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
Thanks
Z565 output transformer question
Captain Coconut- Posts: 108
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Bob Latino- Admin
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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- Posts: 108
Join date: 2009-10-13
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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- Posts: 211
Join date: 2009-02-04
Age: 63
Location: Texas
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
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- Posts: 108
Join date: 2009-10-13
Age: 60
Location: Great White North
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.
Luddite- Posts: 211
Join date: 2009-02-04
Age: 63
Location: Texas
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
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- Posts: 108
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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- Admin
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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- Posts: 108
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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- Admin
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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- Posts: 108
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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!