An appreciation of an Ampex 351 tape deck

[tapepath]

The transport weighs 50 lbs and each electronics chassis weighs 18 lbs, Ampex offered this model as a portable version in two road cases. Not too much weight to lug up three flights of stairs to a remote recording location, I guess. Recording engineers were tougher in those days. Or, they had "assistant engineers" more likely.

 

[Foxbat]

Thank you... not too bad, probably 100-110 lb total. My memory of that transport is "Heavy as hell!"

 

[tapepath]

I have nothing but a great deal of respect for the engineers who designed this machine and the people who built it. I'm not sure how the transport compares to more recent decks, but the 351 transport reaches correct playing speed within 1/10 of a second with no tape bouncing at all. When the transport is stopped during 15ips playing only 2" of tape will move past the head gap. The timing accuracy is given as plus or minus 3.6 seconds for a 30 minute recording. I've timed the flywheel rotation after the tape has run out and it will keep spinning for over 15 minutes.

 

[Foxbat]

I've timed the flywheel rotation after the tape has run out and it will keep spinning for over 15 minutes.

Part of the reason is small capstan diameter, meaning high rotational velocity. I presume it spins at close to 1,500rpm at 15ips. Of course any belt driven system will stop much, much sooner. Of course it also means good bearings.

 

[Jerome Sabbagh]

Since the playback electronics of the 351 uses an output transformer to provide a balanced output and to reduce distortion I wanted to find out what improvements could be made using a different transformer. I ordered two transformers from the Electra Print company using silver wire for all of the primary, secondary and feedback windings. I also wanted to reposition where the transformer would be mounted, moving it as far as possible from the AC transformer. I used Cardas shielded cable for the output connections to reduce any noise.

Your 351 looks absolutely beautiful! Congratulations.

I am starting to rebuild a set of 351 electronics with a friend, and the help of Dave Dintenfass, who is providing us with a transport. I am wondering if the custom output transformer improved the sound, and if the change in position was worth it. Did you have noise before? Were you able to eliminate it?

Also, did you by any chance experiment with "better" caps (audiophile style) in the 351? We are wondering if this could make a difference and since we are doing the work ourselves, we can order whatever caps we want ...

We are hoping to use this machine to mix all analog records. Dave has converted a transport for half inch 15/30 ips for us, it's shipping to us very soon. Ampex documents show how to implement CCIR EQ at 15 ips, we are trying to figure out how to get AES EQ at 30 ips. If anyone has any information, please let me know!

Thanks a lot!

Jerome Sabbagh
www.jeromesabbagh.com

 

[tapepath]

Hello Jerome,
Thank you for your comments. Dave is a great guy to work with, he reconditioned the capstan motor I use and did a great job. He also helped integrate the Tentrol with the Ampex control box by providing a box with cables attached so I could see what was involved. The change of the output transformer took a while to evaluate. I found that the playback EQ was different after the replacement, I had to remeasure the necessary changes and then install fixed resistors to get back to the correct playback curve. The sound quality was completely different from the stock transformers. If what a person loved about the 351 was that wonderful, rich honeyed, warm golden quality to the sound then keep the original transformers. At first I was disappointed in what I had done and was considering putting the originals back in place. The sound was now, for want of another word, accurate, more unvarnished. Not sterile by any means, but not being slanted to any one sound character over another. It was after listening to all of the superb UltraAnalogue tapes and an assortment of Tape Project tapes and comparing them to CDs that I was able to recalibrate my expectations and have now come to the conclusion that the silver transformers are what I look for in sound.
I would highly recommend positioning the output transformers on the opposite side of the chassis as far away from the AC transformer as possible and use shielded connecting cables. I experienced a very small amount of low level humming before repositioning the transformers and after moving them it is dead quiet (granted I listen with low efficiency speakers). I tried to use the very best quality capacitors I could, film types replaced ceramic and power supply capacitors were the highest quality that would fit in the allotted spaces. My overall plan was to get everything working correctly and then experiment with using sushi grade capacitors as part of any future upgrades. But honestly I'm loving the sound so much I no longer have the urge, but who knows.
Good luck with your project!

