UREI 1008 Mic Preamp Schematic
- Thread starter opacheco
- Start date
Help Support GroupDIY Audio Forum:
The schematic is here somewhere & at waltzing bear I think & I think youl find it via google, type 1008 pre schematic somethin like that.....The pre is also part of the first 1176 limiter & boards for 1176 are here and disgusions about makin the pre, dont no how far anyones got yet, Im gonna make the 1176 and 1008 in one box, just waiting for my boards to turn up, I was gonna make the 1008 pre on vero board but wanted limiter too
http://www.groupdiy.com/index.php?topic=30403.0
http://www.groupdiy.com/index.php?topic=30403.0
kato
Well-known member
Perhaps search for "1108."
Silly me sorry for confusion as you can see I misread posted 1108.......
Havent built that one and dont have correct OP tran too ...I have just bult the Urie 1016 just to confuse things further but looks similar to the 1008 12ax7 followed by 12ay7 push pull type tho sounds good
Havent built that one and dont have correct OP tran too ...I have just bult the Urie 1016 just to confuse things further but looks similar to the 1008 12ax7 followed by 12ay7 push pull type tho sounds good
Thanks to everyone for the comments and help and to Lukpio for the correct link!!...gary o No problem!!!......
By the way what are the transformers input and output, are they the same used in 1108(Lukpio see again.....just kidding!!...jejejeje)???
Who made these trafos??
Thanks a lot again.
Opacheco.
By the way what are the transformers input and output, are they the same used in 1108(Lukpio see again.....just kidding!!...jejejeje)???
Who made these trafos??
Thanks a lot again.
Opacheco.
opacheco said:
Do the 1108 use the same input and output transformer like the 1008????.....I have 4 1108 but do anyone have a 1008 in order to post the transformer numbers and brand too???
I will wait for any comments
Opacheco
Aardman
Well-known member
The 1108 and the 1008 both used the same input transformer. The 1108 used the same output transformer as the class 'A' 1176 which is the 5004. The 1008 used a 5946 which was the same output transformer used in the 175 tube compressor and the 610 mic channel. All of the transformers were custom made and are not UTC's or such. Hope that answers your questions.
Edit: I should clarify what I meant by "not UTC's or such". I mean that they were not an off the shelf UTC transformer. The input transformer for instance had a Universal Audio Internal part number of IT-5000. However, the transformer inside the can could have been made by Peerless, UTC, EE or Microtran. From the documents I've seen, all four brands were used at one time or another. It depended on who could supply them in a given time frame and at what price per quantity required.
Edit: I should clarify what I meant by "not UTC's or such". I mean that they were not an off the shelf UTC transformer. The input transformer for instance had a Universal Audio Internal part number of IT-5000. However, the transformer inside the can could have been made by Peerless, UTC, EE or Microtran. From the documents I've seen, all four brands were used at one time or another. It depended on who could supply them in a given time frame and at what price per quantity required.
Aardman said:
That's great info!!.....Thanks a lot Aardman.......
It is finish for this Topic but......We have a NEW Question for these Transformers, What were the spec(turs ratio, impedance, DC Resistence....) for these Transformers???.......I did Turns ratio measurements for the 5004 Output Transformer and I will post if someone is interest......I must have the measurements in my records......
Thanks a lot to everybody for comments in this topic!!
Opacheco.
Aardman
Well-known member
emrr said:
Hi,
A good buddy gave me scans of some of his docs as a backup and also for a few projects in the works.
I'll leave it up to him to decide if he wants to post any more info himself or if I can. I don't have everything myself but I know he has the full winding info
for some of this stuff.
J.L.
Winston OBoogie
Well-known member
OK, here's "some" info regarding the input transformer for the 1108, 1008 and 1016. Enough to get you close anyway.
Spec calls for:
Primary Z of 600, 150 and 37.5 ohms.
Primary being Bifilar wound.
Secondary Z of 65K +/- 2K although the Peerless version measured 70K - shock!!!!
Core may be EI-375 HYMU .014 3/8" stk or equiv.
Various manufacturers used and the internal part numbers:
Microtran: Micro W5127
Also Microtran M1-A
Peerless: 4786
UTC: 6448
EE (Electro Engineering Works): EE4786-E14650
I have windings DCR of the UTC, the Peerless and the EE but not the Microtrans. Not much between them but the Peerless measures higher on all windings.
A UTC 0-1 was also considered and tested but not used.
I do have the full info for the 1008, 175 output (the 5946). It was made by UTC and, contrary to what I had remembered, also by Electro Engineering Works.
I need to keep this info to myself for the time being. I may need it down the line.
Still, you have a bit more to be getting on with now I suppose.
W.
Spec calls for:
Primary Z of 600, 150 and 37.5 ohms.
Primary being Bifilar wound.
Secondary Z of 65K +/- 2K although the Peerless version measured 70K - shock!!!!
Core may be EI-375 HYMU .014 3/8" stk or equiv.
Various manufacturers used and the internal part numbers:
Microtran: Micro W5127
Also Microtran M1-A
Peerless: 4786
UTC: 6448
EE (Electro Engineering Works): EE4786-E14650
I have windings DCR of the UTC, the Peerless and the EE but not the Microtrans. Not much between them but the Peerless measures higher on all windings.
A UTC 0-1 was also considered and tested but not used.
I do have the full info for the 1008, 175 output (the 5946). It was made by UTC and, contrary to what I had remembered, also by Electro Engineering Works.
I need to keep this info to myself for the time being. I may need it down the line.
Still, you have a bit more to be getting on with now I suppose.
