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Golden Age Carnhill Transformer!! Single-Channel Preamps
Old 17th December 2010
  #2
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PihSant's Avatar
 

I was just looking at these on ebay. Have you tried to put these in before? I have no electronics experience and this seems like a really cool idea.
Old 17th December 2010
  #3
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theproduca's Avatar
 

Like the auction says, looks easy, all the work is done. Thinking about it
Old 17th December 2010
  #4
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PihSant's Avatar
 

Quote:
Originally Posted by theproduca View Post
Like the auction says, looks easy, all the work is done. Thinking about it
If you do go through with it, let me know how it goes thumbsup
Old 17th December 2010
  #5
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theproduca's Avatar
 

Quote:
Originally Posted by scottyjneilson View Post
Dude this is the wrong area to be putting this up man that is what the classifieds are for.
Yo po po, It's information, not the sale!!! It's NOT my auction, #1 This would be considered equipment #2, Last but NOT least...where's your GURL at?!!! That's what I thought!!
Old 17th December 2010
  #6
Lives for gear
 

I just had Dave Thomas at Advanced Audio mod my GAP 73 with a Carnhill/St Ives Input transformer and the 7 tantalum caps - NOT the output transformer.
Dave has 40 years audio circuit experience and engineering chops. He claims the original Neve Carnhill OT was crude and the Chinese GAP OT is its equal in sonic terms and every other measurable way. The best bang for your buck would be the input transformer and the tantalums.

I did one of my GAPs and the other is still stock. I can tell you right now that as soon as the holidays are over I'm sending the other to Dave.

BTW, I saw that ebay listing - maybe he'll start offering a similar drop in for the IT. But probably not as some extra holes had to be drilled for the Input tranny....

JN
Old 17th December 2010
  #7
Gear Maniac
 
digibiu's Avatar
 

Quote:
Originally Posted by scottyjneilson View Post
sorry but it sure looked as though you were advertising your ebay auction. Not quite sure I understand your reply entirely though. Maybe if you reststed it in proper english?

How Ironic,
Now that's just funny!
Old 17th December 2010
  #8
Gear Maniac
 
Yfoiler's Avatar
Quote:
Originally Posted by John N View Post
I just had Dave Thomas at Advanced Audio mod my GAP 73 with a Carnhill/St Ives Input transformer and the 7 tantalum caps - NOT the output transformer.
Dave has 40 years audio circuit experience and engineering chops. He claims the original Neve Carnhill OT was crude and the Chinese GAP OT is its equal in sonic terms and every other measurable way. The best bang for your buck would be the input transformer and the tantalums.

I did one of my GAPs and the other is still stock. I can tell you right now that as soon as the holidays are over I'm sending the other to Dave.
JN
Having one modded and the other stock you are in a FANTASTIC position to compare them...Can you give us a description/comparison on what you think. A review would be great! I've got 2 GAP 73's also. So I'd love to hear your opinion on how much the mod changes things. Thanks...
Old 17th December 2010
  #9
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emrr's Avatar
or you could just buy them directly from Carnhill.
Old 17th December 2010
  #10
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Stitch333's Avatar
 

Quote:
Originally Posted by emrr View Post
or you could just buy them directly from Carnhill.
but they wouldn't have the molex tails...
Old 17th December 2010
  #11
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Quote:
Originally Posted by digibiu View Post
How Ironic,
Now that's just funny!
I gotta' - (have to) stop pushin' - (pushing) people's - (folks in my business)button's. Yep, it's sooo (so) easy to cram (put) your foot (size 7) in your BIG mouf - (mouth). No one seem to have a problem with this post except you sir. Where's your girl again?heh
Old 17th December 2010
  #12
Quote:
Originally Posted by theproduca View Post
I gotta' - (have to) stop pushin' - (pushing) people's - (folks in my business)button's. Yep, it's sooo (so) easy to cram (put) your foot (size 7) in your BIG mouf - (mouth). No one seem to have a problem with this post except you sir. Where's your girl again?heh
I get everything apart from this bit about his girl.....
Old 17th December 2010
  #13
Lives for gear
 
theproduca's Avatar
 

Quote:
Originally Posted by John N View Post
I just had Dave Thomas at Advanced Audio mod my GAP 73 with a Carnhill/St Ives Input transformer and the 7 tantalum caps - NOT the output transformer.
Dave has 40 years audio circuit experience and engineering chops. He claims the original Neve Carnhill OT was crude and the Chinese GAP OT is its equal in sonic terms and every other measurable way. The best bang for your buck would be the input transformer and the tantalums.

I did one of my GAPs and the other is still stock. I can tell you right now that as soon as the holidays are over I'm sending the other to Dave.

BTW, I saw that ebay listing - maybe he'll start offering a similar drop in for the IT. But probably not as some extra holes had to be drilled for the Input tranny....

JN
Good info!! I had (2), but sent one back to get the companion, COMP54!! Gotta wait til January...but THAT's gonna happen. If you can get info on that as well, please share.heh
Old 19th December 2010
  #14
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Quote:
Originally Posted by Yfoiler View Post
Having one modded and the other stock you are in a FANTASTIC position to compare them...Can you give us a description/comparison on what you think. A review would be great! I've got 2 GAP 73's also. So I'd love to hear your opinion on how much the mod changes things. Thanks...
The difference is not subtle, but I wouldn't exactly say it was dramatic. But I guess that would depend on the scale of your expectations.

