In the last 2 weeks, I've gotten to the point where I can make a clean embossed recording with very little surface noise. However I have to keep the level lower than I expect. A good track has my amp at 1.2vac for a 1K sine at 0Db, using an ART SLA1 100W amp (I've also tried it in bridged mode for 260W, no difference). I was told the head was rebuilt by West Tech and the back has 8ohm hand written on it over the original 500ohm (measure about 3-4ohm DC). If I try to go 3db hotter, the playback is full of skips and distortion. My audio chain is: .wav file has a stock inverse RIAA eq applied and normalized to -23LUF, output with a Scarlett Solo (latest version) to an ART 31band eq that I've set for head compensation (using SlickEQ reference matching, -+2db from flat, end result) and band limited to 30-10KHz then to amp. When distorted, amp is at -10db on the attenuation knob, clean is -13db. Stylus has less than an hour cutting from new (PIAPTK sapphire).
Thinking this through as I write, I just did one more test to see if the 500hz resonance was kicking back up as I upped the level. I added a PEQ at 500hz -8db with a narrow Q. As I cut, I dropped to -12db and widened the Q so the 3db down points were 200 and 1K. First half was no improvement but second half tracked better with some distortion still present.
Mitigating factor, when I bought the stylus, Mike sent a cut disc which I would assume is a target, quality-wise and my clean cut is just as loud if not a little louder. Is it unreasonable to expect a 1D head to get that hot of output?
Jason
Re: 1D head won't cut to 5cm/s without distortion
Hi Jason,
You don't want to use the full IRIAA curve on a 1D head. If you look at the manual (see attached), you can see that they recommend that you add a series resistor to adjust the L/R time constant that provides the 500hz portion of the IRIAA cure. You would only want to apply boosts at 2122 Hz and 50 Hz as the 500hz is inherent in the head.
That said, if the head was rewound, this might change the response of the head such that a resistor is not needed. Note that the 1D was never stock wound for 8 ohms. I would suggest that you start by cutting with no IRIAA or any EQ and see how the head performs. Develop an EQ that flattens the head overall response and "bakes" in the IRIAA as part of the EQ.
To determine the head drive sensitivity, I would cut a 1Khz signal at one watt and measure the playback velocity to see where you sit. Since the impedance of the head may be in question, perhaps assume its 8 ohm and apply 2.83Vrms AC which is the voltage needed to produce 1 watt at 8 ohms. The 1D if properly working it will cut pretty hot depending on how far you decide to push the high frequency response.
Don't expect to be able to cut hot while embossing. Skipping at high cutting levels is expected when embossing. You need to develop a feel for how far you can push bass, treble, and cutting level to create a disc that plays back without skipping and sounds good on a majority of playback systems. There is some art to that.
Hope that helps.
Mark
You don't want to use the full IRIAA curve on a 1D head. If you look at the manual (see attached), you can see that they recommend that you add a series resistor to adjust the L/R time constant that provides the 500hz portion of the IRIAA cure. You would only want to apply boosts at 2122 Hz and 50 Hz as the 500hz is inherent in the head.
That said, if the head was rewound, this might change the response of the head such that a resistor is not needed. Note that the 1D was never stock wound for 8 ohms. I would suggest that you start by cutting with no IRIAA or any EQ and see how the head performs. Develop an EQ that flattens the head overall response and "bakes" in the IRIAA as part of the EQ.
To determine the head drive sensitivity, I would cut a 1Khz signal at one watt and measure the playback velocity to see where you sit. Since the impedance of the head may be in question, perhaps assume its 8 ohm and apply 2.83Vrms AC which is the voltage needed to produce 1 watt at 8 ohms. The 1D if properly working it will cut pretty hot depending on how far you decide to push the high frequency response.
Don't expect to be able to cut hot while embossing. Skipping at high cutting levels is expected when embossing. You need to develop a feel for how far you can push bass, treble, and cutting level to create a disc that plays back without skipping and sounds good on a majority of playback systems. There is some art to that.
Hope that helps.
Mark
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