W.
edanderson
Well-known member
thanks for the info mr o'boogie. always appreciated!
ed
ed
Winston OBoogie
Well-known member
Bloody Hell! Just found another manufacturer for that 1108 input transformer. 
This one by Pacific Magnetic Corporation of Electronic Center Romoland, California. Unless that's the one Ed mentioned, the "BPMC" one. According to Bushnell notes, these were ordered because the cost of the UTC6448 was too high at $12.75 per.
That makes six different types floating out there. What's a DIY guy to do? :-\
This one by Pacific Magnetic Corporation of Electronic Center Romoland, California. Unless that's the one Ed mentioned, the "BPMC" one. According to Bushnell notes, these were ordered because the cost of the UTC6448 was too high at $12.75 per. That makes six different types floating out there. What's a DIY guy to do? :-\
edanderson
Well-known member
yep winston, the bourns pacific magnetic corp of romoland made a few of the 1108 inputs that i've seen. they were a division of the well known bourns, but spun off and bought up by datatronics many years ago. sadly datatronics had a basement flood about 10 yrs ago which destroyed all their paper files, so they have no docs on this ~40 yr old design.
EE and UTC (via TRW/OPT) were both bought by Magnetika. a few of the 175 and 1008 outputs i've seen have mentioned UTC "pacific division" which i'm guessing could have been a smaller winder bought by UTC (new york based), so who knows if Magnetika even have the design data. i'm just glad that someone who values the design has a copy.
microtran is now a part of tamura, who mostly make telecom and switchmode stuff now, though they do have some audio and tube transformers in their catalog. mostly looks like tamura designs though, and i don't think they have any manufacturing facilities in the US any more.
magnequest supposedly have all the altec/peerless docs, but they haven't really seemed interested in serving the pro-audio market. mike is friendly though, so i suppose it couldn't hurt to ask.
ed
EE and UTC (via TRW/OPT) were both bought by Magnetika. a few of the 175 and 1008 outputs i've seen have mentioned UTC "pacific division" which i'm guessing could have been a smaller winder bought by UTC (new york based), so who knows if Magnetika even have the design data. i'm just glad that someone who values the design has a copy.
microtran is now a part of tamura, who mostly make telecom and switchmode stuff now, though they do have some audio and tube transformers in their catalog. mostly looks like tamura designs though, and i don't think they have any manufacturing facilities in the US any more.
magnequest supposedly have all the altec/peerless docs, but they haven't really seemed interested in serving the pro-audio market. mike is friendly though, so i suppose it couldn't hurt to ask.
ed
Winston OBoogie
Well-known member
Thanks for the info Ed, all this stuff helps piece together a more complete picture.
Do you mean that EE and UTC were, at one time but before being bought by TRW/OPT then Magnetica, once part of the same company? Or are you just saying that they were both bought individually?
One of the blueprints I have is a UTC Pacific Division document. Most are Electro Engineering Works...
Part of my wishing to keep a lot of this stuff to myself "for now" is that there is a Universal Audio tube desk that has been restored and the owner wants to expand it. He will be having the 1008 outputs and inputs made as part of that process and I may get to earn some money from this old paperwork for a change! Some of this stuff has cost me dearly over the years, either in cash or in sweat and tears chasing it down.
Not trying to be a hoarder or a jerk. I'm sure you understand.
Thanks again for the info Ed,
W.
edanderson said:
Do you mean that EE and UTC were, at one time but before being bought by TRW/OPT then Magnetica, once part of the same company? Or are you just saying that they were both bought individually?
edanderson said:
One of the blueprints I have is a UTC Pacific Division document. Most are Electro Engineering Works...
Part of my wishing to keep a lot of this stuff to myself "for now" is that there is a Universal Audio tube desk that has been restored and the owner wants to expand it. He will be having the 1008 outputs and inputs made as part of that process and I may get to earn some money from this old paperwork for a change! Some of this stuff has cost me dearly over the years, either in cash or in sweat and tears chasing it down.
Not trying to be a hoarder or a jerk. I'm sure you understand.
Thanks again for the info Ed,
W.
edanderson
Well-known member
no, i do think EE and UTC were separate (at least at some point) but magnetika did buy them both:
http://www.magnetika.com/news.htm
as far as keeping the hard-bought winding data to yourself, that i can totally understand. the info you've provided will help folks who want to build a 1108 style preamp. maybe i can scare up a larger high ratio input transformer design that will work for the 1108 and some of the tube preamp designs floating around. in the meantime there are options from cinemag, lundahl, et al that should work "close enough" to get something started.
thanks again for sharing with us!
ed
http://www.magnetika.com/news.htm
as far as keeping the hard-bought winding data to yourself, that i can totally understand. the info you've provided will help folks who want to build a 1108 style preamp. maybe i can scare up a larger high ratio input transformer design that will work for the 1108 and some of the tube preamp designs floating around. in the meantime there are options from cinemag, lundahl, et al that should work "close enough" to get something started.
thanks again for sharing with us!
ed
Winston OBoogie
Well-known member
Thanks Ed.
I will see how this UA desk extension goes and maybe after that we can work out having some transformers made for 1108's, 1008's etc.
I'm sure you have this already but, if not and it helps with building 1008's and 175's, the turns for the 5946 output are:
Pri: 30K/7.5K split
Sec: 600/150 split
Tert: 600
Min L with 10mA DC = 55Hy.
I will see how this UA desk extension goes and maybe after that we can work out having some transformers made for 1108's, 1008's etc.
I'm sure you have this already but, if not and it helps with building 1008's and 175's, the turns for the 5946 output are:
Pri: 30K/7.5K split
Sec: 600/150 split
Tert: 600
Min L with 10mA DC = 55Hy.
