Two Questions 0n 33

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22-Oct-2017 03:48 PM

Jonners

Jonners

Posts: 8

I have a 33 and 303.  I have 3 questions/queries.
1. I had my Quad 33 upgraded by someone back in 2005 - I forgot about it to be honest - and have just bought the DaDa upgrade.  The one before is a Net Audio v1.3...  Not found out about anything to do with it yet.  How does this change what I need to upgrade?

2. I want to remove the 33Hz filter Quad put on the 33 to allow the Pre to go down as low as it can.  Any ideas how and what, please?

3.  The last is a corker!  Last night I was playing with cables and plugging and pulling, and some how, stupidly blown a capacitor (47nF 100 ohm 240v ac 630vdc) across the on/off switch.  Add to that it is DEAD, completely and i am no electrical engineer.  Can use a soldering iron with simple instructions, pretty well, but, eek anything else gets ify.  Any ideas, please?
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23-Oct-2017 11:24 AM

Joost Plugge

Joost Plugge

Posts: 938

If the Net Audio upgrade also means the boards are replaced with net Audio boards, our kit will not help you.

On numourus places in the 33 there are filters built in. So there is not a simple capacitor upgrade that will do the job.

The sparc supressor can be find here:

http://www.dadaelectronics.eu/shop/quad-second-hand-parts/new-quad-original-spare-parts/x2-supressor-capacitor-100nf-100r-evox-rifa

Joost Plugge

DaDa Engineering

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23-Oct-2017 12:15 PM

Jonners

Jonners

Posts: 8

Thank you, Joost

1. I did the DaDa upgrade yesterday.  Nice and simple, great for someone like me and was able to do the power board, mainboard and the turntable board.  The rest were net-audio specific and couldn't touch them.

2. 33Hz filtering.  I feared you would say that.  And not helped by the Net-Audio boards too I suspect.  On the Main and Turntable boards, do you have any ideas where the filters would be, or is this really too difficult?

3. The powerboard board is the original.   I am hoping that once the blown capacitor arrives (I found a source in Germany last night) and is fitted it will work again.  fingers crossed.

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23-Oct-2017 10:03 PM

Jonners

Jonners

Posts: 8

OK, so tried to contact Net-Audio.  The website is still up, but had no contact so tried the company recommended for fitting.  They were kind enough to get back to me.  Seems the owner/engineer died in 2015.  A sad loss.

The chap was kind enough to give me some advise.  Firstly all Net-Audio boards have the filters removed and will do the full range.  SO that's good.

He suggested that the capacitor blowing was not that uncommon and I said his suggestion was not to replace it but use a 3 capacitor delta filter instead.  And to also check the on/off switch as the contacts often oxidise after the capacitor has blown.  Not sure what to do and how with both of these points.

SO this means that once I work out how to do the cap and switch I'll have a Quad with both mods.  Shall be interesting....

Kind regards

Jonners
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24-Oct-2017 04:09 AM

EJP

EJP

Posts: 1405

What 33Hz filter? A Quad 33 is +/-0.5dB from 30-20KHz, and when renovated according to the Dada kit is -3dB at 19Hz, which is accomplished by increasing C202/3 to 2u2F looking into the 50k volume pot.
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24-Oct-2017 09:19 PM

Jonners

Jonners

Posts: 8

Page 18 of the user manual....  And it is described all over the place.  It was put in to reduce rumble from records...  The filters are in a number of places and is very strog as seen in the graph, but like all filters it is not absolute, it slopes off down from 0db at circa 40Hz to -40db at 5Hz.  Does it matter, it is sub hearing level?  Depends if you think sub and super audio sounds are important and what you are trying to achieve.  For me the Quad 33/303 is there to support super tweeters and sub bass, so, yes.
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25-Oct-2017 01:14 AM

EJP

EJP

Posts: 1405

Nothing about it on page 18 of my copy (yellow cover), and the specification I quoted is on page 19. I see some wording about a20Hz filter, and evidence for it in the response curves, which are flat to 30Hz. 20Hz is very different from 33Hz, more than half an octave.

