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Post by Superman on Jul 13, 2006 9:01:16 GMT 7
may MC step-up ba na hindi tranny-based, doc?? thanks!
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Post by garp on Jul 13, 2006 13:20:10 GMT 7
Superman may recommended JFet based na MC sa diyaudio. Kaso mahirap hanapin yung particular JFET. For an MC stepup, here's what I recommend given a 7K budget: Go to silver strings (or get a buddy to buy you) and get the LL9206 for P6.4k. Have jojo make a you nice small case (2x4 inches is enough, aluminium case is available sa Alexan) and get him to configure the gain (10x or 16x). Like this: You don't need the PCB. Just P2P will do. The wiring diagram on the LL9206 is on the datasheet at K&K audio. Depending on the loading of your chosen cart, parallel a resistor with your MM's input load which is usually 47k (again, Jojo would know). Voila! You have an MC cart that's used by Art Audio Vinyl in their Blue Moon awardee Vinyl Reference phono here (actually this is just white label K&K audio phono): But if you have more to spend, the Jensen is reputedly slightly better and if have $1K to spend get the S&B TX-103 at diyhifisupply. Sowther is available too at a higher price but will sound only marginally better daw.
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Post by JojoD818 on Jul 14, 2006 11:46:40 GMT 7
Very nice input there Garp!
Jen,
For non-tranny based step-up, I think I have a 6922-based and a JFET-based (as Garp said). I may have a pair of JFET for that particular purpose. Both these approaches, however, are powered types, meaning they use a small, well-designed (for low noise) power supply.
Cheers
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Post by Superman on Jul 14, 2006 13:04:41 GMT 7
Very nice input there Garp! Jen, For non-tranny based step-up, I think I have a 6922-based and a JFET-based (as Garp said). I may have a pair of JFET for that particular purpose. Both these approaches, however, are powered types, meaning they use a small, well-designed (for low noise) power supply. Cheers thanks doc! sige, please PM me details of both so i could evaluate, especially in terms of cost, hehehe!...the 6922-based, u mean tube?? anyway, will eagerly await from advise from you, bro...thanks and god bless! Superman
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Post by garp on Jul 14, 2006 14:03:13 GMT 7
Not based on experience but research only. Tube MC phono doesn't seem fall into favor among designers. Designer Thorsten L himself admits that he's done everything to make an MC using only valves but still find them too noisy. Maybe that's why you hardly see any them in commercial designs. As for hybrid design using Jfet as mc stepup and tubes, lots of people at diyaudio have tried it and said that the result is not bad at all. Someone in diyaudio has compared the jfet vs tranny using the highly esteemed 2sk170bl vs. the LL9206 and said that after 100 hours of burn in the LL9206 tranny is clearly better. So based only on this bit of research, the recommendation is junk the tube mc stage, go for the jfet or the tranny.
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Post by JojoD818 on Jul 15, 2006 10:58:19 GMT 7
it's true, tubed mc can still be plagued with noise problems. for ease and simplicity, nothing beats a tranny step-up but at the expense of $$$.
I think I have the 2SK170BL stocked around here, I remember using it for a mic preamp buffer before.
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Post by Superman on Jul 15, 2006 12:05:32 GMT 7
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tony
Audiophyte
Posts: 1
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Post by tony on Aug 14, 2006 13:41:46 GMT 7
it's true, tubed mc can still be plagued with noise problems. for ease and simplicity, nothing beats a tranny step-up but at the expense of $$$. I think I have the 2SK170BL stocked around here, I remember using it for a mic preamp buffer before. jojo, you may want to try this one: users.ece.gatech.edu/~mleach/headamp/the ouput will go to your regular tube phono preamp of course, and you won't spend over a thousand for this mc head amp. there are many japanese transistors that are wothy to be employed in this circuit, just choose one with low noise characteristics..
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Post by JojoD818 on Aug 14, 2006 16:14:50 GMT 7
Tony,
Built that one already sometime ago chief. Thanks!
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symon
Audiophyte
Posts: 28
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Post by symon on Jan 4, 2007 10:46:43 GMT 7
Master Jojo,
May tanong lang po ako tunkol sa diy tweeter/super tweeter. Ano po ba ang difference sa circuitry at sound characteristics ng 1st order at 2nd order configurations ng tweeters? Sana po pag pasensyahan niyo po ang pag ka inutil ki dito. hehe.
symon
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Post by joel on Jan 4, 2007 20:22:18 GMT 7
1st order - mami muna
2nd order - siopao na, pero me choice pa --- asado o bola-bola.
tama ba ako jo?
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Post by JojoD818 on Jan 4, 2007 22:12:55 GMT 7
joel,
tama! pero nakalimutan mo yun hot sauce... Tabasco!
symon,
hindi kaya yun topology ng passive crossover ng tweeter ang tinatanong mo? kasi wala akong alam na order ng tweeter eh.
