Advice on purchase of Quad 909

[arj]

That it should be paired with a passive pre-amp to bring out the best.

I am really not too sure about the Passive Pre. it is not from the Power amp's capability, but from the CDP point of view..I've had experience with Marantz CDps (CD63, 6000 OSE) many years back , but in those times they could not maintain their voltage constant (my inference) across all loads and hence needed a good tube buffer to make the sound really smooth..else had a tendency to make the sound Grainy.

Do try out a passive pre to see if it works at low volumes. if it does Great..if not then i would still recommend you get in touch with viren to get a low gain tube Pre OR 2nd (and not that great option) put a tube buffer between the passive pre and the CDP.

 

[Asit]

Do try out a passive pre to see if it works at low volumes. if it does Great..if not then i would still recommend you get in touch with viren to get a low gain tube Pre OR 2nd (and not that great option) put a tube buffer between the passive pre and the CDP.

Arj,

I hope I am not misunderstood here. But the sonics of the quad 909 are very lush and as far as I understand these things I'd not encourage that part any more by having a tubed pre or buffer. A very silent and neutral pre (active or passive) would do. Promitheus seems to be doing a great job in budget, and hence the suggestion. It's nearly impossible to find a quality active pre in budget unless some great used deal shows up.

Regards.

 

[arj]

hi asit, i did not really intend it to sound like i am recommending a "lush" sound in anyway.
Tube buffers can be very neutral..at least my X10D does not lush up the sound though i dont use it !

and i meant tubed pre only since Viren goes by that philosophy else a SS pre is also fine it is just that i am not very sure if the CDP would be able to handle the input impedance of the power amp directly as at that range the power supply in CDPs tend to a wee bit wimpy. the only exception i have heard is the rotel 1070/1/2 series.

 

[Sidharth Trehan]

A mighty informative piece of discussion. Heartfelt thanks to all flagbearers who contribute here to our learning.

Slightly off but intricately related questions:

1. Whats that a pre-amp can do that a passive control unit cant?

2. Would we need two passive units to run two 909's, feeding each speaker?

3. In a DIY Passive, whats the ideal set of components that could be used to pair with 909's.

4. I am going the passive way with Viren sir's help, so you may pls answer the questions you feel like, shall just help me discuss with him more on the apprehensions, options n component suggestions you share in here.

5. Anyone that u know selling a 909? Need not more than a 2yr old new like piece.

@ Arup ji
a.. Sir, modding the 909 would be a mammoth task? with what u have suggested in one ur early post in here.

b.. Will it anyway effect the life w.r.t tampering the original circuitary of the amp.

c.. Approx Costs involved?


@ Capt
sir, just wanted to inform you that price of the Dali was misquoted to you. The new ones are coming at 65k, hence my asking wud hv been much lower BUT i shelved the thought of selling these and rather would make space for them somewhere at home when i intend to upgrade.


Many thanks

 

[rikhav]

Hi Sid
If you are using a single 909 for each speaker you will run the amp in bridge mode, basically making them mono
So you dont know 2 pre. If you are thinking about bi-amping them i am not sure about its working. Audi_engr, Cranky, Asit and others will answer to you soon

Are you planning to use 909 as mono for your Quad BS? Will it not be an overkill for those?

Lastly I am sure Virenji will help you out with the mods auido_engr has suggested

 

[Sidharth Trehan]

Hi Sid
If you are using a single 909 for each speaker you will run the amp in bridge mode, basically making them mono
So you dont know 2 pre. If you are thinking about bi-amping them i am not sure about its working. Audi_engr, Cranky, Asit and others will answer to you soon

I HAVE NOT DONE THAT YET SIR, I INTEND TO SEEK GUIDANCE ON IT, IF IT 'COULD' WORK TOWARDS A BETTER DELIVERY OR WILL THEY JUST BE PUMPING POWER HERE ACTING AS MONO. IF POWER IS THE ONLY RESULT OF THIS, THEN I AM SUFFICIENTLY COVERED AND WILL NOT GO FOR THE SECOND 909.

Are you planning to use 909 as mono for your Quad BS? Will it not be an overkill for those?
I DONT LISTEN TO LOUD MUSIC, THE IDEA IS TO ASSESS THE AREAS OF IMPROVEMENT WITH THIS EXERCISE ..IF ANY.


Lastly I am sure Virenji will help you out with the mods auido_engr has suggested.
YES, VIREN SIR WILL BE THE ONE TO ASSIST ME WITH PASSIVE & 909 MOD FINALLY.

thanks / regards

 

[rikhav]

Hi Sid
If you have purchased the amp from Delhi itself, you can request the dealer to loan you 909 for few hours
You will come to know all you want to know how they behave with your speakers in mono. I think its the best way to go

 

[Sidharth Trehan]

Hi Sid
If you have purchased the amp from Delhi itself, you can request the dealer to loan you 909 for few hours
You will come to know all you want to know how they behave with your speakers in mono. I think its the best way to go

will do that indeed.


brgs

 

[captrajesh]

@ Capt
sir, just wanted to inform you that price of the Dali was misquoted to you. The new ones are coming at 65k, hence my asking wud hv been much lower BUT i shelved the thought of selling these and rather would make space for them somewhere at home when i intend to upgrade.

