[Aljaheejus]

Well the thread "The Ripper and Moving-Coil cartridges" from 2007 only went so far to confirm that gain and load can be changed like in the Bugle to allow use with MC cartridge output levels / load requirements.  Since it was so old it was suggested to start a new thread.

Where can a non-Electrical-Engineer-version step-by-step procedure be found to modify the stock Ripper for different gain / load levels?  Also, could someone help with a design modification to allow a switch between 2 gain levels - "MM" vs "MC"?

Thanks in advance,
David

[Aljaheejus]

Okay.  I dug in to the post about increasing gain in Bugle and found this:

"I want to increase the gain of my newly-built Bugle from 40dB to 50dB. All I need to do is change R5, R3, R23, R21 from 13k to 707R?"

I understand the changing resistors part, but from 13k to "707R" ?  What does this mean?  Is the "R" supposed to mean "ohms"?  Reducing resistance from 13,000 ohms to 707 ohms?

Thanks,
David

[Brinkman]

  What does this mean?  Is the "R" supposed to mean "ohms"?  Reducing resistance from 13,000 ohms to 707 ohms?

You got it.

Also not uncommon: 5K1, meaning 5100 ohms, etc.

[Aljaheejus]

Thanks, Brinkman.  I appreciate the confirmation.

Can you advise whether switching is feasible between MC and MM modes?   I see that feature on some equipment, but if it would not be sonically invisible, or logistically achievable with some point-to-point wiring I will abandon the idea.

Thanks again.

[Brinkman]

If you look at the schematic, R5 (L&R) and R3 (L&R) control the gain for each respective channel, by proxy of the op amp voltage division.

Where these resistors join the circuit, you would need a run two pair of wires (both resistors, each channel) to a four pole double throw switch (4PDT).

One throw would send all four wires through a low gain (MM) setting, the other through a high gain setting (MC).

Shielding these wires would be a good precaution, but is not crucial.

[Aljaheejus]

Neat.  This is starting to sound like fun.  Thanks!  Yes, I will study the schematic, and hopefully take it from you description.  I have some shielded wire, but I don't really know what the shield would be connected to at one end (or both ends?)  A suggestion for that would be greatly appreciated.

Seems I have four 680 ohm 1/4 W 5% Carbon Film.  Would these be close enough to the 707 ohm recommended previously to use?

Looks like R5 and R12 are L & R, and R3 and R15 are a pair also.  These would be the switched resistors per your post. 

What about the R23L & R23R?  Also, the R21 seems paired with R17.  Do all these need to be changed, or switched, per the original "Bugle" post?

[Brinkman]

Oops.

I was referring to the Bugle schematic, which is okay, because Jim took his Bugle design and implemented it for use in the Ripper

Just build the first two stages of the Ripper to resemble the first two stages of the Bugle. The resistors I was referring to are correct for the Bugle schematic, and the Bugle schematic also gives you the two values you would want to switch between.

If you do shield the wires to the switch, just connect one end of the shield to the ground those resistors are shunted to.

I prefer 1% tolerance resistors, not because the specified parts values are always critical, but because between those two channels and two gain stages you have four voltages dividers. That's eight resistors. Closer tolerance is going to yield tighter Left & Right channel matching in the EQ network.

PRP resistors are available through Parts Connexion and Handmade Electronics.

There's also the fact that the op amp characteristics might vary, so that may have a bigger impact than resistor tolerance. So if you don't want to sweat the 1% precision, you should be able to get away with what you have.

[Aljaheejus]

Okay, no problem.  I have not started hacking things up yet.  I will retrieve the Bugle schematic and compare to find out which resistors to "switch".

I reviewed the hagtech website, and found the Piccollo.  What would be the advantage (presumably sonic) to putting that between the MC cartridge and the Ripper (vs. modding the Ripper)?   

Presently, I am using the Ripper wide open and turning up my preamp way up which is yielding some noise...  Hopefully either the MC mod to the Ripper or the Piccollo step-up will cure that.  For economy I'd like to try the Ripper mod if that makes sense to you, or JH, or others that have knowledge of these options.

