API jukebox

Author: matthew; Published: Jun 29, 2009; Category: API 3224; Tags: , ; No Comments

I haven’t posted in forever, mostly due to the fact that I’ve been working like crazy or travelling. Since the last post I’ve been toiling in our new room, which is anchored by a beautiful vintage API 3224 installed by greg mcneer and myself. wiring was planned and executed beautifully by mike rhodes and his crew of miscreants.

API 3224

API 3224

front before fader mod

front before fader mod

two down twenty-two to go...

two down, twenty-two to go...

The monitor section of the API has incredibly chintzy faders that are prone to seizing and failure. They also sound bad compared to the P&G faders used for the GML automation system.

The solution is replacing the monitor faders with sweet-sounding P&G models with the same throw. Luckily Dale Manquen is available to help you with any P&G needs you may have

click on any of these images for the huge, blurry cameraphone version.

back before fader mod

back before fader mod

front with P&G fader installed

front with P&G fader installed

back with the new fader

back with the new fader

The new faders feel and sound much better than the old ones. the original caps and card faces hide the modification and keep things looking vintage.

SDM45 getting born

Author: matthew; Published: Jan 14, 2009; Category: Amplifiers; Tags: , ; No Comments

it’s coming along. so very slowly.



Projects for 2k9

Author: matthew; Published: Jan 7, 2009; Category: Amplifiers; Tags: , ; No Comments

I am in the process of building a knockoff of the insanely valuable Marshall offset prototype (one of the ones from Jim’s kitchen) that’s here at Echo Mountain. It’s been done before (and is being done now, by me,) but this version will be reasonably priced, look cool, and should sound pretty great. I hired my friend Alex to do the chassis drawing for CNC machining.

One of the reasons I respect Echo is that the offset and the straight JTM-45 prototype are both in use on many sessions. They sound like rock n’ roll and are happy being played.

I’ve also come up with a new sort of pedal prototyping platform. More on that as it develops.

Studer A800 Resurrection…

Author: matthew; Published: Dec 27, 2008; Category: New Studio; Tags: ; No Comments

Way back in ought-six, Steve, the owner of Echo Mountain, acquired three Studer A800 machines in dubious condition. One was rebuilt and has been in use as Echo’s 2″ 8/16/24 track for the last two years. The remaining two have languished in the amp room as parts machines, keeping the primary 24-track working more or less flawlessly. They came in on a truck from NYC and all had been mostly stripped of tantalum/poly caps due to someone deciding that capacitor technology was old and bad and would catch fire. While it’s true that tantalum caps love to fail short I think the solution applied of replacing them all with electrolytics was ill-chosen as a long-term remedy, but great for job security for whoever gets to re-cap the machine every five or ten years. It’s true, we decided to stick with electrolytics as the more durable technologies are crazy expensive. So, I give you the re-cap team:

This project took place during two four-day sessions over the last two months and was overseen by Greg McNeer and myself. Prior to working on the tape machine itself I robbed the power supplies from both for rebuilding. Each A800 has five separate power supplies in a sweet daisy chain. The audio supplies have a fancy interlock while the transport/logic/etc. supplies are more straightforward.

Problem – Like most 80′s technology the wires carrying power and the .1″ molex used to connect it aren’t really rated for the current demanded (and heat created) by the machine, so the wires are brittle and corroded and the connectors are stiff and burnt.

Solution – Replacing worn-out wire and parts. I selected some 16 ga. wire with a higher-temp insulator than the original and kept wire colors the same so the excellent manual could still correspond to the real circuit. I didn’t have a better connector option that I could stuff in the holes available so i stuck with sweet sweet molex.

Problem – The middle audio supply negative rail is getting pulled down.

Solution – An electrolytic in the back plane of the middle card cage has failed short. With it replaced all power supplies are operating to spec.

The heads have been sent for re-lapping and capstan and tach rollers sent for sandblasting. The tape path is square according to the alignment blocks.

SSL days at Zac Recording

Author: matthew; Published: Nov 25, 2008; Category: Studio Maintenance; Tags: , ; No Comments

soldering! testing!

soldering! testing!

reassembled and working.

reassembled and working.

Problem – The SSL 4000 G+ at Zac has a plethora of niggling issues with various channels. Many of the switches that pass actual audio (sometimes referred to as ‘analog switches’ to distinguish them from switches controlling relays or JFET ‘relays’) are dirty and failing.

