Eastern Electric DAC mods

Gopher · « **Reply #240 on:** 14 Jan 2011, 09:33 pm »

I was exchanging messages with Mike as he demoed the DAC and I don't think it was so much that he thought the fuse was making the largest difference as it was that he was floored by the difference the fuse made.

He clearly heard and appreciated the differences.

Wayne1 · « **Reply #241 on:** 15 Jan 2011, 05:26 pm »

Gopher,

Thank you for interpreting Mike's comments. Your explanation sounds correct.

Bill@LakeGeorge,

Did you try to change the orientation of the fuse in the fuse holder in the Level 2 DAC? All the others that have tried it have noted some change. Maybe by doing that the Pavane tube might open up some more for you. I did notice on the one modded unit I got to listen to for a bit that it continued to change for 400-600 hours. With the Teflon bypass caps on your unit, it could continue to change for 1000 hours.

Bill@LakeGeorge · « **Reply #242 on:** 15 Jan 2011, 05:49 pm »

Wayne it continues sounding better everyday, I'm letting it burn 24/7 with Isotek, after another week I'll try the fuse and tube thing.

Downsize · « **Reply #243 on:** 16 Jan 2011, 01:46 am »

Hi Wayne,

At the risk of getting laughed off the forum, have you experimented any with different feet/cones/isolation devices under the EE DAC ?

Stillpoints make a big difference under my amplifier.

goldlizsts · « **Reply #244 on:** 16 Jan 2011, 03:02 pm »

Just to drop a note here, I have a pair of Psvane 12AU7-T's I'd like to sell off. Since everybody is raving about the tube, I thought there might be interest. $70 shipped to lower 48. They have about 10 hours mileage; excellent soundstage, etc., good match for the EE DAC. PM if interested.

mfsoa · « **Reply #245 on:** 16 Jan 2011, 03:26 pm »

PM on the way...

Wayne1 · « **Reply #246 on:** 16 Jan 2011, 04:15 pm »

Quote from: Downsize on 16 Jan 2011, 01:46 am

Hi Wayne,

At the risk of getting laughed off the forum, have you experimented any with different feet/cones/isolation devices under the EE DAC ?

Stillpoints make a big difference under my amplifier.

I am sure vibration and resonance control will change the sound of the DAC. Alex did use higher than standard quality feet. A lot will have to do with exactly where the DAC is placed. If possible, it would be best to have it on a shelf by itself, not sitting on top of another component.

If you are using a SqueezeBox wireless, make sure it is as far away from the DAC as possible. The mechanical switching system used in the EE DAC can and will pick up the RF. Using Ethernet and turning the Wi-Fi card off would be a very good thing to do. Look into the software mods from soundcheck soundcheck's Touch Toolbox 2.0

There are many alternatives depending on your system. In some spikes work well to "drain off" mechanical energy. In others, isolation feet would be the best. I have used different things over the years. For my system, isolation seem to work the best. I like the various solutions from Herbie's Audio Lab.

If anyone is interested in buying singles of the Pavane 12AU7-T, please get in touch with me. I bought some extras to use in the mods, but I do have some spares. I also have the silver fuse on hand.

Downsize · « **Reply #247 on:** 18 Jan 2011, 04:42 pm »

Hi Wayne,

I am very new to computer audio, and pretty much ignorant about it. I recently turned my EE DAC's volume up all the way to see how it sounded like that. I have been experiencing random 1 second bursts of white noise at levels that blow the listening room apart, and would have absolutely MURDERED lesser speakers than I use !

So to try and help with this, I have now turned the gain all the way up on my laptop, and turned the volume on the DAC way down to about 9 or 10 o'clock. This makes the bursts of white noise MUCH quieter, although still loud.

My question is this : I have read that most Alps attenuators have left / right volume differences when used below about 12 o'clock .... Should I be worried about that until I can have someone help me figure out what the hell is making the white noise bursts ?

Thanks for taking the time.

Wayne1 · « **Reply #248 on:** 18 Jan 2011, 08:19 pm »

Forget about the possible mistracking of the volume control. The noise is the BIG problem. This noise is saying that something is dropping the signal and sending random bits of information to your DAC.

Both the DAC chip and the analog circuit have muting built in. I do not feel it is the DAC causing the problem. It is probably something to do with your source or the connection from your source to the DAC.

Wayne1 · « **Reply #249 on:** 21 Jan 2011, 03:01 pm »

The Level One modded EE DAC has made it to NYC.

goldlizsts is bringing it to the NY Audio Syndrome meeting tonight. This will be the first time a group gets to hear the modded unit. I do hope it will show off what it can do. It usually does need a day or so to warm up after transport. I realize this is not possible in a big meeting like tonight's.

