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Post by Clive on Apr 8, 2016 10:51:00 GMT
I installed the new PS capacitors last night. I've not been in the mood to fully assess and compare the sound with my other amps as my dog died, my best friend of 12 years. It'll sound OTT to non-animal lovers but this hard. Anyway, from a quick listen using my 100db sensitivity open baffles I found the sound to be flowing and rhythmic with plenty of detail. Where a good class D amp (eg Temple Bantam One 40W) does "start/stop" and dynamics in spades the Quad sound is more flowing and closer to a valve SE amp yet it's not short on dynamics either. I need to reset the gain on the 306 so I'll pop out to get the required resistors. All in all it's very promising but very early days in terms of my assessment. ![]()  |
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Post by Clive on Apr 15, 2016 11:31:04 GMT
Having listened further to the 306 and contrasted it with the new Temple Audion Bantam One and my 300B SE amps, my conclusions are that the 306 is very good. Vs the One the 306 is marginally less detailed and less "fast". The 306 flows a little more from note to note vs the start/stop capability of the class d One. Vs the 300B the 306 has much of the flow of the 300B but is closer to having the detail of the One. The 300Bs present the bones of the music really well but ultimately don't provide the same level of resolution.
The work I've done on the 306 so far is just to replace the main PS capacitors and reduce the gain little. My next step is to implement the rest of the Dada Electronics upgrade, probably late next week. This replaces the small value ceramic capacitors with polystyrene and polyprops for the slightly bigger ones. The two remaining elect caps will be replaced too, and 10 decoupling caps will be fitted. The opamp circuit will be modified to use the values used in the later 606mkII and 909, it seems these are better optimised.
I hope I like the changes! The amp is easy to work on and a pleasure to work on. Even with the cost of the upgrade kit the amp is one heck of a bargain.
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Quad 306
Apr 19, 2016 21:25:04 GMT
via mobile
Post by Clive on Apr 19, 2016 21:25:04 GMT
Tonight I finished the upgrade to the 306. Playing into my 100db sensitivity open baffles and some 88.5db reflex speakers I'm impressed. The sound is fast, dynamic, clear and super clean. I'll review once I have some more hours on the changed capacitors.
With upgrades the amp has cost me £250. Amazing value.
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Post by Dave on Jun 16, 2016 12:14:14 GMT
Clive, I'd be interested to learn what I'd need to do to reduce the input gain on my 306. Whilst it was okay with the BTE passive pre, the Little Dot mk2 can overdrive it somewhat, although I can negate this by adjusting the levels on my computer (not an ideal solution). Incidentally, I've found that driving the Quad with valves seems to be the way to go, to my ears anyway.
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Deleted
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Post by Deleted on Jun 16, 2016 16:03:07 GMT
I am sorry to hear about you friend death it bloody hurts, I was very upset when mine died a few years ago and often think could I have done anything to change it.
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Post by Clive on Jun 17, 2016 10:47:16 GMT
Clive, I'd be interested to learn what I'd need to do to reduce the input gain on my 306. Whilst it was okay with the BTE passive pre, the Little Dot mk2 can overdrive it somewhat, although I can negate this by adjusting the levels on my computer (not an ideal solution). Incidentally, I've found that driving the Quad with valves seems to be the way to go, to my ears anyway. I'm not sure what Colin is referring to but it doesn't sound great. Re 306 gain, here are the words direct from the Dada manual (BTW the std resistor is 9R1): The standard input-sensitivity is 0.375 Volt. If you want to change it to 0.775 Volt replace R13 with 18R – if you want to change it to 1.0 Volt (Line-voltage) replace it with 27R. The alternative resistors are included in the kit.
If you are using the 306 with a 33, 34, 44 or 66 preamplifier you might not prefer to change the sensitivity. But in most cases the 0.775V or 1.0V setting makes the volume pot range on Quad pre amps more usable. For other preamplifiers you would prefer the 1.0 Volt sensitivity. Of course you can always change it afterwards.
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Post by Dave on Jun 24, 2016 5:51:36 GMT
I am sorry to hear about you friend death it bloody hurts, I was very upset when mine died a few years ago and often think could I have done anything to change it. Hi Colin, if your comment was meant for me then I have to say I am a little confused, please enlighten me... |
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Post by kettlechips on Jul 31, 2016 16:09:32 GMT
I run a pair of modified 306's to bi amp my speakers and they sound pretty dynamic. There are a couple of mods beyond the Dada ones that are worth considering, including replacing the diodes with better "faster" ones. I agree that these amps are particularly easy to work on, and they respond very well to sensible modification/updates.