Solution – replacement of the ‘in,’ float, split, phase, and pan switches. Our three-man switch-replacing and diagnostic team included Grammy-nominated (and Zac Recording head) engineer Tony Terrebonne and Suspect Device occasional staffer Tommy Terrebonne who was visiting his twin brother while soldering. After all switches were replaced a few channels were still ill-behaved. Edge connector issues were corrected by cleaning and logic problems by replacing an open small fuse on the power rail coming in to one channel.

New mains for a new room

Author: matthew; Published: Nov 17, 2008; Category: New Studio; Tags: , , ; No Comments

looking in the door of the new control room.

looking in the door of the new control room.

a hole for the connector.

a hole for the connector.

Today was a day of new mains for the new control room. I connector-ized the 10-gauge speaker cables I pulled through the studio conduit with the Amphenol connectors I got from PEI genesis. I poked holes in the speakers for the panel-mount connectors and got a brand-new 140-watt soldering iron that would handle heating such large wires and solder cups. New tools are so exciting. I don’t normally deal with wires this substantial and had to build a little jig to get them all in the same plane as the solder cups/pins without significant bends.

male connector

male panel-mount.


female from the amp.

The holes for mounting the panel-mounted male connectors are super small: you can see the #4 brass wood screws used to mount it in the photo at the left. I was worried the little screws wouldn’t be beefy enough to actually hold the connector, but once it was all assembled and mounted this solution seemed sufficient. (I have some 4-40 screws/lock washers/nuts just in case.) Luckily, this assembly will just sit there 99% of the time without much disconnecting/reconnecting. I do wish the mounting screws were black anodized, but since this whole thing will sit inside the wall I guess it’s no big deal.

LA2A day

Author: matthew; Published: Nov 13, 2008; Category: Outboard Gear; Tags: , ; No Comments

Problem – Two of the Teletronix LA2As are behaving badly. One is noisy and one is not compressing appropriately.

Solution – Both compressors have noisy/scratchy gain pots, so I cleaned them with Deoxit. The box that isn’t compressing well gets a new T4-B and R25 because it’s handy, but nothing changes. I test the tubes on the non-compressor and find that both 12ax7s are pretty bad and the 6aq5 is really bad. I grab (and test) a good 6aq5, but we’re out of 12ax7s. I order some 12ax7s and a new FP-type filter cap from Antique Electronics. The now non-noisy LA2A is back in service with the non-compressing one standing by waiting for tubes and filter caps.

LA2A schematic

LA2A schematic

New Studio, Leaving Town

Author: matthew; Published: Nov 12, 2008; Category: Studio Maintenance; Tags: , ; No Comments

Today I went next door and pulled speaker cable for the mains in the new room. Ordering locking bayonet large-gauge connectors from PEI-genesis has been a long and mostly enjoyable process – they are cheerful and helpful people, and I am aware we’re just getting four pieces. I am looking forward to poking holes in each of our Ausberger-designed JBL speakers to accommodate the new gold interconnects. Hopefully they show up tomorrow.

The SM69 finally showed its true colors and the sides have become unmatched. It seems to be an even split between tube and interconnect issues. Should be fun sorting that one out.

Next week I’ll be in atlanta refurbishing the 4080 G+ SSL desk at Zac Recording’s Stonehenge Room. It warms my heart to work on the desk (and in the very room, even,) where ‘London Bridge‘ was tracked.

More on Watkins Amps

Author: matthew; Published: Nov 12, 2008; Category: Amplifiers; Tags: , ; No Comments

After installing the new power transformers in the Watkinses and replacing bloaty and old electrolytics both combos are sounding great. I plan to get Perry to trace the circuit of each on Friday so I can offer it here for all the internets to see.

Watkins before

Watkins before

KM56, SM69, Watkins Amplifiers

Author: matthew; Published: Nov 10, 2008; Category: Amplifiers, Microphones; Tags: , , , ; 2 Comments

Spent the morning helping set up for the new session. Balanced the Genelec near-field monitor levels to the NS-10s. Oriented the visiting engineer.

Problem – One of the matched KM56 mics and one side of the stereo SM69 have the delightful sounds of cracklin’ potatoes after being on for an hour.

Solution – I left the mics powered up on the bench for more than 24 hours. none of them show any evidence of problems. This is irritating. I applied various stress positions to no avail. The capsules seem to seat properly and the cables seem intact. I do not know what mic cable was used for either microphone when the initial problems presented.

Problem – The newly acquired Watkins amps sound good but are too quiet.

Solution – Upon examination it turns out that both amps are set up to run only on British voltages and when I apply 220 volts both amps sound great. I discussed the situation with the studio manager and she preferred that I change the power transformers in the amps rather than run them from external transformers. I ordered transformers from Weber.