Tape Project Forum
Tape Machines => Reel to Reel Tape Machines => Topic started by: xcortes on June 11, 2009, 09:19:18 PM
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My Technics Deck is going to the workbench for a while. In the meantime I plan to use a Tascam BR-20 that I purchased some weeks ago. It is actually my second. I sold the first because it had some issues but came across this pristine, cheap and local one.
I've been using it and it seems to be a very good machine but it's electronics didn't sound as good (of course). So tonight I bypasssed and I'm listening to it right now through the Seduction. Too early to make any judgement except that it sounds miles better than stock and that it seems to work very well with a 100k load. After connecting it's chassis to the the Seduction ground post it's completely noiseless. Volume seems to be a tad lower than that of the technics. The rewiring was very easy (after figuring out what to do, of course). And since it has two 1/2 track heads you can use one for the outside repro and keep the other connected in case you want to listen through the internal electronics (or record since it's a record / playback head).
It runs very smoothly and handles tape spectacularly. It has a "spool" option that rewinds/ff tape at about 1/3 the regular rewind speed and very smoothly. In that aspect it's much better than the Technics. The bearings and guides look less refined though. And I don't think the heads have anything to do with the Technics heads, much less with my extended response head. But as a spare and for the occasional bedroom listening I'm pretty sure it will provide with lots of enjoyment.
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It has a "spool" option that rewinds/ff tape at about 1/3 the regular rewind speed and very smoothly. In that aspect it's much better than the Technics. The bearings and guides look less refined though. And I don't think the heads have anything to do with the Technics heads, much less with my extended response head. But as a spare and for the occasional bedroom listening I'm pretty sure it will provide with lots of enjoyment.
The slower winding speed is called "library wind". Really a great feature.
I glanced at the users and service manuals (free on HiFi Engine) and wasn't able to find specific spec's on the heads. It must be in there somewhere though. It had three different reference levels 185, 250, and 320 mHy but I'm guessing that the 250 and 320 are for the playback and record/playback sync head (which is which,.. ?)
If you have a hard time finding out there are a bunch of BR20 owners on the Tascam forum and they may be able to set you straight. You could probably contact John French and he could tell you.
http://tascamforums.com/index.php?s=0d85ab8d69b32de69e2cc44609083bc1&showforum=12
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No good. The tape magic is just not there. Yes, it plays tape but it doesn't sound like tape. Everything collapsed. Maybe with a different load on the Seduction but I'm starting to think it has to do more with the transport. Wow, if the transport can make a tape sound so bad I just can imagine what a pro transport can do for the sound.
I guess no one will give me much for a rewired Tascam but I should probably start looking into an ATR.>)
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I don't know why you jumped to the conclusion that the transport sounds bad. Unless the heads are bad, I would say it is an interface issue with the seduction that is causing you not to like the sound. The transport is "merely" playing the tape and that transport is professional level quality. Maybe the tape head is the wrong impedance for the seduction input and you are losing lots of signal which would cause lower output from the seduction and more noise as you tried to accomodate by increasing the gain from your preamp.
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Yep. You are right. I jumped to conclusions too fast. It was late and I was somehow deceived.
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Hey Mark. You were right indeed!
I tried a set of set up transformers and the magic is there. I'm not sure if the specs are the right ones but they must be close.
As I mentioned in another thread the BR-20 has the same set of heads (5378301800) both for recording and playback. Other Tascam machines (ie the Tascam 32) use the 5378301000 head that JRF installed on Mickey's machine replacing the stock (Technics) RS-1500 playback head as supposedly more tube friendly:
http://www.tapeproject.com/smf/index.php/topic,31.0.html
I was thinking of maybe trying the "800" heads but today I just put a set of Denon setp up transformers for MC phono cartridges and voila. It looks like these heads have much lower gain and impedance. The transformers are Denon AU-300LC with 40hz primaries and 4khz secondaries.
Time to try it with my Peerless stepups. And I know Doc has some nice stepups in the pipeline (I don't know if they're Magnequests').
Wo hoooooooooooo!
btw. Last week I emailed John French to see if he could provide me with some information on the heads but no response yet.
