Modifying my Carver TD-1700 (Aiwa AD-F880) for Better Sound

[@eleanorschrag4759]

Wait for it…the mighty, magnificent Boardwalk Hall organ in all its splendour!😮

[@asbcustom]

Nice work Jeremy. I use Alex's modifications also, he's a brilliant engineer and freely shares his wealth of knowledge. Something I've noticed is that the effect of his mods are more clearly heard on analog sources of well mastered material. When doing A/B comparisons on typical digital sources or, God forbid, online streams, I'm not certain I can hear much difference. Just for grins, try out your mods on an old record or open reel. It's more helpful if you had a lot of listening time with this deck but maybe there is another one in your collection that you're very familiar with. Anyway, nicely done again.

[@Oklawolf]

I can't wait to try the mods for the Technics deck. Unfortunately the seller I bought the new gears from and I have concluded that the gears are lost in the mail so I'm having to wait for another set to be sent over from the Netherlands. At this rate the first deck from Japan is going to get here first and totally upstage the Technics. My third OPA2228 is reserved for a future XK-009, whenever I can find one of those for a price I can afford. Maybe I should get a few more of those chips if I can still find some next parts order.

[@asbcustom]

I just go ahead and backorder the op amps and even though it takes months, they do eventually show up. I'm realizing I need to plan way WAY ahead now.@@Oklawolf

[@JamesE707]

By the way, I meant to say that I've never heard of Carver, but may be because I live in the UK? I like the rounded handles on this deck, nice touch!

[@Oklawolf]

Carver is mostly a North American brand known for amplifiers but they dabbled in other things as well. They've been known to use Sanyo as well for cassette decks, so you're not always guaranteed an Aiwa with them.

[@akozaki827]

Nice...

[@mark902]

gone are the days of getting something nice from america on ebay. in 2010 the canadian dollar was on par and i would get top of the line sonys (k700es, k777, k730es, k950es, fx1010, k75...) for less than a hundred, with shipping of 50 or 60 bucks with usps. not to mention the countless DD walkman, and small beautiful metal bodied walkman, and exciting tape formulations. for less than i can even remember paying. i had packages from ebay coming weekly.

[@borlibaer]

I am pretty sure there will be no revival on compact cassette as it happened to vinyl, unfortunately 😢

[@JamesE707]

Same model-numbered machines can sound different because their (unintentional) pre-emphasis and de-emphasis maybe is slightly different. And this will be exaggerated further when we rec/pb between different machines, as their pre-emphasis/de-emphasis is intentionally different. It was never truly standardised until the Prague 1981 STD was introduced, but even then, I've noticed that some later models also have not conformed to this - the AIWA AD-F770 (1982+), an even my later 1991/1993 Sony TC-K730ES. Oh, and the TEAC V8030S too, not truly a Prague 1981 standard machine it would appear. Quite often PB from a recording made from a non-Prague 1981 Std machine, on a Nakamichi (Revox, or equivalent) will sound brighter as the Nak/Revox have less de-emphasis. Personally, I'm I'm not so sure about the re-capping myth - that 'improvements' can often/always be heard. However, I think it is good practice to do so, if the machine is old. Just my 10 cents worth. (Edited x 2)

[@asbcustom]

Greetings Eric. I'll see your 10 cents and raise you a nickle. Regarding the re-capping myth, I have my own thoughts. Firstly, completely removing the old substandard lead-free solder and replacing with high quality lead, using best practices (we can speak more to this sometime), can reduce circuit noise. I proved this to myself long ago. Secondly, old caps will have higher ESR, and themselves induce more circuit noise as the result of their age, and material tolerance. In my own personal tests, I found noise reduction to be the main quantifiable factor. The perception is a change in the sonics, this can be heard monitoring the source or the tape. As to whether a particular capacitor has a measurable sonic signature, well, maybe yes, maybe no. I make no claims about it, but I do my re-caps with deliberate choices based on my perception of past experiences. Statistically speaking, I don't think we could ever find a suitable test since two identical machines, often sound different in subtle, or very profound ways. Your call.

