OPA2134 Op Amp Evaluation and comparison

Jack Stoner · Post by **Jack Stoner** » 18 Apr 2010 9:10 am

On another post I noted how the OPA2604 op amps (what has been used to "mod" the Nashville 1000, Nashville 112 and Profex II) had made a big improvement over the stock factory sound.

Today, I installed the OPA2134PA Op Amps in my Nashville 1000, that Ken Fox is selling and now using as the replacements in the Peavey amps and Profex II. There is definite improvement in clarity,tone and even an increase in volume level over the 2604's. If you still have the stock factory chips and maybe the 2604 mods, I would recommend contacting Ken to get the mod kit (new chips). The same OPA 2134 chips are used in Ken's Nashville 112 "mod" kit but to be truthful I tried the OPA2604's in my Nashville 112 and I like the stock Nashville 112 better. I may try the 2134's in my Nashville sometime just to see but it will be after our playing "season" is over.

The 2134's are designed for audio where the 2604 is a "general purpose" op amp (but a good op amp). Keith Hilton is now using the single op amp version (134) in his volume pedals instead of the single op amp version (604) of the 2604.

I have uploaded four samples - that you can listen to for yourself (disregard the sloppy picking as it was quick samples). There are both E9th and C6th samples with the 2604's and the 2134's. That is the only thing that is changed. I ran directly from my Franklin D-10 (with Lawrence 710 pickups and old strings) to the input on the Nashville 1000 with a George L’s cable. The settings on the amp were, Pre Gain 1.5, Low +9, Mid -3, Shift 800Hz, High and Presence +3, Reverb 0 (off) and Master Gain 3. I used an SM57 mike to my recording studio PC that has a Focusrite Saffire Pro 40 recording interface unit and Sonar recording software. Nothing was added or changed in Sonar. The files are wav files since they are relatively small and that provides full fidelity over an MP3 which is not full fidelity

Links to sound samples:

2609 E9

2604 C6

2134 E9

2134 C6

John Gould · Post by **John Gould** » 18 Apr 2010 10:05 pm

Thanks Jack I can hear a difference I will be getting some of the 2134's in my Nashville 1000 here soon.

Larry Robinson · Post by **Larry Robinson** » 22 Apr 2010 6:43 am

Just for the heck of it, I replaced the four each RC4558 chips in my Bandit 65 with the OPA2134PA chips. It certainly improved the quality of sound for the amp and gave it a sparkle it didn't have before. I paid 2.57 each from Mouser. Well worth the change.

Bobby Burns · Post by **Bobby Burns** » 22 Apr 2010 7:04 am

Larry, that is good to know. I have a bandit 65 that I really like for small room gigs. I use it a lot, and I had thought about trying that myself.

Chuck Snider R.I.P. · Post by **Chuck Snider R.I.P.** » 24 Apr 2010 9:15 pm

Hi Jack, I was curious to see what your recordings of the chipset comparisons sounded like. However, I can't seem to get to any of them. Is there something I need to do to access them?

I'm using an Alumitone pickup, and since going to that, my NV112 with Burr Brown Chipset seems quite harsh, and blaring, and can't seem to dial it away with tone controls. However, my guitar sounds great through either of my un-modded chrome cornered NV400's or my '73 Vibrosonic. I get the same harshness when I play through my Ken Fox modded NV400. I had Ken send me some of the stock chipsets so I could swap them in my NV112 and see how it sounded with stock chips. I had been using the NV112 as my main amp, but since going with the Alumitone pickup, I've had to go with the unmodded NV400's or the Vibrosonic. I want to continue using the Alumitone pickup, but I'd like to go back to using the NV112 amp if possible.

-Chuck

Scott Appleton · Post by **Scott Appleton** » 24 Apr 2010 9:47 pm

I could not hang with the NV 112 with my Emmons so I know what you mean .. I use the NV 400 unmodded and a Vibrosonic reissue . they both beat the pants off the 112. I also use a Deluxe Reverb with a JBL D120 F that sounds fantastic for small gigs .. Like I say some NV 112 just don't cut it with some guitars .. try a BF DR.
you might like that in the small amp territory.

Jack Stoner · Post by **Jack Stoner** » 25 Apr 2010 2:15 am

Chuck, they are standard mp3 sound files. If you can't get them, you have something on the PC that is blocking them.

Others have been able to access them without problems. When I click on one of the sample files, Windows Media Player opens and plays the sound file.

I don't think it's the Alumitone pickup. I have Lawrence 710's on my Franklin and when I installed the OPA2604's in my Nashville 112 I didn't like them at all. It was "too clean" and I couldn't find a setting on the amp that I liked. I played two jobs with the OPA2604's installed and was constantly fiddling with the EQ and never could get something I liked. The Nashville 112 didn't sound like a Nashville 112 anymore. I gave up and put the original chips back in the Nashville 112 and it was back to "my sound". I don't know what the 2134's will do for the Nashville 112, I'm going to install them and try them at our club jam in May and see what happens. However, in the Nashville 1000 the upgraded chips work great. The Nashville 112 has a conventional "analog" power amp where the Nashville 1000 has a "digital" (Class D) power amp section.

Carl Kilmer · Post by **Carl Kilmer** » 28 Apr 2010 6:24 am

I install the OPA2604's in my N112 and N1000 it made no
difference in the sound on either one, but it did add quite a
lot of noise to the N1000. I orderd 10 of the OPA2134PA's
and hope to see a good difference in both amps after I put
them in. I'll post the results after I get them installed.

