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Post by gouge on Jul 15, 2015 21:00:40 GMT -6
I am about to embark on refurbishing my atr 700 and as there is little information on the net about this deck I thought I'd start a thread keeping up with the process.
whilst not the be all end all of reel 2 reel machines this deck has served me well over the past 1-2 years. it was sold as a mobile recording deck. mine is the 2 track 1/4" version. it has balanced inputs, 7.5 and 15 ips, 3 heads etc. the transport has been very solid and reliable.
the circuits are pretty much all discrete except for a pair of opamps in the repro eq circuit and the mic preamps. I use it in line mode and the mic pre part of the circuit is bypassed out in line mode so that leaves only 2 opamps which I will upgrade once I get into that card.
I'm intending on doing a ground up electronic rebuild.
the electronics are filled with 5% carbon resistors. i'll be replacing all of those with 1% film resistors. there are also a bunch of capacitors i'll replace. my intention is not to reinvent the wheel so nearly all caps will replaced with modern versions at similar values. there are a bunch of mica caps i'll leave alone and some mylar caps i'll leave also.
the intention is to replace all electro caps and use mkt and mkp caps where possible. 1 or 2 mylar caps in the direct audio path will also be replaced. not sure about transformer upgrades at this stage. I will also replace all of the audio transistors with more modern low noise versions.
I've got a bunch of parts here already and the majority of work will be done on spare cards I've acquired. in the post are low noise transistors from futurelec and I've got a bom ready to go from a local parts supplier here. I've also got adaptors to allow me to swap out the opamps which are not known for their audio quality.
museumofmagneticsoundrecording.org/RecordersAmpexATR700.html
I'd very much enjoy anyone's input and thoughts. it's all up for grabs.
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Post by gouge on Jul 15, 2015 21:07:45 GMT -6
first up is the output/phones card. i'll post tonight with a photo of the card and a description of new parts.
in short it's all fairly straight forward. all audio path caps under 2.2uf will become mkp or mkt. the 1000uf output caps I was replacing with larger silmic II caps and a bypass cap and I was going to double the size of C320.
all other electros will become fm/he low esr types.
2sc1000/2sa842 transistors will be replaced with 2sc3329 and 2sa1316
anyone wants to add their own thing please do.
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Post by keymod on Jul 16, 2015 3:56:28 GMT -6
Following this thread with interest. Have you been using this as a mix-down deck? Must give nice results.
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Post by gouge on Jul 16, 2015 5:44:58 GMT -6
I bought it to use as a mixdown deck and figured if it sucked at that I'd have a decent tape delay. I currently mix down to dsd.
After doing a lot of ab with the converters my music partner and I decided we preferred guitars, vocals and bass after going through the deck so I started tracking through it. On vocals it took away the slightly harsh edge and guitars smoothed off the top and added some weight. Bass i slam through it.
It does have a tone to it. I'm hoping I can clean up the signal a touch more.
My tech set it up very hot which improved the noise floor.
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Post by keymod on Jul 16, 2015 6:53:55 GMT -6
Would you mind explaining your tracking procedure? How do you sync to your DAW?
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Post by gouge on Jul 16, 2015 7:34:47 GMT -6
no problems.
I use it when overdubbing mainly. so each artist gets tracked in isolation.
I set it up on a multed channel insert and record a digital take and a tape take t the same time. the tape take is out of sync of course because of the distance between heads so artist monitor feed is taken from the digital tracks. using this method I can monitor the direct to converter version in real time and also monitor the return from tape going to the converters. I monitor the return from tape to get the right amount of compression off the deck for each instrument overdub.
then the song gets built up. once complete all tape tracks are on the daw and out of sync the same amount making them aligned, so I press play and mix. for tracks that don't go through tape like drums because of lack of tape channels I sync up in the daw. I worked out the sample difference by looping a blip through the console/tape chain. that number is written on the side of the tape machine. the distance between heads is also written in the manual but I've found it not reliable for post syncing in the daw.
sometimes with drums I'll take a feed from every mic and send a stereo feed to the deck and then trakc that. I've not been happy with that to date because it adds to much time to the mixer settings up front and locks me in to sounds I didn't quite nail.
I also use it for vocal bounces at mixdown. I hit the tape 4-5 times to get it heavily compressed and distorted.
the plan is to eventually get an 8 track deck setup the same way so I can track more channels. there is a method of using a latency delay plug so the tape hits the converters in sync but I've not been able to get that working and haven't really spent the right amount of time to set it up.