[@JamesE707]

@@asbcustom Hi Peter, personally, I think there is forum over-hype regarding re-capping, but overall, it's a sensible thing to do. As for ESR, well - I sense that this will make a difference only in certain circumstances. As for mathematically modelling a circuit (this is how they are designed) , the extra equiv resistances adding to say a high impedance input will make almost zero differences, inc noise I suspect. I could explain here, but I'll need space for diagrams etc. The whole discussion may be 'polluted' by the desire to be 'right' (web 'street cred') and from a selling of new components point of view. But all that aside, re-capping is indeed something I do almost always, but I'll be honest - I'm not sure if I can remember or tell the difference, so I go with what's probably the best thing - re-capping. :o) I have often measured old caps, and many are fine, inc ESR. Many folk talk about 'ESR' but if prompted to explain, many cannot, apart from what they read on the non-scientific forums.

[@asbcustom]

@@JamesE707 Yes, forum over-hype exists everywhere but even more profoundly in audio forums. In automotive racing forums for example, gratuitous claims are easily quantified, but in audio forums, it seems kissing slippers in an agreeable fashion is the most highly honored custom. I'd be very interested in your ESR soliloquy, diagrams et all. You understand that I'm a man devoted to metrology and love every aspect of it. Audio is difficult for engineers as so much of it is perception. When I was younger and schlepping gear for a recording engineer, he had a saying that "if it tests good, it sounds bad". He demonstrated this to me multiple times. Still, I love anything that measures anything, so please wax away anytime you wish. The only additional thing I'll add is that when I overhaul a deck, recapping is but one of a number of elements of the job. Attributing the enhanced sonics to capacitors is a claim I would never make because I know better. I also could not say with certainty that they didn't contribute, I only know the end product is superior to the one with which I started. Always a pleasure speaking with you.

[@JamesE707]

@@asbcustom Fully concur with your first and last paragraph Peter. As for forums, they are sometimes laughable, and sometimes necessary, for there are good, wise people there too as well as the deluded fake experts. Slightly off topic and regarding HiFi magazines, I recall once back some 20+ years ago when the author of a review into equipment stands, claimed there were sonic differences in the audio - I jest not!!! The corrupting element of money and, or generating more sales was, and will always be interleaved into life - it's the way of the world. ;o) ESR: When I get the time, I may write some theory material on my blogger pages, and may even add what the predicted impact of ESR is on the amplification of a single stage signal (not power) amplifier. I can't add noise measurements as I don't have the equip, although I could do a fourier analysis? Come to think of it, I'll need to find some old capacitors with a high ESR! Decibels: it is important for folk to understand that the human ear responds approximately logarithmically, that is - it responds well to powers of 2 in loudness. In dB terms, a double amplitude (not power) is +6dB, and double again is 12dB, double that is +18dB etc. We are able (correct me if I am wrong) to discern about 2dB differences - this is somewhere on our limits. Amps too are involved in massive signal gains, which is why we talk 'decibels'. A few percent (fractions of a dB) here and there in audio spectral variation or loudness, very probably will not be 'picked up' by a listener. The fact is, I'm not an 'expert', I am educated enough to know there are conmen, fake-engineers, fake-know-alls, and fantasists out there in noddy land, who have always had their hand in influencing others. Go check out KZbin for 'experts' on amps and speakers - they seem to find the best speakers 'I've ever heard' over and over again! ha ha ... it is rather funny.

[@olaniyi570]

There is probably an Azimuth difference between your two decks, hence the Dolby mistrackiing.

[@Oklawolf]

More than likely. That tape hasn't played well with Dolby on several decks now. I have an alignment tape now so I'll be checking that from now on.

[@JamesE707]

@@Oklawolf Yes, I think that is a possibility too. The problem with having a number of decks (and I have 30!) is that we all find that they don't kinda 'match' well as we would like. Too many little variables between them which are hard to correct.

[@Oklawolf]

We have a winner. The azimuth was messed up on the Carver. I ended up having to pull the transport out and pick the old paint off the adjustment screw to dial it in, but I got there.

[@borlibaer]

Yes, Trevors Bench is cool man. I myself di have a lot of gears to service and repair. Unfortunately I am only equipped with basic tools and I suffer for lack of money. I take this as an extra challenge to fix stuff with all I have in the first place. It is a chain of desaster, where it starts with the need of broken multimeters to get them repaired. 😁 An idler rubber for my various Technics tape decks even costs 40 - 50 Euro. 🫣