 

[Jerome Sabbagh]

Hello Jerome,
Thank you for your comments. Dave is a great guy to work with, he reconditioned the capstan motor I use and did a great job. He also helped integrate the Tentrol with the Ampex control box by providing a box with cables attached so I could see what was involved. The change of the output transformer took a while to evaluate. I found that the playback EQ was different after the replacement, I had to remeasure the necessary changes and then install fixed resistors to get back to the correct playback curve. The sound quality was completely different from the stock transformers. If what a person loved about the 351 was that wonderful, rich honeyed, warm golden quality to the sound then keep the original transformers. At first I was disappointed in what I had done and was considering putting the originals back in place. The sound was now, for want of another word, accurate, more unvarnished. Not sterile by any means, but not being slanted to any one sound character over another. It was after listening to all of the superb UltraAnalogue tapes and an assortment of Tape Project tapes and comparing them to CDs that I was able to recalibrate my expectations and have now come to the conclusion that the silver transformers are what I look for in sound.
I would highly recommend positioning the output transformers on the opposite side of the chassis as far away from the AC transformer as possible and use shielded connecting cables. I experienced a very small amount of low level humming before repositioning the transformers and after moving them it is dead quiet (granted I listen with low efficiency speakers). I tried to use the very best quality capacitors I could, film types replaced ceramic and power supply capacitors were the highest quality that would fit in the allotted spaces. My overall plan was to get everything working correctly and then experiment with using sushi grade capacitors as part of any future upgrades. But honestly I'm loving the sound so much I no longer have the urge, but who knows.
Good luck with your project!

Thanks for your advice! This is very interesting. I am looking into replacing the output transformer as well, and in touch with a couple of high end transformer makers.

 

[Jerome Sabbagh]

I wanted to keep you updated on my Ampex 351 project.

I am happy to report that the half inch Ampex 351 has been completed, with the help of Dave Dintenfass and John Chester, who built external EQ enclosures that allow us to record and play 15 ips NAB and CCIR, as well as 30 ips AES. It wasn't easy but the machine sounds great and is remarkably flat.

All electronics have been redone using the best parts possible, chosen to the best of our abilities (caps are VH Audio, Miflex, Jupiter, depending on space and fonction, resistors are Mills, Riken etc, mostly metal film except for a couple of spots where wire wound is preferable). We have new Flux heads from JRF. Dave completely reworked the transport and rebuilt the motors.

We tried recording using the three types of tapes available today, SM900, SM911 and ATR. On our machine, ATR sounds the best to me, pretty clearly.

I was able to record at the Power Station in NYC a couple of weeks ago. James Farber did a live to 2 track mix at 30 ips. The band was Joe Martin on bass, Al Foster on drums and myself on saxophone. We were all in the same room. In addition to recording on the Ampex, we recorded to the studio's Studer A820 (also 1/2 inch, 30 ips), as well as straight to digital at 96/24. Tape stock was ATR on the Ampex and SM900, left over from my previous recording session, on the Studer. Both tape versions are much superior to the digital, and they both sound great, but for my taste, the Ampex wins clearly over the Studer A820. It's smoother, deeper, captures more of the sense of the room. Saxophone in particular sounds better, acoustic bass too.

I am also planning to use the Ampex to mix a record I already did last year, to multitrack tape. I will be fundraising to finance the mastering and cutting of both these albums by Bernie Grundman, and the pressing. Stay tuned and feel free to contact me for details etc.

Meanwhile, I am looking to source an additional 1/2 inch 15/30 ips motor for the Ampex. I would like to have redundancy and be set, as I am planning to use this machine to make records for a long time. MDI Precision Motor Works is unfortunately no longer active, I have been in touch with Jeff Gillman. If anyone has a lead on a good capstan motor, or on someone who can rework one, or manufacture a shaft for half inch (I have a new additional Beau motor, but without a shaft), please do let me know. I would be interested.

Thank you!

 

[tapepath]

That's great news! It's so satisfying to know that music is still being captured by these wonderful machines. Keep us posted on your future releases. Any chance of making tape copies?

 

[Jerome Sabbagh]

That's great news! It's so satisfying to know that music is still being captured by these wonderful machines. Keep us posted on your future releases. Any chance of making tape copies?

Actually, yes! I already have tape copies available for my last record, "No Filter", also recorded live to 1/2 inch tape at 30 ips by James Farber, although this time on the ATR 102 at Sear Sound. And I will make sure to be able to make tape copies for the upcoming projects as well, absolutely!

