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Non ADA Gear => Rack Gear => Topic started by: rabidgerry on February 08, 2017, 04:09:13 AM

Title: Hafler T2 - Anyone heard of this or had any experience??
Post by: rabidgerry on February 08, 2017, 04:09:13 AM
So I got this the other day

http://www.ebay.co.uk/itm/Hafler-T2-valve-guitar-preamp-/162377957429?nma=true&si=ZiNYrdFjKMNum17HGW4s7kPugjY%253D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557 (http://www.ebay.co.uk/itm/Hafler-T2-valve-guitar-preamp-/162377957429?nma=true&si=ZiNYrdFjKMNum17HGW4s7kPugjY%253D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557)

no idea about these things other than they are US built.  I have come across very little info on them, but anything I have read is generally positve.  Anyone have any info they can share about this preamp?

I bought it for the hell of it as I won it for quite cheap and no one else bid on it.  I wanted a basic preamp and possible backup just incase (yeah cause I don't have backups already lol who am I kidding   :facepalm:  GAS)

If this is shit sure I will sell it on but let's hope it's good.
Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: rnolan on February 08, 2017, 04:49:41 AM
Hey RG, never come across them before but looks like fun  :dunno: .   Let us know what you think when you get it. (it could probably use new tubes LoL..). Probably go ok in a loop ? (if you like the tone)
Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: Samuraipanda on February 08, 2017, 09:40:24 AM
I knew a local guy that had one and he ran it through a Rivera TBR power amp. I thought it ripped.

I have a demo of his somewhere on cassette in my archives. I'll have to dig it up.
Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: rabidgerry on February 08, 2017, 01:15:58 PM
I knew a local guy that had one and he ran it through a Rivera TBR power amp. I thought it ripped.

I have a demo of his somewhere on cassette in my archives. I'll have to dig it up.

Those would be good to hear SM if you can get em transferred.

When you say ripped do you mean in a good way?

If it turns out to be a little demon then hell yeah I'll be happy.  I got it for £110.  Guy was looking £160 but no one hit the "buy it now option" and no one else bid but me so could be a little steal!  Or perhaps a turd.  I like the stereo loop option.  Very handy.
Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: Kim on February 08, 2017, 03:01:10 PM
Seems like a good score, RG.    I've heard of these, but never actually tried one or knew anyone local that I could check one out.  At thast price, doesn't hurt to try it....if it's a turd you can throw it back on the market.

Now, I recommend you send me that crappy Peavey Rockmaster you have hanging about as soon as possible...    ;)
Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: rabidgerry on February 08, 2017, 03:13:59 PM
 Exactly Kim, so we shall see.  I heard some clips (all three of em) on youtube.  They're poor quality but one give me a kinda idea of the high gain sound.  There is a secret boost apparently in the drive knob, like the Rockmasters, pull it for that extra layer (like adding a pedal in front).  Who know's what this thing will sound like.  I like the simplistic nature of it and as I say nice to have another unit and may be even something unique tonally about...................and if anything just another backup unit  :thumb-up:


:lol: I laughed out loud for real at
Now, I recommend you send me that crappy Peavey Rockmaster you have hanging about as soon as possible...    ;)

Uh Rockmaster? I aint got no Peavey crap in my house  :lol:

Ok I lied Which one man?  I own two  :facepalm:.  I've modded the one I use in my home studio and I plan to try a few more little cap tweaks as well.  Recording with it currently.  Love those pre's.
Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: rnolan on February 09, 2017, 02:27:33 AM
Ahh a secret boost  >:D , sounds like a fun gadget to roll a few tubes through  :whoohoo!: , is the loop parallel ?
Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: rabidgerry on February 09, 2017, 02:36:10 AM
Ok so it has arrived!!  It's sitting beside me in work!!  Looking forward to tryng it.

