ECP Torpedo III [indexed in first post]

Interesting in your listening impressions with the choke ... and game plans for fitting it in the case ...

 

I hear a nice improvement of the sound - actually a bit bigger, than I anticipated. I should mention, that I have installed both the Takman plate loading resistors and the electronic choke. Now I will let everything settle, burn in the parts, and then replace the choke with R2 again to isolate the effect of the choke from the effect of the Takman plate loading resistors.

Really hard to describe sound in a second language, but I'll give it a try:
The improvements are mainly in 3 areas based on my preliminary listening for 2-3 hours last night:

Tonality and ''realness'' if that is a word.
Treble quality
Sense of space around instruments / performers


Tonality and realness
To me it's a good thing when the sound becomes both more more natural and more explosive at the same time. In a way both more laid back and coherent, and more detailed and dynamic at the same time. Often you get one, but not the other. I would say these changes gives both. So the sound get's even more natual, live and real. Maybe the tonality is slightly darker, or maybe this is just the impression because of the more natural sound.

Treble quality
There is more layering in the treble, and again the sound more natural and life-like. For instance when the drummer hits a hi hat, the sound has a more natural attack and more layered decay. Even slightly bad recordings now sound a bit more resolved in the treble. You know, the recordings where the ''S'' sounds just tend to become an annoying ''peaked'' sound. Some might say, that the treble is not as forward and aggresive as before, others will say that it's not a forward/backwards thing and that the change is because of more layering and a more natural sound.

Sense of space around instruments / performers
This one is more difficult to explain. I'm not talking about the size of the soundstage with this. What I mean is, that you hear the space around the performers more clearly. Are they playing the live session in a small jazz club or on a big stage? This kind of thing.

These are preliminary impressions, and they are with the Mullard military spec CV4024 / M8162. See the excellent review a few pages back where these are also included. I would call these natural sounding, but not warm and full like the ''regular Mullards''.


And I think this completes my ideas on areas where even more sound quality can be tweaked out of this amazing design:
- Top quality RCA connectors
- Quality wiring from RCA's to pot, with grounding near the pot
- TDK pot
- Electronic choke instead of R2
- Takman carbon resistors on critical places, these are cheap and just a bit to the warm side. (use something like Allen Bradley or Riken carbon resistors as plate loads, if you want a warmer and fuller sound. Use quality metal film or foil like Vishay, if you want a cleaner and brighter sound. Use Shinkoh tantalium for a full and natural sound)


It's interesting actually, that often the last small improvements in sound are found in the power supply. On a design like this, that is already extremely good and maxed out with top quality OPT etc the signal path is fully optimized. I have seen/heard several designs, where the focus can then be on the power supply. Implementing a choke is often positive on the sound because you reduce ripple so much. In this case the signal path is fully balanced and this might mean a smaller difference in sound compared to an unbalanced design. If that's the case, then that is an indication of, how good this design is already...

 

You ask for the implementation of the electronic choke, this is how I have fitted it. Mind you, that this is the location in the circuit where we have the highest DC voltage..! Care must be taken and heat shrink must be used on component legs..! I don't know the English name of this stuff, but I have installed it vertically with a pad of this double sided foamy stuff towards the transformer. It fits tight between the transformer and the two caps.

 

Which choke did you use mec-50 or mec-100? I am thinking about getting this myself.

Edit: didn't see it with my small phone screen...

 

MEC100, see my post above...

 

Just curious, Morten - what did you put in-between those Mundorfs to keep those leads from shorting out? They look perfectly in line and are too close to have heat-shrink, I think.

 

Thanks Tom,

I used teflon tubing on both legs of all 4 caps, it's the best possible insulation.

 

Well, you did a great job of getting them fit in there!

 

Thanks Tom,

I like to build things as good as I can, so I used the teflon tubing, glue between the caps and the PCB and I used some spacers to hold the caps in place while the glue dried.

The teflon tubing is thin walled, but still more durable and with better insulation than heat shrink tubing, so I feel it's the best posible option for the job.

 

Just an FYI, but I've built a couple of the T3s with Solen PB caps. They're probably 80-90% of the Mundorf in quality, with perhaps more bass. I'm going to use them as the standard from now on instead of the Epcos. They fit in quite nicely and safely - no shoehorning them in.

I have a few assembled versions for sale again, now. Parts are as listed on Beezar, but shoot me an e-mail and we can work out any special details.

 

Some will understandably roll eyes, but an interesting (to me) take on resistors from Goldpoint based on their trials in stepped attenuators... The KOA are cheap until you get into the 1W variety which are $3+ a pop.

KOA Speer brand, MF1/4 and CF1/4 Series The MF1/4 series are truly excellent sounding 1% Nickel Chromium (NiChrome) semi-precision through-hole resistors. They are our most highly recommended brand of thru-hole resistor. Although very afforable, we recommend them because of their clear sound quality, which is likely impossible to beat at any price. For resistor values of 10 ohms or higher, use the KOA MF series (1% metal film). For values below 10 ohms, use the KOA CF series (5% carbon film) (see bottom of this page for both MF and CF Series) - The resistor values are color banded - (see our Resistor Color Code Chart). All resistor values are avilable from garrettelec.com. Some stocked at www.mouser.com.

