestly, don't, that's a joke)

 

[tomb]

Quote:

 
That's a valid argument. Heat may speed up the process. Raising the temperature also means particles which need a higher energy to react have a higher probability of doing so.
 
But honestly, there's no way powering it up again will release more barium. This stuff boils at 1897 °C (3447 °F). I doubt a tube gets that hot. It is originally flashed using radio frequency of the type used in microwave ovens.
 
So, anyone willing to "burn in" a NOS tube using a microwave oven? 

 
(honestly, don't, that's a joke)

There are a lot of other materials used besides Barium.  I'll admit that I didn't look up the vaporization temperature, but you seem interested enough to read this, maybe you can tell us why the old advice about burning out residual gas in NOS tubes is a lie:
http://www.emissionlabs.com/Articles/GETTER/getter.htm
 
Besides, why wouldn't adsorbed gas on the surface of the plates vaporize easier under heat so that the getter flash can react to it?  I'd rather believe the old advice - I'm satisfied that there's enough going on to provide ample explanation for reducing the gas when the tubes are on. 

 

[KimLaroux]

Quote:

There are a lot of other materials used besides Barium.  I'll admit that I didn't look up the vaporization temperature, but you seem interested enough to read this, maybe you can tell us why the old advice about burning out residual gas in NOS tubes is a lie:
http://www.emissionlabs.com/Articles/GETTER/getter.htm
 
Besides, why wouldn't adsorbed gas on the surface of the plates vaporize easier under heat so that the getter flash can react to it?  I'd rather believe the old advice - I'm satisfied that there's enough going on to provide ample explanation for reducing the gas when the tubes are on. 

 
I've never said it's a lie, so no I can't tell you why it would be one. In fact, in my last post, I agreed with you about heat improving the efficiency of the getter. And I still agree with what you're saying here. I have nothing to say against it. It makes perfect sense. 
 
This web page is amazing, thanks for the link.