I need to get some tubes RN, I just hate the dam price of the things!  I have some spare to experiment with in the mean time.
Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: rnolan on February 09, 2017, 03:01:59 AM
Hey RG, The Mullard LPs are costing me $30 AUD (used to be $22 AUD but then the dollar dropped  :facepalm: ) so not a fortune, but not trivial either.  IIRC you still have some of the original chinese bottles, they would do ok I recon (though I'd go the MLPs  >:D , no surprise there LoL).  Hey this gadget may be great  :dunno: , you can eq elsewhere if you need to e.g. in Fx unit), and/or put the rockman in it's loop  :whoohoo!:
Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: rabidgerry on February 09, 2017, 03:41:34 AM
Well I hope so Richard.  Fingers crossed eh!

If the initial bed tone is good and I find the EQ is too limiting hell yeah use another EQ like my Rockman intrument EQ to carve it to perfection.  If it stinks, well sure back on ebay it goes.  Yeah I have the Chinese bottles still in my regular mp1.  They still sound good to me. 
Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: rnolan on February 09, 2017, 04:16:27 AM
Hey RG, well looking forward to your reaction to it  :thumb-up: (and what tubes its got etc etc), I do like its simplicity, my gut says you'll like it allot LoL (particularly really loud  >:D :metal: ), I suspect I wouldn't mind one either... :facepalm:
Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: Samuraipanda on February 09, 2017, 09:55:24 AM
Here's a youtube link to their Demo: JJ is a great player.

https://youtu.be/FBASl5_nyrw (https://youtu.be/FBASl5_nyrw)

https://youtu.be/FBASl5_nyrw


Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: rabidgerry on February 09, 2017, 11:06:01 AM
Thanks Samuraipanda will check these out!

So I got it home, out of the box and played it!

I like it.....................but!

The tone is amazing, to me it sounds different from anything else I own.  Has these crazy texture harmonics!  It reeks of 70's amp but then being pushed hard.  Well I think it does.  Then with the boost it has MASSVIE amounts of gain.

But the draw back is, even at quite lo gain setting there is something unpleasant for me about the feel.  It's like a compressor with all the attack cut off but you get singing smoooooooooooooth susatain.  However as it is pushed this squash effect gets more obvious and to me I could not handle that.  I really soft strumming kind of a guy might but it doesn't suit my style of playing.  And this is a shame a that amazing smooth singing sustain is actually sensational feeling and sounding.

With the boost off it's better, but that squash thing is still there.  In place of the boost if I use an external boost (in my case one from my boss GT5 using an OD) I get less of the squashed attack and it's pretty usable.  External boost gives that chunk but not as much squash.

I kinda would like the option to use an external boost and use the onboard boost which would be really great without the dynamic theft.  I wonder could it be modded to allow the attack to come through but keep all the distortion.

Rolling back volume on my guitar works also but you can't compensate the loss of distortion on the pre amp itself by turning it more.  You can a little bit but not enough.

I like it and I think I will keep it, but I think I will only do so if I can modify it somehow.  I think Richard you would actually like this, has an older flavour to it compared to say an MP1 or Peavey Rockmaster but despite this it can give you as much distortion if you like.  I dialled in more 70's rock tones almost immediately using a dimarzio super d equipped guitar.
Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: rnolan on February 10, 2017, 01:13:50 AM
Hey RG, what tubes are in it ?  That could make a big difference  :dunno: , the squishing will probably be related to how the 4 triode gain stages in the 2 tubes is setup.  Do any of your compressor style gadgets have expander options ?, may help get some dynamics back into the signal.. certainly worth a try.  As you say I probably would like it given the more recent direction of my guitar playing (wind the distortion back (allot), roll the guitar vols back to 2.5 - 3 ish although I'm mostly playing bass currently (and loving it), crap MB-1s are good  :thumb-up: >:D (and I've heard allot of bass amps over the years).
Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: rabidgerry on February 10, 2017, 02:34:39 AM
well the compressor on my FX unit has basic Attack, threshold and level.  But I don't want to get into needing one of them all the time.

If I could mod it some how that would be awesome.

I aint checked the tubes but I will.  I have a feeling they are Hafler own branded tubes.  Correct me if I am wrong, but I have never come across tube swaps that made as big and drastic a change as it would need to sort this squash out.  Would different tubes of the right flavour really be able to give me dynamics and attack again?

