preamp

Had severe distortion in left channel of a Sony STR-7055, traced it to a bad transistor in the preamp, replaced it, clean sound but the low volume remained. Confirmed it wasn't an amp issue by flipping the separate switch on the back and using another pre to test. Equal and clean volume from...

Looking for some advice from the experts here. I ordered a new pair of very nice powered monitors. Among other things they eliminate the need for an amp, so the preamp will be basically the entire guts of the system. I have an Adcom GTP-500 which I love but it recently lost a channel, so I got...

Here's what happened :) Got my hands on a NAD 114 for 55€. Fully working, even sounded alright, no crackling pots and just a slight noise on full volume in speakers and headphones. Fully original condition. But the transformer was buzzing, mechanical vibration and like sizzling sparkish sound...

Hi all, Have had this pre-amp with me for a few years and have never had any eletrical or mechanical issues until now! I rotated this out of daily service about 4-5 months ago; was dormant until I reintroduced it into the main system, driving a Yamaha M-65 on Class A mode. Chain: Technics...

Hi all, looking for help in trying to get a NAD C162 (circa 1999 - board N6C1162DD01 DC741130) up and running. About me, setup and goals: I’m using this project to learn more about analog electronics and would love that it could be fixed but not too worried if it can’t. I took some EE...

I have a Yamaha surround sound receiver with all the bells and whistles, including many channels of amplification. However, I use all separate power amps, so this a bit of overkill. Since that is a major expense in these units, why not make something that has all the bells, but no amps? It would...

Hi, I'm trying to fix this preamp which appears to be an early version. So far I had one defect 4013 chip and several relays with open coil (I replaced all of them with yellow HB2E-DC24V). After powering it up, I found that the LEDs of 2>1 Tape Copy and Low Filter always dimmed (or turned on...

Hi y'all, long-time forum lurker, first time poster. I very recently came into possession of an Audio Research SP14, in very good shape from a very reputable dealer (online, but with a high end brick and mortar store). Worked perfectly fine, sounded great on CD, but realized the phono out...

Howdy howdy folks The Heathkit AP-1800 is a veritable fidget board of knobs and switches. Some of which tie into these neat linear selectors. There was some distortion and channel dropout when I first got the thing about 6 or 8 months ago off a guy on ebay which a liberal application of deoxit...

I have a WiiM Ultra streamer as my main source. If I’m using ReplayGain for my Qobuz and personal library listening, but not the WiiM's room correction or PEQ, is it safe to apply some positive adjustment in the WiiM's Pre Gain control under Inputs without causing distortion or clipping? I use...

Reclaimed a Yamaha C-80, as I sold the first one without really understanding the potential of inverted pre out. Not a bad price, but not one that I'm singing into the hills on. Anyway, seller stipulated public meet-up. Fine by me! Only how to test? I brought over-ear headphones, RCA-to-3.5mm...

I've recently bought a McIntosh mx110z that still has the old selenium rectifiers id like to take precautions in changing them out with silicone diodes but am inexperienced in how it should be wired with a diode bridge if anyone has an example I could follow any help would be appreciated. A few...

Good morning AK, I have a quick question... I have a Marantz 2230 that I use as a preamp connected to a Peachtree Audio Amp500 that powers my Infinity CS-3008 floor standers. A few months ago, I picked up a nice little pair of Kef Q150 bookshelf speakers on sale. I gotta say, I was VERY...

Imagine an interesting new product: Two sets of analog inputs (when I say sets, I mean each set has single-ended and also balanced), one volume attenuator that controls output synchronously BY WAY OF TWO SETS OF SYNCHRONIZED RESISTOR LADDERS (analog-domain attenuation, not digital) between the...

I've been away from the repair bench for a while but I'm finally back at it, clearing out some pieces I have neglected for a long time. First up is the adcom preamp mentioned above. I have the service manual, but before I dig in too deep, I figured I'd stop here and see if anyone has experience...

Pedal Pimp Fosi X2 Mod Ever since purchasing my Fosi Audio Box X2 Phono Preamp, I’ve become obsessed with making it the best it can possibly be. After plenty of trial and error and extensive A/B testing, here’s what I’ve settled on: Outside Mods Feet: The stock cheap adhesive plastic feet on...

Hey AK's Just a short intro into this project I wanna share. After several protobuilds where all worked, this end-build might be in sight within a few months. I have most of the parts, except chassis/relays and other minor parts, but most I have in my inventory. All drawings are made in KiCAD...

Hello, I am new to buying audio equipment >$500/component. I’m overwhelmed by the choices online that one cannot listen to without ordering and possibily returning, but the limited choices within a total budget of $4000 at a local audiophile shop, where listening or borrowing for home trial is...

Hello everyone, This is my first time posting on this forum, I've enjoyed vinyl for a long time but only recently I've been able to invest much more time and money into the hobby and I have some questions about preamps. My current setup is an LP120 with the internal preamp bypass mod and a...

I picked up a used Yamaha C-80 for a c note. Excited to get it workng. I read the forums here and saw that typical issues included glue corroding the resistors and film caps near the power transistors in the power circuit. I had exactly that problem and so I cleaned off the the glue and...

Specifically, I am repairing/restoring a DX4000 and most of the pushbutton caps are either missing or cracked. I designed and 3D printed replacements for all 15 using TPU filament. TPU is nice because it is a bit flexible so the prints can be made to grip the switch posts tightly without ever...

Hey all, I picked this little oddity up earlier, and can’t find anything about it online. Has anyone seen anything else made by “KZ Audio Specialty”? The VU meters look like Berlant, has triad transformers, but no chassis markings at all. The front panel says it’s a “Remote Mixer Preamplifier”...

So basically, I am getting an upgrade for my desktop speakers, I'm going from $20 Logitech plug and play speakers, to Sony SSCS5 bookshelf speakers, a Elac SUB1010 subwoofer, and i'm not sure what AMP I should get, or if I need an external DAC or preamp. In regards to AMPs, I'm thinking about...

Hi all, Brandnew to this forum. Ive been a phono listener for years and enthusiastic guitar pedal builder. So I thought let's try and build a tube preamp for my TT. And that's where trouble starts. I've build a Chinese Ear834 clone, but I'm getting 50hz hum when playing. The preamp does...

I have a Rotel RTC-970 Tuner Preamplifier that has several issues that all seem to be related. The obvious operational issue manifests itself as the volume control turning itself down after the unit is on for about 20 minutes. At that point, to turn the unit off, you have to unplug the unit as...