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Then again the Seduction page had it already in the conversion to tape instructions!:
"Low impedance heads may want to see a lower impedance load. It is noted that one well known commercial tube tape head preamp offers an input load adjustment range of 4Kohms to 250K ohms. This may be indicative of the range of values one might find necessary with different heads. One may even find it necessary to employ an impedance matching transformer between the tape head and the preamp input in the case of very low impedance heads. This would be similar to implementing a step-up transformer between a low output moving coil phono cartridge and the stock Seduction in it's stock phono preamp guise"
http://www.bottlehead.com/et/adobespc/Seduction/bottleheadtapeheadpreamp.htm (http://www.bottlehead.com/et/adobespc/Seduction/bottleheadtapeheadpreamp.htm)
As well as post by PJ at the BH forum:
"Tape head preamp design depends a lot on the type of tape head in use. (In this way it is similar to phono preamps; MC and MM cartridges have very different requirements.)
Ordinary tape heads are usually specified by their inductance.
High inductance heads run 400mH to 1000mH and perform like MM cartridges in that the preamp input capacitance and resistance combine with the tape head inductance to create a second order filter which sets the high frequency performance, usually a resonance in the 12kHz to 20kHz range. These are ideally suited to tube amplification, with input impedances of 100k to 250k ohms being usual. I think this would be typical of heads in the Ampex 350s.
Low inductance heads run 30mH to 100mH generally (as I understand it). They are usually optimized for low-impedance transistor input preamps. Step-up transformers might be a good approach with tubes.
Intermediate impedances would be in the range 100mH to 400mH. The Technics and ATR heads run about 200mH; so does the special custom head developed for the Tape Project. These work like the high-impedance heads but with a resonance at 30kHz to 40kHz the tuning of that resonance is less critical and (IMHO) the treble is cleaner. More care is needed in making the preamp quiet, and more gain is needed, but otherwise they are well suited to audiophile-type tube designs"
http://www.audioasylum.com/forums/bottlehead/messages/13/130902.html (http://www.audioasylum.com/forums/bottlehead/messages/13/130902.html)
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OK. Now I've been listening to it for a while. It sounds very good now. Very, very, very good! Air and extension are incredible. To me this seems to make a very good TP machine.
Moreover. I connected the internal electronics to one channel of my preamp and the other head via the sut and Seduction to another channel. Matched volume and started ABing. I'm using much better cables than before on the "stock" output and that improved the sound a lot. When ABing there's much more air and high frequency extension with the tube electronics but the stock ones are sounding really good too. A notch below but still very good.
More later.
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I am so glad you got to the bottom of the problem! Using MC step up transformers is very interesting.
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There's more. Yesterday I thought that I could be needing of adjusting the Seduction input impedance because it sounded a little bright and so I thought I could be causing a resonance. I took my alignment tape today and response is very good. Less than 1dB from spec at 10khz and 15khz. As expected with the Seduction it is -2dB at 60hz and -8dB at 30hz.
So I measured the internal electronics against which I had been comparing and these were -3dB in one channel and -6 in the other at both 10kHz and 15kHz. Of course my "new" setup was sounding bright but it was because I was not comparing to the right reference.
:>)
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I have just bought Tascam BR-20 and considering using external repro. I'm thinking about King/Cello or Bottlehead Repro. I have only heard the later with Technics RS1500 and it was unbelievable.
But first I need to rewire heads. I'm rookie on that subject it is my first deck, so I need good advice. I read that to use external tape preamp, internal stock electronic have to be disconnected. But xcortes wrote that :
". And since it has two 1/2 track heads you can use one for the outside repro and keep the other connected in case you want to listen through the internal electronics (or record since it's a record / playback head).
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I like that approach better.
From manual BR-20 has:
Erase Head
Record/Sync Head
Reproduce Head
So how do you rewire it (could you elaborate a little more, so rookie can do it, or at least be able to explain it to local technician what to do).
What exactly have you done ?
How is you deck wired so you still can use internal stock electronics and external pre amp at the some time.
Did you use Record/Sync Head for stock electronics, so it is now used for playback and recording ?
And Reproduce Head is now connected only to RCA jacks (have you mounted additional RSA jacks on the back chassis of Tascam) ?
I would appreciate your comments.
Regards
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The simplest approach is to cut the internal cables that go from the repro head to the internal preamp in half. Extend the ends attached to the head by about 18"and add rca plugs. Connect the ends attached to the internal preamp to some rca jacks mounted on the back of the deck. Now you can plug the head into an external preamp or back into the internal preamp via the added jacks. Just don't do it while you are playing a tape.
