https://hagerman-audio-labs.myshopify.com/products/piccolo-mc-headamp
I made the Hagerman Piccolo for a friend using MM tube preamp, very easy to make, also to adjust, not too expensive and the most important: very good sound quality.
You use carbide or steel tools on that machine?
If below 4 mm, one shop used special tools for engraving, steel outside with a carbide core.
They do not break as easily as carbide can at times.
If below 4 mm, one shop used special tools for engraving, steel outside with a carbide core.
They do not break as easily as carbide can at times.
I do not see a link below, but I'm using 1/8" collet and about 20k rpm. The problem with the tool was that I'm used it too much. Edge gets less sharp and it eventually brakes.
To make clean cuts, I'm using tools like this:
Tried with V engravers also, but it created a lot of burr for me.
Anyway, now I've ordered the PCBs, should be here in 2 weeks. I will order new tools also, but by the time I hope I will have the PCBs in my hand from the vendor.
Thanks,
JG
To make clean cuts, I'm using tools like this:
Tried with V engravers also, but it created a lot of burr for me.
Anyway, now I've ordered the PCBs, should be here in 2 weeks. I will order new tools also, but by the time I hope I will have the PCBs in my hand from the vendor.
Thanks,
JG
At 20 k rpm, it must be less than 1 mm or 0.040"
If you can, try a 1/8" tool at 2000 rpm or less. Maybe 1500 rpm.
That may not do well on fine lines, but on larger areas, it will do very well.
And it may be cheaper to buy 10 unit packs of the tools, they are much cheaper in larger packages, rather than single units.
If you can, try a 1/8" tool at 2000 rpm or less. Maybe 1500 rpm.
That may not do well on fine lines, but on larger areas, it will do very well.
And it may be cheaper to buy 10 unit packs of the tools, they are much cheaper in larger packages, rather than single units.
I do not think we are speaking about the same thing. Do you mill PCBs? What do you mean 1mm? The tool makes about 0.1mm isolation. With 2000 rpm it would not work, unless I set a very, very slow feed like a mm per second. ... and yes, the tool I use is about 15EUR each, if I buy 10+ it is "only" 11. That is still expensive.
the picture is getting cutted out somehow. I rather include a link then: http://gis-tec.de/deutsch/d_fraeser_fg02.htm
Cutter diameter...your are using a 0.10 to 0.25 mm actual cutting diameter on a tapered shaft, that fits a 1/8" collet.
And it is a two step cutter, for hole and milling tracks together.
These seem to be HSS.
See if you get tiny miiling cutters for use on steel from places like Micro Tools.
Single cutters, 0.8 mm for PCB holes, and 0.25 mm for tracks, may be much cheaper.
Just change and use as needed, drill or mill first. Then second operation.
And it is a two step cutter, for hole and milling tracks together.
These seem to be HSS.
See if you get tiny miiling cutters for use on steel from places like Micro Tools.
Single cutters, 0.8 mm for PCB holes, and 0.25 mm for tracks, may be much cheaper.
Just change and use as needed, drill or mill first. Then second operation.
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Now I remember (vaguely)😀. I used to absorb those TAA like a sponge when they were first published. I know I read that article 'cause I penciled in some margin notes on the parts list page. Already had a decent phono pre at the time, so it was not in line for build.
The MPQs have exactly the same pinout as THAT, makes me wonder if THAT is just the modernest versions. Digikey says they can still get the MPQ6100, just need to see if the specs make it compatible w/THAT. THAT seems to fly under the radar. Good products, but not well known.
I still have 1 PCB left from my Leach build. PM if you're interested.
Yah, most LOMC don't need input load cap, but there are a few that do specify a value. Smart to at least have a spot to put one if needed. Hana SL doesn't specify.
If not putting a low-pass filter cap on the output (feedback cap instead), 100 ohms should be more than enough, unless the tube RIAA stage has specific needs.
I have recently made this MMMC preamp based upon the LT1115 datasheet appnote, with a little mod.
No sim and no measurement, but tested on an Ortofon MC30 and it performed well.
Silent, no hiss, no hum, virtually no offset,
🙂 morten
No sim and no measurement, but tested on an Ortofon MC30 and it performed well.
Silent, no hiss, no hum, virtually no offset,
🙂 morten
You should lose the CCS to the negative rail. It doesn't do anything useful with modern op amps. It gained popularity with class B output stages. A CCS was an upgrade to a uA739 circuit, and better designs used a CCS. The uA749 and cheaper designs use a resistor.
Just yank R3, you shouldn't hear any difference. If anything, negative supply noise might be a hair lower.
Just yank R3, you shouldn't hear any difference. If anything, negative supply noise might be a hair lower.
You can bias the opamp output stages into class A using this trick
https://hifisonix.com/preamplifiers/class-a-buffering-the-correct-way/
I got it from jcx who used to frequent the forum but is no longer around. I’ve simmed it and built it (I use it in the HPA-1 headphone amp) and it works very well.
https://hifisonix.com/preamplifiers/class-a-buffering-the-correct-way/
I got it from jcx who used to frequent the forum but is no longer around. I’ve simmed it and built it (I use it in the HPA-1 headphone amp) and it works very well.
That is exactly what it is for. But today's op amps don't need that trick. The horrible 4136 really benefited from this, but not a nice modern op amp.
Thanks for nice info! For anyone wanting to build the appnote RIAA it could do the trick.
On the other hand, I think Jim Williams, who used this biasing scheme, knew what he did as well. Elswhere in the forum threads, it has benn noted that the CCS could be replaced by a single resistor to obtain the same result. I guess it would.
But for the two of us who has already build this amp according to Jim Williams design, I think we are quite happy with this mmmc RIAA amplifier!
Note that the buffer I used instead of the LT1010 is also advised by Jim Williams in another appnote.
Sell the MC and use the get an MM instead 😉 - I have been using Nagaoka MP series pickups for a few years now and couldn't be happier.
No, a single resistor adds distortion. It does bias the output stage into class A for a certain range.
The best example, look at the data sheet for the uA739.
With modern op amps, forcing an already well biased stage into class A does nothing for you except increase running temperatures at best. The older op amps benefitted from this mod. The 4136 being the most notable. It was used everywhere. You could improve things with a bias on the output, but honestly the best improvement is to replace it with anormal audio op amp on an adapter PCB.
The class A addition is something that is a holdover from poor op amps. Best solution, install a good op amp and you improve everything all at once. Just like magic. If the circuit uses a modern op amp, you are simply messing with things for no good reason.
The best example, look at the data sheet for the uA739.
With modern op amps, forcing an already well biased stage into class A does nothing for you except increase running temperatures at best. The older op amps benefitted from this mod. The 4136 being the most notable. It was used everywhere. You could improve things with a bias on the output, but honestly the best improvement is to replace it with anormal audio op amp on an adapter PCB.
The class A addition is something that is a holdover from poor op amps. Best solution, install a good op amp and you improve everything all at once. Just like magic. If the circuit uses a modern op amp, you are simply messing with things for no good reason.
Well, I am not skilled enough to claim that LT doesn't know how best to use their own amplifiers... (!)
Maybe some of you guys are.
Maybe you are all right.
Maybe my amplifier sounds good.
Maybe I am satisfied with that,
Here's the LT1115 datasheet showing several (audio) designs using this biasing scheme.
🙂 morten
Maybe some of you guys are.
Maybe you are all right.
Maybe my amplifier sounds good.
Maybe I am satisfied with that,
Here's the LT1115 datasheet showing several (audio) designs using this biasing scheme.
🙂 morten