Marantz MM8077 or Monolith 7x200

KEW

KEW

Audioholic Overlord
Thanks for all the info guys! This helps out a lot. I do know its overkill to use an amp with these speakers. I wanted to future proof my setup just incase I move on from the klipsch since i need an amp to power the 2 additional speakers anyway. I saw another good deal for an Outlaw 5000 for $400. I did get the Monolith 7x200 price down to $1050 though.
I would consider either of those units at that price a win!
But go for the monolith, just check it for hum first just to make sure you don't have to hassle with it.
And let us know. I'm hoping mine was a rare thing!
 
Auditor55

Auditor55

Audioholic Chief
Thanks for all the info guys! This helps out a lot. I do know its overkill to use an amp with these speakers. I wanted to future proof my setup just incase I move on from the klipsch since i need an amp to power the 2 additional speakers anyway. I saw another good deal for an Outlaw 5000 for $400. I did get the Monolith 7x200 price down to $1050 though.
Why not wait until the future and then decide on amp?
 
P

PENG

Audioholic Slumlord
The 50-65% seems like the "average" range I've read in lab tests at 8 ohms and 0.1% distortion going back 20 years (when the transformer size is stated, like in the AH reviews).
As agreed, those are good average, typical numbers for efficiency. That is however, as I mentioned before, not always a reliable way to estimate an amp's transformer's VA rating. Efficiency is just one factor, albeit an important one as class AB is so much more efficient than class A. For transformer VA sizing, It is more about the designer's approach, in terms of how much they want to take advantage of transformer's overload capability and the nature of music and movie contents that are not continuous sine waves at constant levels. So while an AVR manufacturer may be comfortable with a really low factor of 0.7 VA/W as cited in the Elliot Sound article, or a reasonable one of 1VA/W, whereas the much more robust 2 VA/W 8 ohm rated output approach may be adopted by more expensive amps such as Bryston, Parasound Halo, Anthem's P and STR series power amps. There are also the >2 VA/W approach at the extreme end such as your Citations, and some Passlab models, with the likes of Anthem's MCA series, Adcom, Monolith, Outlaw amps that seem to fit in between, just loosely and as examples only.

There are very few articles on the web on transformer sizing, but Elliot Sound has at least one article on that topic. Other than that, one would have to resort to forums where knowledgeable people hang around, and/or do your own calculations.

Here's the Elliot sound article on Linear Power Supply Design:


It is a long one to read, but you can always jump to near the end and just read the VA Rating paragraph pasted below.

"VA Rating - Class-AB
The minimum VA rating suggested is equal to the amplifier power. A 50W amp therefore needs a 50VA transformer, or 100VA for stereo 50W amps. Larger transformers (up to double the amp power rating) will provide a 'stiffer' power supply, and this may be beneficial. For continuous operation at full power (never needed for hi-fi but common for guitar amps), the transformer should have a VA rating of up to 4 times the amplifier power.

It is suggested by some transformer manufacturers (and no doubt gleefully adhered to by many amplifier makers) that the VA rating needs only to be 0.7 of the maximum amplifier power. While this will work well enough in most cases, you will not have a 'stiff' power supply - a more appropriate term would be 'soggy'. The DC voltage will collapse as more current is drawn. It's unlikely that you'll hear any significant difference between the smaller and larger transformers with music."


Here's a DIY thread that has some useful suggestions, I think Nelson Pass, Gedlee do join in some of those conversations occasionally.



I still have one of Pass's F5 amp to build yet. I have only ordered the amp kit, will soon have to figure out the power supply transformer need soon. Being class A, I think I would go with 300 VA, or may be 400 VA maximum.

Would a specific Class A/B amp model's output also depend on how much class A bias it was designed for?
Yes, definitely, the higher the bias the warmer it runs, all else being equal. I am not an amp designer but I have read enough to know that it doesn't mean you need bias high enough to be in class A for the first several watts to sound the best or to achieve minimum crossover distortions. If designed well, it could be just high enough to ensure there is a good overlap such that both output devices in the push and pull cycle are fully on and conducting long enough so there is no dead zone around the zero crossing point; and of course good use of feedback will be key to keep distortions low. Benchmark claimed they also use their feed-forward technology, to virtually eliminate cross over distortions.
 
P

pcosmic

Junior Audioholic
Do you think that the Marantz will make the mid-range more Chocolatey due to the extra refinement ? :rolleyes:
Ah, a chocolatey mid guy! You are a special rare breed like me! a brotha from another mutha!...If you want sweet chocolatey mids without going bankrupt , run your receiver pre-outs to this beautiful class A beast.


This amp will pour chocolate on your ears and give it a massage/happy ending. It is actually 120W/ch into 8 ohms and 160W/ch into 4....approx 25 to 30 in Class A.

Prepare to turn up the air-conditioning in your house though.
 
P

Prodigy

Enthusiast
Did you end up buying one of these two AMPs?
Yes, finally got my hands on the Monolith 7x. Ended up getting the price down to $900. Everything works great! I didn't hear any hum at all either @KEW . I really couldn't pass up this deal, especially around my area and how much this thing weighs. Glad I went for it!
 
VMPS-TIII

VMPS-TIII

Full Audioholic
Yes, finally got my hands on the Monolith 7x. Ended up getting the price down to $900. Everything works great! I didn't hear any hum at all either @KEW . I really couldn't pass up this deal, especially around my area and how much this thing weighs. Glad I went for it!
$900 is an amazing deal. I would buy one at that price any day. :D
 

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