OK to run the amp at 50% output?

muncybob

We are loving the 2 channel set up that has taken months to get together. I have paired up a Parasound HCA1000a and a Rotel RC-990BX pre with good results except that controlling volume is difficult. Just a touch on the remote will give a lot of gain. The amp manual says to run at full output. Will I be doing any damage by cutting output to say 50% on a continued basis to have better volume control with the Rotel remote?

steveinaz

I don't see why it would hurt anything. I could see it possibly affecting your S/N ratio, but I'm just speculating...maybe contact Parasound?

Emlyn

The attenuators are there so that an amp can be better matched with a preamp from other manufacturers. Running the amp at 50 percent output limits the amount of current available to drive speakers of course. It could cause clipping problems if the amp is driven too loudly in that configuration depending on the speakers being used and the volume level. Personally, I would prefer to run an amp at full output level and get a preamp that matches up with the amp a bit better. Shouldn't do any harm as long as you are careful with the volume level though, but that may be no fun!

jeremymarcinko

I thought that the amps gain attenuated the incoming signal, and didn't limit the current to the amp. It is my understanding that the amps output is only relative to the strength of the incoming signal. Being that turning down the amps volume isn't reducing output but rather decreasing input. The amp amplifies the incoming by x number of times, all the same. Right?

tonyb

Emlyn wrote: »

The attenuators are there so that an amp can be better matched with a preamp from other manufacturers. Running the amp at 50 percent output limits the amount of current available to drive speakers of course. It could cause clipping problems if the amp is driven too loudly in that configuration depending on the speakers being used and the volume level. Personally, I would prefer to run an amp at full output level and get a preamp that matches up with the amp a bit better. Shouldn't do any harm as long as you are careful with the volume level though, but that may be no fun!

This ^^^

Spot on....I'd much prefer running the amp at full power and getting a better pre to fit the bill.

muncybob

a better pre.....I'm never getting out of this rabbit hole am I?

I kinda figured a better pre would be the answer, a shame as the Rotel does sound good but then again I have nothing to compare it to. I wish the only local hi-fi shop had some used equipment I could borrow to audition and get the Mrs to agree on spending some more coin.

mhardy6647

The responses so far are a little convoluted, though not inaccurate.

The power amp has input level controls; these are attenuators. The power amp's manufacturer recommends running the input level controls 'full on' to maximize signal to noise ratio, but the attenuators are there for a reason. If your input source (in this case, your preamp) is too "hot" -- you should, by all means, reduce the input sensitivity of the amp. This has no effect on the "power" output of the power amp but it will afford more control of the volume level.

I'll offer no comment on the quality or sonics of the components because I am really in no way qualified to do so.

EDIT: You have the amp's manual, right? Parasound themselves explain the scoop on the input level controls pretty clearly.

Each channel has its own rear mounted "set and forget" input level control. Your amplifier sounds best with these level controls set to maximum, where they are effectively out of the audio signal path. However, if your preamplifier has very high gain, and its volume control cannot track properly for left-right channel balance near its minimum position, it may be necessary to reduce the input level control settings on the amplifier. When using the HCA-1000A in a THX installation, each level control must be set at maximum, which corresponds to 0 dB THX reference level.

source: https://www.parasound.com/pdfs/vintage/hca750_1000om.pdf

EDIT^2 -- jeepers my syntactic skills have atrophied lately! :-P

Emlyn

muncybob wrote: »

a better pre.....I'm never getting out of this rabbit hole am I?

I kinda figured a better pre would be the answer, a shame as the Rotel does sound good but then again I have nothing to compare it to. I wish the only local hi-fi shop had some used equipment I could borrow to audition and get the Mrs to agree on spending some more coin.

If you like the Rotel sound, you may want to try something unconventional. Their RSP-1068 AV preamp sells on Ebay routinely for $150 or less if you keep your eye on them there. I had one at one time and found it to be good for two channel listening. You could adjust channel levels there if you needed to, plus get subwoofer outputs. Some of the AV preamps sound great in a two channel system, and the prices they sell for now are a great bargain.

Putting the gain all the way up on the Parasound that way would remove the attenuator from the circuit.

tonyb

Agreed, some A/V pre'pro's make excellent 2 channel pre's. B&k...Anthem...Arcam...Outlaw...Cary...Classe, just to name a few and can usually be had used for under 400. Except the Cary, lol.
Pick up a B&k REF 30 pre....under 200 bucks used and you'll forget all about the Rotel.

muncybob

DSkip wrote: »

I haven't been a big fan of anything Rotel. It's not horrible gear, but I've never heard any soul from them. I'd assume yours is detailed on the high end, but a bit muddy in the mids, with a decent amount of bass to it.

