Quad 33 NET Audio Upgrade - User Impressions and Questions

[Beechwoods]

I'm seriously interested in getting my Quad 33 NET Audio upgraded.

http://www.net-audio.co.uk/quad33upgrade.html

I would appreciate any thoughts from members who have already gone down the NET Audio upgrade path. My specific questions at the moment are:

1. Is power still switched on by the 33's volume control, or is that bypassed, and only controlled by the power switch the wall-wart is plugged into, when using the external PSU.

2. Is the internal PSU 'better sounding' than the external PSU, or is it just more convenient having it all in once box? Instinct tells me that an offboard PSU is likely to sound best from an EMI perspective.

3. Is the 33 upgrade significant without an upgrade to the 303 as well?

4. I assume the 'Mono Left', 'Mono Right' switches still work. I use these a lot in conjunction with mono single-track reel to reel playback where the signal is mono on one or other of the stereo tracks. Not all my playback machines are switchable at source.

5. The Grounding Point on the back of the 33 is still effective? I use this to ground my Turntable.

--

These are the things I would like to think will be improved after an upgrade. Do any current users have any experience of whether my expectations are realistic?

- Crosstalk between Radio 1 and Radio 2 circuits eliminated.
- Lower background noise.
- Improved phonostage - would be interested in particular with any views on this as it's a main driver for my desire to upgrade.

Thanks for your advice everyone.

[Rare Bird]

Hi Nick
You could ask Steve
http://theartofsound.net/forum/showthread.php?p=310818#post310818

Id have thought only if you remove the original Volume Potentiometer you would loose the power switching facility.. Building the power supply outboard with it's own power switch is a good idea, but i feel you still want to retain the switching outlets for the 'FM3' & '303'..To be honest i always found it a pain having the tuner switched on all the time.

[Beechwoods]

I'd forgotten about Steve's thread. And Graham owning one. The PSU internal upgrade looks really easy. It'll be interesting to see what their experiences of the other upgrades have been. Thanks Andr'e.

[Beechwoods]

Anyone out there able to comment on my specific questions? I'm itching to drop some money on the upgrade, but don't want to be disappointed! I'm not *sure* that these questions have been answered elsewhere :scratch:

Thanks peeps :)

[The Grand Wazoo]

I'm not sure, but Barry may have some knowledge Nick - he'll be checking back in, in a couple of days, I expect.

[Beechwoods]

Has Barry been NET Audio upgraded? I didn't realise...

[The Grand Wazoo]

I'm not sure, but I can't believe he doesn't know at least a bit about them!

[northwest]

Nick, I am sorry. I kept on meaning to reply to this thread, sorry - scatterbrain:doh:
As you know, I have completely upgraded my 303 with all of the Net-Audio upgrades - Power Supply, Amplifier Board Components, Capacitors etc. etc.
The top and bottom of it is the amp has real presence and drives my ESL's effortlessly. the "upgrades" - which in my mind are not so much upgrades as much as refurbishments and an alternative way of getting to the same place are very worthwhile and in my opinion modestly priced. You get a lot for your money, I look around and see some of these so-called "improvements" for systems and the associated costs and this represents good value for money. If nothing else, the power supply mods are a must.
I wouldn't hesitate in reccommending them.

[Beechwoods]

Graham, thanks for this. Have you done anything to your 33, or do you use a different pre-amp? For my the first step will be to do up the 33, and then think about the 303...

[Barry]

Has Barry been NET Audio upgraded? I didn't realise...

Hi Nick,

No, I haven't been NET upgraded - it would take a lot more than that to upgrade me! A complete component upgrade and re-wire!

Alas, I have no experience of either NET or Dada upgrades, but from their websites would have complete confidence in approaching them for upgrades. Would suggest you contect either of them and describe in writing what you are looking for. These guys seem to know their business.

My own Quad 33/303 is used for AV duties, is unmodified and does the job.

The Quad 405s used in my main system have been modified by me as described in the Library article on Quad. The Quad 520f I also use is unmodified; though I want to modify it for balanced operation and await Dada's approved mod (they are sceptical about using a transformer).

Regards

[The Grand Wazoo]

Foiled again!...........if it hadn't'a bin for them pesky kids.........

[Beechwoods]

I dropped quite a detailed email to NET Audio yesterday... I'll post back with their comments.

[worrasf]

Only just seen this thread - the internal PSU is a significant upgrade from the already "better than oem psu" external one NA do. Timing, detail, PRaT all improved. Yes, main on/off/volume still controls power to the unit and output to the 2 240v outlets.
It's an easy DIY upgrade and builds on the improvements the other NA boards bring.

Yes, left/right mono functions as normal and chassis ground is untouched.