Also would new tubes lose the cool texture-tweedy harmonics?
Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: rnolan on February 10, 2017, 03:28:33 AM
Hey RG, some compressors also have expanders built in (most don't), DBX used to make a compressor/expander to increase/restore the dynamic range of LPs (as LPs were often compressed in the mastering to prevent the cheaper PU cartridge needles/stylices jumping out of the tracks. (compressing (2:1) on record and expanding (1:2) on playback is how DBX (tape) noise reduction works BTW)
Hey the right tubes may make the difference  :dunno: , or a combination of 2 different tubes in V1 and V2. Since there seems more gain than you need, you could try lower gain tube(s) eg a 12AU7 or even a 12AT7 (not a 12AY7 yuck, the Y means why  :dunno: is how I remember it..LoL). They will all work (the 12AT7s need more/sufficient power though as are higher ampage output (thus great phase splitters in a poweramp)).
The biggest difference in tubes I've ever experienced is when I put Mullard LPs in my MP-2 (after changing the original tubes to Boogie SPAX7s (ie JJs)). Also it may just be that the tubes are old and lost all their sparkle  :dunno: .  IIRC MJMP changes the JJs in his 3TM monthly(ish).
Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: kawai2g4b on February 12, 2017, 01:18:00 AM
I owned a T2 for a while.  I personally didn't like the tone of the pre compared with my T3. You are right about that squashy feel to the attack, which is why I unloaded it. Plus the clean channel wasn't to my taste at all, a bit lifeless. The T3 however is a a gem of a thrash pre on the yellow channel.
Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: rabidgerry on February 12, 2017, 05:10:36 AM
Jeeezzz so I bought the  :poop: :poop: :poop: :poop: one   :facepalm:

I genuinely like the tone.  I just can't live with that squash.  It's very extreme.

Got to be something that can be done.

I have been searching on the internet and I found some evidence on giving an amp more squash, so I expect if this can be done you can also give it less, am I way off on this one?

I really would like to keep it, I think it has great potential.
Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: Kim on February 12, 2017, 07:56:45 AM
I have been searching on the internet and I found some evidence on giving an amp more squash, so I expect if this can be done you can also give it less, am I way off on this one?

I think there's a fair chance that it could be modded to lessen the squash; having the schematics and Signal Flow chart would help.  Most amp manufacturers have a schematics available somewhere, but I suspect few would have an actual Flow chart available like ADA was gracious enough to provide for at least the MP-2 and Quad Tube that I've seen. 
If the information available shows a "squash" circuit between the Input and preamp tube section, there's a good chance it can be hardwired to bypass that.  If the "squash" circuit is after the tubes, it may be more involved than that.  I'm not so sure about your scenario, but I have heard of people bypassing certain things internally with amps to accomplish something in particular they needed or were looking for.

Bottom line: do you think it's worth the troubles to go through all that (if it is indeed possible) and perhaps chance that the desirable tone that it once had is no longer there?  Or just say "Well at least I got to try out this preamp anyway" and put it back on the market and try again with another brand/model? 
Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: rabidgerry on February 12, 2017, 08:03:08 AM
Yeah I think it would be worth it.  I could be barking up the wrong tree but I would like to give it a go.  It really had something different from my other preamps.  It had all the distortion, and the controllability and nothing an EQ couldn't sort out that I would want so to me it is something I would like to own.

The squash however ruined the fun.  I'll try record a few clips later.  Could be my setup but I was able to dial up 70's priest tones within a few seconds, and then as I turned the gain up and then the boost imagine the seem but sent straight to hell!!!!!!  Why wouldn't I want to keep that?  The squash is there on lower gain but nowhere near as bad.  Id it just did not duck so bad I could even live with this!

EDIT:
I'm gonna contact Digitech, they bought the Hafler designs, perhaps they have a schematic for the T2.