Carl "Lucky" Kilmer

Chuck Snider R.I.P. · Post by **Chuck Snider R.I.P.** » 28 Apr 2010 8:24 pm

Jack, FYI I finally swapped out the 2604's in my NV112 for the stock chips Ken sent me. I gave it a quick trial tonight and it did bring it back into a tolerable range for me. That fixed the blaring tone it had with the 2604's. I only noticed the blaring tone after going to the Alumitone pickup. I do like the Alumitone best of all the pickups I've tried so far. So I will stick with it, and wrangle the amps to suit me. At this point the NV112 now sounds much better, but strings 3 and 4 around the 10th or 12th fret are still a bit shrill, but I'm hoping I can dial that out. If I'm not able to dial that away I'll let you know. Didn't mean to highjack your thread, but I thought you and others might be interested in this.

-Chuck

Jack Stoner · Post by **Jack Stoner** » 29 Apr 2010 2:24 am

Carl, I didn't hear any "noise" form my NV1000 after installing the new chips. The new chips are a little hotter and I had to cut the volume level down a tad for an equivalent volume level. I normally set my pre at 4 and the post at 5 or 6 on the amp.

Chuck, putting the 2134's in my NV112 is a "ROUNDTUIT" job for this summer. We did our last show of the season this past Tuesday and now have to get caught up with some things around the house that have I've left slip.

Mike Bowles · Post by **Mike Bowles** » 1 May 2010 11:31 am

i just tried a set of kens kits in my 112 i heard a big difference in the amp made my tele sound better without any effects at all the amp reverb sounded much better i didnt play my steel much though but what i did play i could hear a difference will hook my lexicon up later tonight guys if i can hear a big difference i know you more experienced players surely will i will be adding chips to my 1000

Mike Archer · Post by **Mike Archer** » 1 May 2010 2:07 pm

well ive never been a fan of replacing
factory parts untill today......
Charles Powell ordered a set from Ken for my nashville 112 and put them in and WOW!!
amp sounds cleaner/bigger/ string separation
is way better and best of all

the reverb sounds fantastic!!!!

yeap im sold on um

Mike

Mike Bowles · Post by **Mike Bowles** » 2 May 2010 10:03 am

mike last night was my first time out of the bedroom with my steel never could get up enough nerve i was going to play with a blue grass group that switches over to country after their first set they were almost ready to start country someone came to me and said russ hicks is setting in the audience boy was i nervous italked him into playing some i told the group this guy wants try to play a little he has only been playing a little over 4 months when he started their eyes got as big as baseballs any way my steel sounded great that was the high light of my night russ is a great player that meant a lot to me

Mike Archer · Post by **Mike Archer** » 2 May 2010 11:00 am

hey Mike
it gets easyer as you go along
I was on the road 20 years and met many steel players
never met one that put me down
most are nice fellas and most will show you stuff if you ask at the right time
if you need any help let me know
ive been playing steel 27 years and guitar
for 47 years

Mike

Chuck Walker · Post by **Chuck Walker** » 2 May 2010 11:13 am

Jack, how many OPA2134PA chips are needed to mod a 112 or a 1000?

Carl Kilmer · Post by **Carl Kilmer** » 2 May 2010 11:38 am

Hello Chuck,
You'll need 5 of the OPA2134PA chips in each one.
I got mine on Friday, but haven't put them in yet.

Carl

Jack Stoner · Post by **Jack Stoner** » 2 May 2010 12:15 pm

I just got a call from Don Sulesky and will be installing them in his NV112 tomorrow. It will give me a chance to hear what they sound like in a 112.

Chuck Walker · Post by **Chuck Walker** » 2 May 2010 12:26 pm

Thanks Carl.

Ken Fox · Post by **Ken Fox** » 2 May 2010 4:14 pm

I sell the kit on my website. I buy 200 at a time, package them in an a static tube and put that and instructions (with a drawing) in a small static bag, ship by Priority Mail and make a forum contribution for each kit sold.

Don Sulesky · Post by **Don Sulesky** » 3 May 2010 3:30 am

Ken
I wish I had read this before contacting you.
The 5 chips are packed so tight I thought I had one long one.
We solved that error thru an e-mail.
Thanks Ken.
I got my chips in 2 days.

Jack will be installing mine today.
Leg pain and shaky hands are not the best method for installing chips.
Don

Ron Bryson · Post by **Ron Bryson** » 3 May 2010 5:17 am

I picked up a set of 2134's at the Opp show on Saturday from Ken. I had already installed the 2604 chips, and was curious if the 2314 chips would make an appreciable difference. While talking to Ken, he mentioned the 112 having "useable mids" after this mod. A good description! Also it further opened up the amp. Definitely an improvement. Seems to have more volume response as Jack described.

Don Sulesky · Post by **Don Sulesky** » 3 May 2010 6:22 am

Jack Stoner just installed my mod kit from Ken in my NV112 and right away we both noticed the note separation and the cleaner tone from my amp.
Don

Bill A. Moore · Post by **Bill A. Moore** » 3 May 2010 11:32 am

Just so happens, I have a Bandit 112 transtube chassis open right now. Resoldered a few traces, and cleaned the contacts on the pre-out jack. Have to build a cabinet for it,(my nephew took a shortcut off the mountain). It shows to have 4560 op amps, U1-5. Is there any reason not to try the 2134 chips in this unit?
Thanks for the knowledge, Bill.

Carl Kilmer · Post by **Carl Kilmer** » 3 May 2010 12:26 pm

I just put the OPA2134PA chips in my N112, and think it sounds better now.
If I get the time tomorrow, I'll put a set in my N1000, and see if if helps.
That one needs a better sound. The 2604's don't sound as good as the originals.

Carl

Ken Fox · Post by **Ken Fox** » 3 May 2010 5:22 pm

They should work fine in the amp, Bill

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OPA2134 Op Amp Evaluation and comparison

OPA2134 Op Amp Evaluation and comparison

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upgrade

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thats cool Mike