The only board not NA upgraded to date is the disc adapter board although David Pritchard tells me he has plans for one. I've updated a couple to modern spec with 47Kohm impedance instead of the oem 68Kohm and been very pleased. Just completely stripped an old board and punted a load of dollar to HiFi collective for set of Takman carbon film resistors, and Amtrans capacitors to bring it up to spec.

Steve

[worrasf]

Just completely stripped an old board and punted a load of dollar to HiFi collective for set of Takman carbon film resistors, and Amtrans capacitors to bring it up to spec.

Steve

Now done - not a load of dollar - in reality less than £50.

See post http://theartofsound.net/forum/showpost.php?p=319204&postcount=1

Well worth doing IMHO.

Steve

[pavalon]

I was wondering if the Net Audio 'Full upgrade' package for the 33 is worth doing or should one be spending the money on a pre-amp instead such as the Croft micro basic.

[Beechwoods]

I think Graham here (Northwest) has a Croft pre- going into a Quad 303 power. Me personally, I like the aesthetics of the the Quad 33, and it has a tape loop, which is important to me. I'll not be swapping my 33 for something else for a long time, least not for the foreseeable anyway :)

[Rare Bird]

Good for you Nick, i love the '33' asthetics & i'd of course use one but cannot live with that plastic back pannel & flaps nor the Dins

[DSJR]

No need to go too mad on a 33, as the circuit boards are ancient and I'm sure wouldn't really benefit from boutique components unless the track was stripped and gold plated at least - just my view...

My 33 was updated by me with a dada kit. The main improvement was to the basic and rather dated power supply arrangement, upping the voltage and updating the cap values and in my case, some utra fast snubbered rectifier diodes too, since I had some spare The other thing I did was suggested on Vinyl Engine and consisted of replacing C400 on the output boards with 1uF to replace the .068uF ones, this all but removing the bass filter on the output boards, retaining the one on the phono stage I think.

The Net-Audio mods basically take the old innards out and put new ones in, the preamp not being a true 33 any more. I suspect this is the best thing to do, but you don't have a 33 after this apart from the case and controls - IMO.

Is a 33 really worth messing around with like this? The 303 certainly is and many still regard the 303 as the best amp for 57's sonically. The 33, even when modified, can sound small and midrange led, with little going on at the frequency extremes and, with standard low filtering, a one-note bass too. Mine was rather better after I'd done it up, but it still altered the sound of a signal fed it via the tape monitor loop and more so fed through the radio input. Disc ain't too bad though. - Oh, and the original circuit doesn't offer a very high output either, hence the 303 and 405 being too sensitive for many modern line drivers (easy to adjust though with a soldering iron and a couple of the right value resistors changed - gives less noise too :)).

Net-Audio full 33 update, or a new Croft Micro Basic? Do I really need to ask the question??????? :rofl:

[Barry]

Good for you Nick, I love the '33' asthetics & I'd of course use one but cannot live with that plastic back panel & flaps nor the Dins

Agreed - I hate the rear appearence of the Quad 33 and FM3 with those 'cheesy' plastic panels. Yet the fronts are a design icon and worthy of the Design Centre award.

[pavalon]

No need to go too mad on a 33, as the circuit boards are ancient and I'm sure wouldn't really benefit from boutique components unless the track was stripped and gold plated at least - just my view...

My 33 was updated by me with a dada kit. The main improvement was to the basic and rather dated power supply arrangement, upping the voltage and updating the cap values and in my case, some utra fast snubbered rectifier diodes too, since I had some spare The other thing I did was suggested on Vinyl Engine and consisted of replacing C400 on the output boards with 1uF to replace the .068uF ones, this all but removing the bass filter on the output boards, retaining the one on the phono stage I think.

The Net-Audio mods basically take the old innards out and put new ones in, the preamp not being a true 33 any more. I suspect this is the best thing to do, but you don't have a 33 after this apart from the case and controls - IMO.

Is a 33 really worth messing around with like this? The 303 certainly is and many still regard the 303 as the best amp for 57's sonically. The 33, even when modified, can sound small and midrange led, with little going on at the frequency extremes and, with standard low filtering, a one-note bass too. Mine was rather better after I'd done it up, but it still altered the sound of a signal fed it via the tape monitor loop and more so fed through the radio input. Disc ain't too bad though. - Oh, and the original circuit doesn't offer a very high output either, hence the 303 and 405 being too sensitive for many modern line drivers (easy to adjust though with a soldering iron and a couple of the right value resistors changed - gives less noise too :)).

Net-Audio full 33 update, or a new Croft Micro Basic? Do I really need to ask the question??????? :rofl:

Sorry to ask again......you mean Net Audio is better than Croft ?

[DSJR]

Don't be silly now, you'll be getting me going in a minute.....