Here's a youtube link to their Demo: JJ is a great player.

http://www.youtube.com/watch?v=FBASl5_nyrw

https://youtu.be/FBASl5_nyrw

If this is a Hafler T2 then it sounds really f**king good!  I aint not hair metal fan but the guitar sounds excellent to my ears  :thumb-up:
Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: rabidgerry on February 12, 2017, 09:27:21 AM
ok attached to this post is the schematic

but guess what......I can't read schematics  :facepalm:

can any of you guy's tell from this diagram what's exactly going on?
Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: Dante on February 12, 2017, 09:32:02 AM
Here's a youtube link to their Demo: JJ is a great player.

http://www.youtube.com/watch?v=FBASl5_nyrw

https://youtu.be/FBASl5_nyrw

If this is a Hafler T2 then it sounds really f**king good!  I aint not hair metal fan but the guitar sounds excellent to my ears  :thumb-up:

Agreed! That's some nice punchy tone...I'd beef it up a bit for my tastes, but it sounds nice  :thumb-up:

Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: MarshallJMP on February 13, 2017, 03:49:36 AM
From looking at the schematics, it's more opamp (SS) based then tube.From what I can see there are 2 tubes, on for distortion and drives a output transformer.Clean is also opamp based.
Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: rnolan on February 13, 2017, 04:42:56 AM
Now I started this post before I read MJMPs  :bow: ...

Hey RG, ok simple answer (and I have some sympathy for Kims suggestion BTW).
After a couple of wines and a cigarette and some contemplation (and a ~decent gawk at the schematic (to the extent I understand circuits  :facepalm: not nothing but not something MJMP ish).
My gut feel (and I hear you, you like it) is chuck in a couple of Mullard LPs and wind any gain trimpots back  a bit (if you can/and they exist) and it might just do the trick.

Now taking a more "lets try to understand the circuit" approach... seems to me there is a fair bit of stuff happening in the V1 stage between T1-A and T1-B triodes (do you remember a 12AX? tube has 2 gain stages ie 2 triodes ? I'm hoping MJMP will chime in and save me here LoL). You'll notice (I hope) on the schematic how each triode of each tube is depicted (T1A & T1B, T2A & T2B and you can see how they all (each triode) gets power from the power supply (so how a tube and/or to some extent a transistor work is you give them some power then you use a lower level input signal to control its (the power) flow to the output (more signal more output  >:D ))). T1's circuit is more complicated (I'd proffer in here lies the squish (and  :dunno: the place to change/vary/fix it) and T2 is basically just a more (even) gain stage (it's way less complicated).
Now to vary the squish (if I'm right) I've thought of 2 approaches (just changing tubes).  You could go for a lower gain V1 tube (so if squish is triggered by signal threshold (like a compressor) and less signal is coming from T1A because of lower gain tube, it may not be triggered/exceeded quite as much ? (so a 12AT7 or probably better  :dunno: a 12AU7) Gain of 70ish or 50 ish mu (12AX7's are 100+ mu  >:D and why we like them LoL) . The squish is triggered by something (and changing whatever that is is also an option).
The other approach is just use really open headroomy tubes and keep the gains down a bit ? Again the Mullard LPs are good for this (they are highly recommended for HiFi Audiofile applications) but there are others as well.

An aside.. when you look at the schematic and see the circuity around the 4 triode stages, this is also how our beloved ADA preamps work.  The various "voices" in MP-1/2, Classic and MB-1 alter things in these circuits (between the 4 triodes) to create the basic tones.
Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: MarshallJMP on February 13, 2017, 04:53:32 AM
I think you get so much compression is because the majority of the distortion is made by only one tube that gets hit hard by an opamp.
Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: rabidgerry on February 13, 2017, 05:40:47 AM
To clarify, the Clean channel is indeed SS.  One thing I do know about this pre amp.

Interesting information there Richard.  Wish I could read that diagram and know what it was telling me.

Both you and MJMP have mentioned the T1 area, so this could possibly be the offending zone.

I could just swap tubes yeah sure.  I'll try this tonight and see what difference it makes.

If this preamp is more SS than tube, it still sounds good and has nice breakup.  I'd like to get it to work.

MJMP what would you recommend?  Just a simple change of tube?  Or could something be modified without losing the distortion amount.

