Project Ember

when it packed up Ian, did it just die or did you notice anything untoward in the days before? ie noise in sound

I have no idea when it will be available.

It would be a good thing if you need longevity. Switch mode power supplies tend to have short lifespans because of how they are built.
Sometimes leakage currents can be high and when connected to other gear may introduce nasties.

For that reason a year or 2 ago Jeremy started to build the power supply.
So for longevity, having a power switch under the amp (is now the plan) and perhaps to reduce hum under circumstances the linear power supply can be an option.

It will be heavy in weight, and possibly price (because of the shipping and parts) WHEN it becomes available....

It appears to me that he took the Ember schematic, made some changes, and laid out his own pcb with those modifications.  He didn't modify an existing Garage 1217 Ember pcb.  He also apparently didn't do a very good job of it either, as the other posters have pointed out several errors.

Proid (also a member here) indeed made his own PCB design based on the Ember and a different power supply.
That wrongly executed starground seems the cause of the hiss in one channel.

Unfortunately he went for a star ground and didn't do a good job concerning 'return paths'.
Designing a schematic is one thing, to make it work as well as expected a proper layout (with a well thought out ground-plane) is essential.
Especially with switching power components layout and proper ground circuits is very important.

A learning moment...

Ember 2.0 board rev:

1: Supercharger now built in so tubes with heaters >500mA can be used. To use >500mA in Ember (and Horizon) the 'supercharger' had to be installed.

2: The way the input capacitor bypass is done is different. The functionality is the same but when you remove the jumper in Ember-II the sound cuts out where in the Ember 1 this doesn't happen.

3: When a headphone is inserted the line-outs are disconnected in Ember-II, in Ember I the line-outs are always 'on'.
This functionality in Ember-II can be changed to Ember-I alike behaviour by adding solder drops on specified spots BUT when a headphone is plugged in that has a varying impedance AND the output R is set to 'M' or 'H' the tonal balance is altered by the (impedance of that) headphone.

4: An 'anti-volpot-scratch' modification is implemented which counters the 'scratchy sound' you hear when the input capacitors are bypassed and sometimes even (faintly) with input cap in line.
Of course this has a disadvantage too and with some specific tubes
Tubes that run under starved plate conditions (the ones intended to be run on plate voltages of 200V etc.) and/or have high grid current leakage may cause a noise current over the used resistor and this may become audible on sensitive headphones.

5: The Ember-II has an attenuation module which can easily be changed to get another amount of attenuation (if needed)
The Ember-I has an attenuation jumper but you can only choose between no attenuation and a fixed amount of attenuation where in Ember-II you can alter the attenuation by plugging in another module.

6: In Ember-I there was a circuit that switched off the output relay when the output stage overheated (added in the design stage).
Because in reality the output stage never even got luke-warm this functionality is left out (was pointless it can't overheat) in Ember-II.

7: For sort-off the same reason (protecting the output stage) a resistor that was added in the design stage of Ember-I has been removed in Ember-II.
This results in slightly measurable (but not audibly) more output power in Ember-II for low impedance headphones only.

8: 2 power supply capacitors are used in Ember-II where 4 were used in Ember-I. The total capacitance remained the same though.

9: The extra 'power LED' that was present on Ember-I is left out in Ember-II.

10: The opamp used for heater voltage detecting is now SMD sized, in Ember-I it was DIP-8 sized and mounted in a socket.

11: Ember-II is using different heatsinks (smaller ones) because they were severe overkill.

These are all minor changes that do not affect the sound quality aspects.
Sound and measurement wise the Ember-I and Ember-II are the same.

Ember-I can be 'converted' to Ember-II functionality with a few changes to the boards + addition of the Supercharger.
This involves cutting traces, running some extra wires on the bottom and adding resistors, removing attenuation resistors and soldering 'sockets' in its place etc.

The only reasons why one may want to 'convert' an Ember-I to Ember-II functionality (or want to upgrade to Ember-II) are:
Wanting to use >500mA heater tubes. (but simply installing a supercharger fixes that)
Or are bothered by the scratchy pot (ONLY during volumne adjustment, NOT when stationary)
Or when you want the RCA out to disconnect when a headphone is inserted (when doubling as a pre-amp for instance).

Soundwise they are completely tube dependent and with Supercharger or Ember-II you simply have more tube choices (those with higher heater currents).

I'm looking for another amp to complement my Ember II, and I'm searching for a solid state amp. I'm feeling that Polaris might be a very good choice. After reading in this thread and the Polaris thread it's difficult to pinpoint clear differences in quality between this and the Ember. Can anyone shed some more/clearer light on this matter?

The other amp I'm curios about is the Grace Design m9xx with dac(don't really need dac), and is also almost double the price of the Polaris.

It looks like my main headphone will be the Fostex TH-x00 for a while, and that's a 25ohm load. Maybe the Polaris will be a better choice for this headphone cop
mpared to the Ember?

I'm having a little problem with low level hiss and hum, because I use the Ember at work with a lot of noisy sources messing up and its getting a bit annoying. That's why I think I'll move the Ember back home, and use something like the Polaris at work.

None of my headphones are high impedance, but I've read that the Fostex need some power to not sound too flabby in the bass area. The Polaris might be a much better partner to it than the Ember.

Well....have to wait until Christmas has passed before spending more on this wonderful hobby, and these wonderful products from Garage 1217:-)