If the upgrade to a thirty plus year old 33 is going to cost any more than, say, £250, I'd seriously add the extra and buy a new Croft Micro Basic (older used higher-up models are like hens teeth). The phono stage is better, the line inputs much better suited to modern sources and the bloody thing measures properly as well!

[pavalon]

Not wanting to spend silly money on the upgrade path. Will just look at the minimum upgrade to the 33.

Thanks for the clarification DSJR.:)

[Rare Bird]

I think id be tempted to just upgrade the PSU a bit & swap out all the caps, run a seperate Phonostage for the fuzzies.. You need to utilise an input for CD too.. All that apart from the phonostage shouldnt cost too much.

[DSJR]

£22 approx for an upgrade kit from Dada. I didn't bother with the gain tweaks, as I used the tape monitor input for CD use (and adjusted the levels with the tape playback adjuster taps. A handful of Wima 1uF caps is a quid or so on ebay IIRC for the two needed on the output cards. The difference and improvement to the 33 sonics isn't small, since before the mods, the late 33 I had sounded one-note in bass and treble (one note cymbals and kick drums thumping with no expression at all, whereas an AVI ss preamp reproduced playing differences clearly - leaving out the valvey Croft for a minute). After the mods, the 33 was very much better, but the AVI still had the edge quite clearly, hence my suggestion not to spend too much. Obviously the Net Audio rebuild basically puts a new preamp into the 33 casework and adds an extra power supply if you go the whole way. Nowt wrong with modern op-amps at all, but they don't glow in the dark, sadly :lol:

[Beechwoods]

I'll be going the full NET Audio 33 monty myself. As for phonostage, that'll be for another day but it'll be more than £250 to get something of the quality I'd like.

[DSJR]

Why more than £250, unless you want to pay loads for "intellectual property?" I appreciate a good valve stage including power supply won't be pennies to produce and appreciate the likes of the Croft one at £600 or so will have a lot of power supply gubbins in it and be hand assembled with point to point wiring, but a solid state one? Transistors are pennies each, resistors are several-a-penny, good modern spec caps are pennies too apart from the larger ones which are tens of pennies and even the supply ones are a few quid each. I appreciate that manufacturers need to make a living too, but I baulk at the ten times plus markup from factory floor to retail price that so many old-style makers still try to enforce and some online suppliers are now charging retail prices online, absorbing the dealer margin into their own pockets for the priviledge. OK, we've been spoiled by the Chinese invasion (little active speakers costing £60 imported and selling on the high street in pro audio shops for £300 for example), but this is where consumer electronics is at these days and solid state electronics just don't have to cost this much - especially phono stages IMO.

[Beechwoods]

I like the form factor of the 33 and wouldn't want a phonostage much bigger. What 'giant killer' phonostages might be in the running?

[DSJR]

Obviously, I like Glenn's stuff. I'm also trying to persuade hifi Dave to try the baby Icon Audio one, which is cheaper a fun looking (sounding?). For cheapies, I wonder just how good the Rega Fono USB is? I have one here for a cousin to use for digitising old singles, but haven't got it out to listen to myself.

As said above, for £400, you could have a Croft Micro Basic with excellent phono stage built in and a very fair line buffer too. I wonder if Shane (Southall1999) would sell his on since he's been trying to flog the Series 5 Croft he bought recently?

Loads more out there, from NVA and others, but I have little to no experience of these. the new Cambridge 651? appears to have had a major makeover on its predecessor too.

[Rare Bird]

I like the form factor of the 33 and wouldn't want a phonostage much bigger. What 'giant killer' phonostages might be in the running?

Hi Nick
I fully understand your determination to keep the '33' regardless of being persuaded to buy something else instead of spending loads upgrading! But i wouldnt personally spend so much on it, you can't get blood from a stone..

I think a power supply upgrade & caps are gonna be quite satisfactory, last thing you want is changing the sound of the pre, or maybe you just love the asthetics & the flexability for your tape activities & really deep down at the bottom of it, your not happy with the sound?

An idea could be modify one of the disc card section to be a straight line through & fit a tiny phonostage internally like a graham slee or summert?

[Beechwoods]

To be honest Andre I'm really happy with the sound and I'm really only looking to eek the last bit of performance out of it. I certainly don't want to chuck the baby out with the bath water and end up with something which is something else entirely with a 33 box round it!

I'm inclined, after this very useful advice, to do the PSU upgrade first and see how that sounds. I can manage / match line levels via a mixer / source switch I pass my inputs through before they get into the single 'Radio' inputs on the 33. The only other thing might be a mini phono pre hidden away somewhere as I think that might be the main weakness I currently perceive with the built in phono board.

Will take a look at the Graham Slee et al in a bit more detail.

Thanks to both of you for your help.

