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    new preamp products

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    tubes4hifi
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    new preamp products

    Post by tubes4hifi on Thu Nov 11, 2010 5:09 pm

    see this page for updates on new preamps . . .
    www.tubes4hifi.com/pre11.htm

    SP8 phono & line stage with tube power supply
    SP9 line stage with tone controls
    SP12 premium line stage only
    PH6 phono only (same as SP8 phono section and PAS3-Zmod upgrade)
    PH9 hi-quality phono only
    PH-11 premium all tube phono only pre
    PH-12 premium JFET+ tube phono only pre


    Last edited by tubes4hifi on Sun Mar 13, 2011 5:15 am; edited 1 time in total

    fromans4

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    Re: new preamp products

    Post by fromans4 on Sun Nov 21, 2010 10:22 pm

    The phono preamps look impressive. I was on your site a little bit ago and saw a new mod kit for the Dynaco PAS3 that looked like the PAS3Z kit except it had a different linestage that had tone controls. I recently went back to your site to try and find that kit again and it seems to be gone???

    Whats up, is the kit still available?

    Captain Coconut

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    Re: new preamp products

    Post by Captain Coconut on Mon Nov 22, 2010 11:19 am

    Is there any way you can add a volume pot to the phono preamps and therefore bypass a preamp altogether? I like to run a a phono stage straight into a power amp.

    Bob Latino
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    Re: new preamp products

    Post by Bob Latino on Mon Nov 22, 2010 1:45 pm

    Captain Coconut wrote: Is there any way you can add a volume pot to the phono preamps and therefore bypass a preamp altogether? I like to run a a phono stage straight into a power amp.

    It is possible to place a volume control on a phono preamp. The only issue would be that you would have to drill a hole in your phono preamp to accommodate the volume control. It is probably easier, however, to add a stepped attenuator or volume control to your AMP if it is an ST-70. The stepped attenuator would replace the stereo/mono switch (which is usually unused) on any ST-70 so that the drilling of a hole to mount the attenuator would be unnecessary. Photo below of a stepped attenuator and knob added to an ST-70 amp.

    Bob



    Captain Coconut

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    Re: new preamp products

    Post by Captain Coconut on Mon Nov 22, 2010 2:22 pm

    Thanks Bob for your input. Adding a volume control to the amp would be a logical move except I don't have a ST-70. I'm in the process in putting a ST-35 together (waiting for some OPT'S), so maybe your volume pot would work with this amp as well?

    I have a phono stage right now with volume control but in the future I would like to experiment with other stages and since most phono preamps have no provision for adjusting volume, then maybe a volume control on the ST-35 (if it would work) would be the best option.

    Does anyone here have a ST-70 w/volume control that has run a phono preamp straight into it? Does it work/sound better than running it through a regular preamp and then to the amp? I think I remember in another forum Bob, where you ran a CD player into your amp, but have you tried a separate phono stage into the amp?

    Bob Latino
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    Re: new preamp products

    Post by Bob Latino on Mon Nov 22, 2010 6:14 pm

    Yes - The stepped attenuator could be added to an ST-35 as long as you are willing to drill a 1/4 inch hole. A nice place to drill is where I placed the power switch on the ST-35 in the photo below. There is nothing behind where the switch on the front is shown. That power switch also fits into a 1/4 inch hole. The chassis on the ST-35 is thinner than on the ST-70 and is easier to drill.

    Bob



    Captain Coconut

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    Re: new preamp products

    Post by Captain Coconut on Mon Nov 22, 2010 8:17 pm

    Thanks again Bob. Good to know that I could add a volume control to an ST-35 down the road or at time I get around to building it. So I could bypass a typical control preamp and plug any phono preamp into the ST-35? I'm guessing that the volume control on the amp basically takes place of the same on a typical preamp. Enough gain, as little or less noise and so on? I only use a turntable so a preamp is not necessary in my configuration. I like things really simple.

    Bob Latino
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    Re: new preamp products

    Post by Bob Latino on Mon Nov 22, 2010 9:16 pm

    Captain Coconut wrote: So I could bypass a typical control preamp and plug any phono preamp into the ST-35? I'm guessing that the volume control on the amp basically takes place of the same on a typical preamp.

    Yes - to both questions ..

    Bob

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    Re: new preamp products

    Post by Captain Coconut on Tue Nov 23, 2010 10:57 am

    Thanks Bob for the replies. My only other question (or request) would be: is it possible to put up a wiring diagram for a volume control for an ST-35 on this thread? I notice you have one for the ST-70 on a previous thread.

    Thanks

    Bob Latino
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    Re: new preamp products

    Post by Bob Latino on Tue Nov 23, 2010 11:10 am

    Captain Coconut wrote: Thanks Bob for the replies. My only other question (or request) would be: is it possible to put up a wiring diagram for a volume control for an ST-35 on this thread? I notice you have one for the ST-70 on a previous thread.

    Thanks


    The wiring would be exactly the same on the ST-35 as it would be on the ST-70. Check the photo below which shows the installed stepped attenuator with the rotation shaft facing away from you. You have three connections on each channel.

    1. The far left connection on each channel goes to the ground tab on the input jack.
    2. The center connection on each channel goes to the driver board input. Right now there is a wire going from the center pin on each input jack to that eyelet on the driver board. You remove this wire.
    3. The far right connection on each channel goes to the center pin of the input jack.

    Bob



    tubes4hifi
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    Re: new preamp products

    Post by tubes4hifi on Wed Nov 24, 2010 1:48 am

    Hi Capt Coco . . .
    looks like Bob got back to you 3-4 times, I wanted to answer your question about adding a volume control to a phono preamp. Doing that is possible, but because of the output impedance and very small signal strength coming out of the phono stage, it would need a buffer amp before a volume control, otherwise it could affect the frequency response and load down the circuit.
    Putting a volume control on the input of a power amp though is very simple and very effective, as Bob's answers have already shown.
    Roy

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