My Otari BIII has been SEDUCED! Bottlehead Seduction tape amp arrives....

[joeljoel1947]

After a two-month wait my Bottlehead Seduction tape amp arrived yesterday. )dance(

I'm using this with my Otari MX-5050 BIII via the direct head out RCA's I had added on. So the Otari is essentially now a transport and all of it's internal electronics are bypassed with the Seduction doing all the work.

Last night and today I've been comparing (in real-time with levels matched via remote) the differences between the internal electronics in the solid state Otari and the external electronics of the tube Seduction.

After picking my jaw up off the floor at the staggering differences between the 2, I was able to summarize the differences in my mind. The Seduction is so much more relaxed, smoother, warmer, and has a much deeper soundstage. The Seduction also has MUCH better and deeper bass then the Otari. Such a fuller sound down low. The extreme top end (15-20kHz) is slightly rolled off compared to the Otari. In my system, this was a good thing and added to the richer presentation. I played with both the NAB and IEC switches on the Bottlehead as well. The IEC curve added a little sparkle on top that was missing from the NAB curve---this is no surprise and what it should do with a modern formulated tape.

By **comparison**, the Otari electronics sound bright, brittle, thin, mechanical, forward, pinched, etched and sterile. It also has about 25% "less bass" then the Bottlehead, which was perhaps the largest difference between the 2. This is not to say the Otari sounds bad on its own, far from it: It was COMPARED to the Bottlehead I made those observations.

Wow, and all this time I thought my Otari sounded really good on its own. I still feel it does, but the Bottlehead Seduction takes it to an all-new plateau.

I guess it is really not too much of a surprise that the Bottlehead sounds better then the solid state MOSFET amp inside the Otari, but what did surprise me was by HOW MUCH. I was expecting a subtle difference and instead I have an entirely different sounding machine now---for the better.

I recommend to anyone serious (I think you have to be serious and somewhat nuts if you go down this path!) about the best possible sound from your Otari or any other deck for that matter to check out the Bottlehead Seduction tape amp! Big->

http://i251.photobucket.com/albums/gg315/JoelKozlowski_2007/PDRM0004.jpg

[Doug_Olitsky]

Joel;

That's some nice stuff ya got there! I'm very pleased that it has exceeded all expectations.

I would like to throw one monkey wrench into the works, just a touch.

In the Otari the 'lytic caps and 4558 ICs in the audiopath are likely "not the best".

I bet if you recapped w/ Panasonic FC and Nichicon Muse and replaced all the 4558 ICs with ones such as Burr-Brown OPA2132P or Analog Devices OP 275s you'd have a real comparasion to run the bottlehead aginst.

It would most likely be less than $50 shipped sourcing from mouser and Percy.

I propose that you do this to your BII and run it up against the tubed BIII. Easy for any DIY or trusted tech to do. Maybe an hour or so bench time.

[joeljoel1947]

Hi Doug,
Thanks for the post and advice. You are clearly treading the path I was hoping someone could do. Joseph from Award Audio will likely be on your coat-tails with your post as he is all about modding and improveing decks. And, you have about a 3 month lead time on him as to when he got his 1st Otari!

The bottom line for me is that the BIII electronics were much better then the BII's that you discuss; and if the Seduction is THIS far ahead of my BIII internal electronics I doubt (but do not discredit) the possibility it's a cap issue somewhere.

More then likely, it could be a calibration issue as well on my BIII's internals. I'll get Joseph over here eventually to make sure that the BIII is calibrated to it's best potential and then I can say what's what for sure......

Keep on rockin in the DIY world! I love it!! I am a DIY loudspeaker designer so I'm all about the tinkering..... Big->

[Doug_Olitsky]

I'm thinking about it myself, but I want to spend a bit of time enjoying it before I do make serious of it.

Plus, I have not gotten my otari back yest from alignment, I called the place today as it was due the 13th. Turns out the guy who does alignments has been out w/ Mono the past month.

I told them no worries, get well first and then call me , no rush.

Speaking of speaks... I did a pair of BLH's w/ fostex drivers.

