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-   -   Tube rolling in ARC preamps? (https://www.audioaficionado.org/showthread.php?t=29136)

2fastdriving 11-24-2014 11:25 PM

Tube rolling in ARC preamps?
 
I've often wondered why McIntosh preamps are so popular for tube rolling, while many other brands are generally not experimented with.

I used to own a mcintosh c2300, and I tried different tubes with great results.

But my current pre, the Ref 5, comes to mind. I don't believe I've ever read about a single person putting a different brand of tube in their unit. In fact, I don't even know what brand of 6H30P it has? Are they ARC brand? Is there any benefit of trying another brand?

schneice 11-24-2014 11:54 PM

Timely...my 5se is up for a power tube. Interested to hear...thanks

TLi 11-25-2014 01:13 AM

There are only two brands that supply 6H30. They are Sovtek and Electro-Harmonix. EH has golden legs and is slightly more expensive. I have just brought a set of EH 6H30 to try out.

There is also the NOS 6H30-DR, but many audiophiles have said they are just fake NOS and repackage from Sovtek ones.

2fastdriving 11-25-2014 01:24 AM

Sounds like that must be the explanation. What tube comes with the Ref 5?

tima 11-25-2014 02:17 AM

Quote:

Originally Posted by 2fastdriving (Post 653372)
I've often wondered why McIntosh preamps are so popular for tube rolling, while many other brands are generally not experimented with.

I used to own a mcintosh c2300, and I tried different tubes with great results.

But my current pre, the Ref 5, comes to mind. I don't believe I've ever read about a single person putting a different brand of tube in their unit. In fact, I don't even know what brand of 6H30P it has? Are they ARC brand? Is there any benefit of trying another brand?

People who own preamps with rollable tubes - differently manufactured tubes that are electrically the same and available - will experiment. Ask owners of earlier Conrad-Johnson or Atma-Sphere preamps, etc, etc - more folks who can roll tubes do than not. For newer gear, several manufacturers have switched from the 6DJ8 to the 6H30.

Wrt the 6H30, they're all made in the same factory and labeled 6H30П. The normal default version typically has an 'EB' suffix (6H30П-EB). It is the tube you'll find as stock from manufacturers who offer gear using this tube, including ARC, BAT, etc. regardless of branding. The EH gold pins is a gimmick, imo. Fwiw ARC has an excellent implementation of this tube.

There is/was a DR suffixed varietal that was a military version. Ten years ago they could be had for ~$30. Nowadays their prices are very high and provenance typically unknown. The only vendors of DR's I'd trust are Conus audio and Tubestore. Eugene Karna of Conus imported the last of the DRs out of Russia and sold half that lot to Tube Store back in 2005. With current prices and the ease of forgery I wouldn't otherwise bother. The DR does offer some improvement in ARC Reference preamps - I've tried them in the Ref 5, 5SE, Ref Phono 2 and 2SE. Slightly more resolution and some refinement in the top end with a wee bit less grain.

More at this web page from Audiophile Club of Athens.

The last ARC REF linestage to use the 6DJ8-family was the REF 2 and phonostage was the PH-7. If you want to improve the sound of your ARC REF preamps & amps, think vibration isolation, signal and power cords. To have fun rolling tubes, look for gear that uses 6DJ8 family, 6SN7s, 12AX7s, etc.

Harlequin 11-25-2014 04:55 AM

Marc, I have spent a considerable amount of time rolling the 6550 power regulator in an Ref 5se ( more than any sane person should) whereby one may tailor the signal to ones own taste, varying from the Anylitical/Linear to the Harmicaly Rich.

The way to facilitate this tonal shaping is by the use of disparate NOS 6550's manufactured in the main by Tung sol from the late 50's through to 70's and with GEneral Electric 6550A from the 70's.

For my part I would rate the following in tearms of the most A/L through to the most H/R and are entirely my own subjective considerations.

GE 6550A ( Perhaps closest to stock Sovtec ARC 'voicing' however with less grain and more micro detail resolution , a tad smoother when pushed and improved Dynamics.

Mid to late production Tung Sol Three hole Grey Plate ( more similarities than not to the GE's with a touch more Harmonic emphasis )

Early 1960/61 production Solid Grey Plate ( my personal favourite exhibiting a nice balance between the Linear and the Harmonic )

late 50's/1960 Solid Black Plate ( perhaps a little less composed at the frequency extremes when pushed, yet imparts a depth and weight of Harmonic tone and texture, particularly effective on Vocals, think Ella or the Chaiman Of The Board here)

Now the Caviats, I would strongly advise that anyone considering Taking their Ref 5se for a spin to only utilize Thoroughly Tested valves measuring at least 90% emitions and certified safe for Gas and Shorts, preferably sourced from a Recognised dealer or trusted individual. In the main, in order to ensure the safety of your equipment, yet also to ensure the integrity of the valves purchased.

Should your Ref 5se or for that matter Ref 10 ( both 6550's should be closely matched in the latter) still remain under ARC warranty you may consider obtaining sanction from your dealer, however as ARC do not retail NOS 6550's you are most likely to receive the stock * Do not recomend , does not compute , exterminate , exterminate* response!

Although sourcing such valves is getting both more expensive and harder these days it is nothing compared to the Snake Pit that is The Genuine production 6n30 DR, and I would concur with the advice already imparted , however should the intrepid Ref 3/5 owner wish to give it a shot, without selling a vital organ, I would recommend at least a single DR in the associated PS section, adjacent to the Regulator.

This guide may help folks to avoide falling into that snake pit I was on about.

http://www.aca.gr/index/hiend/hiendArticles?row=1988

Jasper.

JCR 11-25-2014 06:58 AM

I can echo some of the comments here regarding tube rolling for ARC. For sure the 6h30 tube, while a very good tube, offers very view option. I do have several of the military version (6h30 - DR) still which I had bought for my previous Ayon gear and in that brand (Ayon) swapping the Sovtek for the DR version of the 6h30 was a life changing improvement. So at least for the DR 6h30 I got, I can assure AA members they were not mere repackaging of the Sovtek - they were much better!

However, then comes ARC in my system. First with a REF DAC and then a REF 10. Both use 6h30 Sovtek. Thinking my previous tube rolling with Ayon would work here the same I tried rolling the Sovtek in the ARC with the 6h30DR version and to my surprise it did not yield good result. My only explanation is ARC really seem to be voiced and tuned to play well with the Sovtek 6h30. I never tried swapping the 6550 for the power supply like the previous member here, so maybe this is a better option.

dminches 11-25-2014 08:08 AM

Quote:

Originally Posted by TLi (Post 653402)
There are only two brands that supply 6H30. They are Sovtek and Electro-Harmonix. EH has golden legs and is slightly more expensive. I have just brought a set of EH 6H30 to try out. There is also the NOS 6H30-DR, but many audiophiles have said they are just fake NOS and repackage from Sovtek ones.

That is not true. There are real DRs which sound nicer than the Sovteks.

dminches 11-25-2014 08:13 AM

Quote:

Originally Posted by tima (Post 653413)
If you want to improve the sound of your ARC REF preamps & amps, think vibration isolation, signal and power cords. To have fun rolling tubes, look for gear that uses 6DJ8 family, 6SN7s, 12AX7s, etc.

What vibration isolation have you used?

TLi 11-25-2014 10:30 AM

Quote:

Originally Posted by dminches (Post 653433)
What vibration isolation have you used?

I use Nordost Sort Kone TC under my reference 10 with very good result.


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