I take it your NP220 uses 6SN7 (not 6SL7) tubes? If so the gain is a mere 18dB and you need "old school" high gain preamps like Audio Research SP10 or MFA Lumi to wake it up otherwise it does sound sleepy. Also the design lacks NFB so bass control is expected to be a bit flabby.
$1000 is highway robbery, those silicone pads can be had for USD 1.50
Its not just me who is using this trick:
Cleaning up the mess requires a lot of patience. Use small spatulas and disposable chopsticks.
EAR tubes will get you...
If you have a Daiso Japan shop close to you then you can buy soft transparent 2" x 2" silicone squares of the same texture and improvise from there.
Scrape the oozing black goo away as much as you can from behind the woofer.
Wipe with disposable cloth (not paper) the goo inside the bass port...
STOP RIGHT THERE he likely DOESNT know what he's doing. I have HAD IT with those who claim to know how to service Counterpoint.
There is a combination of BIAS and DCO and predriver balance which requires 3 multimeters probing 3 things to adjust. He likely over-compensated the DCO pot causing...
Hi Marco, it's the ripple current tolerance and ESR that counts.
Anything over 20000uF per phase will give you plenty oomph.
I like the Nichicons (they are used in my Premium Golds), and I have used EPCOS/TDK with good results on NP100 upgrades.
The woofers should never rumble when in standy...
output stage PS caps for NP220
Mike suggested KZs for the low voltage predriver stages.
For output stage use Nichicon KG Super Through (not gold tune) 22000uF 100V which are almost impossible to find.
ALL Gold Tunes and Superthroughs on Ebay are fakes.
Buy only from Mouser, Digikey, Michael...
Thanks... figure as much
Very helpful info thx! Now I know it's probably a typo in the manuals.
Indeed it is 250 when tube is cold and once it draws it goes down to about 130.
I tweaked the LC stage on mine a bit to get 280/140 by using 2 smaller inductors with 50uF oil cans and it improved...
I am curious if you have tried to match the B+ going into the tubes on both units.
In my unit the unregulated B+ is 255V, regulated to 240V at the top of the plate resistors.
My schematics from Mike says target 315 (see pic). I have serviced a few units, none of them had Plitron chokes...
There are some rectifier tube conversion piggyback sockets for sale
On Ebay, can be interesting. I used it to try out ECC99 and 6FQ7 on my NP220. Never tried it on the EZ81/6CA4 socket. I dont think they have one yet though...
If you don’t want to pull the motherboard to rewire for other rectifiers you can always change chokes to your liking. Similar “sag” effect. Ask the guitar people. I recommend you try Hammond 158L 158M for starters if you don’t have the mega $$$ plitron choke. They change the B+’a wee bit so...
Ever tried Elna Silmic2 lytic caps for bypass on the daughter boards replacing the KZs?
I heard they are better than Nichicon in every way. Only reliable source is Digikey. All the Ebay ones are fake.
Also I want to ask about the tubes B+ bypass caps. I see a light blue colored cap on...
Glad to have found this post. I own several NP amps and I happen to have serviced quite a number over the years I finally got to try a pair of ECC34s in place of my trusty CBS5692 in my low gain NP220. I have modified the B+ to be about 280v and the ECC34s dropped in w plate voltage at 140...
I used a simple assumption of a 2nd order crossover for the mid with assumed driver impedance of 5.5 ohms with a target new impedance of 4.4 ohms or so for the target midrange load. I used a simple crossover calculator and LT spice simulation helped validate the value I chose. Let your ears...
I contacted Margo at Avalon and she sent me 2 silicone retrofit rings in no time.
I also had to restuff the chambers with aquarium filter floss cos the old stuffing was tainted with goo.
I notice even the midrange chambers have the same problem but very little I can do to it.
But I did find...
Eidolon diamonds vs Ascent II
Had the Ascent IIs since 1996.
Monitor, Eidolon, now Eidolon Diamond.
The Diamond has a tendency to become lean and brittle if driven hard.
The Ascent IIs play *music*, not just stereo speakers.