Amplifier knobs...where to "set" on the clock?


Here is a question that has idled in my head for years...

I have a 1983 M-70 Yamaha separate amplifier...paired with a C-70 pre. On the front of the M-70 are two sets of knobs for output...for the A and B speakers. I have never been sure on where to place the output line...as if on a clock.  A  "tech" friend told me that the knobs should be at straight-up "noon"...(not wide-open at 5:00)  He saying the reason: "Let the preamp do all of the work". Then, I asked the tech who serviced the M-70 and C-70 years later and he told me the knobs should be "wide open" at 5:00. no reason, except that is where they should be set.

Hmmm.

What do the fine people here at Audiogon say to those two opposing opinions?

What a hobby!

Thank you in advance.

vinylspin
vinylspin
That's good solid professional advice you got there. The only thing better is this documentary, a few years old but still the gold standard in terms of explaining the importance of where those dials point. https://www.youtube.com/watch?v=4xgx4k83zzc
With the volume set at noon, where is the volume set on the pre when listening at loudest levels.
McIntosh advised me to leave my former SS MC2250 (measured accurately at 305 wpc by them) set at MAX (seems a heck of a lot doesn't it), and then send/pass less from the preamp. SS amp was dead quiet at any volume setting.

Volume (less gain) needed by the preamp, either prior SS preamp, and importantly current Tube preamp, it's tubes need to produce less gain.

Things change when using tube amps. You need to find a/the combo of amp volume and pre-amp volume working together that is noise free.

Then, boost either the preamp volume, or, if integrated amp, boost it's volume, (or both within known noise free parameters) This affects equipment location (height of physical knob rotation or location of remote sensor).

Currently, my tube preamp at 11 am; tube amp at 12 oc. Then, for different cartridge outputs, and/or more volume, I can change either devices volume.

In my particular case, I go from preamp to a Chase RLC-1 remote line controller, then to amp. My volume is a combo of the Chase's default volume/preamps volume/amp volume, which allows me source/volume/balance from listening chair, thus different cartridge outputs, do not effect my paired preamp/amp noise free volume pairing.

Remote balance helps refine individual tracks that benefit a surprising amount from a slight balance tweak. Adjusting from the listening spot remotely makes it easy,
set amp gain at max unless you can’t, such as when you cannot achieve appropriate balance, or your pre is way too hot. Here is the basic technology you need to know to understand why:

The amplifier circuit’s gain (Vout / Vin) is always exactly the same, often around 23 dB of voltage gain. The volume knobs are just resistors in front of that. Often inexpensive and prone to degrading over time. By setting the volume to maximum you minimize the amount of those resistors in the circuit.

Best,
E
+1 erik,
These are resistors in the circuit, all the way up or remove them.
Many japanese power amps of the period had this extra feature, in fact you could connect a source like tape, radio, without having a preamp.

G
Thank you so much all... 

I know I am getting quality feedback (pardon the pun) because I have needed to reread the answers numerous times; why above my pay grade knowledge wise. but, I thoroughly get the gist of where I need to be with my Yamaha gear

I have maxed out the knobs to 5:00...

Since the Cerwin Vegas are rated with sensitivity 101db and the amp is rated at 200wpc I am truly cooking sonically with the volume at 7:30.  My ears are not trained or equipped to officially or  "technically" discern better sound...but whether it is the power-of-suggestion, or not... I think I can sense the sound has a bit more upfront punch...some warmth...allowing the vinyl to work well and sound good.

Listening to Petty.  With the gain adjustment...it seems that the muddy, sloppy and BIG "Dance floor'" CV D-8's are a bit clearer and cleaner. and they can stay.  I did want to move into the Klipsch range of speakers...Forte, Heresy, etc or their "flagship" towers the RF 7 lll.  

Because of my loot...I think my next step will have to be the cartridge.  Moving away from the Grado Platimum 1...into possibly a Hana MH or Hana ML...either the high or low output. Likely the high output to be able to stay with my MM Cambridge Solo Phono Stage.

The good news...I do have very quiet fans pulling warm air out and up from the amp and pre... I have heard these units can have a tendency to run a bit warm.  

Anyway...  What a hobby.

Thank you all again.

