Hugh, I agree that this so-called "new world" is into SMDs and making things smaller and smaller, but I don't personally think that we "have to" or "need to" learn to work with them as long as TH devices are available.
I'll continue to order my Vishay RN55 series resistors and any other TH components I need in order to complete a project.
If a TH PCB isn't available, I'll layout my own if it's a project that I think I can't live without.
Working with SMDs really boils down to the quality of someone's eyesight and to a certain extent one's age, which usually go hand n' hand.
I'm knocking on 50 and happen to see better up close than far away since I've always been nearsighted.
But...there are many folks out there that are just the opposite and are farsighted making soldering SMDs difficult.
By the way, if you can't see some of these devices as you stated above, how in the hell are you going to position them in place and solder them to the board??
Seems kinda counterintuitive to me.
Anyway, I'm not trying to derail this thread into a TH vs. SM debate.
Apparently this "X" character either isn't that old or still has decent eyesight in order to build all these HAs using SMDs.
I would LOVE to compare this AC-coupled "Lender" to a Schiit Magni 3 for preamp duty, especially since I already own the Schiit.
Oh well...
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Impact of Input Cap on Bass Extension
Here is a quick test with and without the 4.7uF 50v Wima MKS cap. The remaining ChiFi 1.0uF cap seems to have a -0.5dB reduction at 20Hz and -1.3dB difference at 10Hz. So it would seem that this is probably not going to be audible from a bass extension standpoint, but from a resolution and transparency standpoint, it may be better to have just one cap.
So I will have a listen to the single 1uF cap and see how it sounds. Those 4.7uF Wima's are not cheap so this is welcome news.
Here is a quick test with and without the 4.7uF 50v Wima MKS cap. The remaining ChiFi 1.0uF cap seems to have a -0.5dB reduction at 20Hz and -1.3dB difference at 10Hz. So it would seem that this is probably not going to be audible from a bass extension standpoint, but from a resolution and transparency standpoint, it may be better to have just one cap.
So I will have a listen to the single 1uF cap and see how it sounds. Those 4.7uF Wima's are not cheap so this is welcome news.
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You are welcome. It was a good learning experience for me to actually verify that the bass falloff really follows the equations that we are told that they should follow. It also shows that the output cap choices I have apparently seem to be doing a good job on the bass extension as well.
For the record, I have the following combo on the output caps:
1. Nichicon VR(M) 1000uF 63v
2. Elna Silmic II 220uF 50v
3. Wima 1uF 250v MKS 4 (p/n MKS4F041004F00KSSD)
So about 1220uF should be good for F3 of 2.6Hz, so very similar to the 1uF input cap, so they are well matched.
Do yourself a favor and get these headband magnifiers. I am knocking on 50 as well and eyesight is not what it used to be either. Even for TH soldering, I wear them half the time. I have used them for 5 years - same basic $7 model (nowadays $9). Also, you will need a good pair of stainless steel tweezers, preferably Swiss made and about $25, a smaller solder iron tip (but I like to use solder paste from a syringe and a hotplate).
SE MH1047L Illuminated Multi-Power LED Head Magnifier - Magnifying Glass - Amazon.com
But, like I said, this Aksa Lender pre is available as all TH construction. Btw, the main board is a healthy 135mm x 114mm.
So I have the M3 as well, and am comparing them now. You will not regret making the Aksa Lender - it sounds better, is quieter, can get way more voltage swing and not go nuts with distortion.
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Hi Ammel,
Easy! I design the pcb on software, which I can blow up very large on a 22" monitor, and then hand it all to my assembler, a factory business with all the gear (including robot pick and place) for building very nice pcbs.
So I design with PC magnification, and then machines and youngsters to put it all for me!! Heck, I couldn't build themselves...... but as it happens, power amps need some high dissipation resistors, so only a few of the small ones are 1206 and 0805.
Here is one of my Maya 200s. You can see that not all are smds, but there are quite a few diodes/optos/transistors which are very tiny. Nicely put together for my assembler, and they always work perfectly every time.
I'm 66, BTW, but I have pretty good eyes, though long sighted. Can't read a newspaper headline without glasses. I have not yet moved to eyeglasses, but I do have a magnifying glass on the bench. I don't do much assembly these days, it's too onerous after a bunch of health issues.
Cheers,
HD
Easy! I design the pcb on software, which I can blow up very large on a 22" monitor, and then hand it all to my assembler, a factory business with all the gear (including robot pick and place) for building very nice pcbs.
So I design with PC magnification, and then machines and youngsters to put it all for me!! Heck, I couldn't build themselves...... but as it happens, power amps need some high dissipation resistors, so only a few of the small ones are 1206 and 0805.
Here is one of my Maya 200s. You can see that not all are smds, but there are quite a few diodes/optos/transistors which are very tiny. Nicely put together for my assembler, and they always work perfectly every time.
I'm 66, BTW, but I have pretty good eyes, though long sighted. Can't read a newspaper headline without glasses. I have not yet moved to eyeglasses, but I do have a magnifying glass on the bench. I don't do much assembly these days, it's too onerous after a bunch of health issues.
Cheers,
HD
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You don’t think they need to match or you don’t think that with the values I have for caps, that they could match? As the output capacitance and headphone load impedance determines the output highpass frequency, one doesn’t want the input highpass to be the rate limiting one.
My boards arrived today. Thank you X.
Question, from my reading the daughter boards let you set the gain. I ordered an extra set of DB, so I hope I read right. Looking for one set with 4v p-p and the other 20v p-p. In my reading haven't discovered what values, guessing here of resistors for setting the different outputs.
Tnx
David
Question, from my reading the daughter boards let you set the gain. I ordered an extra set of DB, so I hope I read right. Looking for one set with 4v p-p and the other 20v p-p. In my reading haven't discovered what values, guessing here of resistors for setting the different outputs.
Tnx
David
Thank you for the suggestions, X!
I've got to try to Hugh's Lender. If it kicks the Magni 3's a$$ in SQ as a preamp, then color me impressed.
Well, it works well in front of any power amp IMO as it is essentially a noise-free way to get volume control and provide a constant impedance to the amp’s input stage to make sure bass extension is a deep as it can be. On ultra low ppm levels of distortion amps, it will give a slight SE Class A harmonic signature.
I use a Pocket Class A as a preamp for the TPA3116D2 and that works very well.
I use a Pocket Class A as a preamp for the TPA3116D2 and that works very well.
The new ALPHA amp thread is here:
http://www.diyaudio.com/forums/soli...hybrid-aleph-alpha-amplifier.html#post5323512
Sneak preview of performance:
http://www.diyaudio.com/forums/soli...hybrid-aleph-alpha-amplifier.html#post5323512
Sneak preview of performance:
I forgot to mention to folks following this thread, in case you haven't seen it yet, there is a nice Class A amp based on this front end that Hugh came up with called the ALPHA (Aksa Lender P-mos Hybrid Aleph). The thread is here:
Aksa Lender P-mos Hybrid Aleph (ALPHA) Amplifier
Here is the PCB layout by JPS64:
FFT for 2.83vrms into 8ohms with 1.2amps bias:
Aksa Lender P-mos Hybrid Aleph (ALPHA) Amplifier
Here is the PCB layout by JPS64:
FFT for 2.83vrms into 8ohms with 1.2amps bias:
