5একটি মূল Arcam আলফা আপগ্রেড করার প্রণালী

পটভূমি

এই পুরানো সাহসী সম্পর্কে নকশা ফিরে তারিখগুলি 1989 এবং আমি বিশ্বাস করি খনি 1991 দ্য Arcam আলফা প্রথম এক ব্যবহার করা হয়েছিল ড্যাক প্রায় চিপ, বিখ্যাত TDA1541(একটি).  এখানে এই চিপ সমন্বিত খেলোয়াড়দের নিবেদিত একটি ভাল পাতা: Lamp­iz­at­or guy.  যে সাইটের লেখক বিখ্যাত DIY পরিবর্তন করার সময় বৃত্ত কিন্তু কয়েকটি গুরুত্বপূর্ণ ট্রিকস ব্যার্থ সিডি খেলোয়াড়দের.

Sec­tions to upgrade

আমি চিন্তা করার ঝোঁক সিডি play­ers as offer­ing three main areas for mak­ing sub­stan­tial sound qual­ity improve­ments: power sup­plies, clock­ing, out­put stage. Many novice upgraders nev­er pro­gress bey­ond fet­tling the ana­logue out­put sec­tion of a সিডি play­er. This is a shame because the really big gains typ­ic­ally come from improv­ing power sup­plies and clock arrangements.

Power sup­plies

The Alpha is bet­ter than some as stand­ard, fea­tur­ing two power trans­formers and a 6 x 1000uF bank of smooth­ing caps for the ড্যাক & op-amps. It seems clear upon intern­al inspec­tion that Arcam have taken a gen­er­ic Philips পিসিবি and power trans­former etc, তারপর তাদের নিজস্ব যোগ ড্যাক / out­put stage board which is powered by a second trans­former. Sadly this trans­former is prone to mech­an­ic­al buzz­ing (a side effect of poorly con­struc­ted frame trans­formers).  One of my earli­er modi­fic­a­tions was to replace this with a tor­oid­al trans­former of the same sec­ond­ary voltages (17.5V — 0V — 17.5V).  প্রধান পিসিবি'গুলি পিএসইউ caps power everything oth­er than the ড্যাক chip and out­put op-amps. Most, সব যদি না, এগুলোর প্রতিস্থাপন করা উচিত, not only to improve sound qual­ity but also because the elec­tro­lyte in the caps could be dry­ing up after 20+ বছর!  It is fash­ion­able and indeed seems bene­fi­cial to change rec­ti­fier diodes with soft-recov­ery types, usu­ally “schot­tky”. In my opin­ion this is a safe modi­fic­a­tion on digit­al sup­plies but may worsen the sound on ana­logue supplies.

To take things to a whole oth­er level it’s easi­est to mount some extra sup­plies off-board and run wires to it. Remotely feed­ing my Alpha I have sup­plies for my new out­put stage, the digit­al fil­ter (SAA7220), সঙ্কেতমোচক (SAA7310), servo driver chips as well as a trans­former ded­ic­ated to the after-mar­ket clock and the র্যাম আইসি.  The rec­ti­fic­a­tion and smooth­ing for clock sup­ply is on-board as I found on a pre­vi­ous pro­ject clock power sup­plies can cause issues when moun­ted externally.

For now I’ll just wrap this sec­tion up by say­ing use good qual­ity, LARGE capa­city caps on the ড্যাক smooth­ing and you’ll be richly rewarded.

Clock­ing

For a long while it’s been a pop­u­lar modi­fic­a­tion to “re-clock” the ড্যাক এ চিপ আপনার সিডি play­er. Repla­cing the stand­ard tim­ing crys­tal with a low-jit­ter clock can be a subtle improve­ment or a pro­found one, depend­ing on the cir­cum­stances. There are vari­ous after-mar­ket vendors of such clocks such as Tent Labs, Audi­ocom, জলজ পালন এবং, আরো সম্প্রতি, Fidel­ity Audio.

Bey­ond ড্যাক re-clock­ing, there are oppor­tun­it­ies to feed a “clean” clock sig­nal to oth­er parts of a সিডি play­er such as the decoder chip, digit­al fil­ter and maybe even parts of the servo. In the Alpha I have so far fed 4 clock feeds from my Fidel­ity Audio C2 mas­ter clock. Two of these re-clock pins on the ড্যাক, one does the digit­al fil­ter and the oth­er the decoder. Three of these are 11.2Mhz, the oth­er is 5.6Mhz (প্রধান ঘড়ি দুই দ্বারা বিভক্ত, which is avail­able on this par­tic­u­lar product).

আপনি নিচে এই পথ যেতে পারেন আপনি খুশি হবেন!

Out­put stage

The last thing I want to talk about is the out­put stage. Arcam did a fair job on the power sup­plies, a typ­ic­ally poor job on the clock­ing and again let us down a little bit with the main out­put sec­tion, কিন্তু সেখানে আরো বেশি খারাপ হয়!  The out­put stage uses two single op-amps per chan­nel and some good qual­ity caps to fil­ter এইচএফ noise. There’s noth­ing intrins­ic­ally wrong with op-amps but the ones avail­able at the time wer­en’t very good. It’s pos­sible to upgrade these 4 op-amps and the res­ults would be good. I tried to replace the final pair of op-amps with some Burr Brown OPA627, but I did­n’t get sound. Without look­ing fur­ther into it I think it may be because they are not unity gain stable, mean­ing they can­not work purely as a “buf­fer”, they must amp­li­fy the signal.

The reas­on I looked no fur­ther was because I was build­ing up a whole new out­put stage using a পিসিবি I sourced from the DIYAudio.com for­um. This was designed by Nel­son Pass, a man fam­ous for his large class A amp­li­fi­er designs sold under the name Pass Labs. This out­put stage was a quantum leap for­ward in son­ics!  Espe­cially so if, আমার মত, you enjoy a warm full-bod­ied sound. The power sup­ply for this is off-board.

Sum­mary

I will add to this art­icle as I think of improve­ments but it’s very dif­fi­cult to fit it all in as there is SO MUCH that can be done to an old সিডি play­er!  I would just hope to whet a few appet­ites of those seek­ing the elu­sive “per­fect sound forever” that Philips prom­ised us with the advent of the Com­pact Disc. If you enjoyed this art­icle and want to request more detail on one par­tic­u­lar area then please drop in a com­ment, আমি এটা দেখতে নিশ্চিত করা এবং সাড়া পাবেন.