Sincerely,

vinylspin
You should always set the dials full open unless you have a very efficient speaker that would not let you use the preamplifier volume hardly at all. When you turn the gain on the amp down it can cause a loss of dynamics and contrasts in the music in some circumstances due to the attenuator used on the amplifier.
 Speaker Level Controls:
In addition to speaker A/B selectors that permit one-touch selection of two sets of stereo speakers, the M-70 features independent level controls for the left and right speakers in two stereo pairs. That is, you have independent left and right speaker level controls for speaker pair "A", and left and right level controls for speaker pair "B". These controls let you independently set the maximum power level that will be sent to the respective pair of speakers, protecting low-power-capacity speakers from excessive power levels, or matching the output level of two sets of speakers of different efficiency. Independent control over left and right speaker level lets you preset the balance of your system for optimum stereo imaging depending on the positioning of your speakers and the acoustics of your listening room.
Don't forget to account for daylight savings time.
Speakermaster...thank you...

With your advice...  To me...that would suggest that perhaps since I have a VERY efficient set of Cerwin Vega speakers...101db...Perhaps I should consider backing the gain off a tad...maybe from Full-On 5:00 to 3:00?  allowing the preamp to "breathe" a bit? Am I making sense?

Also...hobo1452...thank you
With your advice...to me...it suggests one of the reasons for the gain control at all is about a high wattage amplifier not over powering and "cooking" a vulnerable set of speakers... i can customize the output safefly and correctly...while still allowing the preamp to do its job.  Am I making sense?
vinylspin
As with many things, try the options and see. Noon? 5 o'clock? I bet your system works better at one of them.
Macintosh Mc275 comes with no volume control, straight out!
In as much as I would agree the ideal would be not to have to attenuate the amplifier, a 200wpc amp driving 100dB speakers seems a mismatch. In your case, with the amp unattenuated you are using very little of the gain provided by the line stage of your preamp.

Given that you are reaching full volume at 7:30 with the amp at 5:00
I would try setting the amp such that equal volume is attained with preamp set around 11:00 and see what that sounds like to you. You would likely have better control over volume. If it proves detrimental to sonics then return to your current settings.




My McIntosh MC2152 does not have volume controls, but I have plenty of other knobs I can turn!  
Back in the day when the M70 was produced, speakers and equipment were both produced with specs that were questionable at best, and made setting up a system that played well together hit or miss. Being brand specific was the safest bet, and even that didn't always work out. Yamaha came up with a novel approach to part of the problem. 
It depends on which is quieter, your amp or preamp.  At least check the specs.  I would bet it is the amp.
Thank you all for lending your support and advice.  And...since this hobby is fluid and subject to many factors...real or not...including whims and perceptions...please indulge me as I am going to ramble here...in a kind of free-verse-stream-of-consciousness.

I have made a decision to relegate my Yamaha M-70 and C-70 to the second tier position... The separates are beginning to show their age and almost begging to be retired. The right channel is producing less than the left...and I am not going to sink any more loot into the pair.

I am currently using a cheaper and albeit newer Onkyo 50 x 2 TX 8211 receiver.  And...it is a respectable unit...it is sounding better than the Yamaha pair.  I have pulled my Luxman equalizer out of mothballs and fiddled with the settings to give it some acceptable and respectable sonic credibility. 

What is funny about my re-coned Cerwin Vega D-8's... back in 1983, they sold for $800.00 a pair...which is $2,135.00 today.  I noted that an observation made here in the forum told me that my high efficiency (101 db) CV's and 200 x 2 amp were mismatched...not allowing the preamp to perform at its best.  And...since the specs are in question from 1983.. I cannot figure on how to set the gain on the Yamaha M-70.  Since I will always go for high sensitivity speakers (preferably Heritage Klipsch)...I think that a lower wattage amp would be better to have. I am done with the Yamaha pair...though bck in the day...very respectable.

I am looking at the Hana $1200.00 cart. Then that begs the question as to whether I also upgrade my 50 year old Dual 1219.

Yes...this is an expensive hobby... and full of choices...each product basically  has an "upside" and a "downside". For instance...low sensitivity speakers need more power to run...yet,  usually create more lower-end bass.  And...Moving Magnet carts have less detail than Moving Coil...yet MM have what could be considered more "punch".  Upgrading is a puzzle...which makes this hobby so much fun...when all of the stars line up.

What a fascinating hobby.

If you've managed to make it this far in my self-indulgent diatribe / ramblings...thank you.

vinylspin