Recent content by nakdoc

Burnish the male connector pins on every connector. Also check for broken solder at each male and female connector.

It does look like the same knob. Thanks for pointing that out. I might also steal on off a 1000 and put something non-original in its place. I made the typo not on purpose. For years service guys have always called them Flame Linears, but the last 4four 400s I've encountered have all worked...

Before I commit to dealing with the insides of this preamp I need to buy a knob. I need one big knob.

I owned DQ-10s for many years. What you are hearing are the benefits of "No Box". If you think the speaker is bass shy, try sitting them on the floor (or even on the tiny feet) Bass in spades. The optional stands were almost universal and they are responsible for a more accurate bass with no...

The 620 power amp is a cool design. THD is rated at 0.005% too. You could fit 2 amps in the rack and bridge them using a Nakamichi "black box" bridging adaptor.

I've often shared my views about vintage equipment and the sounds they make. Taking an old unit and replacing caps always seems to bring joy, but who really knows if the original OEM sound was better? We don't have new old stock stored in a freezer to compare. As an example, I will offer the...

Use the parts to fix crown DC300 amps.....

I found ECG192A used as a bias transistor in a stock 400. I have 5 more transistors in stock.

Polarized electrolytics like to be polarized. Very often however we see input coupling capacitors feeding an opamp or diff pair, and both sides of the electrolytic at zero volts DC. When audio signals, which are AC, are passing through the cap, (lets assume the + lead is towards the input) the...

My paper version for the 400 is missing the last output transistor buletin. I just repaired what must have been the last 400 biult. It has the fiberglass series II driverboard, a speaker relay, input volume controls ala the 700. But what is interesting is the outputs are all labeled 126-00073...

Noise is generally NOT limited to transistors, and heat usually makes noise worse, not better. Resistors and capacitors (rarely) can cause noise. Make a nozzle on your heat source and carefully narrow the heated air to identify a smaller number of parts which seem noisy. The DH101 suffers badly...

Capacitor tolerance has no effect on sound qualities, unless they are in an equalization circuit. Power supply capacitors, coupling, and bypass capacitors have modes of distortion related to their physical design. Inside electrolytic capacitors are two parallel foil "plates" separted by a semi...

I am not worthy Nav. Nando, thanks for your insight.

Air cores do not saturate at high power levels = lower distortion. If you have an inductance meter, you could unwrap a 1uH coil. Removing 1 wrap to solder the original coil in will not cause problems, because all the parts are 5-10% anyway.

Paint the LEDs black- effective and reversable low tech solution.