 

[Foxbat]

Sounds great! Where? What format and speed? How much?

 

[Jerome Sabbagh]

Sounds great! Where? What format and speed? How much?

Tape copies are made to order and can be ordered through me directly. We generally do 1/4 inch 15 ips CCIR ("No Filter" fits on two tapes) but we can also do 1/4 inch 7 1/2 ips NAB (one tape). Other formats are available as well, upon request. Tape stock is SM900, which is the tape stock we used for that recording session. As far as pricing, please PM me or email me at jerome@jeromesabbagh.com. Thanks for your interest!

 

[Tuckers]

Years ago I had the pleasure of visiting Kara Chaffee of deHavilland Audio (who is a master of vintage tube audio) a few times to listen to her rebuilt 351 and head amps ( I am unsure what the model of the head amps were, 360 or 306??). Listening on 2nd and 3rd generation master tapes of some classic recordings from the 60's were the finest analog sound I ever heard. I was lucky to do some analog to digital capture on a pro interface I had at the time, which I still listen to to this day as references.

 

[Jerome Sabbagh]

I have now used my custom half inch 15/30 ips Ampex 351 to record and mix a couple of projects. I am grateful to the members here for the inspiration and help. The machine turned out really well. We have new Flux heads for all heads. The frequency response is actually very good, thanks to John Chester's work. It really sounds great.

The first project is a quartet record with legendary jazz pianist Kenny Barron, Joe Martin on bass and Johnathan Blake on drums. It was recorded to multitrack tape by Ryan Streber at Oktaven Audio, on a Studer A800, and mixed at Brooklyn Recording by Pete Rende, on the Ampex (both machines at 30 ips). Bernie Grundman will do the mastering and cut the record, all analog. If anyone is interested, I actually just launched a Kickstarter to finance the pressings. Some of you expressed interest in R2R tapes, the Kickstarter offers those, as well as the vinyl.

Here is the link

I hope it's OK to post this here. If not, please feel free to pull this post.

Any and all questions, please ask. Thanks!

Jerome Sabbagh

 

[Elliot G.]

I wanted to keep you updated on my Ampex 351 project.

I am happy to report that the half inch Ampex 351 has been completed, with the help of Dave Dintenfass and John Chester, who built external EQ enclosures that allow us to record and play 15 ips NAB and CCIR, as well as 30 ips AES. It wasn't easy but the machine sounds great and is remarkably flat.

All electronics have been redone using the best parts possible, chosen to the best of our abilities (caps are VH Audio, Miflex, Jupiter, depending on space and fonction, resistors are Mills, Riken etc, mostly metal film except for a couple of spots where wire wound is preferable). We have new Flux heads from JRF. Dave completely reworked the transport and rebuilt the motors.

We tried recording using the three types of tapes available today, SM900, SM911 and ATR. On our machine, ATR sounds the best to me, pretty clearly.

I was able to record at the Power Station in NYC a couple of weeks ago. James Farber did a live to 2 track mix at 30 ips. The band was Joe Martin on bass, Al Foster on drums and myself on saxophone. We were all in the same room. In addition to recording on the Ampex, we recorded to the studio's Studer A820 (also 1/2 inch, 30 ips), as well as straight to digital at 96/24. Tape stock was ATR on the Ampex and SM900, left over from my previous recording session, on the Studer. Both tape versions are much superior to the digital, and they both sound great, but for my taste, the Ampex wins clearly over the Studer A820. It's smoother, deeper, captures more of the sense of the room. Saxophone in particular sounds better, acoustic bass too.

I am also planning to use the Ampex to mix a record I already did last year, to multitrack tape. I will be fundraising to finance the mastering and cutting of both these albums by Bernie Grundman, and the pressing. Stay tuned and feel free to contact me for details etc.

Meanwhile, I am looking to source an additional 1/2 inch 15/30 ips motor for the Ampex. I would like to have redundancy and be set, as I am planning to use this machine to make records for a long time. MDI Precision Motor Works is unfortunately no longer active, I have been in touch with Jeff Gillman. If anyone has a lead on a good capstan motor, or on someone who can rework one, or manufacture a shaft for half inch (I have a new additional Beau motor, but without a shaft), please do let me know. I would be interested.

Thank you!

