Dyna ST70 PWR Tranny 6.3V Crnt Spec?

kegger · 8th July 2008, 05:22 AM

Anybody seen/know what the 6.3v windings on the Dyna 70's current ratings are by chance. (original)

I mean we obviously have 3a for both EL34, then .45a for a 7199 plus the pre socket out front on each side.

So what 4a, 4.5a?

DigitalJunkie · 8th July 2008, 05:41 AM

The manual says that it can supply up to 1A at 6.3V to each preamp socket. So that's ~4.45A per channel.

kegger · 8th July 2008, 05:53 AM

Thank you kind Sir!

As I'm looking to use 4.2a per side on the 6.3v windings and not use the 5v winding at all.

I was hoping my plan has a chance to work and sounds as if it just may.

DigitalJunkie · 8th July 2008, 05:55 AM

Yea,That should work nicely.

danFrank · 8th July 2008, 06:09 AM

Original Dynaco said that it could provide the extra 1 amp per winding but this was an exaggeration. Current through the outputs was also exaggerated in their specs, realistic numbers are 40ma per EL34.
A realistic value for each 6.3volt winding is 3-3.5 amps tops.
Daniel

Edit: I just saw that you won't be using the 5 volt winding, so this will give you some extra elsewhere in the transformer. Try your circuit out and see how hot the transformer gets. If it's too hot to put your hand on it, I would ease off a little. You can always put a small filament transformer under the chasis.

kegger · 8th July 2008, 06:14 AM

Humm, in stock form with nothing plugged into the front your running 3.45ma all the time.

I know the power tranny's in 70's run hot but I've still yet to see a dead one. (yet that is)

Was hoping that not running anything off the 5v winding may help some as well. (yah you saw it)

We'll see how it goes.

Thanks,
keg

MQracing · 8th July 2008, 06:22 PM

Hi Kegger:

From the orig factory blueprints each of the two separate 6.3vct windings are rated at 4 Arms.

MSL

8th July 2008, 05:22 AM	#1
kegger diyAudio Member Join Date: May 2004 Location: michigan	Dyna ST70 PWR Tranny 6.3V Crnt Spec? Anybody seen/know what the 6.3v windings on the Dyna 70's current ratings are by chance. (original) I mean we obviously have 3a for both EL34, then .45a for a 7199 plus the pre socket out front on each side. So what 4a, 4.5a?

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Dyna PAM preamp	Mark Korda	Swap Meet	0	4th August 2009 11:33 PM
FS: Dyna PAT-4 Preamp	al2002	Swap Meet	1	8th January 2009 05:00 PM
Dyna Pas 3X?	Thatch_Ear	Tubes / Valves	17	16th January 2008 06:10 PM
Dyna ST70 experience bypassing input tubes	tubesmuggler	Tubes / Valves	12	20th August 2006 05:54 AM
DIY Dyna MK 2's and using bottlehead C4S	freddymac406	Tubes / Valves	7	18th April 2005 11:45 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read

8th July 2008, 05:41 AM	#2
DigitalJunkie diyAudio Member Join Date: Apr 2003 Location: Portland,Oregon Blog Entries: 4	The manual says that it can supply up to 1A at 6.3V to each preamp socket. So that's ~4.45A per channel.

8th July 2008, 05:53 AM	#3
kegger diyAudio Member Join Date: May 2004 Location: michigan	Thank you kind Sir! As I'm looking to use 4.2a per side on the 6.3v windings and not use the 5v winding at all. I was hoping my plan has a chance to work and sounds as if it just may.

8th July 2008, 05:55 AM	#4
DigitalJunkie diyAudio Member Join Date: Apr 2003 Location: Portland,Oregon Blog Entries: 4	Yea,That should work nicely.

8th July 2008, 06:09 AM	#5
danFrank diyAudio Member Join Date: May 2005 Location: California	Original Dynaco said that it could provide the extra 1 amp per winding but this was an exaggeration. Current through the outputs was also exaggerated in their specs, realistic numbers are 40ma per EL34. A realistic value for each 6.3volt winding is 3-3.5 amps tops. Daniel Edit: I just saw that you won't be using the 5 volt winding, so this will give you some extra elsewhere in the transformer. Try your circuit out and see how hot the transformer gets. If it's too hot to put your hand on it, I would ease off a little. You can always put a small filament transformer under the chasis.

8th July 2008, 06:14 AM	#6
kegger diyAudio Member Join Date: May 2004 Location: michigan	Humm, in stock form with nothing plugged into the front your running 3.45ma all the time. I know the power tranny's in 70's run hot but I've still yet to see a dead one. (yet that is) Was hoping that not running anything off the 5v winding may help some as well. (yah you saw it) We'll see how it goes. Thanks, keg

8th July 2008, 06:22 PM	#7
MQracing diyAudio Member Join Date: Oct 2005	Hi Kegger: From the orig factory blueprints each of the two separate 6.3vct windings are rated at 4 Arms. MSL

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)