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April 22, 2021, 07:39:24 PM

Author Topic: New Eros and a question about loading  (Read 144 times)

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Offline Larpy

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New Eros and a question about loading
« on: March 22, 2021, 08:51:36 AM »
My Eros kit arrived in December and I finished building it in January, but the Sowter SUTs I ordered back in October just showed up last week.  I still listened to the Eros and it sounded loud enough that I experimented with cap replacement, but now the Eros is officially complete.

Sounds fantastic.  Warm, rich, vivid, engaging.  Tubey in all the right ways.  Quiet.

But I have a question about loading.  Right now I'm using the kit-supplied 47K Ω resistors to load the SUTs' secondary using the 1:10 taps.  As I understand the math (reflected load is the loading resistor value times the ratio squared), I am loading my Dynavecter cart at 4.7K Ω.  Dynavector recommends 60 Ω.  (The cart puts out .28mV at 6 Ω.)

Is it worth my time to get some 6K Ω resistors to hear the cart loaded per Dynavector's recommendation?  The reason I ask is because, on another Eros thread, Paul B claimed that the stock 47K Ω resistor will work in 99.5% of all cases.  That suggests that precise loading is not an issue.

I have to say, my Eros sounds great to me loaded as is, but would it sound even better loaded differently?  I realize "better" is a subjective term, so I guess what I mean is would the cartridge be loaded "more appropriately."
Larry

Offline Paul Joppa

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Re: New Eros and a question about loading
« Reply #1 on: March 22, 2021, 09:28:15 AM »
It's an easy and cheap experiment - give it a try, and trust your ears!

You might also want to try load the transformer input rather than the output.
Paul Joppa

Offline Paul Birkeland

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Re: New Eros and a question about loading
« Reply #2 on: March 22, 2021, 10:03:29 AM »
I agree with PJ, give it a shot!  For your situation I would tend to suggest going with the 1:20 ratio if you got the selectable ones which will step down that 47K load to ~120 ohms. This would also bring your output up to 5mV which is helpful also.
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline Larpy

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Re: New Eros and a question about loading
« Reply #3 on: March 22, 2021, 11:13:05 AM »
You might also want to try load the transformer input rather than the output.

Does the same formula (load resistor times ratio squared) apply to loading the primary?
Larry

Offline Paul Birkeland

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Re: New Eros and a question about loading
« Reply #4 on: March 22, 2021, 01:07:10 PM »
No, the primary side is where the cartridge attaches.  You can completely remove the 47K resistors (the secondary of the SUT will provide the grid to ground resistance for the EF86s), then just install the desired load on the primary side.
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline Karl5150

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Re: New Eros and a question about loading
« Reply #5 on: March 29, 2021, 03:04:41 AM »
Clean build, inside and out. The base finish really works with the plate and transformer bell color.
Karl
Karl
Downstairs: Planar3>Eros>Stereomour II>diy OB Betsy+
Upstairs: DIY RP1>Reduction / CD5004>Seductor/SEX 3.1.1>FH3/DT770 pro/HE-4xx
Office: Schiit Modi Uber 2 / Sirius Tuner>SEX 2.1.1>µFonken FF85WK with diy subs
Garage: CA x12 streamer>Quicksand>Minimus 77