Best success Jerome. Love to hear the finished result, bring a copy down to Florida

 

[Jerome Sabbagh]

I am happy to report that the Kickstarter is funded, so the project is definitely moving ahead. There is only one tape left to order on the Kickstarter, and I am grateful for the interest in R2R! The Kickstarter is open until Jan 12. The basic AAA vinyl, mastered by Bernie Grundman, is $35 (it will go up after the Kickstarter is done). I am hoping that between vinyl and R2R tapes at each end of the financial spectrum, this can become a viable business model to produce good sounding analog jazz records in the future, for myself as well as others.

Meanwhile, here is a video of Pete Rende and I with the Ampex 351 in action at the mixing session at Brooklyn Recording:

One of the best features of the Ampex 351 is that it's portable, which allows me to record (and mix) in different spaces. I am looking forward to taking advantage of this in the future! I am grateful for the support and help on this board! Any and all questions, please ask.

 

[Lee]

I am happy to report that the Kickstarter is funded, so the project is definitely moving ahead. There is only one tape left to order on the Kickstarter, and I am grateful for the interest in R2R! The Kickstarter is open until Jan 12. The basic AAA vinyl, mastered by Bernie Grundman, is $35 (it will go up after the Kickstarter is done). I am hoping that between vinyl and R2R tapes at each end of the financial spectrum, this can become a viable business model to produce good sounding analog jazz records in the future, for myself as well as others.

Meanwhile, here is a video of Pete Rende and I with the Ampex 351 in action at the mixing session at Brooklyn Recording:

One of the best features of the Ampex 351 is that it's portable, which allows me to record (and mix) in different spaces. I am looking forward to taking advantage of this in the future! I am grateful for the support and help on this board! Any and all questions, please ask.

Congratulations!

 

[Jerome Sabbagh]

Congratulations!

Thank you Lee!

 

[Jerome Sabbagh]

The album that was mixed to the 1/2 inch 30 ips Ampex 351 discussed above is out. Michael Fremer reviewed it here: https://trackingangle.com/music/saxophonist-jerome-sabbagh-s-latest-aaa-release-truly-is-vintage

For now, it's available on my website only: www.jeromesabbagh.com. Tape copies are also available.

My partner Pete Rende and I are working to further improve the deck. We got an aircraft grade deck plate that someone had handy, and will be installing it. We also have additional guides from Athan and their new pinch roller. We are looking at implementing these tweaks to further improve the transport. The machine will be going back to John Chester's to put all this together, measure and make sure it's as good as can be before we use it on the next recording in 2024.

I do have another album in the can, recorded live to two track tape to the Ampex 351 by James Farber at Power Station, and also cut by Bernie Grundman. I am getting the acetate .... tomorrow! It's a trio record with Joe Martin and Al Foster called "Heart" and I will be creating a label to release it, as well as other all analog projects from other musicians. The label is called Analog Tone Factory (you heard it here first!). We compared tracking to the Ampex with tracking to the studio's Studer A827 and the Ampex won handily, in my opinion (even though the Studer also sounded very good, and both tape versions utterly destroyed the straight digital at 96/24).

I have some support from Stenheim and Ana Mighty Sound for the next project. I am hoping darTZeel, who supported "Vintage" will keep supporting. If anyone here is in a position to support this endeavor, please reach out. I will be fundraising for it in the next year. I hope this can be a sustainable way to create high quality all analog recordings of great music.

 

[Mcsnare]

I am happy to report that the Kickstarter is funded, so the project is definitely moving ahead. There is only one tape left to order on the Kickstarter, and I am grateful for the interest in R2R! The Kickstarter is open until Jan 12. The basic AAA vinyl, mastered by Bernie Grundman, is $35 (it will go up after the Kickstarter is done). I am hoping that between vinyl and R2R tapes at each end of the financial spectrum, this can become a viable business model to produce good sounding analog jazz records in the future, for myself as well as others.

Meanwhile, here is a video of Pete Rende and I with the Ampex 351 in action at the mixing session at Brooklyn Recording:

One of the best features of the Ampex 351 is that it's portable, which allows me to record (and mix) in different spaces. I am looking forward to taking advantage of this in the future! I am grateful for the support and help on this board! Any and all questions, please ask.

Brooklyn Recording? Great studio!