NOSValves

Must of had to build up a boat load of gain to drive the phase inverter transformer. If that is the case they probably do make a pretty large sonic change brand to brand.

1st band Brown =1 2nd band Black =0 3rd band Black =X1 So 10 X 1 =10 Ohms 4th band Silver = 10% Tolerance 5th band Brown = voltage rating but I don't have a chart handy at the moment The only real way you can check the accuracy of the built in meters would be to unhook one of there wires. Than remeasure the resistor value and than measure the voltage on the resistor after the amp is warmed up. Use the ohms law to figure out what the voltage equates to mA wise. All pretty anal retentive since the meters have to be fairly close. The measurements you took so far are totally inaccurate and unreliable.

Yea but the screwy part is I've seen lots of these meter over the years and own a bunch of them myself both US and from the other side of the pond...I've never seen one have even close the 1 ohm of resistance.

What is the color bands on those resistors? It looks like its Brown/Black/Black which = 10 ohms not 1 ohm. I think your reading 1 ohm because its shunted off by the built in meter which has to have pretty low internal resistance. I'm shocked it has 1 ohm or more.... I've never seen one that wasn't at or real near zero. In the end as long as that built in meter is connected to the cathode you can not measure with any meter. When you measured .650 or whatever is was that was .650 of 1 single mA you can't pile meter on top of meter on top of a resistor. All 3 devices were splitting the current running through the tubes cathode. I believe the 10 ohm resistor is there to allow the tube to still work if the meter fails shorting open. The built in meter is shunting the 10 ohm resistor down to the single ohm so most of the current is running through the meter. As the Italians would say use the onboard meters and forgetaboutit.

But when you measure the resistance of the resistor on pin 8 of the output tubes it measures 1.2 ohm? I'm scratching my head big time here.... something is screwy.

Bonzo. I think in the end you're going to find that you'll have more issues with the lower rated pin compatible tubes you can use in VRD's like 6L6GC, 7581A and so on simply because those tubes are running near there maximum design center lines in the amps while the KT88/6550 family of tubes are running nice and easy.

Its been a while since I had a set of PCats here but I do not recall them using a quad of 12AX7's....maybe just brain fog on my part.

Do those meters have a button to activate them? Or do they always display the bias as shown in the pictures above?

See those are purpose built analog DC mA current meters which should have little or no internal resistance.. Can you trace back to the tube socket what pins they are attached to?

The meters I'm concerns with and wanted close up pictures of are the meters built into the amps. I want to know if they are reading current or voltage. Again Maynard is right your can not use the current reading function of your digital meter to accurately read the current across the cathode resistor. That resistor is place there sop you can read voltage and use ohm law to figure out the current just like you do on your other amplifier (or should be doing), I personally do not like to use a 1 ohm resistor because the voltage developed will be very small and subject the error especially with inexpensive meters. I'd much rather use a 10 ohm resistor

So let me get this right in my head. The two wires slide into the ends and butt up against that evidently low temperature solder in the center. Then you heat the solder and the heat shrink with the heat gun? Seams to me like the resulting solder joint isn't going to be super reliable. I guess I'm old school and would rather have a mechanical connection and then high temp solder...

Bump because it took me too long to find this thread after someone asked me about an item.

What are you setting the Klein to measure voltage or current?

Dave, Do you have a decent digital camera? If so take a close up shot of one of those meters. I wouldn't be surprised your measurement is more off than the meters. I again agree with Maynard (I think the red sea just parted) this is much to do about nothing .

Is this the 200 I was called about for shipping address the other day? Man is it in nice cosmetic condition!

Maynard is right you can't get an accurate measurement using the current setting on the digital multimeter. The meter would have to have zero ohms of internal resistance to shunt out the 1.2 ohm resistor which no modern digital meter can do that I know of. So when your reading the current there is still some current sneaking through the 1.2 ohm resistor making your measurement inaccurate. So you use the voltage drop and ohms law. Most likely those resistors are 1 ohm and the meter leads are adding a bit. So again what do those meters on the front say they are displaying on the front of the amp volts DC or current (mA)

change your meter to read resistance and see what the value of those resistors are... also what does the meter say its displaying current or voltage?

get what you pay for I guess ... Are the meters up front for bias? If so why do you not trust them?

No reason a properly working McIntosh preamplifier would have mating issues with the VRD's.

I don't see how noisy floor has anything to do with a CD player. In my experience it's usually caused by improper nailing and lack of construction adhesive

Well first thing I'd do is swap the cables going from your turntable to your phono preamp. If the problem changes channels then you know the problem is turntable related. If it stays in the same channel the problem is in your phono section.... always narrow down where a problem is before trying to fix it.

I'm pretty sure the Grado cartridges are known to have issues with hum. Something to do with a lack of shielding.

Mike is a true artisan when it comes to winding transformers. I've dealt with him a number of times off and on for almost 20 years now. He always delivers top quality!

Dave, Bias them with the lights down low so you can see at what point as you raise the bias the main plates in the tubes start to glow red. Raise them a little at a time, let the amp play for an hour before you determine if they are starting to red plate. Once they start to red plate back them down 5 points... If it sounds too tight/confined to you at that point then lower it a little more until things loosen up and sound more natural.

I have to agree with Maynard 🤔 not enough information. The picture shows no sign of low quality to me. The thing that bugs me is if you study the position of the tubes in the top picture to the sockets in under the chassis photo I don't believe the pictures are of same amp.