Sansui 1000A OPT replacements

[Indy1K]

Hello,
I just purchased a Sansui 1000A to rebuild/restore. This amp/receiver is missing one of the Sansui Output Transformers, and the other one is out of the chassis and impedance readings indicate shorts, so I am looking to replace both of them in the rebuild. I cannot find any good used ones or Hashimoto replacements, so I am looking at the Hammond 1650 series. From what I can tell the 7591 output tubes feed the transformers in a push/pull circuit. The original transformers are rated at 6600ohms P-P, with and 8 and 16ohm output.
Will one of the Hammond 1650 series work? Which one is the best choice as a replacement? The HA or the PA?
Or, do you have another suggestion?
Thank you in advance for the advice

Regards,
Kevin

 

[vinylkid58]

Edcor is another option, and a lot cheaper. I would double check the dimensions thou, as there's a good chance they won't fit in the chassis.

EDCOR - CXPP45-6.6K

jeff

 

[Indy1K]

Sansui 1000A OPT Replacements

Jeff,
Thanks. Do you think the Edcor Xfmrs have a quality equal to the Hashimoto's?
Or are the Hammonds a better quality. I dont mind paying more.
Also, the inputs on the old OPTs only have Plate, B+ and Plate inputs. It doesnt have screen inputs. Will this make a difference? Should I just cap those leads?

Thanks again.

Kevin

 

[vinylkid58]

Do you think the Edcor Xfmrs have a quality equal to the Hashimoto's?

Don't honestly know, I've never heard anything with Hashimoto transformers. You'd hope they would be far superior, given the price difference.

Also, the inputs on the old OPTs only have Plate, B+ and Plate inputs. It doesnt have screen inputs. Will this make a difference? Should I just cap those leads?

Yeah, you just tie the leads out of the way.

You might want to give Heyboer a call. It's possible they can rewind your existing transformer. Heyboer Transformer - Top

jeff

 

[Fusor]

As was said, double check the dimensions. You don’t want to re-engineer the chassis. Between the Hammonds, what does your Sansui transformer weigh? Weight is a good measure of how much power. Mouser tells me the HA is 5.7 pounds and the PA is 6.3.

Regarding Edcor, the wait was always something you had to consider. It used to be about a month. I ordered [and paid] for a power xfomer back on 4/24. I am still waiting…… All the Hammonds I’ve purchased recently from Mouser & DigiKey have arrived within a week.

 

[Francois G]

The Hashimoto HW-40-8 will be a good electrical fit, albeit with 8k primary, but it will be expensive, around $600 per pair plus shipping from Tokyo. I have not checked these nice potted transformers for holes/physical fit in the Sansui 1000A chasis. In my opinion Hashimoto is in the top tier of output transformer manufacturers. Hammond and Edcor are in an acceptable middle tier, and certainly reasonable for the price.

EIFL is a good dealer per reputation. -hashimoto

Unfortunately there appears to be no importer that sells the PP line from Hashimoto in the US, only SE is being imported.

 

[Alllensoncanon]

I would wait for a good Sansui 1000a transformer at ebay to replace it. They do show up once in a while. After all, IMHO, what make this Sansui special is the output transformer. Without, the rebuild is just another reciever.

 

[Indy1K]

Well, drew a physical template of the Edcor that Fusor had recommended. Unfortunately, it is slightly to large a footprint to fit. I could make them fit by modifying the chassis mounting, but they would be resting against the 7591 output tubes. I think I will wait on the Sansui originals popping up for sale. While I am restoring for my own personal use, I do not want to devalue it either.

 

[OldHector]

How about remanufactured Dynaco OPTs from Triode Electronics?
Dynaco replacement OPT

 

[directdriver]

I would wait for a good Sansui 1000a transformer at ebay to replace it. They do show up once in a while. After all, IMHO, what make this Sansui special is the output transformer. Without, the rebuild is just another reciever.

I totally agree. Replacing the stock output transformers render it not a 1000A anymore. I sold my extra output transformers before so they are out there. Sometimes beater receivers are up for sale cheaper than the irons! Just have to be patient and ready to pounce on them.

 

[spind]

Is the 1000A similar to the 1000? If so, check the swap meet--a pair listed today. No affiliation.

 

[imontoya]

IIRC Hashimoto were OEM providing Sansui with the OPTs for 1000A ??

 

[Indy1K]

IIRC Hashimoto were OEM providing Sansui with the OPTs for 1000A ??

Yes, they were

 

[trobbins]

Perhaps be aware that just replacing the OPTs may not be avoiding future damage to the OPT's - imho it would be wise to try and assess what could have caused the OPT faults, and what can be done to avoid that (eg. fusing the HT secondary, and adding cathode current sensing and screen stopper to the output stages).

Also you may be digging yourself an instability hole to jump in to if you don't use the original OPTs.

 

[Francois G]

Is the 1000A similar to the 1000? ….

No. They are using very different output tubes and therefore different OTs. The 1000 uses PP 25E5 power tubes, and IIRC the transformer primary is 3400 Ohms.

 

[Francois G]

Indy1K,

I have measured the resistances for my pair of Sansui 1000A OTs and posted them here:

https://www.diyaudio.com/forums/parts/374977-sansui-1000a-opts.html#post6751291

Hope this helps.