Project Ember

i assume if i buy one of these, i will be clobbered for import duty?

Simon I can assure you that the Ember can be used as a pre-amp via the line out and it does make a very very good one at that.  You are correct in that the MFV1&2 cannot be used as a pre-amp unless it has been modified.

Frans helped me out a few years ago to turn my V2 into a pre-amp and it was one of the best things I have done to my HiFI- it makes another very very good pre-amp.  Thanks again Frans

Back to the Ember, As you can guess I have been playing about with it today, but I seem to be struggling to find time to have a really good long listening session.  Is it OK to hang on to it for another week?

Everybody just seems to want me to do things for them at the moment, mend their car, fix their iPhone etc so I have been struggling finding the time to have a good listen.

Ian have you by-passed the input caps yet, if not do so.

I didn't comment on moving them because some think it's academic and makes no difference, but I thought I'd go the 'purist' route straight away!!

I'm also using at low output impedance and lower gain. (With Senn HD650) It's delicious!!!

It's also acting as a buffer into some Roland near field active monitors.

Actually, with the source stopped, if I put the volume pot at the top and quickly turn, I do get a slight scratchiness but if you listened up there, you'd be mad!!

A little bit more twiddling today, now that I have a grip of the amp's sound.

I have bypassed the input caps (I did that from the start). TBH, I wasn't aware of any sonic changes but since theoretically, bypassing is better, I left it at 'bypassed.

Today, I looked at the output impedance. Mine was set in the middle. (35 ohms) I thought it was at it's lowest, but not so. So I moved the jumpers from virtually zero to 100 ohms. I can hear the difference immediately on the HD650.

From 100 to 35 - the headphone has more sparkle. From 35 to virtually zero 0.1, even MORE sparkle on an HD650!!! That surprised me. I could hear the difference between 35 and 0.1 ohms. I didn't expect to hear much. Another thing, I set the jumpers by ear and wasn't aware what high or low was. In fact, I'd presumed that low was at the back end when in fact it's on the front so my ears were telling me that there was in fact a difference and here is another of the great strengths of this amp - the fact is, you can tune your treble to bass ratio slightly, simply by moving little jumpers. This is the easiest amp I've see for personal configuration; especially given that you can take the top off in seconds. It is absolutely no hassle and the differences are instant.

So now, my HD650 has a little extra sparkle.

Not only that, but I was listening to Radio 3 (Classical DAB) which has less compression than many other radio stations on DAB (Believe it or not!!) and it tends to be a little low on volume output.

Simple ...... go to the back and move the input gain jumpers to high and you instantly have 6db extra gain available.

I am now listening to Radio 3 at 9:00 on a Sennheiser HD650. ie - it's like driving a portable headphone. Not only that, the HD650 sounds absolutely superb. Less bloat in the bass region at 0 ohms output and a slight sparkle put on the top too. It is a great match for the HD650. I'm really enjoying the sound a lot.

It does make you wonder whether a lot of commercial amps just don't put out enough to drive some headphones properly.

So, Senn HD650 people - it is a brilliant match. You can have virtually zero output impedance to 'sparkle' the sound a tad and up the input gain so that it feels like you're driving a PX100. It's as though the amp has no load on it at all.

One thing though - at this setting, be sure to turn the volume off so that you don't have an accident when you next turn on. It can go bloody loud at this setting and it could turn your headphone inside out.

This is one of the best headphone amps I've tried. The configuration aspect makes subtle differences that overall, really DO improve your listening experience and having this kind of power on an amp gives you real confidence in its ability to provide excellent transient response.

The ease of taking the plastic top off is brilliant and adjustments are an absoslute doddle to do, but the real bonus is that you hear the result straight away and can even toggle between settings while listening.

The HD650 that I have is one of the older ones, so it isn't perhaps as bright as the newer ones and is supposed to have a so called 'veil'. I don't get this 'veiled' sound with mine and I often wonder whether people complaining of a veil are more tuned in to 'lively treble' type headphones. At o.1 ohms output impedance, these headphones are great.

Welcome Chinook9 !

Advantages of Ember over SR-II are the auto-bias/heater selector and generated heat.
When you like to roll tubes Ember is definitely in the advantage here.
Also when you feel it should be mounted in a (sealed) metal enclosure the Ember has advantages (as it doesn't get hot)

However, if you have no problems adjusting the bias (with the bias LED's or voltmeter) after a tube swap and output power is more than enough for you there seems little reason to have a go at Ember other than the ones mentioned above.

The sonic signatures are closely the same BUT the tube itself (which is designed for voltage rails of around 100V to 200V) does perform slightly different because of the higher voltages involved (twice as high on Ember). How and whether this 'translates' in better SQ I cannot say.

The linear power supply is already 'under development' and Jeremy is working on getting some good quality parts and enclosure.
It will be able to provide 24V or 48V depending on some settings inside the box.

Even though the supplied SMPS is of good quality and has relatively low common mode noise and 'mains leakage' it still might cause some problems with audio when lots of equipment is all tied together and more than one is fed via SMPS's (think PC/laptop).
A linear power supply can lower the problems that might occur under specific circumstances.

No idea how far the development at this stage is though...

Solderdude and Rabbit, thanks for the reply.

Please put me in line for one of the power supplies....kit would be fine because I expect it should be pretty easy to build.

I spend my winters in Arizona, about an hour from Jeremy, so if timing is right I could run down to Coolidge and pick one up.

I will not rule out getting an Ember. I do a lot of tube rolling and I wouldn't mind a cooler amp......My main amp is an old Class A Krell KSA-100 and I'm careful how I use it during the summer due to the heat problem.

Thanks again!

Glad you're still down there Jeremy....and not quite so far from my place.   Based on a couple of your posts elsewhere, I'm now on the hunt for a couple of 12bh7a tubes to try.

I really have enjoyed that amp, however, I rarely listen to the big system nowadays.  I don't need it like I did when I had pressure-filled work days and I really enjoy my DBV#3/Sunrise II so much.