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symon
Audiophyte
Posts: 28
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Post by symon on Jan 5, 2007 3:24:56 GMT 7
joel, tama! pero nakalimutan mo yun hot sauce... Tabasco! symon, hindi kaya yun topology ng passive crossover ng tweeter ang tinatanong mo? kasi wala akong alam na order ng tweeter eh. tama, topology nga nang passive crossover ng tweeter yun, unless may additional order ka ng kanin o iced tea, hehehe. sir kung may nalalaman ka dito, paki expound lang po yun differences, may balak kasi ako mag DIY ng tweeter, gusto ko sana malaman kung anong mga components ang kelangan. salamas...
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Post by JojoD818 on Jan 5, 2007 9:59:31 GMT 7
mas mataas ang order nun filter, mas matarik yun cut-off o yun tinatawag na F3. Ito yun point na kung san yun signal ay bumabagsak na sa -3dB.
yun first order capacitor lang ang gamit nito, yun naman second order meron pa naka shunt na inductor sa tweeter para mabypass pa yun mga low freq. hindi porke matarik ang second order ay ito na ang pinakamaganda, dapat mo malaman kung magiging tama ang phase angle ng super tweeter mo kumpara sa midrange at bass mo. ika nga dapat in harmony sila. meron din tinatawag na phase delay diyan, ingat ka dun kasi pag mali yun application, it will do more harm than good sa overall sonics ng system mo. parang jeepney na biyaheng meycauan-recto na naka pioneer kp-5 at pt-6 na tweeter yun. hehehe
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symon
Audiophyte
Posts: 28
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Post by symon on Jan 5, 2007 10:59:11 GMT 7
Masta Jo, Wow, salamat sa mabilis na reply. So sa pagka intindi ko, mas malinis o fine ang highs sa second order kasi naka filter ang lower frequencies, ngunit/datapwat dapat tama ang phase angle nila. Sir, btw, please note, naka full range driver ako. Na bi-bitin lang ako sa highs, so magda-dagdag lang ako ng (passive/independent) tweeter (na naka passive crossover lang), yung parang ginagawa ng mga naka open baffle speakers. Therefore, follow up questions po: - pano po malalaman/compute yun phase angle (kung applicable sakin, since crossoverless naman ako)? - pano po malalaman/compute yun phase delay (if applicable)? - yun pong sinasabi niyong inductor sa 2nd order, ito rin ba yung attentuator na linalagay nung iba na naka series (sa positive signal) sa capacitor? - kung ang frequency response ng 1st order ay 16khz-22khz (using a .68uf cap), ano po ang effect sa frequency response kung mag da-dagdag ka ng inductor (para maging 2nd order), same lang po ba? Pag pasensyahan niyo na po ang kakulitan ko.
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Post by JojoD818 on Jan 5, 2007 12:13:02 GMT 7
ah ok, parang may nabasa na ako na ganyan thread sa ibang forum. ;D
kung ituturo ko sa iyo yun math baka maupod na yun daliri ko kakatype. pero na gets ko na application mo. yun inductor, hindi attenuator yun, para sa second order lamang ito ginagamit. for your application mas mabuti pa ang first order upang wala maging phase angle o delay ek-ek problems. yun attenuator kailangan mo para matimpla mo sa full range mo. kailangan lang na sasaluhin ng super tweeter mo yun upper frequency cut-off ng fullrange driver mo.
katulad nito, gamit ito sa isang JBL VOTT (voice of the theater) setup na may jbl super tweeter. yun mid at tweeter meron attenuator since yun mid niya ay 110db+ yata ang sensitivity kaya kailangan nito. speco technologies l-pads ang ginamit dito upang maiadjust nun may ari ang level ng mids and highs niya.
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Post by JojoD818 on Jan 5, 2007 12:18:42 GMT 7
btw, ganun pa din ang frequency response ng second order compared to first order ha. mas steeper cutoff lang yun second order. pero kung may attenuator ka baka overkill na.
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symon
Audiophyte
Posts: 28
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Post by symon on Jan 6, 2007 15:12:58 GMT 7
Alright! Maaasahan ka talga master! actually yun talaga ang gusto ko malaman eh, kung anong application ang babagay sa set-up ko. Actually, may thread nga sa wiredstate tunkol dito, kanyalang ayoko mag tanong dun! Di ko pa maintindihan! hehehe! Ok, so 1st order it is. Mas simple na, mas mura pa. Basta dapat saluhin ng tweeter ko yun freq cutoff ng full range ko. Freq range ng full range ko = 33 hz - 20 khz. Iniisip ko mag lagay ng 1.0 uf cap para mag start ang cutoff around 12khz. Maramaing salamat master. btw, sir kung meron ka pics ng L-pads, pa post naman. hehe. salamat ulit.
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Post by JojoD818 on Sept 12, 2007 16:24:28 GMT 7
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Post by akyatbundok on Sept 12, 2007 18:01:53 GMT 7
ok to doc jojo, akala ko external hard disk hehe hanap ko agad yun usb port.
gumaganda ang design fafi.
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