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Post by gouge on Jul 16, 2015 8:01:52 GMT -6
I wanted to add keymod,
I only use tape if I think it adds something. like for inde/rock.
for almost everything else I go direct to the converters avoiding the console as well and only recording off it if i need something the console offers.
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Post by donr on Jul 16, 2015 9:07:32 GMT -6
Cool. I've got an ATR700, ¼ and ½ trk headstacks. Very low hours. Also a Teac 3340s and an Akai 1214 12 trk and console. I can't get rid of any of them, if I ever want to play my tapes again. My buddy has my Teac 80-8 ½ inch. Still works.
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Post by gouge on Jul 16, 2015 9:21:55 GMT -6
Cool. I've got an ATR700, ¼ and ½ trk headstacks. Very low hours. Also a Teac 3340s and an Akai 1214 12 trk and console. I can't get rid of any of them, if I ever want to play my tapes again. My buddy has my Teac 80-8 ½ inch. Still works. is 1/2 track the stereo head? I may be interested. the other thing I've been looking for is some replacement switches from the back panel. the ones that select line or mic input. mine can be a little moody. |
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Post by donr on Jul 16, 2015 9:29:50 GMT -6
I have to keep the recorders, I've got lots of tapes in boxes. I did a 3 CD set of my demos, in the early oughts, I had to bake all the Ampex 456 to play them. I made an oven out of a plastic dog kennel and wire shelving, with a cooking thermometer and a space heater firing into the kennel. About 8 hrs at 160º F.
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Post by gouge on Jul 16, 2015 9:35:38 GMT -6
slowly starting to replace parts on the output card. will order some parts so will leave it until they arrive but this is the situation. I changed a few caps types from what I mentioned above once I'd looked up what I could get, what fitted and what I had in my box already.
done.
C302 0.47/50v elec cap -> 0.47/63v 5% mks2 C303 22/16v elec -> 22/50v FM C311 100/16v elec -> 100/50v FM C319 1/50 elec -> 1/63v 5% mks2
to be ordered.
C313 100/16v elec -> 4700/25v UKA with wima bypass C307 & C315 10/16v elec -> 10/25v FC C320 100/35v elec -> 220/50v FM. (I tired some 220/100v I had left over but they were too big) Attachments:
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Post by wiz on Jul 16, 2015 16:54:48 GMT -6
I have to keep the recorders, I've got lots of tapes in boxes. I did a 3 CD set of my demos, in the early oughts, I had to bake all the Ampex 456 to play them. I made an oven out of a plastic dog kennel and wire shelving, with a cooking thermometer and a space heater firing into the kennel. About 8 hrs at 160º F. Oh thats fantastic! 8) cheers Wiz |
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Post by gouge on Jul 16, 2015 22:40:50 GMT -6
had an hour to kill this afternoon so I got the IC boards happening.
i'll be replacing all of the TA7136P IC chips for modern components. there is only really 2 in the audio path that I need to deal with.
those are 2 on the repro eq card so I've got some adaptors to try lme49720 chips in place.
as an aside, the select card also has 4 which form the mic preamps. because I use line select the mic preamps and all of the circuitry surrounding them is bypassed. but you never know so i'll do this card as well even though it probably will never be used.
I was going to try opa1612 soic chips in the preamps so have some soic to dip8 adaptors to allow this to happen. the opa has a 3.6mA current draw making it close to the ta-7136p
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Post by jimwilliams on Jul 17, 2015 9:48:42 GMT -6
Got scope? You will need to test on the bench first. 2SA1316 have low hfe, use 2SA1084. Use Wima FKP-2 for the EQ caps.
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Post by gouge on Jul 17, 2015 19:21:54 GMT -6
thanks jimwilliams
I've got a scope, variable dc power supply and a distortion meter. part of the thing for me is to learn how to use the scope.
should I also get the complementary transistor to the 2sa1084 as well or will the 2sc3329 be ok. I've ordered more than I need of the transistors so I can try and match things. |
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Post by jimwilliams on Jul 18, 2015 11:54:19 GMT -6
Renesas 2SC2545 is the comp to 1084/5. The 3329 is very close, made by Toshiba. Renesas are available in 2500 piece reels for about $500.
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Post by gouge on Aug 16, 2015 18:55:49 GMT -6
so I'm still waiting on components to arrive. i ordered a bunch of transistors and it's now 4 weeks and they have not arrived yet. i'll hang off ordering jim's transistors until i get the original order. the postage was cheap so i can only assume it's a 6 week delivery from the states thing.
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