7412533694

ANOTHER FIRST FOR HEATHKIT®

. . . amplifier power rating standards

Heathkit is accustomed lo pioneering . . . lo leading the way. Wc lcd the way into che kit field of dcctronic cquipincnt. Xo\v. wc arc leading thr way to audio amplifier power rating standards . . . standards clcarly dclincd to assurr you of Heathkit quality . . . to enable you to compare lx*fore you buy.

The Heathkit amplifier standards havc been established upon thesc following beliefs after rcvirwing o\ er one hundred published treatises on the subject:

WE BF.IJEVK any amplifier should lx- rated for its intended usc . . .

PROFESSIONAL ampliliers must lx* so nearly perfect that no audible changc oecurs in the program materiał.

HIGH FIDELITY ampliliers must be almost as perfect. almost as efficient.

UTILITY ampliliers can ł>e less perfect and still fullill their practical job.

WE BELIEVE the rated power of an amplilier in any of the above “usc” categories should bc that power which satislies all requirements in that category.

I.ach of the three “usc" categories we havc choscn has require-ments which can be translated into performance specilications with rather delinite limits . . . liinits established by recognized author-ities. The Heath requircments and their limits for cach of the categories are as follows:

PROFESSIONAL RATING

The professional power rating shall bc that power which satislies the following livc tests:

1.    Maximum power at which total harmonie distortion (THD) does not excced 0.3% at 1000 CPS.

2.    Masimum power at which total harmonie distortion (THD) does not cxcccd 2.0% at 20 CPS.

3.    Maximum power at which total harmonie distortion (THD) does not exceed 2.0% at 20.000 CPS.

4.    Maximum power at which response does not dcviate by morę than ± 1 db between 20 and 20.000 CPS.

3. Maximum equivalent single-frequency power at which intcrmodulation distortion does not excced 1.0% (60 and 6000 CPS. 4:1).

HIGH FIDELITY RATING

The high fidclity power rating shall be that power which satislies the following live tests:

1.    Maximum power at which total harmonie distortion (THD) does not cxcccd 0.7% at 1000 CPS.

2.    Maximum power at wbich total harmonie distortion (THD) does not cxcced 2.0% at 30 CPS.

3.    Maximum power at which total harmonie distortion (THD) does not cxceed 2.0% at 13.000 CPS.

4.    Maximum power at which response does not dceiate by morę than ± 1 db between 30 and 1 5,000 CPS.

5.    Maximum cquivalcnt single-frcquency power at which in-termodulation distortion does not excccd 2.0% (60 and 6000 CPS. 4:1).

UTILITY RATING

The utility power rating shall bc that power which satislies the following fivc tests:

1.    Maximum power at which total harmonie distortion (THD) does not excred 1.0% at 1000 CPS.

2.    Maximum power at which total harmonie distortion (THD) does not cxceed 3.0% at 60 CPS.

3.    Maximum power at which total harmonie distortion (THD) does not cxceed 3.0% at 7000 CPS.

4.    Maximum power at which response does not deviatc by morę than ± 1 db lxtwccn 60 and 7000 CPS.

5.    Maximum equivalent single-frequcncy power at which in-tcrinodulation distortion does not excecd 3.0% (60 and 6000 CPS. 4:1).

We at the Heath Company arc now rating all our ampliliers to thesc standards. To show you just how this rating system works, lets look at the Heathkit EA-3 amplilier:

As a professional amplilier—

1.    Maximum Power at which T.H.D. does not cxceed 0.3% at 1000 CPS: 15.1 watts

2.    Maximum Power at which T.H.D. does not excced 2.0% at 20 CPS: 13.9 watts

3.    Maximum Power at which T.H.D. does not cxcced 2.0% at 20.000 CPS: 15.3 watts

4.    Maximum power at which response does not deeiate morę than ±1 db between 20 and 20.000 CPS: 17.6 watts.

5.    Maximum equivalent single-frcqucncy power at which intcrmodulation distortion (60 and 6000 CPS, 4:1) does not cxcerd 1%: 18.0 watts.

Taking that power which satislies all five tests, we could ratę the EA-3 for professional usc. at l 3.9 watts. Its advcrtised professional rating is a conscrvativc 12 watts.

A review of the chart below shows why the EA-3 is rated at 14 watts for high fidelity applications. and 16 watts as a utility amplilier.

Notice that our specilications are set at rated power for one or morę classilications (when our customers need an amplilier for a particular usc. we believc thay want it to delivcr its rated power under those particular conditions). Observe that our distortion figures are specilied at the limits of the amplilier frequency rangę as well as at the traditional 1000 CPS (the common practice of rating distortion only at 1000 CPS does not tell you what happens throughout the fuli rangę of the amplilier).

As an cxamplc of how thesc standards work on scecral coin-pctitivc ampliliers. we havc prepared the following chart. Notice that if the ampliliers did not mect standards at rated output power, we havc determined the power output whcrc they do mect the standards set up under the three categories.

AMPLIFIER COMPARISON CHART

Amplifier Description and Priee	Heath Standard Rating		Masimum Power Output Satisfying:
	Classification	Power (watts)	Power Ratinf at Test 1 Stds.	Power Ratinf at Test 2 Stds.	Power Ratinf at Test 3 Stds.	Power Ratinf at Test 4 Stds.	Power Rating at Test 5 Stds.
Kit "A"	Professional	Disqualified	8.4 watts	0.02 watts	0.65 watts	0isqualified	3.9 watts
"12 w. HI FI"	High Fidclity	Disqualihed	9.1	1.3	1.67	Disqualified	5.9
$23.90	Utility	8.6 watts	9.8	8.9	8.6	12.3 watts	11.6
Assembled Amp.	Professional	0.3	4.7	0.3	4.8	1.2	4.0
"B" "14 w. HI FI"	High Fidefity	1.1	12.1	1.1	5.7	5.3	8.2
$39.50	Utility	7.8	13.2	7.8	12.9	15.8	13.9
Kil “C*	Professional	3.6	11.0	3.6	7.5	7.5	6.5
"12 w. HI FI"	High Fidelity	8.0	11.8	8 0	11.2	13.4	14.3
$34.95	Utility	11.9	12.0	12.0	11.9	15.0	14.9
Assembled Amp.	Professional	3.8	13.2	3.8	14.5	12.0	14.6
"D” ”15 w. HI FI”	High Fidefity	10.6	14.3	10.6	14.5	18.3	16.3
$64.50	Utility	14.7	14.7	14.7	15.0	23.7	17.0
Heathkit EA-3	Professional	13.9	15.1	13.9	15.3	17.6	18.0
"14 w. HI FI"	High Fidelity	15.5	16.2	15.8	15.5	18.3	18.9
$29.95	Utility	16.4	16.5	16.6	16.4	19.0	19.5

me neain*n ampnuer power ranng sianaaras nave Deen esiaonsnea as lurtner assurance lo you oi we high ęuality of our producls. We will lirę by these standards until industry-wide standards are established.

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