Well, the ARC D70-II does an excellent job. And two of my preamps are tubes too...
🤣 🤣 🤣
It probably does........ I woldn´t know. If you look closely at the VU. it says "Hybrid FET and Bipolar", so ARC-D70-II......... Nooooooo.
Advance Acoustic MAA-1000 monoblocks. Long obsolete (Had them since 2009). "Designed in France" probably means, they were
made at "Tonewinner" or some similar plant in China to Advance´s spec´s. Nevertheless the most "full bodied" sounding amplifier,
I´ve ever owned, and they are not going anywhere...........ever.
Built like tanks. Each monoblock is a hefty 70.5 pounds, and they drive anything with ease an finesse. They made a very good match
soundwise with their combination of MosFet-drivers and bipolar output´s.
Seems, they are still well regarded in asia. Just found a brand new set still for sale........
https://sonicsoundaudio.com/ADVANCE ACOUSTIC - MAA-1000 1 pair 1 year warranty
The ARC D70-II is likely one of the best amps ARC has ever built.
Just two 6550s per side. and another 6550 for regulation. No transistors monkey around, not matching multiple devices.
If you can live with 60 wpc, you shouldn't look much further. Just drink cognac when you listen to them.
In my case, I got Maggies and then I needed more power. I looked at D125 and then VT100 but the Nelson Pass bug bit me...
Just two 6550s per side. and another 6550 for regulation. No transistors monkey around, not matching multiple devices.
If you can live with 60 wpc, you shouldn't look much further. Just drink cognac when you listen to them.
In my case, I got Maggies and then I needed more power. I looked at D125 and then VT100 but the Nelson Pass bug bit me...
That´s understandable......
But these were bought at a time, when working took most of my time.
I was "shipped out" to Mexico, Orlando FL, cruise ships in the Mediterranian a.o. and didn´t have time to diy.
Think it took 4 years to finish my X-Ono clone, so instead I bought these brand new. Never regretted that 👍
Hey everyone,
Need some assistance if possible, just finished my Iron Pre and Pearl 3, Iron Pre worked perfectly on first test but Pearl 3 is revealing a bit more difficult.
I have an MM Cart (Goldring 1042), and the distortion is unbearable with Pearl 3 (Iron Pre + Rega Phono MM is fine), testing this with jumper cap ON and all dip switches OFF,
What I did to troubleshoot this:
0. Re-read this complete thread;
1. Voltage Check is ok, -22V and +22V at board input, leds light up fine.
2. Biased at 4.5mA and 4.9mA (R7=570ohm, 2.6V and 2.8V) (didn't have correct resistor values, had to put 470ohm+100ohm in series)
3. Measured all resistors, all measure as per spec; R9 and R22 measure 200ohm, I assume because they are in parallel (2.2K+220)
4. Checked capacitor polarity, all seem fine;
5. Regulators are in correct position;
6. Q6 and Q7 are in correct position; (one user had them face backward)
7. Re-Checked continuity on smd transistors; checked OK.
8. Opamps are correctly placed;
I ran out of ideas.... Any help is appreciated..
Currently at work but..., any chance the dip switches are all on and not all off?
Thanks,
Need some assistance if possible, just finished my Iron Pre and Pearl 3, Iron Pre worked perfectly on first test but Pearl 3 is revealing a bit more difficult.
I have an MM Cart (Goldring 1042), and the distortion is unbearable with Pearl 3 (Iron Pre + Rega Phono MM is fine), testing this with jumper cap ON and all dip switches OFF,
What I did to troubleshoot this:
0. Re-read this complete thread;
1. Voltage Check is ok, -22V and +22V at board input, leds light up fine.
2. Biased at 4.5mA and 4.9mA (R7=570ohm, 2.6V and 2.8V) (didn't have correct resistor values, had to put 470ohm+100ohm in series)
3. Measured all resistors, all measure as per spec; R9 and R22 measure 200ohm, I assume because they are in parallel (2.2K+220)
4. Checked capacitor polarity, all seem fine;
5. Regulators are in correct position;
6. Q6 and Q7 are in correct position; (one user had them face backward)
7. Re-Checked continuity on smd transistors; checked OK.
8. Opamps are correctly placed;
I ran out of ideas.... Any help is appreciated..
Currently at work but..., any chance the dip switches are all on and not all off?
Thanks,
Hello barbosas,
on the case of the dip-switch there should be mentioned / written in which direction the switches are 'on'.
With a MovingMagnet-cartridge (Goldring 1042) you will have to switch on one of the two capacitors (100pF or 220pF / C10 or C11).