I have not done an exhaustive comparison but here's what I find right off the bat:
- The top end in less veiled, more open - although by design (Neve-ish) it is not intended to be crystal clear and neutral pre.

- There appears to be more harmonic content (pleasant harmonic distortion) when you turn the input gain up.

- The low end is clearer and tighter, less wooly.

I just emailed Dave a couple of days ago asking for more information about his take on the output tranny. I don't want to quote him without his permission, but essentially he said the original Neve output tranny had crude specs and he has had it and the Chinese tranny on his bench and both have the same readings on his test equipment. Also he can hear no difference - so why bother. Then again there are guys ONLY doing the output tranny and doing it themselves because its the easiest thing to upgrade without changing things. And they think they hear a difference. Who am I to say?

JN
Old 19th December 2010
  #15
Quote:
Originally Posted by John N View Post
I just emailed Dave a couple of days ago asking for more information about his take on the output tranny. I don't want to quote him without his permission, but essentially he said the original Neve output tranny had crude specs and he has had it and the Chinese tranny on his bench and both have the same readings on his test equipment. Also he can hear no difference - so why bother. Then again there are guys ONLY doing the output tranny and doing it themselves because its the easiest thing to upgrade without changing things. And they think they hear a difference. Who am I to say?

JN
Well, maybe a better output transformer on an original neve would make a (gasp) improvement? or at least a change...

If the input stage of the pre73 is inferior to the original neve (which it's fair to say it is), maybe changing the op transformer will have an effect, even if it's not as dramatic/worthwhile as the input stage.
Old 19th December 2010
  #16
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All I'm saying is that a well respected engineer and audio circuit guy (who's not a newbie in the biz) claims that the biggest improvement to the GAP 73's circuit will come from the Input transformer upgrade and the tantalum caps.

best
jn
Old 31st December 2010
  #17
Here for the gear
 

Carnhill O/T drop-in upgrade for GAP Pre-73

As the guy who has the auction on eBay, I thought I would chime in here.... There are many people who want to perform modifications to their Pre-73 but don't have the tools/skills or money to pay someone to do those mods. The O/T replacement is the only mod you can perform without massive surgery to your Pre-73. Period. I have read where people have destroyed transformers, connected the primaries and secondaries incorrectly, ruined their Pre-73, etc., etc., and as a result I sourced the same board connectors as the Pre-73, use improved cabling, solder in the Zobel network, solder the proper connections on the primaries and secondaries, and fully test each transformer in a Pre-73 to ensure it will be right every time and to make it completely monkey-proof. This adds up to between 60 and 90 minutes per transformer.

I have performed mods on dozens of Pre-73s and the perceived difference in which mods give you the most bang for the buck vary greatly by individual because sound "quality" and sonic "differences" are mainly subjective. I modified a unit (input xformer, output xformer, tantalum caps) for a well known producer in Muscle Shoals and he tells me HE can't tell the difference between the modded unit and a stock unit. I've made other mods for people (tantalum caps only) and they swear THAT is the best mod for that unit and the transformers make no difference. So, while the engineer that is mentioned in the previous posts says there is no point in replacing the O/T, I'm sure that - to his ears - that is the gospel truth to him but, again, we are talking about audio and it is completely subjective.

The people who have purchased the O/T upgrade have told me everything from "VERY noticeable difference" to "very subtle difference". The common, recurring comment I seem to get is that the biggest difference lies in the clarity of the highs,low-mids and lows when the unit is pushed. There seems to be a somewhat general consensus that the midrange is the least affected by the upgrade. This would make the most sense from a purely objective standpoint since the Carnhill O/T weighs 44 grams more than the stock Chinese xformer - extra mass. In magnet wire terms, this would equate to approx. 1,000 more feet of magnet wire on the Carnhill.

Just my 2 cents....
Thanks,
Richard Dabbs
[email protected]
Old 31st December 2010
  #18
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Slikjmuzik's Avatar
 

All good news. I really love the brand and like what they offer. Very usable gear. I have 2 TT modded Pre73's here, but I'd like to add the Carnhill tranny soon. If it does tighten things up, it's something I'm looking forward to.
Old 28th January 2011
  #19
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I just sprung for a GAP73 and since I lve about 3 miles from the Carnhill headquarters, I called them & got sent to their distributor audio maintenance dot com in Manchester, UK.
They are very helpful guys & Colin who is "the man" says the best and most commonly bought transfo is the CA-18 VTB9045 input transformer.
And the UK price is £41.75 plus 20%VAT (UK sales tax) and packing and postage.

For the time being I am going to ahve a "getting to know you" sesion with my new toy and then see about maybe trying the tantalum bead conversion.

What is really reassuring is that Carnhill bought St Ives and Granta Windings, both of whom I dealt with back in the early seventies when I built mixers and amplifiers. And they are still operating from the same site forty odd years later.
Old 28th January 2011
  #20
Here for the gear
 

Mods

Yes, Colin is "the man" at Carnhill. I have bought ALOT of product from him and I have gotten great service from Carnhill. With VAT, shipping, international transaction "fees", etc., it costs about $70 US to get the VTB-9045 to your door in the US.
I have performed mods on dozens of Pre-73s and the mods that give you the most audible bang for the buck really depend on the way you use the preamp. If you attempt any mod at all on these units that require desoldering - such as the input transformer or the tantalum cap mod - please use a temperature controlled soldering iron with the lowest setting possible to melt the solder. The circuit boards in those units are not of the greatest quality and the circuit traces lift very easily.

Richard Dabbs
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