Nagra HD Pre Amp arrived today

[Ovenmitt]

I just purchased the HD preamp and have had similar experiences to John. I came from an Aesthetix Callisto signature with a bunch of NOS tubes. I really liked my Aesthetix and had it for many years. I listened to the Classic pre with MPS power supply (a must for this preamp IMHO) and really loved it. I was able to compare and preferred the Classic/MPS to the Koda and the ARC ref10. The Classic was more resolving with greater texture and color. It had a certain ease and beauty that none of the other preamps possessed.

Then I made the the mistake of taking the HD for a listen. Big trouble.... it’s really a game changer. Everything I loved about the Classic, the HD took to another, even happier place. It’s really interesting; I don’t think I’ve experienced a single audio component that made this fundamental of a change to the overall gestalt of music reproduction in my room before.

 

[jfrech]

Congratulations. I've heard all the preamps you've auditioned. I feel the exact same way. Happy New Year

 

[sefischer1]

What a beautiful and inspiring piece. Congratulations.

Can it support a processor loop? How flexible is the SSP bypass support if any?

 

[Jpspock]

Best preamp I never heard, so transparent...

 

[Ovenmitt]

Hi Sefescher,

The HD does have a bypass loop on either XLR or RCA. I have not personally used it as I am two channel only in this system.

I did have the balancing transformers installed and the sound took another step forward - more resolution without adding any hi-fi nastiness. In fact I get more textural and tonal saturation. The bottom and top are both more extended. Dynamics are off the charts.

 

[sefischer1]

Hi Sefescher,

The HD does have a bypass loop on either XLR or RCA. I have not personally used it as I am two channel only in this system.

I did have the balancing transformers installed and the sound took another step forward - more resolution without adding any hi-fi nastiness. In fact I get more textural and tonal saturation. The bottom and top are both more extended. Dynamics are off the charts.

I see the BYPASS input and that it can be selected on the front knob. I assume that once set to BYPASS, the signal is simply fed through to the output without any sort of level control, which would be useful for integration with a home theater, but how do you connect an EQ or processor, or that classic Nagra reel to reel? I saw an output on the back marked REC/AUX which I assume is a fixed level output of whatever input is selected on the selection knob. But how do I then select the processed (or tape output) signal?

 

[SuperDave]

Hi Sefescher,
I use the HD pre within a home theater. It is simply a bypass with no level control, sorry I can't answer the other question.

Congrats Ovenmitt!
The HD pre makes music sound more like music.

 

[Ovenmitt]

For those interested, my HD preamp came with NOS Phillips JAN 6922’s (USA manufacturing). After about 300 hours break-in and the installation of the new balancing transformers (plus another 100 hours), I rolled NOS Mullard E188CC ,Mullard E88CC/01 (their cca), AMPEREX E188CC SQ, and Siemens E188CC’s. All were slightly different. In the end I went with the Mullard E188CC’s. They are clearly superior to what came in the unit. They have more information at the frequency extremes and much greater tone density, and texture. They are a bit more resolving and I am hearing a deeper and more wrap around 3-D soundstage.

 

[jfrech]

For those interested, my HD preamp came with NOS Phillips JAN 6922’s (USA manufacturing). After about 300 hours break-in and the installation of the new balancing transformers (plus another 100 hours), I rolled NOS Mullard E188CC ,Mullard E88CC/01 (their cca), AMPEREX E188CC SQ, and Siemens E188CC’s. All were slightly different. In the end I went with the Mullard E188CC’s. They are clearly superior to what came in the unit. They have more information at the frequency extremes and much greater tone density, and texture. They are a bit more resolving and I am hearing a deeper and more wrap around 3-D soundstage.

Hmm. I better try this too ! Thanks for posting.

 

[Ovenmitt]

John, do you know what tubes your preamp came with - I’m just curious? It seems that Nagra is using a few different types. Casey told me that his has NOS Mullard E88CC’s.

 

[jfrech]

I'm pretty sure I have Mullards...but I need to pull the cover off and check...and I've never tried a different tube...seems like I need to play around some...

 

[SuperDave]

I'm pretty sure I have Mullards...but I need to pull the cover off and check...and I've never tried a different tube...seems like I need to play around some...

John,
Let me know if you try something new, I trust your feedback. When Casey installed the balancing transformers, I think I remember seeing Mullards.

Dave

 

[Ovenmitt]

Hi John and Super Dave,

If you have E188CC’s to roll in you might try those. For me my E188CC Mullard, Amperex, and Siemens sounded better than the more standard E88CC valves. I even preferred these to cca Millard’s that I happened to have.