If you have enough space to use them for your second system, that would be a better idea as I you've stated somewhere that they are very good speakers & you like them.

More so because one would never be able to recover more than 60% of value by reselling the equipment, however well kept they are. Sad but true.

 

[arj]

Sidharth Trehan, If you are using a Quad pre ampp you need only 1 preamp to run both.
check out page 7 of this PDF file you may need a special Quad connector for the same as yours is a Stereo power amplifier

 

[malvai]

@Sid, if you use each amp as a mono, you'd need much more powerful speakers... do you really wanna do this? Plus, its at best a small sideways imrovement at a great cost...

Dude, save up for something that is a giant leap in soundstage. hyeah:

 

[Sidharth Trehan]

If you have enough space to use them for your second system, that would be a better idea as I you've stated somewhere that they are very good speakers & you like them.

More so because one would never be able to recover more than 60% of value by reselling the equipment, however well kept they are. Sad but true.

I get it Capt. saab. but since the speakers gave me no other reason to sell them off (technical/cosmetic flaw) than to purely dispose them for upgrade hence i had no reason to sell it off at that dip. So they shall do good back home in one set or the other, space would not be an issue.


My regards

 

[Sidharth Trehan]

Sidharth Trehan, If you are using a Quad pre ampp you need only 1 preamp to run both.
check out page 7 of this PDF file you may need a special Quad connector for the same as yours is a Stereo power amplifier

Thanks ARJ.
I was trying to first assess how much worth is adding another 909 in terms of all other musical aspects but power. Since i have enuf of power for the room. And i guess my friends dont like me rich, so i shall go by what Malvai suggested and wait a while.



@ MALVAI
sun lia, sun lia (heard you, heard you! ..*hope everyone understands Hinglish & basic Hindi? ..but translation was just in case.)

 

[arj]

I would agree with you..you definitely do not need more power....and if your speakers are easy to drive you will not get too much of a benefit for the price you pay.
was just giving you the info since you asked about it and did some googling since i am not familiar with Quad much

 

[Sidharth Trehan]

I would agree with you..you definitely do not need more power....and if your speakers are easy to drive you will not get too much of a benefit for the price you pay.
was just giving you the info since you asked about it and did some googling since i am not familiar with Quad much

eshmart brother you be!
Danke

 

[Sidharth Trehan]

Thanks Arup ji.
Spoke to Viren sir and hv been suggested to assess the passive unit first, which am going for, to be delivered by next wk and if need be then we can go for 909 mod.

Yet, could u point me to the circuit diagram for a 909 and any other for the mod. I shall personally discuss with Viren sir when i go to pick the pot.

Appreciate your reply and guidance there in.

Wishes

 

[Sidharth Trehan]

just to my eyes the looks are not too convincing for its shell.
But coming from you it has to outshine its looks by eons, afterall they are made to be 'heard'.

 

[odyssey]

The primaries of both transformers are connected in series for the 6db voltage gain

@ Sid :



1. A preamp can provide you additional GAIN that a passive cannot. And just in case, the impedances between your source and power aren't very favorable, an active Preamp comes to rescue where the passive is helpless.

Nevertheless, an Active Preamp will have the additional Gain stage using power-supplies hence WILL NOT be as silent as the Passive that's powerless! The passive without any circuits will also be a lot cleaner sounding without being clinical.

However, Transformer based Passive by Promitheus is offering a 6dB Gain but am NOT sure as how he's managing that.

2. No, only 1 passive pre will drive both channels using one 909 or even 2 x 909 for (bi-amping or bridged mono-blocking).

3. Completely depends on the passive's design - whether its a simple L-pad that uses ONLY 2 resistors (1 fixed for shunt while the other is the variable for the switch) or is it a Transformer based design.

4. & 5. --



Will discuss over PM!

As far as your concern regarding tampering of the circuit and its life, the 'serious people' who uses the 606/606-II/707/909 in their daily lives have modded their units and I have YET to come across a soul who claimed his amp being damaged. It actually betters the amp by a HUGE margin! So big is the improvement, that you'll feel the Quad has grown up to the likes of a Krell/ML etc with that glorious midrange intact! The overall bandwidth just opens up from close to DC all the way to 70kHz.

Finally - the 909 itself is a fairly powerful amp with 140watts per ch into 8 ohms and 250watts per ch into 4 ohms. What speaker do you want to drive that mandates an even higher output amp or requires bridged mono of 909 to generate 300watts at 8 ohms, 500watts into 4 ohms?

 

[captrajesh]

Hi captain , Whats the marantz Amp you are considering. If you have marantz in mind then go for PM 15 and above .

Sorry Dali missed your post. I was considering Marantz PM15 S1. Now shelved the plan.

 

[suri]

Sorry Dali missed your post. I was considering Marantz PM15 S1. Now shelved the plan.

hi captrajesh,

so, what is the plan - which amplifier?

regds