For the rest, it depends on what you listen to. 40Hz is essentially the lowest note on a double bass or bass guitar. The piano, the tuba and double bassoon, and any large pipe organ go lower than that: a big pipe organ down to 16Hz or even 8Hz. Bass drums ditto, at least large orchestral bass drums, but the way they pad and record bass drums in pop music it's just a 'pat', no low frequency at all really.
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26-Oct-2017 09:25 AM

Joost Plugge

Joost Plugge

Posts: 938

Apart from needing loudspeakers/poweramp/room for coping with very low frequencies, from a technical point you can do something about it. If it is noticeable or creating issues is another question. Look at all the capacitors which are in series with the signal, input and output of the tape adapter, input/output of the main amplifiers and so on. You could decide to increase those values, again no garantee by me for the effect. A note on the Net Audio boards, David used op-amps instead of transistors. The single supply makes it neccesary to introduce some sort of virtual earth and probably input and output capacitors, I personally don't believe the boards will work at DC levels.

Joost Plugge

DaDa Engineering

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27-Oct-2017 10:40 AM

Jonners

Jonners

Posts: 8

EDJ

I think you have slightly over exaggerated how low things go, but I do take your point.  I just feel that when you create a hard stop or restrict then it has an impact, plus there is so much beyond human hearing that we sense and adds colour beyond the normal senses.  yes, there are different thoughts on this, but when the system is playing properly, which it has been doing it sounds amazing.


Joost

As always, thank you.  I have it confirmed that the Amp is working full range with the Net Audio boards.  And whilst they do sound great, I do wonder, as you say they use ICs instead of transistors that he has gone off the mark of a true Quad 33 and 303.  When is a 33/303 not a 33/303.

So, I now have a combo upgrade.  Looking forward to trying it out once my delta suppressor arrives.  I just hope I haven't done anything really silly and killed my baby when I blew it.


Thank you for all your're help.  I may be back for more questions if it turns out I have done something silly and it won't start.

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27-Oct-2017 12:28 PM

EJP

EJP

Posts: 1405

I have 'slightly exaggerated' nothing. The pitches I gave above are all objective facts.
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27-Oct-2017 02:07 PM

Jonners

Jonners

Posts: 8

Whatever you want to believe.  I only take my information from scientific journals and ISO standards - sheets are available for download.  But I didn't come on to this website/forum to have arguments and one one-upmanship contests with people who have nothing to do, I asked for some technical input, which I got.  Yours is just un-welcomed noise that wasn't asked for.
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27-Oct-2017 02:27 PM

Joost Plugge

Joost Plugge

Posts: 938

About when is a 33 a 33, if you look at the Net Audio website, the boards work with op-amps, also there are a lot of capacitors, as aspected. I don't have diagrams of the Net Audio boards. My personal opinion; if the functionality is not altered/limited, it is a 33. But a lot of our clients have a different opinion. Thats why we have the Engineering department for more out of the box solutions within the Quad bracket.

Joost Plugge

DaDa Engineering

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27-Oct-2017 03:21 PM

Jonners

Jonners

Posts: 8

Joost
I have had great joy out of the Net Audio, but when I installed them 12 years ago, I didn't realise what I was buying.  Personally, I like the idea of keeping as was intended, so maybe I shouldn't have installed those Net Audios.

Now I have a hybreed.

I would share what I can with you if I could upload pictures.
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27-Oct-2017 11:18 PM

Jonners

Jonners

Posts: 8

Joost
I am getting a lot of hum/buzz.  Any ideas, please?

Jonners
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28-Oct-2017 08:54 AM

EJP

EJP

Posts: 1405

The information I provided will be found in the Grove Dictionary of Music editions 1-5, and the New Grove Dictionary of Music, among many other places, but it follows directly from A=440.

The pitches produced by musical instruments are not defined by ISO standards or scientific journals. And neither of these use language like 'whatever you want to believe'. If you have some relevant information please provide it, and cite it properly.
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