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In Reply to: Thanks for the responses posted by Dave Kingsland on December 30, 2006 at 09:47:56:
Accuphase audio circuits use the finest grade of components available! You cannot better them. New electrolytics may solve your percieved bass issue.Then again, you most likely aren't use to the ultra-accurate, linear and realistic sound reproduction that is exclusive to Accuphase.
Follow Ups:
"Accuphase audio circuits use the finest grade of components available! You cannot better them. New electrolytics may solve your percieved bass issue.Then again, you most likely aren't use to the ultra-accurate, linear and realistic sound reproduction that is exclusive to Accuphase."Have you ever owned or worked a T-101, and examined the parts used inside it?
I'd love to know your thoughts on the tantalum caps used in the audio signal path. Ever compare Black Gate or polypro film caps to tantalum caps in the signal path?
The quality of components used in 1974 has improved a little bit over the years. It has been 30 something years.
Tantalums are only used in regulatory stages. Only the finest audio-grade mylars are used in the audio path.
Your enthusiasm for Accuphase is entertaining, and encouraging at times, but in the case of the T-101 you're way off.There are a lot of tantalum caps in the audio path after the MPX IC's. Every series/coupling cap in the audio path is Tantalum (there are 5 per channel). Most shunt/parallel caps in the audio path are poly film, with a few electrolytics mixed in. Basically, it seems that all the small value caps are poly film, medium value caps are mostly tantalum, and the few larger caps are electrolytic. The only mylar film cap in the audio path is in the MPX filter. There's also one mylar film cap across two pins of the MPX IC, but I don't know what it's for.
There's also a handful of resistors in the audio path, and they're all garden variety gold banders (+/- 5%).
In short, while the audio board's circuit design is definitely audiophile grade, probably top notch for its time, the parts quality seems to be nothing special, at least by today's standards.
"Only the finest audio-grade mylars are used in the audio path."Do you have the schematic? If so, tell many how many audio path caps you count, and the schematic designations. I'll gladly do it, but after you.
The schematic also lists the cap type. I'll give you a hint - I have never seen a production tuner that has all film caps in the audio path. I don't have my T-101 anymore, but still have my T-100, and my statement includes it.
George;
What your agenda regarding Accuphase is, I can only guess. Short posts, with no technical information, telling everyone how great Accuphase is, seem odd to me. I service, build, and modify my own audio gear, and have a complete RF lab with the best FM stereo generators to align them. I do this as a hobby only.
Here's the list of tantalum caps in the Accuphase T-101 I recommend people replace. The value is given below as size in uF, and cap voltage rating as uF/voltage.
C2 22/16
C16 .1/35
C17 .1/35
C18 10/16
C19 10/16
C20 .22/35
C21 .22/35
C22 .22/35
C23 .22/35
C26 10/16
C27 10/16
I would replace the .1 and .22 with polypropelene or polystyrene film caps, and the 10/16 with black gates, standard if you are cost concious. The whole lot will likely cost under $20.
Any tampering whatsoever with the critically-voiced design will ruin both it's sonics and it's value! If you have nothing but Tantalums in the audio section, either its been modified, or less likely, you own a rare example of the first production run.All vintage Accuphase unit's should have audio-grade mylars in the signal-path, coupled to a polystyrene at the output (depending on its production date).
Anyone looking to correct unauthorized tamperring and modifications should immediatly send their unit to the Accutech service center.
Those with impeccable repair skills should correct their units under the guidance of someone that knows Accuphase units well.
I'm staring at the T-101 service manual listing the parts, and parts listing for all the audio caps say solid tantalum type. Why would Accuphase design the tuner, publish the service manual, and then "switch" all the caps? It was not their first tuner. Are you telling us they never listened to the tuner until after the service manual was printed? The model before this one, the T-100, did have mostly film caps, so it was not a case of not knowing. Your theory that someone modified the tuner and installed tantalum caps is totally absurd.
I'll scan and post the schematic and parts list if anyone would like to see it.Dave, who stated the thread, is telling us he is staring at an open T-101 tuner full of tantalum caps. I guess he has an ultra rare one, too.
