FYI
Just finished calibrating one of Dave Reich's classics the Classe A(udio) DR-3 power amplifier.
A technician had serviced this amplifier for a friend of mine because the railfuses kept blowing when the amp was turned on.
It took the technician quite a while to source new Darlington TO3's powertransistors and with a service manual I supplied to him with clear instructions which substitute axial caps he should use, which he didn't, because two of the caps (the red radial caps) he just took from his shelf it seems...
https://www.diyaudio.com/forums/attachment.php?attachmentid=993208&stc=1&d=1635346761
After months the amp came back and it sounded awful clinical and harsh. Eva Cassidy had a very unpleasant ringing to her sweet voice which gave me literally a headache. My revised McIntosh Mc-2205 which I swapped for the DR-3 was, although sounding somewhat dark and flat on the Y axis (less depth in the soundfield), much more tolerable than this DR-3.
The technician did not calibrate the amp, which is necessary after a repair where all the powertransistors are replaced. He just turned down the biastrimmers to a intake of 75 Watts making this amp effectively a Class B amp in most listening situations.
This amp was designed to compete with the Krells and Levinsons (ML-2) of its time and now it was reduced to just a mediocre performer.
With the elaborate service manual I managed to get the music "back"
I took hours to finetune it because of the two biastrimmers and two DCO trimmers.
Now the amp takes 2 amps AC from the wall and the energy meter on the Variac says I waist 480 Watts every hour...
"You don't need a ticket, you just thank the Lord."
https://www.diyaudio.com/forums/attachment.php?attachmentid=993209&stc=1&d=1635346761
https://www.diyaudio.com/forums/attachment.php?attachmentid=993210&stc=1&d=1635347003
https://www.diyaudio.com/forums/attachment.php?attachmentid=993211&stc=1&d=1635347003
Just finished calibrating one of Dave Reich's classics the Classe A(udio) DR-3 power amplifier.
A technician had serviced this amplifier for a friend of mine because the railfuses kept blowing when the amp was turned on.
It took the technician quite a while to source new Darlington TO3's powertransistors and with a service manual I supplied to him with clear instructions which substitute axial caps he should use, which he didn't, because two of the caps (the red radial caps) he just took from his shelf it seems...
https://www.diyaudio.com/forums/attachment.php?attachmentid=993208&stc=1&d=1635346761
After months the amp came back and it sounded awful clinical and harsh. Eva Cassidy had a very unpleasant ringing to her sweet voice which gave me literally a headache. My revised McIntosh Mc-2205 which I swapped for the DR-3 was, although sounding somewhat dark and flat on the Y axis (less depth in the soundfield), much more tolerable than this DR-3.
The technician did not calibrate the amp, which is necessary after a repair where all the powertransistors are replaced. He just turned down the biastrimmers to a intake of 75 Watts making this amp effectively a Class B amp in most listening situations.
This amp was designed to compete with the Krells and Levinsons (ML-2) of its time and now it was reduced to just a mediocre performer.
With the elaborate service manual I managed to get the music "back"
I took hours to finetune it because of the two biastrimmers and two DCO trimmers.
Now the amp takes 2 amps AC from the wall and the energy meter on the Variac says I waist 480 Watts every hour...
"You don't need a ticket, you just thank the Lord."
https://www.diyaudio.com/forums/attachment.php?attachmentid=993209&stc=1&d=1635346761
https://www.diyaudio.com/forums/attachment.php?attachmentid=993210&stc=1&d=1635347003
https://www.diyaudio.com/forums/attachment.php?attachmentid=993211&stc=1&d=1635347003
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Always wanted to try these one of these on my 1 ohm Apogee scintillas.
A clone of the VHC model would get my attention
Very clean inside condition, looks like new !
A clone of the VHC model would get my attention
Very clean inside condition, looks like new !
That would work just fine according to the Audio magazine review of it.
Besides the obvious Krells (had a pair of KRS-100's which took 1.5 kW from the wall) the Levinson ML-2's and the DR-3's (VHC even better) should pull it of.
I'm not sure about a Threshold SA/1...
I was wrong it was Stereophile:
"The DR-3 did remarkably well driving a pair of Apogee Scintillas. These speaker systems sound best (to my ears, footnote 4) configured as a one-ohm load, which most amplifiers have difficulty driving. Aside from the biggest Krell amplifiers (the mono KMA-100s and -200s), I know of no other amplifier that makes the Scintillas sound as good as the DR-3. Run full out at the Audiophile Society's meeting for a crowded roomful of audio buffs, two DR-3 biamping Scintillas played as loudly (that's not a typo) as the big 200wpc KMA-200s. Actually, the Classé Audio amps sounded mellower and richer, while the Krells were cleaner, had more presence, and were more transparent and detailed in the highs. Neither was a clear winner, but both sounded great."
Copyright: Stereophile mag, Larry Greenhill. dec. 1985
Besides the obvious Krells (had a pair of KRS-100's which took 1.5 kW from the wall) the Levinson ML-2's and the DR-3's (VHC even better) should pull it of.
I'm not sure about a Threshold SA/1...
I was wrong it was Stereophile:
"The DR-3 did remarkably well driving a pair of Apogee Scintillas. These speaker systems sound best (to my ears, footnote 4) configured as a one-ohm load, which most amplifiers have difficulty driving. Aside from the biggest Krell amplifiers (the mono KMA-100s and -200s), I know of no other amplifier that makes the Scintillas sound as good as the DR-3. Run full out at the Audiophile Society's meeting for a crowded roomful of audio buffs, two DR-3 biamping Scintillas played as loudly (that's not a typo) as the big 200wpc KMA-200s. Actually, the Classé Audio amps sounded mellower and richer, while the Krells were cleaner, had more presence, and were more transparent and detailed in the highs. Neither was a clear winner, but both sounded great."
Copyright: Stereophile mag, Larry Greenhill. dec. 1985
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