Quad 66 preamp & 606 MkII power amp

I was just wondering whether anybody own these amps. I am curious what speakers are you using with these vintage amps. I would appreciate some input. Thanks in advance.

Hi Ryder,

I have a 34/606mk2 driving a pair of Harbeth SHL5 that I bought recently. Previously I used a pair of 3ES and then Pink Triangle Ventrical. They have since moved to my AV set-up.

Hi mthoi,

Thanks for your response. I am sure the sound you are getting with the Quads/SHL5 is optimum since these two are meant to go hand in hand together.

On a separate matter, may I know if your 606Mk2 has any humming sound? I have had mixed receptions. Some say the transformer in the Mk1 has hum while some others say it's the Mk2 that has hum.

May I know what other amps you've used with the SHL5 apart from the Quads?

Thanks in advance.

I dont have the humming noise on my mk2. The Mk2 comes with a toroidal transformer whereas the Mk1 does not. I undersand that the huming may happen on the Mk1 and 405 models.

Dada has a toroidal transformer kit to fix the humming problem.

Staying with the Quad. Tried my friends Krell 300i. Not bad but his Krell/SF is a better match.

I owned a 34/606 driving a pair of Quad ESL63.It was the original recommended set-up from Jebson & Jason,the local distributor then.With the ESL rebuilt not too long ago,it is singing as good as before.

Recently have added Yaqin tube buffer between the Micrmega DAC & the 34.It offers a wider sound stage and warmer vocal.I have noticed a better bass output too.A worthwhile investment.

Thanks for chiming in leeck. Looks like you have a rare vintage setup based on a full Quad system, certainly a gem on its own. It is good to note that the ESL 63's are rebuilt successfully as parts for this electrostatic speakers can be hard to find especially with the membrane. Since you have managed to hold on to the system for such a long time, I reckon the system must be serving you very well.

If at any instance you feel it's time for a speaker replacement, you can always consider Harbeth. I can reassure you that Quad amps, especially the 34/606 match Harbeth speakers very well. Since I own a pair of SHL5 I was seriously looking at the Quads at one point of time but reshuffled my priorities after careful considerations.

leeck wrote:I owned a 34/606 driving a pair of Quad ESL63.It was the original recommended set-up from Jebson & Jason,the local distributor then.With the ESL rebuilt not too long ago,it is singing as good as before.

Recently have added Yaqin tube buffer between the Micrmega DAC & the 34.It offers a wider sound stage and warmer vocal.I have noticed a better bass output too.A worthwhile investment.

How much is the Yaqin tube buffer?

I paid RM430.00 for the tube buffer.Upgraded the original tubes 6J1 to Electro Harmonix 6AK5 and modified the output capacitors from 1uF to Panasonic audio grade 2.2uF.A remarkable improvement from the original set-up.This is a good gadget to do some self mods.

Actually I am the second owner of the whole Quad set-up.You would not believe it,the whole set was given to me by a golfer friend of mine!The ESL were not working then.It took me many weekends and painstaking labour to rebuild the speakers.It was well worth it.Given the time and opportunity,I would like to rebuild one of them again,which is not as perfect as I would like it to be.

I am still keeping my original Quad 34/405 MkII.

I met Sam of Tropical Audio at the HiFi Show.His combination of Quad 66/606 with the Harbeth SHL5 was brilliant.It out-performed many of those that costs many times more.I would definitely get my hand on a pair of HSL5 if given the chance.

Glad to hear your findings on the Quad 66/606 and Harbeth SHL5. I share the same notion as well. There are many excellent mega-buck systems, some encroaching into the 6-figure category that most can only listen and not purchase, and the Harbeth system that is a fraction of the cost provides much musical enjoyment at great value which is within reach for most folks.

Found quite a few Yaqin6J1 on sale on ebay. Sellers mostly from HK. Price about RM430.

Think would be easier to buy here, cash and carry.
(Only found one crazy fella here asking for SGD200(RM490) for an eight month old unit)

leeck wrote:I paid RM430.00 for the tube buffer.Upgraded the original tubes 6J1 to Electro Harmonix 6AK5 and modified the output capacitors from 1uF to Panasonic audio grade 2.2uF.A remarkable improvement from the original set-up.This is a good gadget to do some self mods.

Read in some other forum that even a change of the stock 18AWG power chord that comes with the Yaqin to a 14AWG increases the bass definition.

Anyway how much is the 6AK5?

I changed the original power cord to a DIY power cord using a pair of Belden cables twisted together to make it around 10 AWG, Wattgate IEC and MK tough plugs.Much better than the original.

I got my pair of Electro Harmonix from a forummer for RM70.00,used pair.

I am having a pair of Northern Electric 403B for rolling.If you are keen,let me know.Hardly used.