[Aljaheejus]

Okay, I found the neat online calculator http://www.hagtech.com/equalization.htmlto determine resistors for different gain levels on the Bugle!  (Thanks, Jim.) 

Once there I am targeting 65dB gain, for argument's sake, to match my new (old) Asak cartridge.   Enter 65 and 289 ohms is given for R5, R3, R23 and R21.

I've worked out the correlations, but design values don't match on first stage pair:
1)  Bugle R5 & R23 (1K3) = Ripper R27left & R27right (316 ohm)
2)  the Bugle R3 & R21 (1K3) = Ripper R25left & R25right (1K3)


Since the first above does not really correlate in value, I don't know if this is correct to change Ripper R27x.  I do see J. Hagerman's hum modification affects configuration of R27x.  I think I'll make that mod first on R27x, but keep the value the same, and change R25x to something near 289 ohms (have to look up a standard value.)

Again, input on the big picture affect of this approach vs. something like a Piccolo would be appreciated.

[analog97]

Again, input on the big picture affect of this approach vs. something like a Piccolo would be appreciated.

I have tried both options.  In my experience, the Bugle is being pushed too hard beyond 60db.  The PICCOLO is a far, far better option.  Getting 20-26 db gain from the PICCOLO and 40 db from the Bugle will be much better and quieter.  I don't have the capability to measure the noise difference between these 2 options, but I am confident the PICCOLO/Bugle combo will be better.  Besides, the PICCOLO will permit loading adjustment.  Go for it and don't look back.

[Aljaheejus]

Thanks for the input, Analog97.   I left the Ripper R27x's at 316 and positioned per the PHOTO in Hagerman's post on reducing hum in Ripper.  Then I replaced the R25x resistors with 316 ohm and had a quick listen this a.m.   More gain, but more hum and such as well.  I guess I knew to expect it, but wanted to try anyway.

?  I don't understand why in the Ripper R27x's are 316 ohm vs. the same circuit position Bugle R5 & R23 are 1.3K ?  Maybe Jim can comment and advise.

[hagtech]

two pair of wires (both resistors, each channel) to a four pole double throw switch (4PDT)

You're just going to add hum if you try this.

jh

[poty]

If you look at OPA2134 datasheet, you can see (taking into consideration that MC cartridges have low source impedance, so mainly we use voltage noise as base) that noise level of the device (OPA) is 1,2 microVolts (RMS). Denon 103, for example, has output level of 250 microVolts, which gives us signal/noise ratio of only 23dB. (For MM type, 5000 microVolts output gives us 72 dB - exactly this number we can see in the Ripper specifications. I do not speak here about the question: is the number right or not?).
Lowering the divider resistors pose another problem - the output current of the OPA is limited. If we choose bigger values pair - we can lost in signal/noise ratio again. So, for correct values and opportunities we should carefully use in calculation all this factors (and not only one - changing divider's resistors).
My suggestion - use SUT or devices like Piccolo.

[Aljaheejus]

Thanks - to JH and to Poty.   I can listen to the MC cartridge with the resistor changes in the Ripper, but there is audible hum and noise.

Though my preamp and amp and efficient speakers can get it to listening levels, the level for digital recording is too low for Spin-it-Again recording software.  So these two factors, plus the theory pointed out by Poty clearly points me toward returning the resistor levels to their original value and either a) get a new MM cartridge, or b) use the low-output Linn Asak MC and get a step-up transformer like Picollo, or the actual Picollo.   

Next question will be to the stylus afficionados whether the diamond is in good shape.  I'll put some photos I have taken on a the vinyl forum. 

[Theo]

Thanks - to JH and to Poty.   I can listen to the MC cartridge with the resistor changes in the Ripper, but there is audible hum and noise.

Though my preamp and amp and efficient speakers can get it to listening levels, the level for digital recording is too low for Spin-it-Again recording software.  So these two factors, plus the theory pointed out by Poty clearly points me toward returning the resistor levels to their original value and either a) get a new MM cartridge, or b) use the low-output Linn Asak MC and get a step-up transformer like Picollo, or the actual Picollo.   

Next question will be to the stylus afficionados whether the diamond is in good shape.  I'll put some photos I have taken on a the vinyl forum.