[joeljoel1947]

Hi Doug,
I understand on enjoying the Otari on its own first. And it is a serious step forward as the Bottlehead assembled costs more then the used Otari deck itself! *?conf?

That's cool you're building speakers too!! I toyed with the Jordan single-drivers t-lines long ago for but my ears always missed the air and wider dispersion range on top. Now I use simple 1st order series filters on my t-line 2-ways which as close as one can get to your "single-driver" sound. Big->

[Doug_Olitsky]

yeah I was thinking of jordans back then too, nice.

The Blh's go nice w/ my 300b's But the rig is in a big room so the K-horns are serving up the tunes at the moment, tho I tweaked them w/ new Crites tweeters and I rebuilt the x-o's w/ film and air chokes.

[Doug_Olitsky]

yeah I was thinking of jordans back then too, nice.

The Blh's go nice w/ my 300b's But the rig is in a big room so the K-horns are serving up the tunes at the moment, tho I tweaked them w/ new Crites tweeters and I rebuilt the x-o's w/ film and air chokes.

[jcmusic]

Doug I too have k-horns, how do like the crites tweeter honestly?

Jay

[Doug_Olitsky]

Its a cheap tweak. The difference is subtle but there.

Sound is smoother and some more top end is apparent. Now if they had ti dia's instead of phenolic I thinl there would be more of a difference. I used those in my chorus II's.

I did not notice an imbalance in loudness as some have complained of in the klipsch forums, which was the main reason I waited so long.

[braxus]

Interesting thread. How common are these Bottlehead units?

[Des-Lab]

Sweet! Now if could just convince "Misses Des" to klet me buy an MX 5050, I'd be able to see for myself all of this.

[joeljoel1947]

They actually have a Bottlehead FORUM, so they are very popular. 99% of them are phono stages, but you can easily transform one into a tape amp:
http://www.bottlehead.com/et/adobespc/Seduction/bottleheadtapeheadpreamp.htm

Funny, I see they used my post from tape trail yesterday on their web site!! :)

[Joseph L]

I wrote this post several days ago and know it is behind by now but here it is any way:

I am real anxious to hear your Bottlehead Joel, I am not at all surprised at the improvement you are proclaiming.

Doug, I have not been into Otari's until just recently although I have owned a MX5050BII for over a year but it needed a capstan motor, which I had, just did not take the time to install, but, after meeting Joel, I decided to complete the repair. I now have 3 Otar's the BII and two NOS BIII machines in mint condition that I recently found. I have done calibrations on them and have become a bit more familiar with Otari now. Upgrading the amp section of one of these machines would be on my to do list as well.

Just a question have you thought about doing your own calibrations? It does take a bit of concentration to keep levels straight and the process in sequence but certainly not a hard task to anyone willing to swap out caps, transistors and ICs. Equipment is not that extensive. The only major piece of test equipment needed is a good AC volt meter that is accurate out to 20hz the other two things needed are a tone generator and a scope to align the heads which can be accomplished with a computer w/audio interface/card and some simple and free software. Someday I will share the details. I had another part of this post with some interesting pictures of test gear but decide to put into the "Do it Yourself" section

[user510]

Joel.
This really captures my imagination.
In a nutshell:
direct wire from the head out to a modified tube phono stage that is altered to optimally receive the signal from the playback head. Like bypass surgery.

Your notes re: the sound before and after the mod. I'll have to agree that when compared to my phono rig, the Otari does seem to sound "lean" in the lower frequency regions. I haven't recently heard that many decks but I would prefer to assume that this is a trait of the Otari and not characteristic of open real playback as a whole.

I like Doug's suggestion of modding the Otari output components with improved ones. This would retain the "stock" look of the machine. This also captures the imagination...and brings up examples of mastering machines with electronics by Tim Paravacini, or Mark Levinson.....


....a Q: why does Doc B. use RCA plugs at his tape head preamp input side rather than the balanced XLR jacks as used by Otari? I suppose I could pose this over at the Tape Project forum.

