I used Lundahl's 1620 and 1620AM for the 45 SE tube amps. The OPT's were ordered with idle current of 30mA. The primary inductance is approx 90 to 100H which is more than double of the Hammond 1628SE.
I measured the frequency response of the 45 amp with LL1620. It is rather surprised to me that it can go all the way to 20kHz and with a dip at approx 35KHz. Then it will come back up. The low frequency response is too good that it stays flat at 10Hz which is the limit of my signal generator.
The 10KHz square wave response looks really good without ringing.
With almost 100H primary inductance, surely you will get excellent bass that ROCKS...................
Tested drive with B&W801 speakers..... My friend said the music was so rich that has fresh, blood and bones.
I know that there are better OPT's out there such as Audio Note double C core and Tamura. However, their price is not affordable for me at this moment. I need to win some money from lottery.
Johnny
I measured the frequency response of the 45 amp with LL1620. It is rather surprised to me that it can go all the way to 20kHz and with a dip at approx 35KHz. Then it will come back up. The low frequency response is too good that it stays flat at 10Hz which is the limit of my signal generator.
The 10KHz square wave response looks really good without ringing.
With almost 100H primary inductance, surely you will get excellent bass that ROCKS...................
Tested drive with B&W801 speakers..... My friend said the music was so rich that has fresh, blood and bones.
I know that there are better OPT's out there such as Audio Note double C core and Tamura. However, their price is not affordable for me at this moment. I need to win some money from lottery.
Johnny
wicked1 said:
hey-Hey!!!,
There are some of us who believe that a PP core should have a small gap; not to allow DC, but to reduce remnance and linearize the permeability. I have not yet done this sort of experiment with power outputs, but for PP grid chokes, I have. Core material must be chosen to allow appropriate perm for a given number of turns for one.
Core choice is always a balancing act; perm, flux density, loss, size/MPL...can't say that any one is best, yes?
cheers,
Douglas
Have you guys seen that comparison of OPTs on silk's page? Thats a good idea, but some of the data seems questionable. Primary L numbers are strange in some cases. james 6123 should have ~20H at 60Hz, not 13H at 120Hz.. and thats at 80mA! And bandwidth is 25Hz-30kHz, -1dB.. whats the problem with that? it can dip all it wants at 80khz, this is audio!
well it would be nice if someone did an unbiased test on many OPTs to see how they do. Even though, yes, the numbers are not necessarily indicative of sonic performance. It may help someone choose a particular type better. The way it is now, the numbers from different manufactures testing are all over the place and use different test conditions.
msl: ok potting means, capacitance goes up, worse square wave (if that test means much in the first place). Looks like a tradeoff yet again. Lots of people like those potted tangos and tamuras, though.
kmtang: wow, i can't imagine a SE 45 amp doing very well w/ b&w801s. yikes!
well it would be nice if someone did an unbiased test on many OPTs to see how they do. Even though, yes, the numbers are not necessarily indicative of sonic performance. It may help someone choose a particular type better. The way it is now, the numbers from different manufactures testing are all over the place and use different test conditions.
msl: ok potting means, capacitance goes up, worse square wave (if that test means much in the first place). Looks like a tradeoff yet again. Lots of people like those potted tangos and tamuras, though.
kmtang: wow, i can't imagine a SE 45 amp doing very well w/ b&w801s. yikes!
Consider O-netics for your project .I could only afford level 1 (~$250 a pair) SET trans for my 45 project but they are truly great transformers with fine detail in, mid bass and gentle natural highs. I read today that Bud Purvine is rising prices so act quickly
. I also have Electraprint Tm3kb (65mA 3.5k ) Opt and it is very good too comparable to O-netics with more accent on treble . (my version is nicely poted and was >$400 a pair)
Regards, L
. I also have Electraprint Tm3kb (65mA 3.5k ) Opt and it is very good too comparable to O-netics with more accent on treble . (my version is nicely poted and was >$400 a pair)Regards, L
wicked1 said:
Electraprint.
There is a little problem with my comparison because Electraprint is 3.5k primary and O-netics 5K. Both were used in Yama 08 clone(45) . O-netics trans started from the day one with great "resolution" (hate that word) in midbas ,detail and suprising "kick' for 2W 45 amp. I was listening only for about week before I had to leave home for over a month but my conclusion was that O-netics is a wonderful transformer for $250 a pair. I just wonder how level II and III sounds.
limono said:
This comparison might be a non starter simply because the two transformers don't reflect the same load impedance to the output tube, and in the case of the EP the primary inductance is probably considerably lower given its 3.5K primary Z thus further reducing output at low frequencies.
kevinkr said:
Kevin ,you may be right , but it was detail and quality of the midbass which was noticable not quantity of lows which was plenty on electraprint too. (I also used VT-52) I'm still out of home so cannot even play with load (secondary taps) to report more. Anyway whoever buy Electraprint should be happy for the price and I've met guys on audioshows that said they (electraprints) are the best transformers on the market for normal money. But ,I wanted to share my experience with O-netics because I think those transformers are something special and deserve some publicity.
Any fresh observations / comments to add to the Silk vs. any other options...
my word.. (and wish)
A amourphous core cost maybe 50% more then normal iron but the core cost is just a fraction of the total cost so no, no reason to buy amourphous if they cost 2x more.
I used a pair of Silk S-325F to build my 300B monoblocks and I'm very happy with their sound. These are my first tube amps in 40 years so I documented the design/build process at AmpWerks :: Home.
I haven't compared the Silks to any of the other brands. Next time I will probably try Lundahls or EPs.
John
I haven't compared the Silks to any of the other brands. Next time I will probably try Lundahls or EPs.
John
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