Bottleneck line stage competition

[RayP]

Since our MD/VA/DC/DE/PA/NJ group really enjoyed the 6V6 competition, we have decided on a new competition for a line stage under $100 that uses Russian tubes. This time, the chassis needs to come from Target. Doc B has kindly given us permission again to use the forum to let you all know about it.

The rules are at the link below.
http://829b.com/LineStageCompetition.aspx

Please note that as for the 6V6 competition, all entries have to be carried in the door by the builder.

From some of the comments last year, I gathered that a few of you who don't live in the mid Atlantic area would have liked to participate. To this end, if some of you are interested, I am proposing a team build of three people (not novices) who will together come up with a schematic and layout design. All three will undertake to actually build the line stage so that it can be optimized. I will copy the design and take it to the competition. Naturally, there will be disagreements along the way and these will be resolved by simple vote (2 to 1). If necessary, I will make the decision. If you are interested and are ready to treat this as a fun project, let me know. My only design requirement is that I would like the power supply to be battery powered since I have never done one of those before.

This link has pictures and schematics from the 6V6 competition.
http://829b.com/6v6entries.aspx

ray

[Paul Joppa]

Cool - looking forward to seeing what people come up with!

Do the batteries count in the $100 limit?  :^)

[RayP]

Yes, the batteries count toward the $100.

ray

[RayP]

We have decided on the date of Saturday April 2. The event will be held at David's house in Reston, VA.

Details may be found at http://829b.com/LineStageCompetition.aspx.

Note that wall transformers may also be used as well as the standard IEC. Batteries are also acceptable.

So you have two months to get ready. Start your engines.

ray

[bobster]

sounds like fun - can non-entrants attend?

[RayP]

Yes you are quite welcome.

ray

[dbishopbliss]

sounds like fun - can non-entrants attend?

Absolutely.  We had many non-entry attendees at last year's competition.  I think the more people participating make the judging even better.

[dbishopbliss]

Depending upon the number of entries we get, I might toss my stock Foreplay I into the lineup to see how it compares to the entries. 

[debk]

This sounds like fun.  Does the chassis from target count tword the $100.

I have never designed any tube component from scratch.  If my schedule permits I think I will give it a try

Debra

[dbishopbliss]

This sounds like fun.  Does the chassis from target count tword the $100.

No, chassis is not included in the price.  This means you can install the $100 linestage in a $4,000 flat panel TV if you like. 

[RayP]

Well I have saved $3999 on my chassis. My wife will be pleased.

My tubes are ordered and on their way and I've more or less worked out my schematic and how I'm going to mount it all so I'm ready to roll.

ray

[Jim R.]

Ray,

6n27p?

-- Jim

[RayP]

No, not the 6N27P which I see is much similar to 6GM8.

I've actually ordered a few different tubes from Sovcom I would like to play with now I am retired. They certainly are inexpensive.

6S17K as used in the Barbour phono stage (AudioXpress 11-2001). It's a planar triode (4 for $9) that is going to be problematic with a high mu. in addition, I have read it is a tough load, but this is a hobby and mistakes are what it is all about. I probably will use the Edcore line transformers (10K : 600) that I have used in various projects over the years.

1J24B for a battery powered linestage. (10 for $8)

6S7B which is used in the 2nd half of the Barbour phono stage (4 for $9).

6N6P which a lot of people seem to think sounds good and is a less unusual choice. (8 for $19) I have plans for these in other projects but I don't think I will use them for the competition.

ray




 

[dbishopbliss]

I've been on a bit of a Craigslist terror lately.  I just picked up an old Nakamichi CDP2A CD Player.  It has a TDA1541A chip in it and I must say it sounds really great.  The only modification so far is to disconnect the output filter caps.  I think I will eventually add a tube output stage using 6N2P tubes but maybe not.  I also have a magnavox CD471 with a TDA1541 that doesn't sound nearly as good so this one might get the output stage first.

What does this have to do with Ray's post... He mentioned the 6N6P tubes and got confused with the 6N2P tubes.  Also, we could end up using the Nak for the linestage competition.  That or the ARCAM CD73 with Wolfson DAC.  The Nak seems more lush or rich than the Arcam - not necessarily better, just different.

I need to finish soldering my linestage now.

[Jim R.]

Hi Ray,

I'll have to check some of tosee out, especially the 6n6p, which I've also wanted to use for a while now myself.

I knew yo were going to use a battery supply, so that's why the 6n27p came to mind.  I used these in my Cosecant when I hadd it and liked them better thall but the best a-frame amperex 6gm8/ecc86s I had, and they were far less expensive.

I was going through my tube stash just last week and found 3 OS military 6h23p-evs and a matched pair of 6n2p-evs  whichh I might use to build a buffer for my LDR when  I get the SR45ss finished.

Good luck with the competition -- sounds like fun.

-- Jim