[Theo]

Hey Jim,

The Oct issue of Stereophile says step up transformers are hot.  Will you be designing a step up transformer for the MM stage in the PL-10?   

[hagtech]

I was aiming towards the Lundahl 1681 (or some number like that).  Not the 9206.  Or perhaps the Jensen JTX-44.  Or the Sowter.  Curious about that Tamura now!  I am looking for that organic, musical sound. 

Hadn't really thought of winding my own.  But I suppose I could.  Maybe for mark 2.  I don't want to bite off more than I can chew right now.  That's the whole reason I abandoned the RGP for the PL-10.  Have to get my R&D costs down to something reasonable.  Streamline the process between now and product launch. 

On the other hand, it's nice that I leave one of the phono inputs as MM only.  That way you can choose your own external step-up!

jh

[Steve Eddy]

I was aiming towards the Lundahl 1681 (or some number like that).  Not the 9206.  Or perhaps the Jensen JTX-44.  Or the Sowter.  Curious about that Tamura now!  I am looking for that organic, musical sound.

Then you should also give a look at the CineMag CMQEE-3440A.

se

[hagtech]

Looks good, maybe I'll pick one up a pair for a try.  Was hoping for multiple secondaries.  Thinking it is better to run the secondaries through relays instead of the primaries.  But I could be wrong about that.

jh

[anumber1]

2nd the CineMag CMQEE-3440 (http://cinemag.biz/mic_input/mic_input.html).

[Steve Eddy]

Looks good, maybe I'll pick one up a pair for a try.  Was hoping for multiple secondaries.  Thinking it is better to run the secondaries through relays instead of the primaries.  But I could be wrong about that.

Well, I guess if you're going to do anything which may have an effect on sound, it would be better to do it at a higher signal level rather than a lower one.

But there may be some tradeoffs tapping off the secondary versus the primary that could be worse in the end.

Give Tom a call and talk it over with him.

se

[hagtech]

it would be better to do it at a higher signal level rather than a lower one

But do we prefer to switch the higher voltage or the higher current?  That's what I am researching right now.  So far I have been led to the hermetically sealed gas-filled telecom relays.  They were designed for this type of application.  Also looked at reed relays.  The advantage of a relay over a switch is the gas tight seal, plus you can bounce the contacts on each power up sequence, keeping them clean.  Must be very careful regarding dissimilar metals and photoelectric and chemical processes at these signal levels.

My paper design (at the moment) has cartridge loading on the secondary, prior to the relay.  So signal switched by relay is the higher voltage and carries very little current, being independent of cartridge loading.

jh

[ecir38]

I guess something like this would be included in your new line up as an accessory maybe. Your blog gives us and idea for when some of the 10 series will be out. Can you give us an idea when something like this would be available?

[hagtech]

The plan is to have the step-ups built into the PL-10 preamp.  Due out for RMAF08.  The preamp will have two phono inputs, one MC and one MM.  So you can choose to use your own external step-up if preferred.

jh

[tubesforever]

I have ordered some CineMag step up transformers to evaluate.  I would like to have a three pole switch so I can select the low or high gain settings. 

Do you think this will fly given your experience with SUT's or do you expect ground loop issues from this arrangement?

[Steve Eddy]

Do you think this will fly given your experience with SUT's or do you expect ground loop issues from this arrangement?

No ground loop issues. The trannie's being driven straight from the cartridge. You'd no more have a ground loop issue with that arrangement than your amplifier would have a ground loop issue with your loudspeakers.

se