-Steve

[Doug_Olitsky]

Hey Joseph;

I saw your post in DIY and would love to learn how to align. I have DMM, scope, just need a link for tone generator software.

I think this would make a great step-by-step DIY guide.

Can it be done w/o MRL's?

I'd also like to know which caps and IC's are in the audio path (input and output) I have the schematics but dont know the audiopath. IE. McIntosh indicated the audio path in their s/m's.

[joeljoel1947]

Hi Steve,
Yes that's a possibility. Matter of fact, I hooked my Bottlehead up to my phono stage and it actually made nice sounds. Obviously the EQ curves are different between NAB/IEC for tape (which is what my Bottlehead is set for) and the RIAA curve that lp's need but let me tell you this: The Bottlehead tape amp didn't have me running from the room driving an MM cart!

I'm sure it's just a few cap/resistors worth of difference to mod a phono stage to a tape stage......

[joeljoel1947]

Doug/Joseph--
You guys are really making headway with these decks!! Great job and keep pushing the limits!

Soon I envision some crazy schematic you guys come out with which take the stock Otari electronics to all-new-levels! )dance(

[fa8362]

Joel speaks the truth.

[joeljoel1947]

Nice setup! Big->

Are you running the Tape Project tapes yet? Also, what tubes are you using on your Seduction?

[fa8362]

No Tape Project for me...too expensive, although I'd LOVE to have some of those tapes. Currently, I'm using Sovteks. Those Electro-harmonix tubes are so fat that it took me about 5 minutes per tube to remove them and I was afraid they'd break in my hand. I have some Mullards and Siemens in the garage, but they're in a CAT preamp and I'm too lazy to dig it out. I tried some Phillips...they were good, but old (I ordered some new) with low output.

Biggest problem I had was eliminating hum. Had to use Monster M-1000 (remember them?) from the Technics to eliminate hum. Weird seeing M-1000 next to Purist Proteous, huh? All my other interconnects (Wireworld, Goertz, Audioquest, Purist, etc.) had too much hum...thank god I didn't throw out the 20 year old Monster.

I'm in the process of archiving all my reels and LPs to DSD. Note the little Korg unit on the right.

[joeljoel1947]

No Tape Project for me...too expensive, although I'd LOVE to have some of those tapes. Currently, I'm using Sovteks. Those Electro-harmonix tubes are so fat that it took me about 5 minutes per tube to remove them and I was afraid they'd break in my hand. I have some Mullards and Siemens in the garage, but they're in a CAT preamp and I'm too lazy to dig it out.


Too expensive??? And you have a CAT preamp in the garage??? Last CAT I priced out was about 7k so maybe you could sell it and have change left-over!:-oo

I had a hum issue too, and it also was very microphonic on the top plate. I read that you need to eliminate the springs on the tube dampers, which I never did. I actually sent it back to have them look at it and there was a loose connection causing other various faults.

Are you grounding your Seduction somewhere? Or is that what your Monster cables do? I actually had to float graound on the Seduction to get the least amount of hum but it was still there when I cranked it (you could hear it faintly between tracks). I wish the gain was higher on the Seduction, but I guess that's what the pricer Repro amp offers. Any help you can provide me on the grounding or eliminating hum trials and tribulations you had would be much appreciated! I have a feeling I'm still going to have that hum when I get it back and would like to know how to attack the issue.

[fa8362]

I tried grounding the Seduction to the Technics, but that didn't help. Didn't try lifting the ground, nor did I try grounding it to the wall. In my case, it was the interconnects because the hum changed when I move them around. I used the peak reading meters on the Korg to see this. Try a tape deck in record standby from your Seduction outs and move your Seduction input interconnects around. If the meter reading changes, the shielding on your interconnects is probably the primary culprit. Don't forget to turn the unit off before changing interconnects. :)

[joeljoel1947]

Thanks for the reply. So then your Seduction isn't grounded at all and it's ground screw down on top is "empty"?

Paul at Bottlehead told me it needs to be grounded to the interconnect. He wrote:

"You know, it also occurs to me that if you are not using shielded cable between the tape heads and the Seduction, you will definately get noise. The ground post between the input jacks is where that shield should be grounded. I just thought I'd double check since I don't know much about your tape rig."

