Monday, December 16, 2013

Custom-Built MQ-565s on Sale


We have SOLD OUT pairs of M6 nickel pinstripe MQ-565s in stock. These come in black oxide steel covers, but could be switched into brass bell ends for an additional fee.

These babies have a primary impedance of 7100 ohms CT with UL taps, and a secondary impedance of 8 & 16 ohms, MOL 17.5 watts.

Nickel lams are increasingly harder to find at any price, and these puppies are not a regularly stocked item, so snatch up these nickel pinstripe MQ-565s before they're GONE!

$400 per pair M6 nickel pinstripe

We'll accept payment via PAYPAL (you pay shipping) or by U.S. POSTAL MONEY ORDER (in which case, shipping is on us).

Email if you have any questions or would like to place an order.

Peerless catalog of 20-20 Series output transformers


Click on the photo above to enlarge.
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Friday, October 18, 2013

Friday, September 27, 2013

Glamour Shot: EXO-046s

This EXO-046 is one of a pair. Built with nickel lams and housed in steel channel frames, they're sleek and sexy.

Primary impedance 5000 ohms. Secondary impedance 16 ohms.  MOL 2++ watts.  Parafeed. Most often used with the 45 tube and a  BCP-15 plate choke. Great for use with 16 ohm single full range drivers.

Want to own a pair? Email us at acrosound [at] aol [dot] com.

Monday, September 23, 2013

Glamour Shot: FS-030

This FS-030 is one of a pair built with special covers. We love the contrast of the pale green with the black painted lams. Don't you?

For complete specs

Interested in owning your own pair? Email us at acrosound [at] aol [dot] com.

Thursday, September 19, 2013

Build and Let Build

"C'mon, this is a hobby -- you enjoy it your way, and I'll enjoy it mine, and if aesthetics and industrial design happen to be important to me, who cares? Listen and let listen. Build and let build."

So wrote member Jim R. of the Bottlehead forum on a post a while ago about polishing brass bell ends. While transformers and DIY audio are our business, we hope our customers enjoy themselves when using our products.

And he brings up an interesting question: What's important to you in audio transformer design? (Speaking of aesthetics, don't you love the above picture of our MQ-470?)

Monday, September 16, 2013

From the Bottlehead Forum: About the BCP-15

MagneQuest BCP-15
The BCP-15 was an original Freed design.  It was originally spec'd at 50 madc and 40 Henries. We built many of these to the original specs. These would tend to have only the BCP-15 marked on them.  

Later... realizing that most people who were purchasing these plate chokes were using them with the type 45 tube which runs moreso typically at 35 to 40 mils of plate current. After careful analysis of the original design we were able to regap the unit and optimize it for use with the 45 tube at the ballpark 40 mils instead of 50 mils of plate current. With the smaller airgap, we picked up more L (50 henries).

Once we offered the second choice -- 40 mils at 50 henries or 50 mils at 40 henries -- I've tried to be consistent (bearing in mind the existence of human frailty) and mark the coils that were gapped for 40 mils. Often times (but not always) this demarcation might be written on the back side of the coil.  

The 50 mil coils may or may not have the marking -- if it's not marked--- again allowing for the occasional human error -- it is most likely gapped for 50 mils. 

This description comes from the Bottlehead forum for "All things MagneQuest." Check out the thread here.

Friday, September 13, 2013

Have You Met Our Robin Hood Series?

The Robin Hoods' series consists of three single-ended air-gapped output transformers. The aim of the series is two- fold. First is to offer a transformer for folks who are bi-amping and don't need the huge inductances and AC power capabilities of say our legendary FS-030 single ended  output transformer.

The second aim/goal is to make these the best VALUE output transformers available in the marketplace. The "Robin Hood" series is named in honor of the man who took from the rich, as in the richness of MagneQuest's proven designs, to give to the poor, as in DIY lovers who crave high value without sacrificing top quality.

The primary copper circuit is smartly crafted to keep resistive losses at a minimum (the dcr is approx. 185 ohms). The copper losses from the full secondary and the full primary are equal in magnitude. The primary inductance is carefully designed to fully support the published low frequency extension of each model at the maximum stated power level. The total (AC and DC combined) magnetic flux density is kept BELOW 16kg in each model offered in this series. Therefore, these will not saturate or "run out of iron" when used within their published specs.

Simply put, these are expertly designed transformers with an emphasis on sound quality. We didn't skimp in the goodies department. All of the RH series are made with pure Teflon insulation on the inside. All solder connections are made with silver bearing solders. All units are housed in channel frames with easy to solder to terminals. They are as easy to install as they are musical in their sound delivery.

Currently, three different models are available in the following configurations. All have 5K primary impedances.

Here are the specs for the RH-40, RH-60, and RH-80 which cost $125 each.

