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    Z565 output transformer question

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    Captain Coconut

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    Z565 output transformer question

    Post by Captain Coconut on Tue May 04, 2010 8:12 pm

    Does anyone know where I could source a Dynaco Z565 output transformer with an eight and sixteen ohm winding. Triode Electronics has a Dynaco ST35 with this transformer but only with 4 and 8 ohm windings. Any help would be appreciated.
    Thanks

    Bob Latino
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    Re: Z565 output transformer question

    Post by Bob Latino on Tue May 04, 2010 9:17 pm

    Captain Coconut wrote:Does anyone know where I could source a Dynaco Z565 output transformer with an eight and sixteen ohm winding. Triode Electronics has a Dynaco ST35 with this transformer but only with 4 and 8 ohm windings. Any help would be appreciated.
    Thanks

    Captain,

    I do not believe there is "clone" Z565 output transformer out there with 8 and 16 ohm secondary windings. You will probably have to look on Ebay for someone selling an ORIGINAL Dynaco Z565 if you want one with 8 and 16 ohm secondary windings.

    Bob

    Captain Coconut

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    Re: Z565 output transformer question

    Post by Captain Coconut on Wed May 05, 2010 9:01 pm

    I was afraid that this would be the answer. I wanted to cobble together a Dynaco ST35 clone with 8 and 16 ohm taps. Quad ESL'57's (which I have) apparently like a 16 ohm tap from a tube amp, but amps with 16 ohm are hard to find.

    Luddite

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    Re: Z565 output transformer question

    Post by Luddite on Thu May 06, 2010 11:37 am

    Captain,

    There is a possible, if not optimum, solution when using the 4/8 ohm output transformers. To match the 16 ohm impedance of your esl's, you could insert an autoformer in the speaker line. An autoformer, if you are not already aware, is a transformer with a single coil, but having multiple taps. You could, for example, connect the ST-35 output to the common and 8 ohm taps of the autoformer, and connect your speaker to the common and 16 ohm taps. The drawback, of course, would be the additional effect of another transformer in the signal path. I have used this method in the past with very good results. A lot depends on the quality and size of the autoformer. BTW: Autoformers are considered to be commercial/professional audio devices. You will probably need to source these through a commercial sound contractor. I personally used a couple of Electro-Voice model AT-100 units.

    Best Regards,
    Charlie

    Captain Coconut

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    Re: Z565 output transformer question

    Post by Captain Coconut on Thu May 06, 2010 3:12 pm

    bnc31 wrote:Captain,

    There is a possible, if not optimum, solution when using the 4/8 ohm output transformers. To match the 16 ohm impedance of your esl's, you could insert an autoformer in the speaker line. An autoformer, if you are not already aware, is a transformer with a single coil, but having multiple taps. You could, for example, connect the ST-35 output to the common and 8 ohm taps of the autoformer, and connect your speaker to the common and 16 ohm taps. The drawback, of course, would be the additional effect of another transformer in the signal path. I have used this method in the past with very good results. A lot depends on the quality and size of the autoformer. BTW: Autoformers are considered to be commercial/professional audio devices. You will probably need to source these through a commercial sound contractor. I personally used a couple of Electro-Voice model AT-100 units.

    Best Regards,
    Charlie


    Thanks for mentioning an option Charlie. I'm not sure if I want to go this route , or not. I was hoping that someone would have a mint ST35 laying around that they would want to sell me. Laughing

    Luddite

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    Re: Z565 output transformer question

    Post by Luddite on Thu May 06, 2010 4:07 pm

    I agree. The best solution would be 16 ohm output transformers. In fact, I was previously using the autoformers to match a 4 ohm load to an 8 ohm output. When I built my ST-35 last year, I was able to eliminate the autoformers and go directly to the Z565's 4 ohm outputs.

    FYI: I just found an output transformer (model 1650E) listed in the Hammond catalog that appears to have very similar electrical properties (ie. 8000 ohm primary with 4, 8, & 16 ohm secondaries) to the Dynaco. I'm not certain if the dimensions are exact or not.

    Best Regards,
    Charlie

    Captain Coconut

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    Re: Z565 output transformer question

    Post by Captain Coconut on Fri May 07, 2010 9:17 am

    Thanks again Charlie for the suggestion. I'm guessing that the ST70 that Bob offers doesn't have a 16 ohm secondary winding as well? Or does it? I kinda' have my heart set on a ST35 but if the ST70 offers a 16 ohm tap, I may consider it.