I guess I will also try wiggling the cables around when I get it back. I'm also having the Hammond shield installed under it which might help too. The hum isn't intolerable but I'm hoping I can eliminate it completely with some playing around. I run a LOMC cart and I have no hum at all out of that, so it isn't a preamp issue.

[fa8362]

Yes, it's empty, no ground wire attached or connected to anything. Not sure I understand what Doc was saying, but most interconnects ARE shielded, just not well enough for the small signal from a tape head. The Monster M-1000 is shielded well enough so that nothing registers on the meters 90% of the time in record standby. Occasionally, a tube/electronic noise will register 1 or 2 bars (-42dB) for a split second, but silent recorded tape (before the music starts) moving past the heads registers more than that on the meters, and I can no longer hear any hum, even with headphones on.

[joeljoel1947]

Great, thank you. I'll play around with the cables then. Sounds like your Monster's are the cats-meow. BTW, I like Monster stuff a lot, especially the old stuff like your cables-----despite the somewhat negative disposition the "high-end" has with them.

Thanks for the tip on using my reel meters for a "noise count". Good plan!

I also had no idea what Doc was talking about, so at least I'm not alone. I was going to try to tap into the shield on my cables and "start-a-grounding" but it looks like if I get the right cable then the issue will be solved without using the grounding post on the Seduction. Thanks again, and happy rolling.

[ecir40]

Joel, do you know if your seduction uses a variable resistor from the input to ground or does it have a fixed value?

Here is a quote from this link
http://www.bottlehead.com/et/adobespc/Seduction/bottleheadtapeheadpreamp.htm
"It might be worthwhile to keep a trimpot on the input if you plan to use the preamp with a variety of transports. I found a 100K input load to work well with the RS1500 heads and 250K to work better with the older Ampex heads. If you want to use a fixed value on the input, try starting with 250K ohms."

Just wondering if Doc ever came up with a fixed value for the Otari.

Thanks

[joeljoel1947]

I had them install that variable resistor trimpot Doc spoke of. That way I can mess around with what works best with what. I also had them put in a balance control on the Seduction. Many of my older 4-track pre-recorded tapes have severe channel imbalances and my preamp has no balance control!

The Seduction will be back this week and I'll begin playing with the values they installed. I will post my impressions once I get comfortable with what sounds like what. Feel free to PM me in a while....

[ecir40]

Thanks Joel, let us know how this works out.

Do you know if the BII and BIII have the same impedance heads?

[joeljoel1947]

Yes, identical headstacks for all the Otari's since about 1982 and on. They are completely interchangeable as well. My old B2 headstack plops right in to my B3 and my Mk.3 console and vice-versa. Makes for some EASY headstack swapping interchangability!!!!!! :-)<-

[jcmusic]

Joel;

That's some nice stuff ya got there! I'm very pleased that it has exceeded all expectations.

I would like to throw one monkey wrench into the works, just a touch.

In the Otari the 'lytic caps and 4558 ICs in the audiopath are likely "not the best".

I bet if you recapped w/ Panasonic FC and Nichicon Muse and replaced all the 4558 ICs with ones such as Burr-Brown OPA2132P or Analog Devices OP 275s you'd have a real comparasion to run the bottlehead aginst.

It would most likely be less than $50 shipped sourcing from mouser and Percy.

I propose that you do this to your BII and run it up against the tubed BIII. Easy for any DIY or trusted tech to do. Maybe an hour or so bench time.

Hi Doug,
In this post you are talking about some changes to the stock unit, do you know if the caps and op amps you listed are a drop in replacement?

Jay

[macman007]

My McIntosh. C-28 preamplfer while solid state, has a dedicated tape head input. I haven't used it yet and am curious how good it would work next to the Bottlehead. Earlier McIntosh pre amps may have this input as well and are tube units. Perhaps a shoot out is in order. These preamps are cheaper than the bottlehead and are easily modified.

Just curious if anyone has gone down this road?

Phil