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Dynaco Tubes4HiFi VTA SP-6 Preamp build thread.


Guest David H

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Guest David H

Here is a Photo of the Output Coupling switch and cap board. This is a 6 position 2 pole self cleaning open frame rotary switch available at Radio Shack for a few dollars. As you can see in the photo I have all of the caps hooked to a common input, the outputs of the caps are hooked to the rotary switch.

The Caps used are Dayton .47uf film/foil, Solen .33uf poly included in the VTA kit, next a 2.2uf panasonic poly, and finally a Dayton 2.0uf 1% poly cap. I was surprised to see how little differece each cap made, but there are definate flavors for each provided. I have 2 more positions for additional capacitors. I am going to try and get my hands on some teflons and possibly some oil filled for comparison.

Much to my dismay, the Cap I like best so far is the $.39 2.2uf Yellow cap. Go figure[:S]

post-24405-13819438032266_thumb.jpg

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Guest David H

Review: of the (Tubes 4 HiFi) VTA-SP6 Tube Preamp.

Build: This is a simple kit to build that requires some experiance working with electronics, but can easily be accomplished by a beginner with a little help.

Skills required: Use of a Voltmeter, Soldering Iron, Screwdriver, Drill, being able to identify elctrical parts ie. resistors, capacitors, and diodes. Respect for High Voltage is not necessarily a skill but a necessity when working with tube gear.

The line stage: I have had many different tube and solid state preamps over the last few years. to list a few Modified Dynaco PAS 3, Pat 5, NAD 1020, Audio Experiance, and others, and I have to say this preamps line stage betters the preamps I have used before. The VTA-SP6 has a majestic tube sound that would lend itself well to nearly any system. The separation and imaging is this line stages strong point, only to be bested by its incredibly fast bass response.

The Phono: The phono stage was my main draw towards building this preamp. My initaial listening test thought was I just cant remeber this much detail from my other Phono stages. So I connected my VP-129 Tube Bellari for an A/B comparison, I was right, the SP6 has much better detail, especially in the midrange. I was confused because to date the Bellari held the title for reasonably priced phono stages, so I rolled a few tubes throught the Bellari, but the detail is just not there. I really could not believe how much more detail I was hearing, and is this normal? It must be normal, because I like the way it sounds. In comparion to my beloved Bellari. The sound of the SP6 moved me into the front row.

Listening test lp's used:

Norah Jone - Come Away with Me

Muddy Waters - Folk Singer

Kim Carnes - Mistaken Identity

Supertramp - Crime of the Century

Steely Dan - Asia and Gaucho

James Taylor - Thats why I'm Here

Laurindo Almeida - Virtuoso Guitar

All of the LP's I have tested sound more life like and spaceous due to the SP6's phono stage.

All in all the Tubes4HiFi SP6 is an exceptional value preamp that is reasonably simple to build, even for a beginner like myself. This was my first venture into building tube based audio gear and has been incredibly rewarding. Less than $450 invested.

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Guest David H

I've always thought it'd be fun to build some equipment and always thought it'd be cool to own some tube equipment....

If you choose VTA SP6 or something like it you will not regret it. This kit is alot of fun and reasonably simple to build.

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Guest David H

Hey Dave, Thannks for the audition. That is by far the best phono stage I have ever heard, the clarity is unbelieveable. How much to build one for me if I buy all the stuff?

Johnny $700 ready to go, that includes using the VTA's sonicap upgrade.

Additional coupling caps and tubes of your choice are extra.

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Guest David H

Sure thing, but it will have to wait til I get back from Sac. I am also in the process of running the inverse RIAA eq test Well see how it fares against the NAD, the Bellari VP129 and the Hagerman Bugle.

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Guest David H

On to the finish work, The faceplate was made By: High Desert Laser Graphics, Victroville Ca. $35

Do you have the contact information for them?

Greg

I do and I will post here when I get to the house.
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Guest David H

I am finished, and very satisified with this preamp. I have been using this preamp for near a month now, and still cant get over how good this preamp is, especially considering the cost.

After extensive testing and comparisons, I must agree with the designers claim that this preamp is easily comparable to much higher priced preamps, most of which do not have built in phono section.

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GotHover:

I wanted to stop in briefly before signing off; it's been a long time since I've visited here. I saw your project, and think you did a fine job with it. The chassis looks quite like those used by Transcendent Sound.

I was just looking at your shielded cable leads, and was curious how you've grounded the shields. I see the the input, wiper, and ground connections on the ALPS control, as well as the ground leads that are connected from the pot to the ground buss on the PCB. Are the coax cable shields connected at the ground node connection on the VC?

Erik

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Guest David H

Are the coax cable shields connected at the ground node connection on the VC?

Erik, No the sheild is only connected at the circuit board ground bus and is floated on the VC to reduce ground loop issues. The coax really isn't necessary, but the extra sheilding never hurts. The only area the sheilded coax is reccomended is the phono input.

Thanks for stopping by.

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