Bottlehead Forum

Bottlehead Kits => Kaiju Stereo 300B amp => Topic started by: vince on July 19, 2020, 11:59:05 AM

Title: Transformer data sheets, please
Post by: vince on July 19, 2020, 11:59:05 AM
Hello;

I would like to model the Kauju amplifier in LTSpice.  To this end, I would like the data sheets for the inductors and transformers used, especially PC-5 and OT-5.  PT-9 is nice to have, but not required.

May I have a copy of the data sheets, or the manufacturer(s) and part numbers of the magnetics?

Thank you

Vince
Title: Re: Transformer data sheets, please
Post by: Paul Birkeland on July 19, 2020, 12:18:51 PM
Hmm, what would you like beyond the specifications listed in the Kaiju manual? 

Title: Re: Transformer data sheets, please
Post by: Paul Joppa on July 19, 2020, 01:47:34 PM
To be clear, there are no data sheets. They are in-house proprietary designs, not available outside of our products. That said, we have made a few measurements to confirm that their performance is adequate to our needs - possibly enough to make up a model. So, as PB said, what information do you need?
Title: Re: Transformer data sheets, please
Post by: vince on July 20, 2020, 09:54:18 AM
Thanks for the speedy responses. 

If these are custom made, there may be an ERS (Engineering Requirements Specification), or similar, that informed the vendor about what to build.  Barring that...

The individual windings identified (e.g., transformer has three windings, around a common core)
Number of turns, each winding
Inductances and DR resistances for each winding (L, in henries and R in ohms)
Leakage inductance
The magnetic coupling between windings (K in unit-less fraction where 1 is perfect coupling and 0 is no coupling at all).
Parasitic capacitances (in farads) 
Core type identified (e.g. E-I or toroidal).

Image, attached.

Thank you

Vince


Title: Re: Transformer data sheets, please
Post by: Paul Birkeland on July 20, 2020, 10:24:09 AM
With a zero feedback circuit, that level of information is overkill for a Spice simulation.  Some of what you're asking for is similarly completely irrelevant to creating a circuit simulation.  Beyond that, a fair amount of what you're asking for is available in the manual for the Kaiju as well. 
Title: Re: Transformer data sheets, please
Post by: vince on July 20, 2020, 10:54:28 AM
It may be overkill, I do not know.  I am trying to learn the craft.  Sometimes this results in mistakes.  Removing a parasitic part from a simulation is as easy as typing "* ". 

Perhaps would would be so kind as to show me where, in the manual, the references are.  Searching for the strings, "OT-5" and "PC-5"  I find no values in henries or farads.  The ohm values are related to speaker impedance.  Am I missing something?
Title: Re: Transformer data sheets, please
Post by: Paul Birkeland on July 20, 2020, 11:10:11 AM
The schematic tells you the inductance of the PC-5.  The voltage checks at the end are enough to get the DCR of the PC-5 as well.  The inductance of the primary of the OT-5 can be measured reasonably easily since you do not need to apply a DC current to get reliable results.  You'd need a reasonably potent signal generator, a DVM, and a 100K pot.

PJ may have an estimate of leakage inductance and interwinding capacitance to use for your model.
Title: Re: Transformer data sheets, please
Post by: Doc B. on July 21, 2020, 07:55:08 AM
Hi Vince, the guys tell me they have some of the data you have requested but not all. I'm happy to share what they have so you can model it. However I'm not inclined to do so on the forum where others besides paying customers might also acquire data that is our IP. I have asked the guys to send me what they have that they feel is pertinent and I will email it to you. 
Title: Re: Transformer data sheets, please
Post by: vince on July 24, 2020, 11:43:50 AM
Thank you!  Message received.