Love my 604e's

**Twodawgz** · October 1st, 2021, 12:10 PM

Just had to replace a HF driver in one. Bill at Great Plains Audio shipped it out fast to California. Got everything working again, and the sound is just stunning.

604's powered by 4 watts per channel Transcendent Sound Mini Beast (transformerless SET) and McIntosh C22 preamp. That combination just kicks ass.

**rogerh113** · October 10th, 2021, 10:29 AM

604's are wonderful speakers.

I have been curious about OTL for a while now. How large are your cabinets, and how is the bass line with 4 watts at reasonable listening volumes?

regards -- Roger

**Twodawgz** · October 11th, 2021, 11:59 AM

I was a recording engineer in the mid 1970s to early 1980s. Mainly I was a mastering engineer for ABC Recording Studios and Artisan Sound Studios, among others, in Los Angeles. All of the studios I worked for, and others that I visited, had Altec 604e's as their main studio monitors, with several others for reference (JBL, Auratone, etc.). The Altec 604e's were known as "The Standard of the Industry", and had been in use in studios since they first came out in 1964.

I bought my 604's new in, I believe, 1977 (possibly 1978), when I read somewhere that Altec had released a limited run of 100 of the e's. I was able to track them down and bought two from Hollywood Sound in Los Angeles. I still have the receipts in a folder.

Next I scoured the world for information on cabinet designs. I built my cabinets out of 3/4" plywood. The dimensions are 29.5H x 25.5W x 19.25D. Because I like bass, I made the port a larger 12.75 x 5. I bought oak veneer to cover the plywood, and it sat in a drawer for 25 years. Finally, a friend and I put on the veneer (which was a lot easier than I thought it would be).

To answer your question on bass with 4 watts, there is plenty coming from those 15" woofers. In fact, depending on the EQ of the material I listen to, I often have to turn down the L & R bass a notch on the C22 preamp.

I used to have my 604s bi-amped with a tube type Marchand Electronics active crossover with a McIntosh MC225 on the top, and a Cary CAA1 (solid state) on the bottom. I loved the control over the high and low balance afforded by bi-amping. But eventually I had problems with the Marchand and didn't want to ship it across the country a second time. So I assembled the Transcendent Sound Mini Beast from a kit after researching SET alternatives.

I wanted to put in new passive crossovers and could not find ready made ones for the 16ohm 604e's anywhere. So I did more research on specs and built my own.

When I finally got everything built, installed, and turned the system on, I was quickly blown away by the clarity of the stereo soundstage across the frequency spectrum and the quietness of the amplification. I had previously thought nothing could touch bi-amplification, but this setup completely changed my mind.

If you're thinking about an OTL amp, I highly recommend them. They run hot as ****, but hopefully that doesn't pose a problem.

By the way, I have a McIntosh MQ107 equalizer in the path, with which I tone down the midrange of the 604e's to my liking.

Today, I am the mastering engineer for the reissue label Eric Records and do the mastering in my home using the 604e's. Any headphone work I do using Beyerdynamic DT770 Pros (my favorite headphones). Check out our sound samples at ericrecords.com.

**magnarc** · October 15th, 2021, 08:10 PM

Just curious, if you purchased your E's in 1977 or 78, were they still on the 15" white frame?
The 8-G was out by this time, and the 16" frame had been in use on most Altec 15" for a few years by this time.