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Bonky
Rank: Trio
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Post by Bonky on Aug 1, 2016 15:56:46 GMT
Hi, I wonder if you could give me specific details re the 306 op-amp mods you envisage? I did look at the schematics of the 306 v the 909 and noticed ...from memory... A few component alterations ... Caps for diodes etc but am away on holiday at present so haven't got the exact details. I notice others envisage changing the zener diodes for faster ones ( I can give details if you wish) and also placing Schotty (sp?) diodes across the output caps. What do you think? I have just bought a 306 with all the caps replaced ...but to the original specs. All I have done so far is to reduce the input sensitivity. thanks, Richard Read more: theaudiostandard.net/conversation/1522#ixzz4G63SeJKT |
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Post by Deleted on Aug 1, 2016 18:37:05 GMT
If you like the '306' get yourself a '240'
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Bonky
Rank: Trio
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Post by Bonky on Aug 1, 2016 20:09:02 GMT
Thanks; not an amp I've ever heard of...but I will do some research!
BW
Bonky
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Post by Deleted on Aug 1, 2016 20:34:52 GMT
I used to have a '306'. I bought a '240' to use in the studio & discovered i prefered it. You could get an 'S' version with no Gain controls..  |
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Post by Clive on Aug 3, 2016 15:17:38 GMT
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Post by kettlechips on Sept 23, 2016 10:07:59 GMT
I've recently acquired a quad 520f and done a fairly comprehensive service, and upgrade. Largely along the lines of the Dada Electronics recommendations, but also incorporating many of the mods I've done to my pair of 306's. I've also converted the amp to take silver plated RCA inputs, and banana plug loudspeaker connectors. Wow! What can I say? More dynamic, greater slam, better clarity.... I think this one's a keeper. I need to go out soon, but it's hard to tear myself away from the music I'm playing.
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Post by MartinT on Sept 25, 2016 14:49:39 GMT
We all have our own individual philosophy where this is concerned...there's room for all. You have a philosophy in common with many Japanese and Chinese high end enthusiasts with their generally small rooms, horn loaded speakers and single ended amps. It's as valid as any other approach. |
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Bonky
Rank: Trio
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Post by Bonky on Sept 25, 2016 21:21:07 GMT
I bought an excellent 306 from a hi-fi shop which had all the main caps replaced. Like an idiot I decided to 'enhance' it further with a DADA upgrade. I tried it first on one channel and it didn't work. In the end I gave it to RedHill Audio of Chesterfield to sort out. The response was that I had used lead-free solder and some joints were thus poor. He fixed this but still reckoned that it didn't sound as good as his upgrades, so I allowed him to add a few tweaks of his own. I have yet to collect it and try it out..but it's against my beloved Suggie A21A.. The chap at RedHill sounds very good, friendly and genuine. (Usual disclaimers).
Richard.
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Post by MartinT on Sept 26, 2016 6:20:36 GMT
Lead-free solder is the spawn of Beelzebub. I have enough stock of lead-tin-silver solder to last me through to end-of-life.
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Quad 306
Sept 26, 2016 7:21:18 GMT
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Post by Clive on Sept 26, 2016 7:21:18 GMT
Real solder is better for sure though I've used lead-free and had no problems providing I turn up the temp on the iron. The joints look matt, which isn't nice. I see little point for diyers using lead free. Mass produced goods... that's a different matter.
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Bonky
Rank: Trio
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Post by Bonky on Oct 12, 2016 19:23:30 GMT
Previous post:
"I bought an excellent 306 from a hi-fi shop which had all the main caps replaced. Like an idiot I decided to 'enhance' it further with a DADA upgrade. I tried it first on one channel and it didn't work. In the end I gave it to RedHill Audio of Chesterfield to sort out. The response was that I had used lead-free solder and some joints were thus poor. He fixed this but still reckoned that it didn't sound as good as his upgrades, so I allowed him to add a few tweaks of his own. I have yet to collect it and try it out..but it's against my beloved Suggie A21A.. The chap at RedHill sounds very good, friendly and genuine. (Usual disclaimers).
Richard."
Well I got the Quad 306 back yesterday from RedHillAudio and mated it with my Tisbury passive preamp and I was immediately impressed! Fast, dynamic and 'weight'. Mind you I'm hard-pressed to discern THAT much difference between it and my Sugden A21A (driving efficient Living Voice speakers ('a match made in Heaven')).
I've just bought a new Cambridge audio CP2 phono-preamp and am just listening to it now - and letting it all 'burn-in'. Then I'll make a decision on which to sell on. The Suggie was recently serviced (by Sugden) and I'm rather pre-disposed to keeping it, but reality must dawn some time I suppose (?) (The deck is an Inspire Apollo + Roksan Nima + AT-0C5MC cartridge -probably past its best).
Anyway, I can testify to the 'audiophile nature of the new combination...if that's any help to others.
PS I'm still very impressed with the R Pi3 + Audiophonics sabre DAC + case + OLED screen.
Bonky/Richard. (Sheffield UK)
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