[proid]

Quote:

By transparency I mean a clean sound which is very clear and super crisp. I don't necessarily mean dot neutral.

 
Transparency you mentioned is exactly what a solid state amp should sound like. When i rolled the Gold Lion 12AU7 into my Sunrise II, it sound a lot like a solid state amp: clean and clear but i much prefer the warmness and smooth sound from the 6n23p-ev, that's the reason why people love tube amps. But in both case, O2 is more clear and crips than the sunrise and the soundstage is much better.

 

[techboy]

But I need pre out

 

[smitty1110]

Check out this thread for some information about different tubes. This thread has a lot of discussion about the amp, including a lot of detailed reviews of its performance and what tubes the users were using. One thing to consider is this post by the designer where he discusses the issue of harmonic distorion casued by amps in general.

 

[RAZRr1275]

@ techboy as far as tubes that would fit what you want I'd look into an RCA Cleartop 12AU7
 
also just generally for everyone
 
if you have any questions or want me to try anything out just let me know and I'll try to do a mini-blog entry on the specific topic. Just so that you can request something that I can do, I'll list my headphone and tube inventory. 

First I'm using the ODAC as a DAC

Headphones that I have are the Grado SR80I with L Cush, AKG K240 Sextett, AKG K702, Denon D2000, a modded set of Fostex T50RP (to my own configuration which I'll make a post about at some point in the near future) and Sennheiser HD280 Pro

Here's the fun bit. My tube inventory is

Electro Harmonix 6922 and 6N1P
Phillips 5814A
Tung Sol 5814WA and 12AU7
RCA 6CG7, 12BH7, 12AU7 Cleartop
GE 6GU7, 12AU7 and 12AV7 Cleartop
Sylvania 6CG7
Voshkod 6N1P-EV
Telefunken 12AU7
Siemens 12AU7
Amperex Bugle Boy 6DJ8
Tesla 6922
Brimar 12AU7
Mullard 12AU7
CBS/Hytron 12AU7
Sylvania/Baldwin 12AU7

 

[TIMITS]

Thanks for offering to answer questions and I have one about whether or not the Project Ember will play nicely with Final Audio Design earphones.  They are only 16 ohms but I notice that there are a number of output resistance jumper settings and tube choices that might work for these?  Because this is such a powerful amp would there be enough travel in the volume pot to make adjustments without channel imbalance or risking hearing damage?  

 

[smitty1110]

To answer your question about channel imbalance and the volume pot, here's a post from another site from the guy who builds the amps:

All of our factory built amplifiers receive what we call A grade pots. I literally hand test them in batches of 100qty. Only excellent potentiometers make cut, the rest go to ebay, used for projects and so forth. In fact, only about 1/3 of all tested make this cut. All A grades match excellent down low. There is a threshold however generally between the lowest volume and just a few degrees of turn where even an A grade may have a slight imbalance. That only makes up about maybe 3-5% of the volpots actual range. Keep the amplifier in the low input gain default setting and I highly doubt you will ever want to listen in this range as it is close to zero.

jhelms, DIY Audio Heaven Forum Post

The TL;DR is that the post are hand-selected for quality, but there is a chance that a very small portion of the pot's range will experience channel imbalance.

For your other question, the amp is officially acknowledged on the Garage1217 site to work with 16 ohm headphones, but I think that you will need to put the jumpers on their highest output resistance setting to be safe. You could always send an email to Jeremy to get his opinion - admin@garage1217.com

 

[TIMITS]

Thanks Smitty for the suggestion so I emailed Jeremy and received a quick and helpful response.  I'm sure Jeremy wouldn't mind me posting some of it here.
 
"The Final audio's will be a bit tricky because of the very high sensitivity and impedance of 16 ohm. Ember easily handle the load, in fact will probably not even notice they are connected to the her, but with phones so efficient and being at the threshold of our impedance rating, you are more likely to hear background noise (she is a tube after all) The good news is you can adjust most of this out. Set the output impedance to high / 120ohm. Leave input gain on low and I would not recommend using any high gain tubes like 12ax7's / 5751's and I feel you should be fine."
 
I'm clueless with tubes so what would be a good choice for a low gain tube?  

 

[RAZRr1275]

A 12AU7 should suit you well

 

[TIMITS]

Excellent.  Just submitted my order on eBay.  Thanks for the helpful review.

 

[RAZRr1275]

Quote:

Excellent.  Just submitted my order on eBay.  Thanks for the helpful review.

No problem. It'll sound great with your Thunderpants and if you set the gain to high and bypass the input caps, It'll make those Grado's of yours entirely non fatiguing.

 

[techboy]

Waiting for a reply to my questions

 

[Nowhere]

anyone know how this compares to the bottlehead crack (with/without speedball)? for sennheiser hd's specifically. (oh and darkvoice 336se).

 

[techboy]

I would like to know this as well.

 

[proid]

Quote:

anyone know how this compares to the bottlehead crack (with/without speedball)? for sennheiser hd's specifically. (oh and darkvoice 336se).

Sure Crack will sound better.

 

[techboy]

With low impedance headphones ember should be much better, especially for orthos like he6