Yea, I would say this is a fairly accurate description. Even so, it is a step up from the Yammie AVR as a pre. This is our 1st step into a dedicated 2 channel rig. As much as I want to upgrade the pre I'm so itching to get the tt back into the mix that a new cart will probably be the next forary into the rabbit hole

steveinaz

Look for a Parasound P/HP-850 used. Cheap, and hits way above its weight.

mhardy6647

ne'ermind...

tonyb

He didn't....but obviously has issues with his current pre's volume control jumping that much. A different pre with a better volume control may be his easiest fix. He can continue to use the gain controls on the amp to better match up with his pre but I have a feeling that isn't going to solve his issue judging by his description of whats going on. Doesn't hurt a thing though to try adjusting the gain to see if it helps out.

Could be too he just needs to clean the volume pots on his pre.

deronb1

steveinaz wrote: »

Look for a Parasound P/HP-850 used. Cheap, and hits way above its weight.

+1. I had the same issue running and adcom gfa 565 with a parasound hca 1500a. Was told it could be an impedence problem between the two pieces. Got a parasound pl/d 1100 and problem was solved. Nice pre with a remote and very good phono stage. Getting a little hard to find em however.

steveinaz

It looks like his problem is the remote turns the volume knob too quickly.

Polkie2009

I didn't even think about that Steve, do pre's or AVR's usually have a sensitivity setting of the volume control? I know my Yamaha has a volume setting in the menu but I believe it's to adjust maximum volume allowed , ( in case someone accidently turns the volume control on the remote to infinity ands blows the speakers.) I think I have mine adjusted to max out around 95 dbs in the room.

voltz

My Dared Sl-2000a remote is a little touchy like that and I have to handle it lightly...and it can be a little hard to fine tune a certain sound level.

brgman

Bob if it helps i have a parasound 2100 pre sitting in its box doing nothing.If you want to arrange getting it you are welcome to borrow it and see if it gives the same result.

Stew

I am using a Dared SL-2000a with an NAD C275bee amp. The C275 has variable inputs and I run them about half way because the Dared has a really hot output. No negative effects that I can tell. There was a little background noise at full input setting but nonexistent at lower setting. Much better volume control. 12:00 is as loud as I'll ever listen. As mhardy mentioned, no effect on power output.

nooshinjohn

muncybob wrote: »

a better pre.....I'm never getting out of this rabbit hole am I?

I kinda figured a better pre would be the answer, a shame as the Rotel does sound good but then again I have nothing to compare it to. I wish the only local hi-fi shop had some used equipment I could borrow to audition and get the Mrs to agree on spending some more coin.

It took me a very long time to find one that gave me the control I was looking for. I would not give up my Pass X1 for anything. I would look for a preamp with variable gain, perhaps something like a Rogue Audio Athena.

muncybob

brgman wrote: »

Bob if it helps i have a parasound 2100 pre sitting in its box doing nothing.If you want to arrange getting it you are welcome to borrow it and see if it gives the same result.

dang, and I was just down that way last week! I'll keep it in mind and do appreciate the offer.

The remote does adjust volume too quick but it really is the pre that's the problem as even manually adjusting volume must be done very carefully. For the time being I have adjusted the amp to 75% and that has somewhat resolved using the remote. The pre's remote sensor is not that great eithere, you have to be at an almost directly in front of it to respond.

On a better note, going through some of my old manuals and such I found a receipt from Shure that finally tells me what cart I have , it's the V15VMR....now onto a new stylus.

voltz

Hey Bob ...My Dared's problem is only with the remote, as the manual control is just fine. that would bug me too if it was both

Stew , paired with my Vincent Amp the Dared is a nice match, put in 2 PSVANE MARK II 12AT7-T and its dead silent I have the same rectifier as you.

Stew

Voltz,
I had the same issue with the remote until I turned down the inputs on the amp. No problem with manual control. I haven't heard a Vincent but those look really nice!

voltz

My Vincent does not have variable input, but the touchy remote doesn't bug me much as it is my 1st preamp with a remote in a long time so manually adjusting volume doesn't bug me much and I've learn to use the remote wisely

Glen B

tonyb wrote: »

Agreed, some A/V pre'pro's make excellent 2 channel pre's. B&k...Anthem...Arcam...Outlaw...Cary...Classe, just to name a few and can usually be had used for under 400. Except the Cary, lol.
Pick up a B&k REF 30 pre....under 200 bucks used and you'll forget all about the Rotel.

+1. Classe SSP-25 can be found for around $400.00. Among 2-channel preamps, the B&K PRO-10MC Sonata and MC-101 Sonata can both be found for about $300-$350. I have owned both models. The Phase Linear CC-3000 Series 2 is also a preamp that is a true sleeper that I have had in my equipment collection and highly recommend.