Sunday, September 08, 2013

Power Transformers: R-080, R-160, R-196

Model R-080 is 275-0-275 at 20 madc and has a 6.3vct winding at 2Arms. This unit was designed by Peerless as a special low flux density preamp power trans. It is way conservative in design. 

Model R-160 is 275-0-275 at 40 madc and has a 6.3vct winding at 2 Arms and a 5 volt winding at 2 Arms. 

Model R-196 is 300-0-300 at 50 madc and has a 6.3vct winding at 2.5 Arms and a 5 volt winding at 2 Arms. 

All are laydown transformers and are supplied with solder lugs (terminals).

Thursday, August 15, 2013

Buy MagneQuest Transformers on Etsy and AudiogoN

EXO-145 Single-Ended Parafeed Output Transformers with Litz wire secondary leads, all-nickel core and brass channel frames

MagneQuest is now set up with an Etsy shop and we're using AudiogoN to list products for sale.

Currently, we've got a pair of EXO-145s with Litz wire secondary leads, an all-nickel core and brass channel frames for sale on both sites.

Buy the EXO-145s on Etsy here or on AudiogoN here, or you can order direct by emailing

Follow MagneQuest on Twitter & Pinterest

MagneQuest is now tweeting @MQIron.

MagneQuest is now on Pinterest.

Tuesday, August 06, 2013

Glamour Shot: EXO-145s with Brass Channel Frames

If you're ready to order vacuum tube audio transformers of the highest quality, shoot us an email at

Friday, July 12, 2013

In the Shop: Dowdy 40 mils with Brass Bell Ends

Finishing a pair of Dowdy plate chokes (40 madc @ 125 H). With brass covers on these weigh 4.5 lbs each. They are approx 3.375" tall and approx 3.5625" from outside bell end to outside bell end. In our universe these are "medium" size plate chokes... not the shirt pocket models that come in channel frames... but not the big muthas like the FS-100-PF or BAC-80.

There are two additional pairs available at $275 a pair plus shipping.

Interested in owning your own pair? Shoot us an email at

Wednesday, June 26, 2013

Backstage with Barenaked Ladies and Wavelength Audio

We were excited to learn that one of our Original Equipment Manufacturers, Wavelength Audio, supplies the amps for the band Barenaked Ladies.

Well, I should say Rosie was super excited. She had to explain to dear old pop what the band is known for. (In case you don't recognize the band name but have kids who listened to pop music in the 1990s, check out this video. You just might know the song.)

Although J. Gordon Rankin of Wavelength Audio is "not at all a fan of Push Pull Amplifiers," he was asked by the Barenaked Ladies to create a version of the Fender Deluxe 5E3. "Yea I know this is nothing like it and for sure I will never copy anything someone does," Gordon wrote on the Audio Asylum forum. "Why? they probably got it wrong in the first place."

Here are the specs for the Wavelength Small Block amp pictured above: "This is a hyper-pinstripped output transformer, PP-6V6, EXO-173 phase splitter, 6072A input, 6FQ7 into the EXO-173, full tone stack and master volume. Kicks out clean to about 15-18W, really killer sound."

Thanks to Gordon for sharing this on the forum and for posting the picture above.

If you're ready to order vacuum tube audio transformers of the highest quality, shoot us an email at

Tuesday, June 25, 2013

In the Shop: Building MQ451s

Today, Rosie stacked a pair of MQ 451s. (This particular pair is 120 watts, 2200 ohms primary impedance and 4, 8, 16 ohm secondaries.) The blueing on the lams is a cool result of the annealing process. 

If you're ready to order vacuum tube audio transformers of the highest quality, shoot us an email at

Thursday, June 20, 2013

Glamour Shot: Dowdy 60 mils

Isn't this Dowdy 60 mils with brass bell ends just beautiful? We love the combination of black and gold.

Interested in owning your own pair? Email us at

Friday, June 14, 2013

Ready to Ship: RS500s Heading to Japan

Today, in the shop, we're getting ready to ship RS500s to Japan. Each pair is tightly matched for winding resistances. Hence we mark each box with a unique symbol so that the two remain together.

Currently, this transformer is export-only. How many of you would kill to get your hands on a pair of RS500s?

Wednesday, June 05, 2013

In the Shop: Cathode Chokes and Outputs Drying Post-Varnish

Cathode chokes and outputs drying off after being varnished. You'll see pictured three pairs of EXO-36s.

Tuesday, June 04, 2013

In the Shop: Rosie Builds her First EXO-99s!

Today, Rosie built her first pair of EXO-99s, and signed both pieces. This inaugural pair of plate chokes will be going to George Lenz at

Rosie, looking pensive.

If you wish to order your own pair signed by Rosie, shoot us an email at