IRC RC55 Series The IRC RC55 series are0.1% tolerance,1/4W through-hole thin film NiChrome metal film resistors. Their sound rivals the sound qualities of the very best SMT (surface mounted) resistors, (as are used on standard Goldpoint stepped attenuators). In my opinion, the RC55s are better sounding than expensive, high-precision Vishay bulk foil or even Caddock non-inductive resistors. Install IRC 55 series resistors on DIY Pro Audio balanced line stepped attenuators or any DIY application where you need/want a high precision stepped attenuator. They are black color with white resistor value numbers.
(Mouser keywords: IRC resistors) (see bottom of this page - available from www.mouser.com.)

Vishay/Dale RN55 (1/4 watt) and RN60 or CMF60 (1/2 watt)These are 1% tolerance, Ruthenium type metal film resistors.Mediocre sound quality even though they are used by many audiophiles.
The "55" is 1/4W size, whereas the "60" is 1/2W watt size. They are brown color with black resistor value numbers. (Mouser keywords: Vishay/Dale RN55D, RN60D, CMF55, CMF60)
(available from www.mouser.com.)

Xicon brand 1%, 1/4W and 1/2W resistors: These are cheaply made 1% tolerance Ruthenium type metal film resistors. They may be the least expensive thru-hole resistors you will find. Their sound quality is mediocre but considered OK or "acceptable". They are light blue/green color with color banded resistor values. (see ourResistor Color Code Chart) They arereadily available and well stocked at Mouser.com. (keywords: 273-1K-RC) (available from www.mouser.com.)

 

I've got some Solens on the way, thanks for the tip!

 

Well, another one down... No fancy pot upgrades at this point, and not as much patience as @MortenB for Mundorf alignment. ;-) I was glad to have just a sliver of space between the Cinemags and the Mundorfs. The only thing pending is I've left C1, C2, and R2 out for now, in ordder to experiment with the choke @MortenB discovered, and it's still in transit. It seems like the choke would be easier to install without the caps in place. Otherwise, pretty much done for now...

 

Siiqqqqq time to listen I've been enjoying mine every evening for a little over a month now. Awesome amp. Was mostly using amperex 7062, and then got an insane deal on a telefunken ecc801s so trying that for a bit while I wait for the brimar yellow t to show up at my doorstep. We should get the T3s together (and @drfindley) to do some side by side tests and actually hear the effect of tubes in quicker succession.

It's strange though, because I severely dislike tube rolling but I'm also curious. I'm navigating that tension by trying some stuff out and hearing it for myself, then I'll prob sell some tubes for other folks to try.

 

That'd be cool. Gotta make sure mine actually works first. LOL I hope the choke arrives soon so I can get on with it!

 

@philipmorgan is invited too cause he's a boss

 

Please don't dislike tube rolling. It is a beautiful thing when it makes system go from average, to good, to great, to outstanding! Tube rolling can be a very powerful thing.
Most manufacturers supply tubes that they can buy in bulk, replace when needed and help their equipment turn on once in the customers home

Not always, but the older greats (Mullard, Siemens, Telefunkens, Amperex, Valvos etc.) turn out to be the great ones. Depends on how they behave in a given circuit...

Again, the higher resolution the gear, the more differences tubes can really make!

 

Agreed! I don't dislike tube rolling either. I just dislike buying tubes that I never want to listen to again! Heh. But yeah, I'm very much a fan of being able to tweak the final sonic signature of my gear through tube rolling.

 

Interesting what you think of the mighty Telefunken ecc801s in the T3..!? As I mentioned a few pages back I just bougt a tightly matche NOS pair. I have compared them with my Mullard M8162 / CV4024 (see review page 27). I find the 801ss extremely transparent, dynamic and open sounding, and with amazing transient snap. It's like any other tube sounds a bit dull in comparison. However they are also brighther with a more forward treble, and to me this is not the best match for the T3 that is a bit on the lean side already. So I actually prefer the synergy with the Mullard M8162 / CV4024.

With a pair of slightly warm sounding headphones the 801ss will be hard to beat (but also expensive tubes).

 

Sorry @shaizada and @bazelio, you misunderstand me. i'm not opposed to getting a good tube to put the final tweak on a chain or improve the sonic signature of an amp or whatever. i just dislike the idea of rolling lots of different tubes as an exercise in itself, because to me, that takes some of the joy out of listening to music. evaluating or comparing gear, be it headphones, amps, tubes, dacs, is kind of a painful process that fries my brain pretty quickly. once i find something that works well and fits the gear i have, i'd rather stick to it. comparing tubes etc is more of an educational/curiosity exercise, and for me, is only valuable insofar as it gets me the sound i'm after.

anyway, @MortenB , i like the 801S more than the 7062 so far. it was a great tube for the price, but the 801S doesn't give up much in terms of stage but adds more clarity and feels like it has lower noise, or at the least much lower microphonics, which the 7062 had a lot of. the nice thing about the 801S as well is that, while it feels quite neutral, the highs don't seem overly sharp or sizzly at all. just very clear and clean so far. but i'm also not a tube rolling expert so there's that