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The Tascam BR20 is an awesome transport but the heads are not top notch. If you want to use them you have to use step up transformers. This is because they require a much lower load (100 ohm in the stock circuit) and have much lower gain. This is a good solution and sounds much better than stock. But if you want it to do it the right way you can order an extended response head from Greg Orton. I have not heard those heads in that transport but in others and are very good. I have one coming my way.
In terms of electronics I have heard very extensively all the range of Bottlehead electronics (eros, seduction and repro) and the king cello. To me there's no comparison, BH sounds much more natural and musical and I see no negatives in the comparison.
Hipe this helps.
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You can do as Doc says but since the machine has two identical heads you can keep one wired to the internal electronics and wire permanently the other to the new rca jacks.
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Welcome to the forum. It's a good place to get answers to this kind of question. But please review the posting rules, the very first topic on the forum. Specifically, we use our real names here. Most of us put it in our profile so it shows up automatically in each post.
But xcortes wrote that :
"And since it has two 1/2 track heads you can use one for the outside repro and keep the other connected in case you want to listen through the internal electronics (or record since it's a record / playback head)."
I'm with Xavier on this. Since they gave you two identical heads (what they call the record/sync head and the reproduce head are literally the same part) you can just keep the record head and listen to that through the internal electronics whenever you want mediocre sound.
But if you want really good sound, I recommend that you consider replacing the repro head with something more suitable, then wire it direct out and use an external repro electronics of your choice. Read the preceding posts in this thread, they lay it out pretty well. To be compatible with most quality repro amps you will want a head in the vicinity of 200 mH. The Tascam head is much lower inductance, and lower output. I recommend the Flux Magnetics Extended Response head.
BTW I like the transport, and I think you'll be pleased with the machine if you make this conversion. I have one on my bench right now, just waiting for the new head I intend to install, and the Bottlehead Eros that will follow it.
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Hey Paul,
In addition to the head I have a new pinch roller and a new band coming my way. Any other mods you have on mind? I haven't investigated if parts of Doc's mod could be applied to the transport.
Also, what position are you planning for the new head?
Thanks
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Thank you all for all advices.
Docd advice is beautiful in its simplicity I could use internal electronics and compare it with outside tape preamp.
What was the rationale behind using two the some heads in Tascam, if I got it right, both are play/record heads.
So seems that one would be enough, and right now one is used for playback only and second one for recording only, so they both only half used. Seems like one would be enough.
Xcortese, Your solution using one head for internal amp and one for external makes a lot of sense if one would like to replace stock head for higher inductance head.
I understand that Tascam stock 100mH head gives you low output not suitable for BH tape preamps. I have found on some forum that King/cello solid state tape preamp have 60dB of gain which is enough for low output head vs 50dB from BH repro.
So question is , are stock Tascam heads inferior only because they require higher gain pre or there is more to it?
Playing devils advocate MC should be inferior to MM because is lower output and requires higher preamplification in phono-stage.
But to compare it I guess one would have compare Tascam + King/Cello vs Tascam + step up transformer + BH repro vs Tascam with high-output head + BH repro.
On some forum some tape guru wrote that Tascam BR-20 with Kind/Cello sounded better than his Studer 820 with stock electronics which is class by itself.
Somebody advice me to try Nortronics heads, but they supposedly do not fit/cannot be easily mounted to Tascam heads compartment.
Does heads from Greg Orton of Flux Magnetics fit into Tascam, how much do they cost ? I understand that they are higher inductance/output heads hence more suitable for tube BH electronics ?
Some claims that BH electronics is better some that King/Cello is better, for sure later have higher gain which is beneficial for low output heads.
Some interesting posts about heads and tape preamps:
http://www.audioasylum.com/cgi/vt.mpl?f=tape&m=14945&VT=T
I?m just trying to figure it out but I have got headache to many possibilities and no experience on my side.
Best to you all.
Slawek
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Charlie King "reviews" his preamp vs. the competition and, astoundingly, he finds his own product to sound better.
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Here's my "built for Bottlehead electronics" extended response head from Flux Magnetics.
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Compared to the old one:
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Nice lookin' shield on that new head!
Is the "built for Bottlehead" head different from the other ER heads?
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I guess so since Greg always confirms with me twice if the heads are to be used with BH electronics.
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Looks like a larger gap head for better bottom end. SWEET!!! Like the MTR-10 heads on my 5050. 20-20K response at 15ips.
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New head installed
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Ready to roll
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Looks great buddy!
That Flux head sure dwarfs the others!