Our WE300b based tape playback amp

[Edward Pong]

We finally finished our WE300b based tape playback amp for Studer A80. This completes the signal path from microphone pre-amp to tape playback using basically all NOS 1956 Western Electric tubes! (WE437a & WE300b) The only non Western tubes are the Red Bank Bendex 6900 in the record amp for the Studer. Everything in this signal path is executed with all silver transformers & wires.

This doubles as a line stage for my TV system.
In "Tape Playback" mode, the volume pots are not in the circuit for absolute purity.

On 1st listen, the soundscape is indescribably natural with a quickness and freedom to transients that is very very close to the real event. On listening closer, the micro and macro dynamics are enormous, timbres and high frequencies of violins and pianos are totally resolved, but do not draw attention onto themselves... it's just there...

This is the collimation of all the thinking that went into building my audio system, described here: https://positive-feedback.com/audio-discourse/ultraanalogue-recordings/

Ed

 

[Foxbat]

Hi Ed,

I am not entirely clear about what this circuit is doing. Does it get the signal from the A80 playback amp output? What is its gain?

Victor

 

[tony ky ma]

Hi Ed,

I am not entirely clear about what this circuit is doing. Does it get the signal from the A80 playback amp output? What is its gain?

Victor

Hi Victor
I am Tony who built the amp . the construction of A80 playback amp is in 3 parts is EQ calibrate and out put stage. the amp's in put is from calibrate part's out put before A80's volume control to a silver inter stage transformer 1:2 then 300B and a out put transformer 600 ohm output. the out put voltage is 2 voltage from a test tape 1k signal sat by calibrate to a very long cable (50 ft) to line stage amp of the listening system . in picture there are a lot of white caps ( Mundrof Evo silver/gold/oil ) which is the replace of the coupling caps in the first two stage's cap ( EQ and calibrate) quality of the coupling cap can change the quality of sound in a different levels
tony

 

[Edward Pong]

I've just been listening to the Mendelssohn Piano Trio tape & some gorgeous Schubert solo piano & the Beethoven Andante & Variations... the sound breathes, with unrestrained dynamics... hard to describe!

Here's a picture of the setup with tube power supply, under the Studer for the 300b tape amp & battery supply for the 1st stage of the playback card.

Ed

 

[Foxbat]

Thank you for the explanation, Tony! It makes sense.

It is simply different from what most people understand under the term "playback amplifier".

Victor

 

[MaxwellsEq]

It is simply different from what most people understand under the term "playback amplifier

I also would expect a tape play amplifier should be taking the signal from the back of the tape head itself.

 

[Edward Pong]

Actually, the reason is, we use the eq section from the Studer for calibration. The other amp is based on the WE437a tube & used for all my tape duplication so output must be calibrated for both NAB & CCIR.

The output amplification stage is the most important for sound. When you take signal from the head, you need to recreate the eq and calibration stages.

If you look at the description of the record & playback amps for the A80 in this article, you will understand what we did. Calibration is critical in a tape deck & we use all the EQ & calibration sections in the Studer as we cannot improve on them! https://positive-feedback.com/audio-discourse/ultraanalogue-recordings/

Ed

 

[Mike Lavigne]

Actually, the reason is, we use the eq section from the Studer for calibration. The other amp is based on the WE437a tube & used for all my tape duplication so output must be calibrated for both NAB & CCIR.

The output amplification stage is the most important for sound. When you take signal from the head, you need to recreate the eq and calibration stages.

If you look at the description of the record & playback amps for the A80 in this article, you will understand what we did. Calibration is critical in a tape deck & we use all the EQ & calibration sections in the Studer as we cannot improve on them! https://positive-feedback.com/audio-discourse/ultraanalogue-recordings/

Ed

Ed,

your tapes sound great. and with my upgraded ATR/MR 70 tape playback, the lower noise and greater dynamics has revealed much more also from your older titles i had. the newer ones are a little better, but it's fun hearing so much farther into the music. appreciate all the effort and passion you put into your circuits and processes......even though the tech details go over my head (but not past my ears ).

best regards,

Mike

 

[tony ky ma]

I also would expect a tape play amplifier should be taking the signal from the back of the tape head itself.

I did a all tube amp direct from head, EQ by a simple passive LCR filter no calibrate (A80's section is silicon feed back type) transformer coupling and out put ( not silver copper only) very simple just like a phono RIAA amp, sound good tube use 5687 or 7119 or 6900 of cause best sounding is 6900 but expensive and hard to find compare with ED's amp in his system ( all 6900) not only the 300B amp even the 437A amp still better sounding because they have all silver transformers and best sounding tube. so there are many ways to improve sounding depend how much money to put on
tony

 

[Foxbat]

Ed,

your tapes sound great. and with my upgraded ATR/MR 70 tape playback, the lower noise

best regards,

Mike

It is not clear how you get noise lower than what is available from pretty much any such preamp, as tape noise by far dominates in any reasonably well designed system.

