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The circuit is not all that bad - direct coupled, differential input, triplet output, though missing some finer elements (current mirror etc). The opamp implementation for gain (phono input and insertion loss for the tone circuit) will have the biggest influence on audio quality based on the...

Haven’t used it myself, but I’ve read that fishing braid works well.

You need to do a 6-way test: B-E/E-B/B-C/C-B/E-C/C-E to check for shorts across all the transistor junctions. Your tests so far look okay.

Consider how much power you need as a start. I have both P-P el84 amplifiers and SE (in fact, the SE is a receiver). To me, while the P-P sounds very good (better than a 6l6gc amplifier I have), the SE is very special in drawing one into the music. It?s also a simpler cct to build, but good...

IIRC, the AU101 has a ground bridge across the loudness switch (L and R ch?s). I?m working from memory, (it?s been a few years), but I do recall that the bridge looked like a blob of solder that shouldn?t have been there. With your loudness switch installed, make sure that the bridge is present...

Sansui 220 will no doubt have Suzuki oil caps in coupling duties. These a very prone to leaking and allow DC to pass to the next stage. This is often proves fatal. Replace all of those caps without delay. As a general rule, capacitance being only one measurement, if you can?t measure ESR and...

I don?t have first-hand experience with the AU-D11, but do own an AU-D9. Very clean, fast sounding amplifier. The sound signature is very nicely nuanced, with no part of the audio spectrum over-emphasized. It?s more ?modern? sounding than Sansui?s that can before. This series (based on...

I can't remember the exact expoxy, but it was a Pratley that comes with two tubes that you mix the contents of. Fortunately for me, I had a replacement knob. The aluminium extension was somewhat thinner than the original stem, but I packed the slot of the plastic insert of the knob with another...

I fashioned an extension to a broken slider stem by using some aluminium, cut to size using tin-snips. For mechanical strength, I cut the aluminium extension with two 'wings' that overlapped the portion of the existing pot stem (in your case, part B). The 'wings' were then tightly folded over...

I only have experience of a Naim Nait5 coupled with a CD5 (slightly modified - opamps changed). Very engaging sound, high on PRAT, adds an 'exhilarating' quality to music - these are not components for background music - you will sit up and take note. Somewhat 2 dimensional (depth is slightly in...

I own a pair of Response 2.5 for 7-8 years now (bought 2nd hand). Great speakers, very balanced and musical. Their designer, Stuart (or is Stewart?) Tyler is a very respected speaker designer. I've never felt inclined to 'upgrade' since buying them. The Tower series came before the Response...

Very nice work. I've done a few Marantz recap/rebuilds from that era, including a 1030 (I bought it with a blown channel). A few tricks I've learnt: you can manipulate the board to have sufficient access to replace components without having to unsolder all the pin connections on most boards -...

It's an 8V bi-pin lamp, in the rgion of 30-40mA. I replaced mine with a 5mm LED. As the feed is AC, you will need a diode/resistor in cct to light up the LED.

I purchased 2240's from Mantech about 2 months ago and 970's, probably 6 months ago. If these can't be had, 2sc1845 and its complement 2sa992 may be a good bet (higher hfe, lower Vceo, lower Pt IIRC - check specs for your application). My local Mantech branch in Durban had 1845's but 992's...

Hi Neil Looks to be a biasing issue. If you are handy with a DMM, I could guide you through some basic checks. Beyond that, it does get complicated. You do owe it to yourself (and the 1060) to get amp restored to all its former glory. I have 2 (one virtually rebuilt and re-capped, and the other...

SeanS's version helps you catch fish.

Hi Neil Like Harry said, lube and work the pots cw/ccw at least 20 times. You can gain access to the 'holes' in the pot by removing the bottom plate. Do this for both volume and balance pots. Getting to the tone pots is a little diffucult, but not impossible - do them as well. It leads me to...

As GECO said. Any transistor with the correct characteristics for an application is suitable.

Sanding does improve things, also setting back as far as possible the LED from the facia (too close and the spot-light effect becomes a lot worse). I've also heard of applying some superglue to the LED and then coating it with baking soda to improve diffusion. I'm going to try that some day.

Download the datasheet, then look for an equivelent, matching the type (NPN/PNP,Fet etc)/Vceo/Ic/ft/Pc/case type, at least. Also consider that transistors don't blow for no reason - something in their environment caused it blow. Find out what by checking passive (or active) components in the...