• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Best SE output transformer for 300B - shootout

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beto1

beto1

Member
Joined 2014
Egindin said:
Why look for exotic, expensive irons when we have top quality, reasonably priced, manufacturer right here in the US?
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I'm not living in the USA, like many in this forum. For me is the same expensive shipping, taxes, etc if I get something in the USA or in Europe, so I can look for the best quality/cost ratio wherever.

andyjevans said:
Who is "we" on an international forum?
Importing to the UK incurs significant shipping and also import duty and handling tax. It doesn't end up as reasonably priced compared with buying Lundahl here in Europe.
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The same here.
Any thoughts on the opt list?
Regards
 
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Celsius

Celsius

Member
Joined 2011
kmtang said:
I bought a pair of Lundahl LL1688 70mA SE OPT which was designed for use with the 845 tube recently. I could not wait and put them in my 300B mono. At first, I configured it with 5K to 8 ohm. It sounds quite nice and not quite right to me. I then re-configured it to 2.5K to 8 ohm. Wowh.... it sounds so wonderful with thunderous bass, deep thick mids, and crispy highs. The primary impedance is measured at about 70H and it is double the size/weight of the LL1623 I used to have. The high frequency isn't too good as LL1623 but the -3dB point is beyond 30KHz which is reasonable to me.

Hearing is believing. The LL1688 is real surprise for me.

Johnny
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Is a very good question, what is the optimum primary impedance to 300b, on simulator y see that at bigger impedance give low distortion.
5k OPT 420v -88v 70mA 9.36w
give h2 =3.894 [%] h3 = 1.761 [%] h4 =0.203 [%] htot = 4.279 [%]

for 3k OPT in similar input values the distortion is four time bigger.
 
S

Schmitz77

Banned
Joined 2015
"TANGO(ISO) is going out of business in September.
They already stopped taking order.
Please do not send order or inquiry .
There will be a new company which succeed TANGO(ISO) business .
I hope I will be able to get order soon."

This is an old lineup of the now closed ISO-Tango company (successor to Hirata Tango)
Ask Koji from Eifl, he was always very helpfull in the past with orders. Never had any probs with Eifl.
For Lundahl, Aquablue Benny Glass is another trustworthy supplier. Ask Mr. Google.
 
andyjevans

andyjevans

Member
Joined 2003
artsandmedia.com
All you guys should know about NP Acoustics in Hanoi, Vietnam. Contact Phương Nguyễn <npacoustic@gmail.com>. See also https://www.facebook.com/npacoustic/

I have been using their 3.2K SE Amorphous Core OPT for a year or so and it is extremely detailed with good clear bass as well as the expected good treble. It's my OPT of choice over Lundahl LL1664 and a couple of O'Netics, which I'm also fond of in a different way (more than the Lundahls). I found the price very favourable for an amorphous core OPT and way under Lundahl prices. For me right now, not having heard Tango, Tamura, Hashimoto or Monolith in my system, it outclasses the usual mid price options. Perfect for a 300b SE amp, though I use it for PSE 4P1L. I think you guys might do well to investigate it.
 
merlin el mago

merlin el mago

Member
Joined 2009
Paid Member
NP Acoustic - NP Hi-End Audio

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Specs
– Chức năng

SE transformer OPT
– Đầu vào 3200 Ω; 45H/1kHz
– Trở kháng ra 8 Ω; 16Ω
– Dải thông 10 Hz đến 80kHz (± 1.5dB)
– Dòng điện 150mA
– Test cách điện 1000VDC
– Công suất 18W
– Kích thước (cm) 11x10x10
– Trọng lượng 2,8kg
 
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