Hooking up two Topaz Isolation trans. in series?

Rod,

I don't know about the question concerning running two in series. That will have to be answered by someone who knows more about it. But I'm using the Topaz myself (have had five different ones in my little AC journey) and they are fantastic, especially for the price/performance

Here's three other thoughts to ponder.

1. I was advised that the output rating of your transformer should be no less than 10x the power consumption of your components. So a component drawing 35 watts should have a minimum of a .35 Kva transformer. Components whose total output draw is 100 watts should have a minimum of a 1 Kva transformer. This is simply to allow more than adequate headroom, like an amplifier.

2. If you're using two transformers, if you hook your digital components into one, and then plug that transform into the other, it will keep any digital AC grunge from flowing back into the line to your preamp and amp. Of course this requires a bigger main transformer.

3. Using the same thinking as above in #2, have your digital components on one transformer into the wall and the preamp and amp on the second transformer into the wall.

Don't be afraid of going too high in power, I'm using a 5 Kva Topaz on a 15 amp circuit. As long as you don't overload the 15 or 20 amp circuit you're using, thinking that you have 40 amps, you should be fine.

Also remember that the lower the capacitance, the better. The .0005 pF is the best, then the .001 pF and then finally the .005 pF.

Chuck

Plugging 1 into another will not give you more current.
The only way to get "more" current is to use 1 transformer for 1/2 of the gaer and the other transfomer for the other 1/2 of the gear. If you have a hum problem, while using these isolation transformers, then it is due to some interaction between the gear plugged into the transformer and you would need to experiment to find out what is causing the problem. There have been many discussion about solving a hum problem, review them.

Thank you,
Chuck, thanks for telling me about the headroom issue. I will use the 1kva on the pre-amp instead of the amp. I will get a 2.5 kva for the amps.
Cford, I read on a post at audiogone were someone said they hooked two of these in series. I too was wondering about how the current would be increases by this as only so much current could go through the first topaz. But there is smarter people than I in the room when it comes to electronics. So I asked.
Also there are several pieces of gear that hum when not interconnected. It is a power problem in the house. I will get a electrician in here eventually. The topaz will help me isolate it and I can still use them after its solved.
Thanks, Rod

Thanks, Rod

You might consider running your entire system from one 5 KVA (or greater) isolation transformer so as to not bottom out your transformer. Check out my power filtration system in my system.

Cford, I read on a post at audiogone were someone said they hooked two of these in series. I too was wondering about how the current would be increases by this as only so much current could go through the first topaz.

Usually that is done for greater common mode noise rejection and not current handling. I bought six 1.5Kva Topaz transformers from a guy who used them all in series. I think each one has 146dB CM noise rejection and he wired them in balanced mode to up that to 220dB(if I remember correctly).

When sizing an isolation transformer, it is important to know the peak power (worst case) of all componants which will be attached and then multiply that by 2-3 times. Source componants such as a CD player vary very little with music levels, however, your amp may have an instantaneous peak power level of more than twice the level with no input.

While you can put selected componants on different isos, there is in general no advantage over using one properly sized for all. The one exception is you might consider putting the digital componants (i.e., CD) on a second smaller iso to keep them from contaminating the rest of the componants.

If you look at my system, you will see architecture and wiring diagrams of how I did this.

If I hook two topaz 1kva iso ultra transformers in series will I double the current capacity? I already have one 1kva topaz and am looking at another. Two of these at 16 amps would be enough for everything in my audio rack.
Roddey99

Roddey99,

To increase the amperage you would parallel the secondary windings of the two transformers together. Care must be taken to insure the two secondaries are in phase with one another. The proper polarity must be observed otherwise the two transformers will buck one another....

Also both transformers must be of the same VA and voltage rating. Best if both transformers are of the same manufacture and model number for secondary windings resistance matching.

In fact, with two transformers in series, you would get slightley less power (1-2%), due to the iron losses of the second transformer. There is no free lunch in Mother Nature.
You will get more isolation, but ALL transformers add slight distortions, so you may be trading isolation for unwanted AC harmonics.
I have measured increased 5th, 7th and 9th harmonic distortion of the AC waveform out of a Felicia DIY project (two isolation transformers in series, with filtering caps in-between).
Google Felicia...I read all the gushing comments and wasted U$ 200 on two custom 500W iso transformers. I heard distortion in the treble, it was confirmed by borrowing a friend's AC harmonic distortion analyser.
Bummer...my Cd player sounds much better connected directly to the wall receptacle.

In order to implement iso transformers correctly and get rid of ground loop issues, I suggest that you read the following paper:
http://www.exactpower.com/assets/pdfs/theTRUTH.pdf

Good luck

I found separate iso transformers gave best results-clearly audible. Amps should be isolated as they create significant noise, digital is obvious, and of course you want to isolate the very sensitive preamp from ac noise.

KVA rating is the peak voltage x peak amp x 1000 rating for the transformer or the peak wattage rating. RMS (root mean square)is wattage rating which is 0.707 of peak voltage. All engineers will size for actual plus fudge factor. Normal fudge factor is 40% above max expected for safety/performance margin. Large margin increases cost and may not protect against certain failures of down stream units.

To get more iso watts add more transformers and move loads to each separate transformer. The sum of the transformers will add watts without connecting secondaries and offer superior performance and safety. Loads will be isolated from line issues as well as each other.