As the thread has gotten so long, I though I would repost what has been done to the DAC that is on tour:

The modded DAC is Level 1. There are over 30 capacitors replaced with higher quality, higher value types. There are an additional 30 capacitors added (under the board) for supplemental and bypass purposes. 12 diodes have been upgraded and 7 resistors had their values changes. A cascoded constant current source has been added to each anode supply for the tube. The op-amps for the I/E (current to voltage conversion) and solid state output have been changed. The output coupling caps for the op-amp output have been removed. The output coupling caps for the tube output have been changed to Sonicap Gen 1 with Gen 2 bypass. Thereis a silver fuse and the Pavane 12AU7-T tube in it. The cost for the mod is $800.00 including tube and fuse.

Some people have asked what would the cost difference be for not having the solid state section modded. The parts that are changed for the solid state is just the op-amps. I also remove the output coupling capacitor. So the parts and labor and very minor. You might be able to save $50.00.

Gopher · « **Reply #250 on:** 22 Jan 2011, 03:31 am »

Just for the tracking number for my modified DAC from Wayne. I think he received it last Friday and shipped it back this one. Very quick turn around for the extensive work he does to it!

Can't wait to get it back and live with it in my system for some time. It will be primarily fed by a Squeezebox Touch Wayne did his digital mods to some months ago... I've never like modifying equipment myself, but Wayne is turning me into a convert!

Expect feedback.

Turnandcough · « **Reply #251 on:** 22 Jan 2011, 03:51 am »

Quote from: Gopher on 22 Jan 2011, 03:31 am

Expect feedback.

Looking forward to it.
I've got the mods "in the buffer" so to speak. I would like to pull the trigger but I can't just now.
In the meantime, through a fluke, I managed to snag a NOS 1950's Mullard at a reasonable price. I've been comparing it with a Gold Lion and I must admit that in the unmodded DAC the GL has nothing to be ashamed about. I don't want to go nuts with tube rolling but I'm curious about the Psvane.

Wayne1 · « **Reply #252 on:** 23 Jan 2011, 11:11 pm »

I would NOT suggest trying a 5751. The 5751 is usually used as a replacement for a 12AX7, not 12AU7.

Jon L · « **Reply #253 on:** 24 Jan 2011, 12:36 am »

Quote from: OzarkTom on 24 Jan 2011, 12:09 am

I googled up a good tube reference chart, I now see why. Since the gain of 12au7 is 19 and gain of 5751 tube is 70, would that blow something out of the Dac?

http://www.300guitars.com/articles/preamp-tube-gain-factors-and-substitution-chart/

They are just completely different tubes. However, I suggest looking at some good 5814 tubes as drop-in replacement for 12AU7.

Wayne1 · « **Reply #254 on:** 24 Jan 2011, 01:48 am »

What's wrong with using the Pavane 12AU7-T I recommend?

It is a great sounding tube for the circuit in the EE MiniMax DAC.

tabrink · « **Reply #255 on:** 24 Jan 2011, 02:59 am »

Wayne
You convinced me. My Minimax is hanging with a good friend for awhile but as soon as it gets back I am going to slap a Pavane 12AU7 in there and let her play for a week.
Incidentally I have been experimenting with this same Psvayne tube in my Virtue Sensation 901 tube buffer and it is positively "ALIVE".
Definitely one of my top two tubes alondg with Sylvamia Gold Brand gold pin 5751.

Bill O'Connell · « **Reply #256 on:** 24 Jan 2011, 05:43 pm »

Just to clarify here.
The 5751 that tabrink is speaking about is NOT to be used the MiniMax DAC,tabrink is using that in his other piece of equipment( a tube buffer). It is a totally different tube than a 12AU7. The 5751 is in the 12AX7 tube family NOT the 12au7.
OzarkTom is not referring to using a 5751 in the Eastern Electric DAC! Do NoT use this tube in the DAC.

Thanks,
Bill

OzarkTom · « **Reply #257 on:** 24 Jan 2011, 06:18 pm »

Quote from: Bill O'Connell on 24 Jan 2011, 05:43 pm

Just to clarify here.
The 5751 that tabrink is speaking about is NOT to be used the MiniMax DAC,tabrink is using that in his other piece of equipment( a tube buffer). It is a totally different tube than a 12AU7. The 5751 is in the 12AX7 tube family NOT the 12au7.
OzarkTom is not referring to using a 5751 in the Eastern Electric DAC! Do NoT use this tube in the DAC.

Thanks,
Bill

Sorry to cause a confusion here Bill.

Gopher · « **Reply #258 on:** 24 Jan 2011, 06:19 pm »

Quote from: Bill O'Connell on 24 Jan 2011, 05:43 pm

Just to clarify here.
The 5751 that tabrink is speaking about is NOT to be used the MiniMax DAC,tabrink is using that in his other piece of equipment( a tube buffer). It is a totally different tube than a 12AU7. The 5751 is in the 12AX7 tube family NOT the 12au7.
OzarkTom is not referring to using a 5751 in the Eastern Electric DAC! Do NoT use this tube in the DAC.

Thanks,
Bill

If you don't see your tube type in this thread, don't stick her in your Minimax DAC: http://www.audiocircle.com/index.php?topic=83902.0

musicear · « **Reply #259 on:** 25 Jan 2011, 12:25 am »

Any update about Minimax Dac from NY Audio Syndrome meeting