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Old 16th March 2018, 06:19 PM   #71
nagini262 is offline nagini262  Viet Nam
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I think 80 x 1.1 = 88w is have no problem with me because I tried 30 x 3 = 90w dissipation on vfetron 75 in the chassic that I showed up
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Old 16th March 2018, 06:52 PM   #72
Michael Rothacher is offline Michael Rothacher  United States
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Old 29th April 2018, 11:23 AM   #73
nagini262 is offline nagini262  Viet Nam
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I built De-lite amp for some years ago, this amp running with 80VDC/1.75A. Now I rebuild this amp with 2SK180 + FG-50S
Hi Mike! You told me try with 32 ohm primary and 8 ohm secondary but now I have no 8 ohm loudspeaker, so can I try 4 ohm and 16 ohm loudspeakers with 4 ohm and 16 ohm tap secondary?

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Old 29th April 2018, 12:16 PM   #74
eduard is offline eduard  Netherlands
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Default maybe some disadvantages

Hello my friend,
Yes the reflected impedance will change. But there some things that will be not so good. I think it is the primary inductance or the power rating.
I am sure others will know. It has been discussed here before.
greetings, Eduard
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Old 29th April 2018, 12:56 PM   #75
nagini262 is offline nagini262  Viet Nam
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Quote:
Originally Posted by eduard View Post
Hello my friend,
Yes the reflected impedance will change. But there some things that will be not so good. I think it is the primary inductance or the power rating.
I am sure others will know. It has been discussed here before.
greetings, Eduard
Wellcome back my friend
I think there is no problem if I connect correct the same impedence of loudspeaker with each secondary tap.
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Old 29th April 2018, 01:07 PM   #76
eduard is offline eduard  Netherlands
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Quote:
could the 8K transformer designed for use with the 16 ohm load be used with the 8 ohm speaker to result in a 4K effective load on the output tubes?
Yes.

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Would doing this substitution likely cause distortion or reduced frequency range?
Yes, distortion is usually not an issue, and the frequency response will be affected. Every case is different, but in most cases the changes are minimal.

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could one just wire up the 16 ohm tap to the 8 ohm speaker without any problems
Same answer as above. I have done both several times with good results. I have made frequency response measurements and found that if you stick to a 2:1 impedance ratio change or less the differences are minimal.

One of my Simple SE amps uses a 3K ohm transformer with the 8 ohm load on the 4 ohm tap for a 6K ohm load. The results are excellent. In some cases the 3K transformer may not have enough primary inductance to work well at 6K ohms causing some loss in low frequency response. In this case the low frequency response (3db point) changed from 24 Hz to 30 Hz.

I have tried to use the One Electron UBT-3 (3K ohms SE) as a 1.5 K transformer. It works but becomes somewhat lossy due to its relatively high DC resistance (235 ohms). I tried is as a 750 ohms (4 ohm load on 16 ohm tap) but much of the power is lost in the resistance of the primary.

I have some 6600 ohm push pull transformers which I routinely use as 3300 ohm transformers. They work good.

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Will this overspec'd transformer operate poorly at the lower power level?
Since many OPT power ratings are optimistic any way a 2:1 over spec is probably a good thing.

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Other than weight and cost are there any inherent problems with using a higher power output transformer than we need? Is there a limit on how overspec'd the output transformer can be before problems set in?
If the OPT is grossly oversized a good percentage of the electrical energy sent to the transformer will be spent in magnetic losses leading to loss of efficiency and possible loss of fine detials in the music. I have seen and heard this effect using 11 pound Hammond "30 watt" transformers in a SE amp operating at 1/2 of a watt.
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Old 12th July 2018, 07:16 AM   #77
nagini262 is offline nagini262  Viet Nam
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After long time....., my SIT Nemesis will finish soon

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Old 12th July 2018, 08:56 AM   #78
Zen Mod is offline Zen Mod  Serbia
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already Fugly!

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Old 12th July 2018, 09:05 AM   #79
nicoch58 is offline nicoch58  Europe
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soo sexy !
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Old 12th July 2018, 09:16 AM   #80
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Wonderful..... Tell us results, please... I am waiting...
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