This also depends on the capacitance of your RCA-cable between vinylplayer and the PEARL 3.
This affects the behaviour / sound in the upper frequencies. It is like an equalizer in the highs.
What you describe - unbearable distortion - will be affected by anything else. I would check the active devices first.
JFets, OPAmp seems correctly oriented, Bias -LED (red) shines, ... HMMM? Q6 and Q7 are for sure in the right spot and oriented correctly?
If that is all o.k., then I would check solderjoints and wires for contactproblems.
Cheers
Dirk
on the case of the dip-switch there should be mentioned / written in which direction the switches are 'on'.
With a MovingMagnet-cartridge (Goldring 1042) you will have to switch on one of the two capacitors (100pF or 220pF / C10 or C11).
This also depends on the capacitance of your RCA-cable between vinylplayer and the PEARL 3.
This affects the behaviour / sound in the upper frequencies. It is like an equalizer in the highs.
What you describe - unbearable distortion - will be affected by anything else. I would check the active devices first.
JFets, OPAmp seems correctly oriented, Bias -LED (red) shines, ... HMMM? Q6 and Q7 are for sure in the right spot and oriented correctly?
If that is all o.k., then I would check solderjoints and wires for contactproblems.
Cheers
Dirk
I see nothing obvious.
It maybe a case of too much gain?
How much gain does the iron pre have? Did you try a passive preamp? Pickup is 4-5mV output I am guessing..
What loading do you use on the Rega for that pickup? How much gain does the Rega RIAA have?
Based on the description, it seems to me some stage along the way is getting overloaded and clipping OR the system becomes unstable with the low gain setting which would be very hard to imagine.
It maybe a case of too much gain?
How much gain does the iron pre have? Did you try a passive preamp? Pickup is 4-5mV output I am guessing..
What loading do you use on the Rega for that pickup? How much gain does the Rega RIAA have?
Based on the description, it seems to me some stage along the way is getting overloaded and clipping OR the system becomes unstable with the low gain setting which would be very hard to imagine.
Thank Dirk, red leds shine fine, Q6 and Q7 are on the correct place and oriented correctly, will check solder joints tonight.
Not shure about the gain of the iron pre, but it works fine with the rega phono MM.
Rega phono MM specs are 47k ohm loading in parallel with 100pF and around 40dB gain, pretty much consumer grade standard.
Goldring 1042 has an high output of 6.5mV, I tried to run the Pearl 3 in high gain mode, the sound is a bit better, but still not listenable and I can barely move the sound knob above zero.
I am going back to 'too much gain' notion and I would want to rule out all possibilities of clipping as the issue.
Going full 70dB gain with a 6.5mV pickup could cause all kinds of clipping/saturation even with 15-0-15V supply so I am not surprised by your result.
Yes, 6.5mv input @70dB gain corresponds to ~21V output = BIG saturation problem.
With the jumper/220ohms feedback, the 49 dB of gain from the pearl3, STILL brings 6.5mV to 1.8V output! If you are pre-amplifying that you may go over the top for the amplifier input.
By contrast your Rega 40dB gets you a nice and even 0.65V output. Much more user friendly!
That looks to be the problem.
Going full 70dB gain with a 6.5mV pickup could cause all kinds of clipping/saturation even with 15-0-15V supply so I am not surprised by your result.
Yes, 6.5mv input @70dB gain corresponds to ~21V output = BIG saturation problem.
With the jumper/220ohms feedback, the 49 dB of gain from the pearl3, STILL brings 6.5mV to 1.8V output! If you are pre-amplifying that you may go over the top for the amplifier input.
By contrast your Rega 40dB gets you a nice and even 0.65V output. Much more user friendly!
That looks to be the problem.
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@barbosas : Is the distortion the same in both channels? Check the mounting pressure on the opamp in its base -- is it tight and secure? Have gotten rid of distortion on a problem build by reflowing a small amount of solder over the SMD legs even though continuity was there. Keep us apprised of what you are trying, please.
Will recheck tonight if distortion is even on both channels, yesterday seemed so, but it was late and i was a bit tired.
No I mean R22, the feedback resistor. R27 is fine. I got more or less the same value for bias.
Before you needlessly go and tickle your SMD components with more heat and potentially fry them, check your gain situation.
You want LESS gain from the pearl3. Look at the schematic 70db wo jumper/49db w jumper and the numbers I posted.
You need 40db RIAA, 49dB seems still too much for your overachiever of a pickup. 😎