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10/22/21 at 14:44:07 


       


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Can Mini Torii be used as preamp? (Read 416 times)
drumrev
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Posts: 3
Can Mini Torii be used as preamp?
07/08/21 at 01:30:56
 
Hello -- new owner of used Mini Torii. I'm a tube newbie, sure to be asking naive questions. I see that Steve describes using the Mini Torii in biamping applications via the RCA outputs.

Can the Mini Torii be used safely as a standalone preamp? I think the answer is no, but would like to confirm.

Thanks!
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Geno
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Without music, life
would be a mistake.
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Posts: 1415
Re: Can Mini Torii be used as preamp?
Reply #1 - 07/08/21 at 16:24:05
 
Hi drum,

Here are features of the Mini Torii listed straight from the website:

6V6 single-ended design giving around 5 watts
Point-to-Point wiring with no circuit boards
Tube rectification for each channel using 6CA4/EZ90
Output-stage regulation using OA3's
Input-stage regulation using OC2's
Dual volume controls
8.5 inches x 11 inches x 5 inches
Requires NO preamp
Input for 2 sources
Variable Line Level Output jacks
Treble adjustment with bypass
Adjustable feedback to control presence
Our Proprietary UFO wide-band output transformers
Easy to move around
High-mass, powder-coated steel chassis
Solid hardwood base with wood options
Enhanced tube life
Self-biasing - nothing to set or adjust
LO and HI impedance speaker switch
Cryo-treated Beeswax caps
Highest-grade internals
Output tube compatibility facilitates custom voicing
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SE84UFO and Spud Kit (Balanced monoblks) OR Sansui AU-222 OR Sansui AU-555A OR Sansui 800 OR Pioneer SX-626
Cambr. Aud. CXN (ModWright) • Cambr. Aud. CXC • ZBIT
Technics SL-1210MK5 (KAB Mods) w/ Concorde 40 cart
Otari MX5050
ZLC
Lii Cryst 10 • Lii W-15
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chapsjon
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Posts: 51
Re: Can Mini Torii be used as preamp?
Reply #2 - 07/09/21 at 19:27:19
 
I have not used mine solely as a preamplifier but as I understand it, the variable output jacks are essentially preamp out jacks. Documentation states that these jacks are post output transformers and allow the mini torii to be used with a power amp to bi-amp where the mt is used to drive the tweeter and power amp is driven via variable output to transit same tone to woofers, essentially acting as a preamp and amp at the same time.
I have used mine exclusively as a headphones amp on occasion with speakers disconnected with no problems, which means it should also work as a preamp with no problems. Since I haven’t actually tried this, I would do so with great caution and attention to quickly turn things off if things went wrong. Ultimately, you may want to call Steve to verify, or go the bi-amp route since Steve singles this out as a feature in documentation. I am referring to either white poet or manual. I will check and let you know which one discusses this feature.
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chapsjon
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Posts: 51
Re: Can Mini Torii be used as preamp?
Reply #3 - 07/09/21 at 19:34:06
 
Here’s the info I referred to from the white paper on mt development:

UNIQUE PREAMP OUTPUT FOR BIAMPING

Because we could, we added a preamp output that is actually driven off the output transformers.  That makes it a low impedance output that is some 20 times lower than most preamps so it is absolutely guaranteed to drive even the most difficult amplifiers and do so with a correct frequency balance / translating to good weight and dynamics.

This would be ideal for a sub woofer or a pair of stereo subwoofers, but the exciting application of such an approach is applied to speakers such as open baffles. Those with more than one driver would normally be bi-amped.  Biamping always has mixed results because the differences in the two amplifiers used and the preamps ability to control both amps equally.

With our approach you can use the Mini Torii SE as your preamp and use it to drive a second amp.  This way the second amp closely follows the signature of the Mini Torii and will respond to adjustments in the volume and treble settings of the Mini Torii.  

To ensure that the signature of the second amp is as close to the first as possible, the even order harmonic signature of the Mini-Torii is embedded into the output signal.  This will not only make subwoofers disappear more easily, but anyone with an open baffle or similar high efficiency full range speaker that uses two drivers is certain to have better results when the signature of both amps are matched.  This means the second amp can be either tube or solid state.
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drumrev
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Re: Can Mini Torii be used as preamp?
Reply #4 - 07/09/21 at 22:53:42
 
Thanks for the replies and great information. I think your idea of checking with Steve is the safest way to proceed. Does anyone know the best method to ask Steve a question?
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Geno
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Without music, life
would be a mistake.
Nietzsche

Posts: 1415
Re: Can Mini Torii be used as preamp?
Reply #5 - 07/10/21 at 00:52:08
 
Give them a call. Don’t try to email.
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SE84UFO and Spud Kit (Balanced monoblks) OR Sansui AU-222 OR Sansui AU-555A OR Sansui 800 OR Pioneer SX-626
Cambr. Aud. CXN (ModWright) • Cambr. Aud. CXC • ZBIT
Technics SL-1210MK5 (KAB Mods) w/ Concorde 40 cart
Otari MX5050
ZLC
Lii Cryst 10 • Lii W-15
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drumrev
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Posts: 3
Re: Can Mini Torii be used as preamp?
Reply #6 - 07/16/21 at 21:43:37
 
Thanks again to forum members who replied. I heard back from Steve. The take-home message is that the Mini Torii is not set up out of the box to be used as a preamp. Here's the answer that Steve sent in an email:

"Hi Ross,

Those outputs are intended to be used to drive a sub or a second amplifier in a bi-amp scenario.  To use them as a preamp, you would need to short the speaker terminals together with an 8 ohm r resistor.

Steve : )"
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joralieu
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Posts: 28
Re: Can Mini Torii be used as preamp?
Reply #7 - 07/16/21 at 22:28:47
 
Mmm, I have a Mini Torri. I wonder if it is a good enough pre amp to put in front of my newly received SEUFO25?
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