Rca ba6a transformer specs

[Thegoldenlockedlamb]

I have a nearly finished Ba6a that I used a hammond 835 for the interstage which is 40k:40k. I've not yet passed audio through it, but itseems to behave nicely on my bench tests.

Other transformers I used are a Gardners 600:10k for the input. I can't remember what the output transformer is, but it could be a triad but from memory it is 8k:600

Oh nice ! Thank you for that info , I am going to have a guy build it for me or at the very least help me build it so I can learn more about these . I’ve only built solid state kits like pier’s ma-1 preamp that Are easy to build and well documented . I have built a clone of a Marshall super bass from a schematic and parts from a kit a few years ago , but I’ve never Tried to build tube recording gear as they seemed more complex than the stuff I built .

 

[Thegoldenlockedlamb]

JH428B which had VCA automation (quite unusual for a 400 series) long since disabled when the comnputer died like most 500's

Oh wow that is unusual . Those 400a sound really cool . Yeah the computer was disabled on my 500 also haha

 

[Rob Flinn]

Oh nice ! Thank you for that info , I am going to have a guy build it for me or at the very least help me build it so I can learn more about these . I’ve only built solid state kits like pier’s ma-1 preamp that Are easy to build and well documented . I have built a clone of a Marshall super bass from a schematic and parts from a kit a few years ago , but I’ve never Tried to build tube recording gear as they seemed more complex than the stuff I built .

If you have made a Marshall then you should have the skills to build this. You can make it less complex by removing the valve / calibration circuit on the rotary switch. Without that it's no more complex than a marshall. Personally I am going to add that part of the circuit once I have got it going.

 

[Rob Flinn]

Oh wow that is unusual . Those 400a sound really cool . Yeah the computer was disabled on my 500 also haha

I maintain a couple of 536c for people. A great console, but on the other hand I do kind of like the simplicity on my board.

 

[Thegoldenlockedlamb]

That's common with varimu since they need to develop a really high signal level to drive the sidechain. The schematic has an attenuator after the output transformer. Not related to changing the design to use off the shelf transformers, will still have a output level that needs an attenuator.

T1: look at ua175 to see workaround for CT secondary and use any 600:60k
T2: DaveP's suggestion to drive the interstage with cathode followers (adding a tube) to use any 10k:10k
T3: This transformer is possible to get, but possibly change to WCF (LA2A) to use a cheap Edcor 15k:600

It's a hard question. If you have a lot of experience with a BA-6A and know it does and sounds exactly like you want, then you should go all in on authentic. I'm still not sure there are any confirmed builds that the sowters can do the job right. Getting originals would take patience and $$$$$.
I expect there are nuances to the original circuit and iron that a modern version would lack (possibly in a good way). But I haven't used an original.
Modifying the circuit could bring down the cost a lot and maybe arrive at something really good.
A tube varimu is an advanced project, so expect it to be hard to build and get right. I would suggest you spend time to understand tube electronics and how the circuit works before attempting the build. Soldering it all together will be the easy part, debugging and calibrating will be the hard part.

Hey I appreciate you trying to help me out . You’re right I do need to gain more experience on how these work . Like I mention below I have only built solid state kit stuff like pier’s Ma-1 , some guitar pedals and one tube guitar amp from a schematic , so no experience with building tube recording gear ( as it probably shows haha) . You are definitely right trouble shooting is the hardest part with anything electronic , for me atleast!

Yeah I would be good with a “ in the ball park” sound . I have used a few of these over the years and love how huge they seem to make vocals sound .

You are right about the sowers, I’ve yet to read where somehow used them and confirmed they do the job like they should . That’s really why I hate to spend the money and it not be right , thank you For taking the time to try and help me

 

[Thegoldenlockedlamb]

If you have made a Marshall then you should have the skills to build this. You can make it less complex by removing the valve / calibration circuit on the rotary switch. Without that it's no mor complex than a marshall. Personally I am going to add that part of the circuit once I have got it going.

Oh really? I didn’t know how bad it would be to build with recording stuff having stricter specs on noise and I’ve also never calibrated a compressor before or in this case a limiter . I guess I’ll Have to give it a shot and hopefully don’t screw it up too bad haha. Thank you for the tip on the calibration circuit .

 

[Thegoldenlockedlamb]

I maintain a couple of 536c for people. A great console, but on the other hand I do kind of like the simplicity on my board.

Yes the simplicity of the 400 series is a plus and I honestly like the sound of the 400 a lot . The 500s is complex with tons of parts and I didn’t know how do basic stuff I now know ( I didn’t even solder at the time ) and it got in bad shape , and I live in the middle
Of nowhere in Alabama and didn’t know of any techs at the time other than Blevins In Nashville which is 3 and a half hours from me and oldie expensive . So I just sold it .

 

[Flundran]

Check this out: utmindustry.com

 

[MidnightArrakis]

Yes I think you’re right , I dug for a few hours through threads a few days ago and didn’t find exact specs, though I feel like I have read it on here at some point. I guess I’ll keep looking. Thank you for your reply .

Also aren’t you the guy who built the API style console a few years ago? If so that is a really awesome build !

[aren’t you the guy who built the API style console a few years ago?] -- You may be thinking of the member who goes by the Screen-Name of "Fix". He's -- Paul Wolff -- who used to own API. He has started and has operated several "Pro-Audio" companies over the decades.

In other related news.....I'm not exactly quite certain on what you are doing with your planned -- BA6A -- build, since you are also looking for custom transformers (NOTE: You might try contacting "CineMag Transformers" and see if they will wind what you need), but if you are planning on "building from scratch" and could use some assistance with either the mechanical design of the chassis or the PCB-layouts, I can help you out there. Check out the attached PDF file. This is what I do!!!

"Standing By".....

/

 

[gary o]

. I have used a few of these over the years and love how huge they seem to make vocals sound .

ou are right about the sowers, I’ve yet to read where somehow used them and confirmed they do the job like they should .

I built BA6A 20 years ago with Sowter transformers at the time there was very little info on the web I spoke to Brian sowter about making me the interstage, He gave me lots of advice on my build too much needed, He completed the interstage for me same one is now in Sowter catalogue (YES expensive) I dont have real BA6A for comparison but can say for sure this thing is a beast, as you said make vocals huge it can crush like a trash compacter and never sounds bad it blows away all other compessors I have made or used its my favorite possession...The Sowters may or may not sound as original but it certainly does the job... I cant imgine it could sound better maybe just different.