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    Built a SP14 for my ST120 (PIC HEAVY)

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    ValleySounds

    Posts : 20
    Join date : 2012-09-25
    Location : Calgary, Ab

    Built a SP14 for my ST120 (PIC HEAVY)

    Post by ValleySounds on Wed Nov 25, 2015 7:50 pm


    Long story short, I got bored and built a SP-14 to go with my Latino ST-120. I am running my amp through a home theater amp for convenience in volume control and switching.
    St -120 build thread here

    After reading some reviews about how nice the SP-14 sounded I thought I would give it a try.
    I didn't want to lose the convenience of remote control volume and source switching. There are a few options out there that allow you to to add these features to the preamp but most were not quite what I wanted or the quality was poor. I decided on an AMB LCDuino-1 setup with volume and source switching. It has many great features and has full user customization, but that project is a whole nother thread.

    After a few months of work the preamp is up and running. I ran through some initial tests and fired it up. Everything worked first try flawlessly. (I didn't think that was suppose to happen with DIY)
    How is the SP-14 sound?
    There is none. in a good way. I hit mute and its dead quiet. My system has always had a little bit of fuzz when you put your ear to the tweeter but this amp has almost made it gone. I hit play and the system comes alive like never before.
    The biggest two changes I have noticed is the background and the soundstage. Its hard to explain but the musical notes spring up front and center (or sides depending on recording) and gently decay into a dark space I never new existed. Vocals are smooth enough to make the hair on my arms stand up. If you are in question of buy this amp just do it. You wont be disappointed.

    About the build.
    Started The chassis the same as my ST-120. Wood front and sides, aluminum top, bottom, and rear. I made the rear out of 1/4" aluminum so I can drill and tap the edges 4-40 to screw the top and bottom plate to it. Its too thick for the rca connectors so I had to machine the inside rear out to about 1/16" thick. That was the hardest part of the whole build since I don't have a machine shop in my basement.
    Heres a pic of getting some holes done



    Inside pic of rcas in the completed amp. You can see the AMB input output selector wiring. I used different wire on different outputs just to try. I had some solid silver sitting here left from another project



    Finished rear looks like this


    Here is the internal wiring of the LCDuino. Left to right we have a small transfomer (always on) 5v power supply, Power mom switch, Motorized pot (used as an encoder, there is no signal going through it), ir receiver, and the LCDuino board with lcd display. Bottom pic far right is the control board for the AMB relay based stereo and selector boards.




    Wiring the SSR and power distribution for the transformers.



    A couple more pics of the inside of the amp.





    Front panel

    Kentley

    Posts : 335
    Join date : 2015-03-06
    Age : 64
    Location : Worcester, MA

    Re: Built a SP14 for my ST120 (PIC HEAVY)

    Post by Kentley on Wed Nov 25, 2015 8:28 pm

    Yikes! How satisfying it must be to make this beauty the way YOU wanted it AND have it meet or surpass every expectation. My hats go off to you, sir. The SP-14 and the ST-120 is a match made in hebbin', and you've built your own version of hebbin'. May I ask what speakers you are using???

    Also I notice that you are using premium coupling caps. That is my next project here, after I procure the four mil-spec 6SN7s which are in the mail.


    Last edited by Kentley on Wed Nov 25, 2015 8:30 pm; edited 1 time in total (Reason for editing : additions)

    ValleySounds

    Posts : 20
    Join date : 2012-09-25
    Location : Calgary, Ab

    Re: Built a SP14 for my ST120 (PIC HEAVY)

    Post by ValleySounds on Wed Nov 25, 2015 10:18 pm

    For speakers I am using a DIY set of LXII's from Raw Acoustics before he went out of buisness.
    I cant find my most recent pics of them but they are in a new set of curved cabinets I made. Here is a pic of the old cabinets I did before the sun cracked the veneer.


    In the SP-14 I am using some Mundorf silver/gold oil coupling caps.
    Parts connection has a 25% off sale so I thought why not try them instead of the silver oils.

    deepee99

    Posts : 1333
    Join date : 2012-05-23
    Location : Wallace, Idaho

    Re: Built a SP14 for my ST120 (PIC HEAVY)

    Post by deepee99 on Thu Nov 26, 2015 3:14 pm

    A sight to behold, ValleySounds. Compliments all around. The Mundorfs are a great supercharger for the SP-14's sound. Populate the 14 with good tubes and your quest for pre-amp perfection is over!

    tubes4hifi
    Admin

    Posts : 1286
    Join date : 2008-11-30

    Re: Built a SP14 for my ST120 (PIC HEAVY)