BTW, save the dealer speak about "unauthorized tamperring and modifications" for those with no technical understanding and fat wallets. Anyone who does their own design and mods is capable of voicing their own designs to suit their own tastes.
Anyone who is unsatisfied with the sound of their Accuphase should sell it. They have no business modifying such treasures!
By the way, what is the shape and color of the capacitors in question?
So Dave, give all of them in there 'THE flick', aka get rid of all of them, even in the RF stages. Ordinary metallised film polycarbonates would sound better.Even Wima MKP's, but mix in some MKS's (styrenes!), they ARE a bit bigger. I'd leave the RF stage 'replace' and alignment work to a pro. RC has sealed unit RF choke filters so you may
WarmestTimbo in Oz
The Skyptical Mensurer and Audio Scrounger'Still not saluting.'
Read about and view system at:
George is our resident Accuphase evangelist, but he doesn't know the T-101. I've given the MPX/audio board a good look over and I'm impressed when it comes to design by not so impressed when it comes to parts quality.From a circuit design POV, things look really good, especially considering when it was designed. De-MPX is handled in an IC, but after that I think the output stages are all discrete. There are low pass filters in little boxes following the de-emphasis stage which I haven't opened, but everything else is discrete. De-emphasis appears to be a simple passive RC, which is nice. There is a Euro/US de-emphasis switch, but at least it's used to switch different caps to ground. Muting is via relay shunting the output to ground, so it's out of the circuit path. The audio board is grounded on the perimeter and the whole thing is shielded.
But when it comes to details like parts selection, the T-101 is a bit dated. For example, there are no less than 5 tantalum caps in the audio path for each channel. Most or all of them are +/- 20%. Resistor tolerances aren't great either. The signal path is also excessively long, thanks to locating the audio board on the opposite side from the IF board, and the output RCA jacks over on the opposite side again.
It seems that parts replacement alone could improve audio quality a noticeable degree, and the size & layout of the audio board makes it really easy to work on.
But -
I'm going to hold off on any mods until I can figure out the source of the noise problem we discussed below. I haven't had much time to investigate, but a few follow-up experiments confirmed that the source of the noise is external and directional. It also varies by day and time of day. And it's definitely strongest towards the low end of the FM band. I think the first task should be confirming that the antenna pattern is what I expect and/or confirming that all elements are connected properly.
Really! I hadn't noticed.I'M the resident 'whole of AA' - sphere evangelist and bore - so that's okay.
Mind you, you could know about 'cap's sound' way back in the late seventies, so the Model 3's all had polycarb Philips yellow blocks in the xover.
They were also a great PSU upgrade I did for integrated SS amps. Viz. I nearly wanted my old Au101 BACK!
The RFI noise source? can you swing the tenna, have head phones?, try finding the freq. or ranges of where it is worse and its 'line of sight' and try to plot that on a map of the town, then go looking, under its line - in your car with its FM tuner. Worth a try, and then ask the FCC for help.
How are your factory / business 'bombing' skills?????? ;-)!!!!!!! whooops, humour!!!!!!
Is there any grouping of 'philes where you live?
Narrowing the effective arc of the antenna's pattern, by stacking more than one, is one option.
BUT if the needed rotator arcs cover where the source/s is/are, your only recourse may be a second antenna/s aimed at the centre/s of that - connected OOP with the main one to reduce that noise. but again this lowers signal strength in that part of the band - which may not 'answer' the need.
I had a weird 'internally driven' RFI problem with my valve 'tuner' - but no effect on the sound at all - it just caused BADDDD TVI on 3 channels - throughout the house' coax network.
I wrote it up here, took a lot of asking, and wrong answers - before we had it figured. And then more 'wrong' answers - until we did a 'closest to source' fix.
Thanks for keeping me in the loop, you never know you might get lucky.
WarmestTimbo in Oz
The Skyptical Mensurer and Audio Scrounger'Still not saluting.'
Read about and view system at:
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