Transformer choice

Next month I will order the HIFIDIY NOS TDA1541 tube kit.
http://us.hifidiy.net/Article.asp?ArticleId=184

I am in the processe to choose my transformer..

I saw this manufacturer (really good price) Antek.
http://www.toroid-transformer.com/

Do you think it's a good choice for this project?

For the tube section I choose this one
http://www.toroid-transformer.com/AN-1T150.pdf

And Those for the other
http://www.toroid-transformer.com/AN-0512.pdf
http://www.toroid-transformer.com/AN-0506.pdf

Thanks for the help, it's my first big project..
 

kevinkr

Administrator
Paid Member
You need to give people a bit of time to reply. Immature comments like the one you posted tend to demotivate people. It would have helped to post some links to technical details and to list the required voltages and currents. The less work people have to do the more likely you are to get an initial response.

Another issue with certain vendors is that they sell boards based on designs of others that they have not taken the trouble to license, and hence many here will not answer any question relating to such a product.

I'll assume you thought about buying this board in total ignorance of the above possible issue, and before you actually do buy it were I you I would check to be sure that such is not the case.

I am not sure the digital thread is the right place to ask about power transformers for a tube based dac. A moderator might have a better take on this than me.

I would say the high voltage transformer you chose is massive overkill, I'd look for something in the 25 - 50VA range. I think you need to rethink the other transformer choices as well.

If the kit is legit, and you do buy it I would recommend buying the transformers that the seller offers for it. They will be r-core types and will have the right secondary voltages and currents for the application.
 

kevinkr

Administrator
Paid Member
I'm going to build a dac using the Twisted Pear spdif module and a pair of COD pcb which will be built as mono dacs and a single IVY pcb.. The plan is to l sum the output currents into a single stereo IVY. I've ordered them and hope to have them by the end of the month.

I've got a pair of PCM1798, but am wrestling with whether I will go with the much better specified PCM1794 instead. (I seriously doubt most systems have enough dynamic range to justify this chip at 3X the cost of the '98, but I am looking for other potential reasons.)

You could use a pair of Cinemag/ Llundahl/Sowter transformers for I/V conversion and a simple tube buffer with the COD dac board. The buffer would be cathode follower with a ccs load on it using something like a single 5687 or 6DJ8. I might do this eventually, but for now I elected to go with the IVY because the meager budget really doesn't allow for the cost of those transformers.

I'm getting a heavy aluminum slab based chassis fabbed by a machine shop owned by a friend. Front panels will be from Front Panel Express.
 

kevinkr

Administrator
Paid Member
The COD has current outputs and therefore is not limited by whatever performance limitations are present in the internal op-amps of a voltage out dac. Obviously this is not the entire story but for maximum performance you want to be able to choose how to handle the recovered audio, and voltage output dacs give you less options in return for the possibility of a simpler implementation. Note that there are some good voltage output dacs and the Wolfson definitely falls into that category.
 
I'm also going to try the COD, I placed on order for a module. I plan to mate it with a tent clock and first lundahls then active like rakk.


faxurda said:
Thanks.

I really like the OPUS... :)

I whanted a tube output do you have a kit or a schematics I can setup with the OPUS.

Thanks

Take a look at the close out section of k and k audio. There are some cheap tube output kits/pcb's that will suit the 1794. They are close-out '07 but you never know.

Jeroen