[DSJR]

The dada website has loads of manuals, upgrade documents and parts for these, with plausible explanations as to WHY they're suggesting the 33 supply mod for example. A good bog too with so much Quad info on various models.. The yahoo Quad group is useful as well and although I appreciate that some amps don't automatically need new caps every fifteen years or so, Quads DID back then!

[pavalon]

The dada website has loads of manuals, upgrade documents and parts for these, with plausible explanations as to WHY they're suggesting the 33 supply mod for example. A good bog too with so much Quad info on various models.. The yahoo Quad group is useful as well and although I appreciate that some amps don't automatically need new caps every fifteen years or so, Quads DID back then!

Hi David.

My 33/303/FM3 have had no service as far as I am aware. The items were purchased earlier this year and apart from testing to see if they were working the items have been in storage since.

I recall that the sound was quite dull musically and knew that a service was necessary. Initially my intention was to send them to Quads but since reading the threads here on the forum........ the Net Audio/Dada upgrades may be cheaper.

I am not very technical regarding electronics so a few more questions if I may:
1) The 33 is set up with phono playback. If I was to use the Dada $22 kit would I retain the facility to connect to my turntable?
2) Can I go for the internal PSU upgrade from Net Audio and would still be ok to use the dada basic upgrade kit?

Thanks.

[DSJR]

The dada update retains the phono AND updates the power supply to 16V as well. PLEASE try to get the docs from their site - you only have to register as they're free and they'll tell you all you need to know.

As for the 303. Mine had been completely rebuilt unkown to me with all new resistors, trimmers, caps including Black gates and high quality Elna supply and speaker coupling caps (original values though, not double the value as is commonplace these days). Depending on the sample you have, the caps are really important as the originals DO age badly and if you're able, the voltage settings should be checked too - loads on the web about the 303 and the Richard Brice site is good too for this.

One quick thing. Low cost amps, especially those which get good reviews, tend to sound toppy and "impressive" for a variety of reasons. "Proper" top end amps don't, the treble having a much more refined quality. A good 303, 405-2 warmed up, 303, 606 and descendants just don't have this "impressive" quality in the treble, and more of a velvet smoothness. Don't think this is dull and bland, because it isn't. It's just not "showy," that's all and if you put a high grade modern preamp on the front and take care over absolute phase (the 33/303 combo is phase correct, but not individually), the 303 can charm the pants off you as long as it's not being pushed or driving a load it doesn't like - it's NOT for hard rock at high levels unless the speakers are huge Tannoys or similar....

[southall-1998]

DSJR,

Can you list some speakers that will work nicely with the Quad 303.

S.

[DSJR]

Many speakers will work, but they ought to be fairly efficient and easy to drive. The 303 has a capacitor coupled output which I think is very rare these days, the output current is strictly limited for the 57 speakers, which are a perfect match I think, but big transmission lines and heavily ported speakers should be avoided I think - and that means vintage BBC derivative speakers as well, although the midrange is lovely through these as a breed. Tannoys of old were always a great match but it's really a suck it and see kind of thing in all honesty.

[southall-1998]

Many speakers will work, but they ought to be fairly efficient and easy to drive. The 303 has a capacitor coupled output which I think is very rare these days, the output current is strictly limited for the 57 speakers, which are a perfect match I think, but big transmission lines and heavily ported speakers should be avoided I think - and that means vintage BBC derivative speakers as well, although the midrange is lovely through these as a breed. Tannoys of old were always a great match but it's really a suck it and see kind of thing in all honesty.

Monitor Golds:eek::eyebrows:

[DSJR]

One of the classic systems of all time could be a Thorens/Garrard with SME/Shure, Quad 33/303 and either 57's or some luverly HUGE Tannoys.. Lovers of squeaky little desktop active's just don't "get" how much more realistic a GOOD big speaker system can be, even if technically, the little 'un is lower in distortion and colouration - the little 'un HAS to be to be listenable at all IMO.

Thread drift, but a few years ago, hifi dave and I were "willing victims" on some dual 15" bass-unit Cerwin Vega's that stood nigh on 5' high or more. Who cared a jot about "fidelity," these bloody things rattled the fabric of the building, short circuited your senses going straight for the soul and sounded so real and "live," you weren't listening to THEM, you were feeling the performance as recorded, mixed and mastered with the biggest naughty grin on your face you could possibly have.

[dantheman91]

Hi Chaps

:rolleyes: seems that my "Mono" Left & Right buttons don't appear to be working on "Radio 1" input not that i use them just wondering if i could fix it servisol maybe but it has been serviced this year.:scratch:

Thanks
Dan

[Desmo]

Can you list some speakers that will work nicely with the Quad 303.

S.

I use B&W P6 floorstanders with my NET Audio modified 303s. They work very well - "great synergy", at they say in these parts. I have them bi wired, and bi amped though...