In my system the Aperex were a bit “sunnier” and happier sounding. They weren’t bright at all and the top end wasn’t more extended. They were just a bit “lighter in balance”. Siemens were really awesome and (I think) may have been a bit more resolving compared to any of the others. They were very linear. The Mullards had a wonderful texture and color saturation, that in my system (horns) was really appealing. They didn’t give up much at all in resolution - if anything. Soundstaging was a bit more 3-D.

I hope that helps. If you all do roll any other tubes, I would be very interested to see what you find. Our systems look very different on paper - I mean “virtually”

 

[jvvita]

Input balancing transformers arrived yesterday. They are quite large and some weight to it. Think of something larger than a golf ball, smaller then a tennis ball but squished so not round on all sides. Both transformers were mounted a board than has some circuity on it. It replaces a board inside the HD pre with similar circuity but no transformers. Took my dealer all of 10 minutes to install. Most of that was talking to me and doodling over the build quality inside this preamp.

I only have a few hours listening. But from the first note you can tell. My only balanced source is my digital (dCS Vivaldi), my phono stage is single ended so it won't be effected.

Their is definitely more energy in each note. Better illusion of space and movement, and just more involving in how it more easily unravels the notes before you. Everything just seems more "in focus".

I am assuming a lot of wire inside these balancing transformers, so I can only wonder if some breaking in will occur over time..

Just chiming in. I think that with the Vivaldi, the input transformer is a must. The Vivaldi xlr uses a floating ground, so it needs the negative on pin3 to work properly. Or you need to tie pin3 to ground on the preamp side (I must certainly would not like to do it). If not, the signal would not have a clear voltage reference, and in extreme cases you would not hear music at all).

I think this explains the differences you heard with your transformer. It should be a lot better now.

This is from the Vivaldi manual
"The most common fault reported when using our balanced outputs is hiss, unstable levels and a thin sound on both channels. This is caused by connecting the DAC’s balanced output stage to an unbalanced input on an XLR connector with pin 3 left unconnected. This does not work correctly with a balanced and floating output stage –
you must connect pin 3 to pin 1 (ground) to complete the signal path."

 

[microstrip]

Just chiming in. I think that with the Vivaldi, the input transformer is a must. The Vivaldi xlr uses a floating ground, so it needs the negative on pin3 to work properly. Or you need to tie pin3 to ground on the preamp side (I must certainly would not like to do it). If not, the signal would not have a clear voltage reference, and in extreme cases you would not hear music at all).

I think this explains the differences you heard with your transformer. It should be a lot better now.

This is from the Vivaldi manual
"The most common fault reported when using our balanced outputs is hiss, unstable levels and a thin sound on both channels. This is caused by connecting the DAC’s balanced output stage to an unbalanced input on an XLR connector with pin 3 left unconnected. This does not work correctly with a balanced and floating output stage –
you must connect pin 3 to pin 1 (ground) to complete the signal path."

The DCS Vivaldi DAC has a proper independent and separate single ended (RCA) output, why using just one phase of the DAC XLR output to get a single ended signal?

 

[jvvita]

That's exactly the point. Should the preamp not be fully balanced, the xlr would become an unbalanced connection. In this case, you should connect single-ended.

But, with the input transformer, the nagra hd becomes fully balanced, and will respond accordingly to the xlr connection.

 

[Ovenmitt]

I heard recently there was a new dealer installable board available for the HD. Does anyone have experience with it - know what it does or how it sounds?

 

[CKKeung]

The Nagra HD HV Preamp :
https://spark.adobe.com/page/QjcCF2cb7aY4I/

 

[QuadDiffuser]

The Nagra HD HV Preamp :
https://spark.adobe.com/page/QjcCF2cb7aY4I/

A very cool website!

 

[jfrech]

I heard recently there was a new dealer installable board available for the HD. Does anyone have experience with it - know what it does or how it sounds?

They have updates for both the pre and the amp. The preamp gets new power supply boards (2). It's quieter, more resolution, more involving. The amp is a software update and a internal ribbon cable change. The amp is also quieter, it's more tube like now in a richness of presentation and textures (not just the bass but everywhere). They pair were fantastic before, these updates are clearly better. On a scale of 1 -5 (5 being best) this is a like a 2. It's not like before wasn't great...just you won't go back after your hear it. I think the boards were $1750 and the sw was $750. I may be off slightly on the pricing (USD).

I like it when companies update what they have already sold you. dCS does this to. They sold (or rather I bought) a platform vs a device.