I can attest to using a Piccolo with the Bugle to run a DL103.  There is no hum from the Bugle when dialed 20dB gain from the Piccolo, and almost no hum when dialed to 26dB gain.  Before that, I upped the gain in the Bugle to 60dB; hum level was high.

[Aljaheejus]

Thanks, Theo, for the confirmation and letting me know that you tried this before also.  I replaced R25 r&l with 316 ohm, so I am at about 63 dB gain with the Ripper now.  This from calculator on http://www.hagtech.com/equalization.html
With your Picollo in place, do you mean you changed resistors back to 1k ohm, yielding 45dB for the Ripper phono stage?   

I still wonder if I do the same - use Picollo, restore Ripper to original gain - I'll get back to 20 + 45 = 65 dB (more or less where I am now) that it will still not be loud enough for digital recording software Spin-it-again.  I may need to still boost output at step-up stage.  I will study the Picollo features more closely to see how these variations are achieved with it - as it appears to have dial-in controls.

[Theo]

Thanks, Theo, for the confirmation and letting me know that you tried this before also.  I replaced R25 r&l with 316 ohm, so I am at about 63 dB gain with the Ripper now.  This from calculator on http://www.hagtech.com/equalization.html
With your Picollo in place, do you mean you changed resistors back to 1k ohm, yielding 45dB for the Ripper phono stage?   

I still wonder if I do the same - use Picollo, restore Ripper to original gain - I'll get back to 20 + 45 = 65 dB (more or less where I am now) that it will still not be loud enough for digital recording software Spin-it-again.  I may need to still boost output at step-up stage.  I will study the Picollo features more closely to see how these variations are achieved with it - as it appears to have dial-in controls.

I set the Bugle to original 40dB gain and 47 kOhm load, and set Piccolo to 26dB gain and 100 Ohm load to run my 0.25mV DL103.  I heard "normal" hiss with my headphone amp at 3/4 volume, and hum was barely noticeable.  My setting equals 66dB gain and it overloaded the my input for recording (I use a M-Audio Audiophile for my recording).  I had to dial the Piccolo down to 20dB when I record.  I'm surprised that 65dB is not loud enough for your case.

[Aljaheejus]

Interesting, so you don't use the Ripper for A/D conversion?  You plug analog RCAs from Ripper phono stage into the computer M-audio card?

I am using the Ripper for A/D and have USB line to computer for digital signal to recording software (Spin-it-Again.)  Yes, even with the Ripper volume up, the software could not get enough volume for normal level recording.

[Theo]

Interesting, so you don't use the Ripper for A/D conversion?  You plug analog RCAs from Ripper phono stage into the computer M-audio card?

I am using the Ripper for A/D and have USB line to computer for digital signal to recording software (Spin-it-Again.)  Yes, even with the Ripper volume up, the software could not get enough volume for normal level recording.

I have a Bugle not a Ripper; they can be tuned similarly.  I suspect you have a gain issue surrounding the A/D circuit in your Ripper, or maybe your software has input level adjustment.  When I fed 66dB into my preamp from Bugle/Piccolo, it was louder than my CD player volume; both overloaded my M-Audio record input.

To isolate the recording level issue, try the following.

1. If you have an alternative sound card, try connecting the Ripper phono output to it to see if it is loud enough.
2. Check if Spin-it-again has input adjustment.
3. JH recommended Audacity for use with Ripper.  That's what I'm using and it's free.  Try it too.

[Aljaheejus]

Okay, thanks.  My cartridge is rated for
Output Voltage at 0.2mV
Load Impedance:   30-500 ohms
Output Impedance:  3.5 ohms
(I do not understand how the latter two items above affect all this, because I am not an electrical engineer, but I plan on studying http://www.hagtech.com/loading.html a page I just discovered today, for more great info on this topic.)

I think the DAC function somehow is amplified by the phono stage, because the volume on the Ripper is  intended to be used to set the digital recording level, as well as for use in analog output to line-stage preamplifier.  Obviously, I had it all the way open when I found digital level was insufficient for Spin-it-Again.

Audacity is great, but for recording LPs I like Spin-it-Again better for it's easy assistance in detecting/creating tracks, tagging and built in filters for eliminating pops crackles on noisy records.