    Post by tubes4hifi on Sun Nov 29, 2015 2:21 am

    hey Valley,
    just got back from a few days off for the holiday. Nice to see your photos and read your comments.
    Darn nice job!!! Should I sent you some customers who want that remote control system? It was too expensive and complex for me.
    For anyone who just isn't sure (about the SP14), you can NOT go wrong with an SP14, unless you don't like tubes, and don't like hearing REAL music!
    Thanks to ALL of my 100's of customers who have built or bought one of these during the past three years.
    Not one single person (wait, I do think maybe there was ONE GUY, you all know the type, he did NOT like it at all . . . !!!)
    has ever said anything other than this is the best hi-fi component they have ever EVER heard!
    Takes me back to my own original review, which I'm going to re-post since it's been 3 years now . . .
    Roy

    ValleySounds

    Posts : 20
    Join date : 2012-09-25
    Location : Calgary, Ab

    Re: Built a SP14 for my ST120 (PIC HEAVY)

    Post by ValleySounds on Sun Nov 29, 2015 6:49 pm

    Thank you Roy for designing such a great product and then releasing to us public.
    You can go ahead and send some people my way if they would like to discuss the remote system. It is definitely not a plug and play.

    Fitero

    Posts : 8
    Join date : 2015-05-10

    Re: Built a SP14 for my ST120 (PIC HEAVY)

    Post by Fitero on Tue Dec 08, 2015 12:49 pm

    Thanks for sharing your thoughts and photos ValleySounds.
    That is beautiful veneer work on those speakers!

    For those that don't want to mess with the innards of their preamps, but want the convenience of an I/R remote control, here is an option that can be connected to the tape loop and works quite well;

    http://www.mcmelectronics.com/product/50-8394



    GP49

    Posts : 733
    Join date : 2009-04-30
    Location : East of the sun and west of the moon

    Re: Built a SP14 for my ST120 (PIC HEAVY)

    Post by GP49 on Tue Dec 08, 2015 9:12 pm

    Input impedance is not specified. If it is low, it will load down whatever source you are listening to. In a stock or lightly modified PAS, too low an input impedance will result in loss of bass when playing phono.

    Would be nice if MCM would let us know what it is.

    peterh

    Posts : 679
    Join date : 2012-12-25
    Location : gothenburg, sweden

    Re: Built a SP14 for my ST120 (PIC HEAVY)

    Post by peterh on Wed Dec 09, 2015 3:04 am

    Fitero wrote:Thanks for sharing your thoughts and photos ValleySounds.
    That is beautiful veneer work on those speakers!

    For those that don't want to mess with the innards of their preamps, but want the convenience of an I/R remote control, here is an option that can be connected to the tape loop and works quite well;

    http://www.mcmelectronics.com/product/50-8394


    This device is close to worthless as they do not make specifications available. Thus input
    impedance could be just about anything. That would in most cases load the preamp to much.

    deepee99

    Posts : 1333
    Join date : 2012-05-23
    Location : Wallace, Idaho

    Re: Built a SP14 for my ST120 (PIC HEAVY)

    Post by deepee99 on Wed Dec 09, 2015 3:22 am

    peterh wrote:
    Fitero wrote:Thanks for sharing your thoughts and photos ValleySounds.
    That is beautiful veneer work on those speakers!

    For those that don't want to mess with the innards of their preamps, but want the convenience of an I/R remote control, here is an option that can be connected to the tape loop and works quite well;

    http://www.mcmelectronics.com/product/50-8394


    This device is close to worthless as they do not make specifications available. Thus input
    impedance could be just about anything. That would in most cases load the preamp to much.
    Is there a difference between the "Intput" and "Input" jacks? Laughing

    Fitero

    Posts : 8
    Join date : 2015-05-10

    Re: Built a SP14 for my ST120 (PIC HEAVY)

    Post by Fitero on Wed Dec 09, 2015 8:01 pm

    LOL. Yeah, the translation is not the greatest, nor is the build quality.

    However, for those who might want to experiment with indolence, it is quite cheap, it does work and spits in the face of "audiophile" snobbery. Sort of a stop-gap until you spring for something like this;

    http://www.dehavillandhifi.com/TW_remote_volume_control_is_the.htm

    Tube Nube

    Posts : 641
    Join date : 2008-12-06
    Age : 53
    Location : Calgary, AB

    Re: Built a SP14 for my ST120 (PIC HEAVY)

    Post by Tube Nube on Thu Dec 10, 2015 12:08 pm

    Kudos on a terrific SP14 project.

    It's a beautie.

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