R-Core Transformer Group Buy Interest?

Geek · 1st February 2010, 03:16 AM

Hi Folks,

I have the chance to import some R-core transformers (Japanese made cores/bobbins) for projects, in the 12VA range (SS, tube preamp filaments, etc.).

I got a sample of a dual 30V, 250mA ICAS (200mA CCS) (each) secondary for a BoZ project:

(click for larger)

Dimensions are 72mm L x 61mm W x 36mm H and weigh 400g each (shipping weight would be 500g for packing+box weight).

The manufacturer was thinking of starting with either dual 30V, 24V, 18V and 12V secondaries (I'm sure I could talk him into dual 6.3V for us tube guys

).

Primary is dual 120V windings and 50/60Hz, so it could be used anywhere. Electrostatic shield drain wire for grounding is supplied.

Pricing would be $25/ea. and I'd get them 4 at a time, so any large orders may take a while.

Any interest? What voltages should I have built?

Cheers!

Jeffrey Davison · 1st February 2010, 06:32 AM

The dual 30 would be of interest to me, maybe just a tad higher. I need to build a bias supply for an amp I'm builing that needs around 70 volts. If I but the dual secondaries in series, there should be adequate voltage to rectify and filter to get the required voltage.

Thanks

JD

Geek · 1st February 2010, 08:58 AM

Hi,

If the bias supply doesn't need to supply any current to the grid, 60V should get you about 75-78V with the losses and trimpot loading, if not too heavy.

Cheers!

Jeffrey Davison · 1st February 2010, 02:58 PM

precisely

JD

Quote:

Originally Posted by Geek

Hi,

If the bias supply doesn't need to supply any current to the grid, 60V should get you about 75-78V with the losses and trimpot loading, if not too heavy.

Cheers!

Tea-Bag · 1st February 2010, 04:05 PM

these seem like good voltage ranges, but 12va seems like not too much current, even for a preamp.

Peter Menting · 1st February 2010, 04:58 PM

Would like to see dual 15v@say 50va for preamp and Dual 25v@250 for Gainclone.
Pete

Geek · 1st February 2010, 08:31 PM

Quote:

Originally Posted by Tea-Bag

these seem like good voltage ranges, but 12va seems like not too much current, even for a preamp.

I dunno, MooseFET and BoZ use within this amount as does this Hafler I have in for upgrade, they are the only SS preamps I'm familiar with in recent years.

The PAS3 uses about the same VA if you use SS rectification and lose that 12X4.

But other than the BoZ, I doubt the VA would be a "Pass crowd pleaser"

Quote:

Would like to see dual 15v@say 50va for preamp and Dual 25v@250 for Gainclone.

Hi Pete,

Larger sizes may be in the cards if this one is sucessful. Start small....

Thanks all for your input!

Cheers!

h_a · 3rd February 2010, 02:36 PM

Are these made by Shilchar/India? Look absolutely identical!

Have fun, Hannes

Geek · 4th February 2010, 02:43 AM

An associate gets them. I'm not sure

Cheers!

jtktam · 4th February 2010, 11:52 AM

I would be down for a few

-joe

1st February 2010, 03:16 AM	#1
Geek diyAudio Member Join Date: Sep 2004	R-Core Transformer Group Buy Interest? Hi Folks, I have the chance to import some R-core transformers (Japanese made cores/bobbins) for projects, in the 12VA range (SS, tube preamp filaments, etc.). I got a sample of a dual 30V, 250mA ICAS (200mA CCS) (each) secondary for a BoZ project: (click for larger) Dimensions are 72mm L x 61mm W x 36mm H and weigh 400g each (shipping weight would be 500g for packing+box weight). The manufacturer was thinking of starting with either dual 30V, 24V, 18V and 12V secondaries (I'm sure I could talk him into dual 6.3V for us tube guys ). Primary is dual 120V windings and 50/60Hz, so it could be used anywhere. Electrostatic shield drain wire for grounding is supplied. Pricing would be $25/ea. and I'd get them 4 at a time, so any large orders may take a while. Any interest? What voltages should I have built? Cheers!

1st February 2010, 04:05 PM	#5
Tea-Bag not politcally affiliated diyAudio Member Join Date: Feb 2006 Location: Kennebunk Blog Entries: 5	these seem like good voltage ranges, but 12va seems like not too much current, even for a preamp. __________________ DCB1/BiB Sign up Sheet Round #2 2012 CLICK HERE\|SSHV2 Shipping\| F5TConvertible Circuit Board Sign Up Sheet (Shipping)CLICK HERE\|Semisouth R100A/R085 available PM

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1st February 2010, 06:32 AM	#2
Jeffrey Davison diyAudio Member Join Date: Sep 2006	The dual 30 would be of interest to me, maybe just a tad higher. I need to build a bias supply for an amp I'm builing that needs around 70 volts. If I but the dual secondaries in series, there should be adequate voltage to rectify and filter to get the required voltage. Thanks JD

1st February 2010, 08:58 AM	#3
Geek diyAudio Member Join Date: Sep 2004	Hi, If the bias supply doesn't need to supply any current to the grid, 60V should get you about 75-78V with the losses and trimpot loading, if not too heavy. Cheers!

1st February 2010, 04:58 PM	#6
Peter Menting diyAudio Member Join Date: Jul 2003 Location: Blackstone VA	Would like to see dual 15v@say 50va for preamp and Dual 25v@250 for Gainclone. Pete

3rd February 2010, 02:36 PM	#8
h_a diyAudio Member Join Date: Sep 2006 Location: Graz, Austria	Are these made by Shilchar/India? Look absolutely identical! Have fun, Hannes

4th February 2010, 02:43 AM	#9
Geek diyAudio Member Join Date: Sep 2004	An associate gets them. I'm not sure Cheers!

4th February 2010, 11:52 AM	#10
jtktam diyAudio Member Join Date: Apr 2009 Location: Toronto, Ontario, Canada Blog Entries: 17	I would be down for a few -joe

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