|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
71.34.43.182
In Reply to: Re: Power Calculations - No Clipping posted by Satelliteman on September 19, 2006 at 16:04:39:
is a good term.The bias has little effect on power, but does affect distortion. B+ voltage affects power output. The amp is speck'ed to make full power (60 watts) into 8 ohms with 120V in (if you are in the US). Generally we do a bit better than that- 65 to 67 watts is common.
A common problem area is the power cord. It is best to run the test with a variac and measure the input AC voltage to make sure there is no sag at full output. Since the amp operates in the A2 window at full output, there can be significant voltage sag in the power cord and the like. It can rob the amp of significant power! If there ever was an argument for upscale power cords and their audibility, this is definately one.
Follow Ups:
Although the current should be considered for the ratings of the powercords ...I can assure you that primary mains current on the toroids is approx 1/2 what is present in the US . We have 230 vac supply here , and I think its approx 240 in Australia . I think the secondary voltages ..esp the output stage supplies , are down slightly because the Toroids were wound with 240 primaries , instead of 230 vac . However - a plus to this is , that if I move to australia ...things will be fine ! - not stressed .
Guys - Im fine with the TOTAL build outcome - really
Stu
Trun transformers around primary as secdaire.Then v. be about on the money thanks T.V.
Hi Ralph , I sent you a pic of both my of amps together on the dining room table .
These are the voltages / references that I have measured in the amps are as followsOutput stage supply is 135 VDC
Driver Supply is +325 & -327 .
Bias value reference is approx -50
Pins 2 & 4 ( V4 ) is +292
Pins 1 & 4 ( v2 ) is 46.9 , and Pins 3 & 6 ( v2 ) is 53.2
Pins 3 & 6 ( V1 + 1.6
Pins 6 ( v3 ) is -92.7 , Pin 4 ( v3 ) is -95
Pins 1 ( v3 ) -226 & Pin 3 = -222Im not after more power , just wanting to confirm that I was measuring it correctly .
My original post was to describe how I was doing it ( at 1khz ) biased at 500 mA ...and then measured V squared / R ...with the Scope & Fluke DDM . The scopes Peak to Peak reading was multiplied by 0.707 ....and the Fluke DDM is good for 100Khz ( so it says )
I have a Fluke 734 02 seriesCheers Stu
New Zealand on 230 and up to 240 vac
Sounds to me like the B+ voltage is a little low. 140V is a better place to be. You could buck that up with a small auxilary transformer.
What is output stag v without tubes.with 135v unloded 150v.Is it good to pull down transformers?thanks T.V.
I have read youre request Tubevibb . What is youre output stages windings AC voltage ..measured at the input to the Bridge Rectifiers ?
Stu
I have 105ac 110ac 120ac at bridge. After 130dc 140dc 150dc.TO RUN a/b 150dc bias up,I CAN GET MORE POWER.But not needed,but I do own ESL all so. thanks My transformers R 1kva per winding.
| ||||||||||||
|
This post is made possible by the generous support of people like you and our sponsors: