Fairchild 660 and 670?

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Tweak

Member
Joined
Dec 30, 2005
Messages
16
Location
Pennsylvania USA
Does anyone know where I can get the schematics and PARTS for any of these two fairchild pieces? I am attempting to build these soon and just want some input on where I can get parts and if anyone has built one and has some advise please feel free to drop some knowledge on a newbe. :wink:
 
Haha good luck as it's one of the toughest projects you did choose. I guess only building a large-frame console should be more complicated.
Anyway i don't think anyone from here has build one yet and i don't think many have planned to do so (apart from CJ but i don't know how far he is).

I guess your best bet as far as transformers are concerned is to check with Sowter. They have some replicas for the Fairchild 670. And if you are in america you can should check out our host as they sell Sowter.

Anyway good luck :thumb:

Flo
 
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That was the easy bit !!! It`s taken 4 years to get to this stage from when I first decided to do attempt the build. Much of that was spent getting the parts. Then another chunk of time getting the chassis made (many thanks to DDT). The biggest headache is working out the the wiring. It`s already almost to heavy to pick up. Believe me this is not for the faint hearted or inexperienced !!
 
Damn Rob! That's hot.

Tweak I think it would be easier to build a high-rise condominium complex than to build a Fairchild clone. Shoot it might be cheaper too. :wink: The iron is quite expensive and there's a reason why any company making a clone charges so much for one. This isn't meant to discourage you. From what I gather, it's amazingly labor intensive and a project for the experienced and well-funded. But if you are both than I'm sure you may be able to dig some info here. Godspeed.
 
[quote author="Rob Flinn"]
IMG_0587%20comp.jpg


That was the easy bit !!! It`s taken 4 years to get to this stage from when I first decided to do attempt the build. Much of that was spent getting the parts. Then another chunk of time getting the chassis made (many thanks to DDT). The biggest headache is working out the the wiring. It`s already almost to heavy to pick up. Believe me this is not for the faint hearted or inexperienced !![/quote]

It looks good so far.
What to use for the variable mu tubes?
 
Looks like a heavy project. :cool: I do feel a little sorry for you - with lots of trouble you gather 8x 6386's and even moderately used it's going to eat them. :? D'oh!

Time for a T-bar mod? Stock up on 6BA6's!
 
[quote author="Rob Flinn"]That was the easy bit !!! It`s taken 4 years to get to this stage from when I first decided to do attempt the build. Much of that was spent getting the parts. Then another chunk of time getting the chassis made (many thanks to DDT). The biggest headache is working out the the wiring. It`s already almost to heavy to pick up. Believe me this is not for the faint hearted or inexperienced !![/quote]

Rob,

Where is DDT? Do they have a website?

Where did you buy all of your materials from?

Can you give us a list of the parts you are using and how many?

What parts do you need to finish the project?

How much has it cost you thus far to build and how much will it cost you in the end?

Happy New Year! CHEERS!
 
The Fairchild 662 preamp is probably what I should try to tackle first as a fairchild project then move on to the 660 and 670. Brent averill made a dual pre fairchild 662 for $1849 in one rack space unit.

If anyone knows about these please give me some feedback. I would love to learn more about making these units.

Happy New Year! CHEERS!
 
http://www.10000cows.com/DaleStudioRight.JPG

It's one channel, (like a 660, then), built with 6BA6's. Buy 20 tubes so you can get 8 to match without motorboating or thumping.

The 662 preamp schematic looks very roughly like a BA31 RCA amplifier - a few changes, but very similar. I would expect a similar sound. I'm not really fond of my BA31 clone but it's not bad.

Sowter makes good iron... that output transformer really needs to be beefy. I burned out a Hammond transformer because I didn't order the right one from Sowter.... but the right one works well. I'm using a Hammond 850N for input but that's because I had one around.
 
[quote author="dale116dot7"]http://www.10000cows.com/DaleStudioRight.JPG

It's one channel, (like a 660, then), built with 6BA6's. Buy 20 tubes so you can get 8 to match without motorboating or thumping.

The 662 preamp schematic looks very roughly like a BA31 RCA amplifier - a few changes, but very similar. I would expect a similar sound. I'm not really fond of my BA31 clone but it's not bad.

Sowter makes good iron... that output transformer really needs to be beefy. I burned out a Hammond transformer because I didn't order the right one from Sowter.... but the right one works well. I'm using a Hammond 850N for input but that's because I had one around.[/quote]

Dale,

That actually looks great! which sowter model do you recommend I use?
 
does it work well with the 6BA6 tubes?

what about 5870? I know alot of people have talked about this but has anyone done any more experimentation?
 
That was the easy bit !!! It`s taken 4 years to get to this stage from when I first decided to do attempt the build. Much of that was spent getting the parts. Then another chunk of time getting the chassis made (many thanks to DDT). The biggest headache is working out the the wiring. It`s already almost to heavy to pick up. Believe me this is not for the faint hearted or inexperienced !!

If it helps with the wiring I could try to get hold of a unit to take some inside pictures. If you are interested then p.m. me, in case I forget to re-check the thread

Michael
 
PLEASE NOTE I DO NOT HAVE ANY 6386 FOR SALE & I DON`T KNOW OF ANYWHERE THAT IS SELLING THEM AT THE MOMENT !!!! If any does know of a source I`d be interested myself !!

Where is DDT? Do they have a website?

ddt is a member here, who is also a good friend of mine. He had the chassis manufactured to my specifications in the Czech republic, & I picked it up from him on my last trip out there. I had to come back using a coach because the chassis is so heavy that it made my baggage too heavy for the plane.

Where did you buy all of your materials from?

All over the place. Some from surplus suppliers, Some from RS, Audio Iron from Sowter, Audio Jumbles (Ham fests to the yanks). It`s difficult to give you specific places because some of the bits I got 4 years ago & I can`t remember.

Can you give us a list of the parts you are using and how many?

I could but I`d have to kill you !! Basically I made a list of parts from looking at the circuit diagram. This may not be that useful because I`m using different transformers for the PSU, & may not relate to parts you are able to obtain.

What parts do you need to finish the project?

I only need the Daven T attenuators. I have the ladder style attenuators, but am looking for the T types. I decided very early on to get all the parts first, before starting the build.

How much has it cost you thus far to build and how much will it cost you in the end?

I have probably spent getting on for £2000 UK, which is why I spent 4 years getting the parts. I don`t know how much it wiill cost in the end because I haven`t finished it yet !
 
If it helps with the wiring I could try to get hold of a unit to take some inside pictures. If you are interested then p.m. me, in case I forget to re-check the thread

Michael

Any close up shots would be useful, escpecially if they are high res. My version is not going to be wired exactly the same as the real 670, but
these pics are always useful. Every time I study these sort of pics I pick up on something !!
 
Sowter part # 8344. It has special low-resistance windings because there is a lot of current flowing in the primaries. It's actually a very large transformer, given that it is line-level.

It works pretty well with the 6BA6 tubes, but you need to match their transfer curves so the compressor will work with gain reductions more than 10dB without thumping or distorting. If you hit it too hard, it distorts, but if it's just a hair, it sounds like some Patsy Cline recordings where you hear a bit of distortion on the loud notes.

I used the 670 schematic and just built half of it, replacing each 6386 tube with a pair of 6BA6 tubes. I would recommend placing a 10 ohm resistor in the cathode of each tube half so you can easily match the current vs. voltage.
 
I think you are thinking of the 5670 tubes not the 5870. The M*nley varimu used 6386s then 5670s and have the t-bar mod which uses two 6BA6s, each wired as a triode to replace the 6386.

Use the search function to find all the vari mu stuff and tube type discussions. There has been a lot of talk on this board on these subjects.

:sam: :thumb:
 
would you guys recommend 5670 or 6BA6 tubes?
I assume 6386 is not an affordable option nowadays
 

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