Tube Power Amp Reviews

Thöress 300B monoblock power amplifier Specifications

Sidebar 1: Specifications

Description: Monophonic single-ended-triode tubed power amplifier. Tube complement: one 300B, two EL803S. Input: 1 line-level. Maximum output power: 8Wpc into 16 ohms (12dBW ref. 1W into 8 ohms). Input impedance: 100k ohms. Input sensitivity: 3.25V RMS. Output impedance: transformer matched to 4, 8, 16 ohms (see text).
Dimensions: 13.4" (343mm) H (including tubes) by 5.9" (152.5mm) W by 23.3" (597mm) D (including output terminals). Weight: 28 lbs (12.7kg).
Serial numbers of units reviewed: None found.
Price: $12,995/pair. Approximate number of dealers: 6.
Manufacturer: Reinhard Thöress, Martinstrasse 17, 52062 Aachen, Germany. Tel./Fax: +49 (0)241-4091368. Web: www.thoeress.com. US distributor: Audioarts, Inc., 210 Fifth Avenue, Suite 301, New York, NY 10010. Tel: (212) 260-2939. Web: www.audioarts.co.

COMPANY INFO
Reinhard Thöress
US distributor: Audioarts, Inc.
210 Fifth Avenue, Suite 301
New York, NY 10010
(212) 260-2939
www.thoeress.com
ARTICLE CONTENTS

COMMENTS
manisandher's picture
Submitted by manisandher on April 18, 2017 - 12:46pm

I've just received my Thöress 300B monos, set up by Reinhard to work with Elrog 300B output tubes. Feeding my Tune Audio Anima horn speakers (109dB/W@1m), I have to say I have the most satisfying sound I've ever managed to achieve in this hobby. I concur with Art's description of the sound, though the Elrog tubes are substantially better than the regular Full Music tubes.

Reinhard took a frequency response measurement of the amps before shipping them out to me. The measurement was taken on the PRIMARY side of the OPT, with a 5 Ohm wire wound resistor as dummy load across the secondary. (He believes this is the best way to take the measurement as the OPT secondaries do not carry a ground potential.)

The amps measure -3dB at 7.5Hz and 150kHz. Also, there is virtually no OPT resonance above 150kHz. Pretty good for a SE amp with zero feedback! And as I said, they sound utterly fantastic.

Mani.

directdriver's picture
Submitted by directdriver on May 9, 2023 - 3:50am

What is the point of measuring the amp at the transformer's primary when your speaker is connected to the secondary? You're bypassing the output transformer to get better results. That's cheating!

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