Ken is doing the battery chip mod for me on both my Profex II and Tubefex at the TSGA. I'm thinking about the Burr Brown Chip mod as well. Real world, does this make a big difference? I'm not using either of these units live at present as I'm using an Evans Stereo Preamp into a TC Electronics M-One, but if I could get similar quality with the Profex II or Tubefex, it would eliminate one item from the rack.

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God Bless,
Steve Stallings

On the Vegas, there was more than just replacing the IC's from what I remember. Seems to me the voicing is changed too through some resistors and cap replacements.

However, to your queston - When I first got my Vegas 400, it had TLO72's. After I put in the Burr Brown 2604's it made a very subtle, but very noticeable improvement to the timbre.

Prior to, I found the sound "hard" and not particularly enjoyable. After, it was "sweet". The sound is virtually indistinguishable if not preferably to a tube preamp, from what I've been able to tell when comparing with my Mesa Formula Pre into the power amp section of the Vegas.

If I recall correctly, I bought a set of 10 OPA2604's for Cdn$40. Pretty cheap. Just go for it.

[This message was edited by Tom Gorr on 11 February 2005 at 06:52 PM.]

Bob M.

[This message was edited by Bob Metzger on 19 February 2005 at 07:04 AM.]

However, I had a Nashville 400 that had the tone mod installed by the factory (an early mod) but it did not have the OPA op-amps in it. I have a friend that had a Nashville 400 with older op-amps too. We bought the OPA's and installed them in our amps. Neither of us could tell a difference, and we are both electronic techs.

[This message was edited by Jack Stoner on 19 February 2005 at 12:57 PM.]

Peavey has these chips at a very reasonable price for those who want to upgrade themselves. I will not be selling the chips outright, just installed. I just wanted to add that as an option while folks have there Profex 2 or Bassfex here for memory chip (batteryless mod!) upgrade. The Burr Brown chips are not for the Tubefex or Transtubefex, just the memory chip mod is all I can do for you there.

I can tell from units I am repairing that they are quieter with the Burr Brown chips.

[This message was edited by Ken Fox on 25 February 2005 at 01:58 PM.]

Eventho the LeMay mod had the replacement chips ID numbers removed and the chips painted with red fingernail polish,

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http://home.comcast.net/~crookwf/

In the component "obliteration", Goodrich also does that. The chip markings are gone in my MatchBro.

[This message was edited by Jack Stoner on 26 February 2005 at 07:27 AM.]

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quote:

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Steel players do it without fretting

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http://www.waikiki-islanders.com

Does anyone have a source for these that they can recommend?

Thanks in advance.

I hate it when companies do that. I don't know how many versions there were for the MatchBro but the info below should help.
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Motorola MC34182P Low Power, High Slew Rate, Wide Bandwidth, JFET Input Operational Amplifier.
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Transistor : J113 = NTE469
Industry Number : J113
NTE Device Number: NTE469
JFET-N-CHAN CHOPPER/SW, TO-92

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Transistor: MPSA18
NTE Device Number: NTE47
T-NPN,SI LO NOISE AMP,TO-92
============================================

Just put several Burr Brown mods in the last few days and I can hear the difference in white noise level for sure. They are much quieter.