C220 disappointment

[2uberoller]

Is this just thru the phono preamp stage? If a line input is selected, is it quiet(er) at the same settings? If one/both phono tubes are noisy, POSSIBLY swapping tube pairs from line<->phono will make things tolerable until a suitable pair can be found for the phono.

The line stage gain is 15dB, but phono is 55dB (total, I assume 40dB from the phono tube stage alone). Swapping in a quieter pair would help, assuming the line pair is still performing to spec..

If it's under warranty, definitely do the dealer thing! At least you would then have a good pair or set as a backup to your $$$ NOS whatever tubes ...

It is only through the phono pre amp stage. All other input's are quiet

 

[vintage_tube]

It is only through the phono pre amp stage. All other input's are quiet

Tell ya what Doc -- I have some 1950's RCA 5751's I can send your way -- try 'em in the phono & if you like, we can come to a deal -- nothing outrageous -- don't care for them -- send 'em back. Or more importantly, if the issue continues, then it's probably not the tubes.

Let me know as I'm heading out Fri evening for Denver & RMAF a week early. Send me a PM ASAP so I can get them in USPS priority channels Friday.

 

[sully1801]

Same story on mine, the phono section has white noise. I think that's typical of most any preamp, atleast the ones I've had, which include (but not limited to) C28, C32 & C40 prior to the current C220.

 

[nsgarch]

In that case,

swapping the linestage tubes for the phono pair will tell you if it's the tubes. However, keeping in mind it's quite possible that all the stock tubes are noisy; just more noticable when installed in the phono section:yes: Anyhow if swapping the tubes doesn't change things significantly, my guess is that the noise is getting in thru your analog hookup. Either the tonearm cables, the internal tonearm wiring and/or cartridge clip connection, or even a TT/TA grounding discontinuity. But first try this: your TT has a two-prong power cord, so try flipping it over in the wall socket. Often that gets rid of TT hum.

It is only through the phono pre amp stage. All other input's are quiet

 

[2uberoller]

Is this just thru the phono preamp stage? If a line input is selected, is it quiet(er) at the same settings? If one/both phono tubes are noisy, POSSIBLY swapping tube pairs from line<->phono will make things tolerable until a suitable pair can be found for the phono.

The line stage gain is 15dB, but phono is 55dB (total, I assume 40dB from the phono tube stage alone). Swapping in a quieter pair would help, assuming the line pair is still performing to spec..

If it's under warranty, definitely do the dealer thing! At least you would then have a good pair or set as a backup to your $$$ NOS whatever tubes ...

swapping the linestage tubes for the phono pair will tell you if it's the tubes. However, keeping in mind it's quite possible that all the stock tubes are noisy; just more noticable when installed in the phono section:yes: Anyhow if swapping the tubes doesn't change things significantly, my guess is that the noise is getting in thru your analog hookup. Either the tonearm cables, the internal tonearm wiring and/or cartridge clip connection, or even a TT/TA grounding discontinuity. But first try this: your TT has a two-prong power cord, so try flipping it over in the wall socket. Often that gets rid of TT hum.

My turntable and other components are connected to a panamax surg protector/line filter. I am looking forward to trying some of the new tubes, I mean old tubes>

 

[ron-c]

The phono section in the C220 has a lot of gain. When combined with the high level stage the gain is 65 dB. This is more than most preamps by 5 dB. To check for noise you should short the phono inputs. If you only have noise with your table connected there are many reasons this could be. TT Phono cables, TT power supply, interference from digital switching power supplies, etc.
The noise level should be looked at when a normal record is played loud on your system then check your volume control setting on the C220. Stop the record then compare the noise to the high level inputs. To throw the phono section wide open when you will never use it at that level is not a valid test.
The high level inputs should have no noise when the volume is set at 100 and you are using a McIntosh amp with balanced cables. 100 will be way to loud through the phono section of course.
With the phono section off you should be able to switch the high level inputs at full volume with no noise. This is true with all of the current McIntosh 2-channel preamps, tube or transistor, since they have the best noise performance.

thanks,
Ron-C

 

[TSmith8605]

Send me a PM if you'd like help on how to change the tubes, but it's pretty easy.

Alberto

The hardest part is getting the lid off. Is there a trick to that?

Mine also developed excessive white noise in one channel of the phono section. I put some NOS Telefunkens (tested and hand picked for low noise by Modjeski) and some Telefunkens from Doug's Tubes in the line section.

The pre-amp is now very quiet.

 

[TSmith8605]

At lower volume levels on the pre amp, say 35 and below, from 2 feet away from the speaker, no hiss or hum. Up close you can still hear white noise. At 40 you can't hear it from 5 feet away, above 50 it is very annoying between songs and quiet passages from 15 feet away. Above 60 you can hear a hum.

Did you say what cartridge you are using? This pre-amp is not designed for and might be noisy with a low-output moving coil type cartridge.

 

[2uberoller]

This noise occurs when the turntable is disconnected or connected. If the problem is caused by crappy tubes, shouldn't Mcintosh supply good tubes ? For what we pay, why do they use a $15 tube ? From what I've seen on this forum a lot of Mcintosh owners have had to replace the tubes . Since my pre amp is only a few months old, will I get another set of these stock tubes from Mcintosh or as replacement tubes do they supply some of the type of tubes others have recommended ? Hey Ron, please do not take this the wrong way because I appreciate your input, but why does Mcintosh use inexpensive noise ridden tubes ?

 

[AudioClassics1]

I just had a customer email me and offer this advice..

does ENTDOC have the C220 on top or near a magnetic field when using the phono. My C220 is above my MCD751 and I HAVE to turn off the transport when using the phono preamp or the hum is unbearable.

 

[Victor]

I just had a customer email me and offer this advice..

does ENTDOC have the C220 on top or near a magnetic field when using the phono. My C220 is above my MCD751 and I HAVE to turn off the transport when using the phono preamp or the hum is unbearable.

That is a good point, when I was using a turntable in my system I was picking up noise in the phono preamp from my TV. I had to move the phono preamp and turntable 4 feet away from the TV to reduce the noise.

 

[Dan ʕ•ᴥ•ʔ]

Get 12AX7's that have been tested for low-noise and balance. You'll be amazed what a difference that can make. Tube Depot in Memphis or Doug's Tubes (sponsor) should be able to accomodate you.

 

[nsgarch]

Hey Ron, please do not take this the wrong way because I appreciate your input, but why does Mcintosh use inexpensive noise ridden tubes ?

Did I not adequately explain the reason(s) why Mac chose the OEM tubes they use? Ron has been asked about the stock tubes before, and understandably, he can't be entirely candid -- we all know that. We also know from other comments he's made,that he uses non-stock tubes in his own gear.

BTW, the last time I checked, 9-pin McIntosh tubes were $20. If you bought them as Shuguangs (or maybe they use Sovteks now) they'd cost you about $8, and that's retail! And just to offer a bit more (financial) perspective on this issue: Back in let's say 1970, an ORIGINAL Genalex Gold Lion KT-88 (the ones Mac used to supply with a MC275 for instance) cost $12 give or take over the counter, OK? Today, adjusting for inflation, that same tube if it were being made, would cost around $67. Today's actual price for a never-used, vintage, Gold Lion KT-88?: $500+ !

EAT (Euro Audioteam) does sell new Czech-made KT-88's which supposedly have the same sparkle as the originals, but for $400 apiece. So maybe that will provide you some perspective and explain why manufacturers of new tube equipment (not just McIntosh) would prefer you make the choice when it comes to spending big tube bucks.

The same situation applies to the small tubes as well.