Need advice for transformer for tube GM 70.

[goodspeaker]

Need advice for transformer for tube GM 70.

Hi
Want to make SE tube amplifier based of GM70 Russian tube like this one http://www.dehavillandhifi.com/GM70_2003.htm
Hope for your advice for transformer.
Not decided yet monoblok to made or three amplifier in one case.(Three because it is for front speaker of home theater)
Need really good quality transformers for best possible sound.
Need
output transformer. The same as for 845, 211 tube.
power transformer V=850-900v, I=150mA(if monobloc) or 0.5A (if or three amplifier in one case) .
Chokes L=10H, I=150-200mA.

I fond all these transformers in Hammond brand
output transformer -1638SEA http://www.hammondmfg.com/1627.htm
power transformer - 726 http://www.hammondmfg.com/700.htm
Chokes - 193J http://www.hammondmfg.com/193.htm

but I look the web , it seems that Hammond not best brand in tube transformer.
See Hashimoto Electric looks much better but it do not make output and power transformer I need.

Need your good advice is those Hammond are worth to buy?
Or you can suggest me other brand?
I prefer European brands because of delivery cost.

[the_manta]

Hi !
Well Hammond....
Let's put it this way: There better transformers out there.
They are heavy and give a good bass, but mine lacked in the high frequency range.

Long ago I made a list of output-transformer dealers. Meanwhile others added lots of pages and dealers.
Look here

Regards, simon

[316a]

Originally posted by goodspeaker
Need advice for transformer for tube GM 70.
Need your good advice is those Hammond are worth to buy?
Or you can suggest me other brand?
I prefer European brands because of delivery cost.

No idea about Hammond , Sowter of the UK provide excellent transformers and service from experience . You may need to implement DC filaments on these valves , I could not get the hum down to acceptable limits using AC .


cheers

316a

[goodspeaker]

I sow Sowter web
seems TYPE SA11 is suitable for my purpose
price £180.42 =360Usd + delivery

And I see http://www.thlaudio.com/indexE.htm
James transformer 6159HS cost 400USD with delivery


price of both the same.
Which is better????

James looks more beautiful with Encapsulated Package.
Sowter has option of Encapsulated Package but the cost is £80 more.

[Tweeker]

Oof, I have no idea, but at those prices Id be looking at using copper plate GM70s over graphite. OPT choice may be a matter of taste and/or operating point, speakers in question etc, rather than 'better'.

You will likely need DC filaments if speaker efficiency isnt poor. I would recommend a choke input supply here.

If allowed I would probably separate the amplifier into a power block and an amp block. This will ease chassis layout with regard to magnetic interference issues, not to mention a monoblock will be a back breaker.