    Bob Latino
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    Re: Z565 output transformer question

    Post by Bob Latino on Fri May 07, 2010 9:37 am

    Captain Coconut wrote:Thanks again Charlie for the suggestion. I'm guessing that the ST70 that Bob offers doesn't have a 16 ohm secondary winding as well? Or does it? I kinda' have my heart set on a ST35 but if the ST70 offers a 16 ohm tap, I may consider it.

    Hi Captain,

    The output transformers on the VTA ST-70 amp kit DOES have a 16 ohm tap to run 16 ohm speakers.

    You CAN run 16 ohm speakers on an 8 ohm tap but you will lose some power from the impedance mismatch. Also, the frequency response of the amp will be altered slightly because of the mismatch.

    Bob

    Captain Coconut

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    Re: Z565 output transformer question

    Post by Captain Coconut on Fri May 07, 2010 2:42 pm

    Thanks Bob for the posting. In the meantime I have learned that Magnequest makes a transformer with an 8 and 16 ohm secondary windings. Would I get the rest of the parts for a ST35 from Dynakits and/or Triode Electronics or even someone else? Also, does the ST35 lend itself to a driver board update?

    Bob Latino
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    Re: Z565 output transformer question

    Post by Bob Latino on Fri May 07, 2010 3:51 pm

    Captain Coconut wrote:Thanks Bob for the posting. In the meantime I have learned that Magnequest makes a transformer with an 8 and 16 ohm secondary windings. Would I get the rest of the parts for a ST35 from Dynakits and/or Triode Electronics or even someone else? Also, does the ST35 lend itself to a driver board update?

    Captain,

    If the Magnequest transformers for an ST-35 that you are are referring is to is what I am thinking of (Magnequest S-240 or S-245) ... Those transformers are about $450 - $460 a pair - almost triple the price of a stock Z565 clone transformer pair ($160) from Dynakitparts. You will then still need about $300+ worth of parts (chassis, power transformer, boards, capacitors, resistors, tube sockets etc.) ... For that amount of money invested ($700+) you could just buy an ST-70 kit ... I don't know if this really makes financial sense unless the transformers that you are referring to are ones that Magnequest carrys and I am not familiar with ??

    RE: The ST-35 upgrades ... Check the Sticky post above on "Rebuild your ST-35 power amp"

    Bob

    Captain Coconut

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    Re: Z565 output transformer question

    Post by Captain Coconut on Fri May 07, 2010 4:04 pm

    They are the MQ-565 which are $225 a pair. There's mention of them on the Audio Asylum Magnequest/Peerless forum. They sound like they would be terrific. Yes, the ST70 would probably be better cost wise but for some reason I'm hung up on the ST35. That could change though!

    mark four

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    z565 outputs

    Post by mark four on Wed Nov 13, 2013 11:03 pm

    you could always look for the integrated sca-35 . they usually go for less money than st-35 . i don't understand why . it is a great amp and you can sometimes score one for less than 300 clams . someti,es less if the face is corroded and ugly . which shouln'd be a prob because you only the trannys out of it . good luck .

    corndog71

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    Re: Z565 output transformer question

    Post by corndog71 on Thu Nov 14, 2013 12:02 am

    I scratch-built my ST35 using Dynakitparts trannys, the driver circuit from DIYTube.com, and Dave Gillespie's Bias circuit. I did it for around $400 although I already had a box on hand.



    Sure, that's not far in cost to an ST70 but I think the EL84 has a really great sound quality to it and they're cheaper than EL34s.

    I really liked the DIYTube driver circuit because you can use more common tubes. Shannon's circuit calls for a 12AX7 for voltage gain and 12AU7 for phase splitter but there are lots of tubes that can be substituted to good effect.




    DynakitParts
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    ST-35

    Post by DynakitParts on Thu Nov 14, 2013 12:09 am

    Captain,
    I have an original ST-35...Not mint...but nice condition...It works also!

    Call or email me on Thursday as I do not want to discuss this kinda stuff on the forum. dynakitparts@aol.com

    A customer of mine had a fit issue with the Magnequest's Z-565 transformers when he tried to mount a pair of these on our the ST-35 chassis. Of course he blamed me first because Magnequest is the Dynaco/Acrosound transformer Guru. End bells were not the right style/size and these extended too far outward over the pc boards. I believe this may also be an issue with Triode's Z-565 version.

    Anyway...Mike makes good stuff but be aware of this possible fit issue with the ST-35.

    Kevin @ Dynakit

    sailor

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    Re: Z565 output transformer question

    Post by sailor on Thu Nov 14, 2013 11:32 am

    Captain,
    Never done business with this place but they do have what you need.
    http://www.edcorusa.com/p/432/cxpp21-ms-8_6k

      Current date/time is Wed Nov 26, 2014 8:00 pm