Hashimoto SE Output Transformer

[Salas]

I would urge you to try RCA 5R4GY as a rectifier in those circuits. It shows very good sonic synergy to 300B in my experience.

 

[WE91]

Thank you, Salas! I have noted your recommendation on rectifier. I seem to remember someone trying different rectifier tubes in the WE91, and finding the GZ34 and 5AR4 not to be as good as the 274b. They just substituted the 274b with GZ34 without modifications, when trying. Is that possible with the RCA 5R4GY?

Regards

 

[Salas]

I suggest you use the 5R4GY with 20uF (poly) input cap in CLC. Yes they are pin compatible. Tell me more about your PSU configuration.

 

[WE91]

Hi.

The powersupply will be more or less like in this one:
http://www.triode-systems.com/uploads/photos/49.png
I will be using Solen MKP-caps in stead of electrolytics.
This is the Brian Cherry/Thorstein Loesch made Lady Day 3+ with common mode choke. The 180 ohm 5W resistor directly after the rectifier has been added to regulate the voltage some.

Regards.

 

[Salas]

Yes, it will work. Just check voltages and see that you compare with same B+. Change 180R for same B+ (more resistance if you get more B+, less if you see a sag vs 274b results). This resistor smooths the initial charge pulse to C 10uf. The choke does the real filtering job. 20uf Solen I have used with 5R4GY for years with no failures. It keeps voltage higher if needed. Else 10uf is totally ok.
I would find it difficult to beat 274a or b for airy soundstage though. See for yourself, maybe 5R4GY compliments your full system better or worse. Its relatively cheap to get.

 

[kmaier]

blatant plug for Hashimoto transformers

I've used both the H-203S and H-507S for 2A3 and 45 triodes respectively. With the right circuit and components these are excellent transformers. I also prefer their power and choke units, also excellent quality.

I did my own design and chassis layout from scratch and the results have measured up to my expectations. Components used included Caddock and Mills resistors, Axon capacitors, pure silver wire and NOS sockets and tubes. I posted some pictures on webshots for anyone interested.

The amplifier shown is for the H-507S with a 45 output. The 2A3 amps are entering build next. I also have their 20-watt H-20-3.5U outputs and matching power and choke units to be used with a set of WE300B tubes. Those are just now in design phase.

Regards, KM

 

[Ciscokid]

Sweet... Where did you get your iron?
Regards,
ck

 

[kmaier]

Thanks, all iron was purchased from http://www.tube-amps.net/Hashimoto_Products.htm. If you decide to purchase their power units ensure you are looking at the correct primary voltage. The 120 and 240V units cost more than the standard 100V versions. The power transformers are dead quiet however and very well shielded.

Regards, KM

 

[andyjevans]

Just reviving this to see if there are any more up-to-date experiences of Hishimoto SE OPTs. The H203S is good value - 7 watts. The H-20-3.5U is a bit more but not stupidly expensive - 20W. Both good for the usual suspects - 2a3, 300b, 45, PSE 4P1L.

 

[mark02131]

I have the phono step up transofrmers and think they are outstanding. If I could aford them I would use them in everything