 

[Mike Lavigne]

It is not clear how you get noise lower than what is available from pretty much any such preamp, as tape noise by far dominates in any reasonably well designed system.

of course, i don't have the tech knowledge to relate things clearly. but i will take a stab at it based on my surface understanding.

in essence, the particular low impedance MR 70 heads provided by Flux Magnetics to match the MR 70 produce higher gain to match the unique ability of the low noise high gain MR 70 hot rodded circuits. i hear deeper into the music with this set-up.

that is my understanding. i know what i'm hearing with tapes i've had and listened to with my 3 Studer A-820's both in stock form and with the King Cello repro over more than a decade. pretty awesome. my visitors have heard the same thing. it's not night and day, but it's musically quite profound.

there is more going on in my tape playback than just the heads and MR-70 pre's. read the details from the link.

but the heads and MR 70's are doing the heavy lifting. for a couple of months i also had a hot rodded 'normal' ATR-102 with conventional Flux Magnetic heads and standard, but 'hot-rodded', ATR output circuits. the noise floor on that set-up was not nearly as low (but still better than the Studer A-820 w/King Cello). the difference was different heads and no MR-70 pre. hence my conclusion.

 

[Edward Pong]

Ed,

your tapes sound great. and with my upgraded ATR/MR 70 tape playback, the lower noise and greater dynamics has revealed much more also from your older titles i had. the newer ones are a little better, but it's fun hearing so much farther into the music. appreciate all the effort and passion you put into your circuits and processes......even though the tech details go over my head (but not past my ears ).

best regards,

Mike

Mike,

I'm very happy to hear you're fully up on and running on your new ATR deck & playback electronics!
We all know any change in a system, as refined as yours, will translate into big changes in what you will hear. As you say, your ears can tell the slightest changes. You've changed not only the transport but more importantly, the topology of the playback tape amps. There is nothing absolute in audio & it's all ones preferences, but you've changed from solid state to tubes in the tape amp, and that should translate into a lot of change in the character of the soundscape....IMHO. We also know that sound is totally dependent on the circuits & tubes used in any component.

I'm also very happy you've tried some of my newest recordings using the NOS 1956 WE437a &WE300b tubes in the mic pre-amp and battery supplies to the 1st stages in the record & playback amps. Again, I believe there is "no free lunch" in audio. Nothing can compare to these early tubes for their purity, naturalness and soundscape...IMHO.

The more resolving your system, the greater will be the differences between my earlier & latest tapes, and between tapes from different companies. I love it when you say "you are hearing deeper into the recording." These lowest level signals is where transparency, emotion & the real music lives....IMHO.

Tony & I are always trying to reach deeper into the recorded sound & with this WE300b tape amp, I am very happy!
If you are ever close to Toronto, you have an open invitation, to come for a listen to the actual masters on my crazy system.

Many thanks for having a listen!

Ed

 

[Edward Pong]

I'm not sure if this is appropriate in this space, but it maybe of interest as it's the "real" sound of violins!

Here's super star violinist James Ehnes with my latest violin, a copy of a G mold 1729 Stradivari violin, just last week while he was playing in Toronto! I always like to test the sound before varnishing. Varnish will smooth and concentrate the sound, like changing interconnects!
Making violins is my other passion & it brings the " real' sound to my ears, to test our recordings...

Links to James on my FB: https://www.facebook.com/100008127183370/videos/pcb.3483341505280055/630396438675842

EdwardFacebook

www.facebook.com

Ed

 

[christensenleif@msn.com]

hi Ed
since you´re hooking up after the original studer eq (at R47 if I remember correctly), you might consider testing the new Nextgen reproboards
they have a se direct out on the front panel, which also is a feed directly after the eq and without the buffer
then you also get the eq curve selector on the front panel of the repro boards
I have also tested hooking up a tube based buffer on my original Studer repro boards, and it was def worthwile, but here I prefer the unbuffered eq out feeding my TVC directly
best
Leif

 

[Edward Pong]

Hi Leif,
Nice to hear from you! Glad to hear you're still into tape! Thanks for you suggestions & comments.
I'm sure these Nextgen cards are very good, but we've really developed the bypass caps side as well & with this 300b output stage, it's an unbelievable sound... the speed, focus, density & drive are truly amazing...
Best
Ed

 

[analogsa]

I also would expect a tape play amplifier should be taking the signal from the back of the tape head itself.

What? Bypass all those indispensable 5532s?

 

[christensenleif@msn.com]

Hi Ed
I´m more into tape than ever, but as you know , my musical taste is so wide, I have to focus on a wider selection, than just classical
I thoght maybe the Nextgen reproboards pre buffer were better than the original Studers as a starting point for tapping the signal to the tube buffer

 

[christensenleif@msn.com]

What? Bypass all those indispensable 5532s?

no 5532s in the A80