So second tube is purely for amplification then, ok  I see.  So I higher gain tube will give louder output and a lower gain tube will give me less output correct?
Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: MarshallJMP on February 13, 2017, 05:46:27 AM
For me one tube is not enough. For a more open no comp sound you need at least 2 tubes and 3 is even better. Tube rolling won't help IMO.
Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: Iperfungus on February 13, 2017, 05:51:37 AM
For me one tube is not enough. For a more open no comp sound you need at least 2 tubes and 3 is even better. Tube rolling won't help IMO.

99,99% you're right.

But I would suggest to try a 5751 tube there...
They are like 12AX7 with 30% less gain.
I had good results with a 5751 in my Zoom 9150: they still have a very good gain amount...enough to rock really hard.

Maybe, when pushed hard by the opamp, that tube would compress less...
Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: rabidgerry on February 13, 2017, 06:43:01 AM
MJMP when you say one tube is not enough, what do you mean?

Are you saying one tube is not able to reduce "Squash"?  Or something else?

It sounds good, but it's just the squash that is the issue. Different from anything else I own. 

Iperfungus, I'll look into getting one of those tubes perhaps.

But I might try some other tubes that I have at home just to see what they are like.  Not sure if I have any medium gain or low gain tubes.  I probably need to buy some new tubes actually but they are so f**king expensive.  Lucky I don't use a tube power amp eh???


Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: MarshallJMP on February 13, 2017, 07:04:42 AM
I mean that one tube is not enough to get a "decent sound".It has to do too much work.It's better to devide it over more tubes.
Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: rnolan on February 13, 2017, 07:12:56 AM
Hey RG, maybe think about it like this, tubes add gain, so do opp amps (in some ways the transistor (SS) version of a tube??). They all come in different shapes/sizes and amounts of gain they bring to a circuit. Eg you can use an opp amp to power your Fx/Aux send(s) on a desk to ensure each send gets good level when you split the input signal to them.  So from what MJMP is saying, this circuit is largely driven by SS opp amps with tubes thrown in to warm it all up (kind of hybrid circuit, not uncommon BTW). So if the tubes aren't doing that much of the distortion/tone, changing them will have less affect. (it will have some though).  Now you could change the opp amps to reduce squish, but that's not as easy as say going to lower gain tubes.  So another approach is go with high gain tubes (again the Mullards would be fine or whatever else you have around) and adjust it such that you have maximum tubes in the circuit.  Eg, my Ivory 5001 hybrid valve 4 ch preamp has SS circuits with a tube to warm them up. winding up the ch input puts more signal to the tubes and winding down the output balances it out (more tube less SS). Seems your gadget is similar...
Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: rabidgerry on February 13, 2017, 08:04:42 AM
I mean that one tube is not enough to get a "decent sound".It has to do too much work.It's better to devide it over more tubes.

This thing would definitely sound  "decent" if it just did not squash the attack.  Everything else is good to my ears.

It sounds good if I use an external boost i.e overdrive in front  Not as squashed.  But then it doesn't have the same tone.

Hey RG, maybe think about it like this, tubes add gain, so do opp amps (in some ways the transistor (SS) version of a tube??). They all come in different shapes/sizes and amounts of gain they bring to a circuit. Eg you can use an opp amp to power your Fx/Aux send(s) on a desk to ensure each send gets good level when you split the input signal to them.  So from what MJMP is saying, this circuit is largely driven by SS opp amps with tubes thrown in to warm it all up (kind of hybrid circuit, not uncommon BTW). So if the tubes aren't doing that much of the distortion/tone, changing them will have less affect. (it will have some though).  Now you could change the opp amps to reduce squish, but that's not as easy as say going to lower gain tubes.  So another approach is go with high gain tubes (again the Mullards would be fine or whatever else you have around) and adjust it such that you have maximum tubes in the circuit.  Eg, my Ivory 5001 hybrid valve 4 ch preamp has SS circuits with a tube to warm them up. winding up the ch input puts more signal to the tubes and winding down the output balances it out (more tube less SS). Seems your gadget is similar...

Maximum tubes?  How do you mean?

Could it be that using a higher gain Tube in p1 would mean more headroom and therefore not pushed as crazily as a lower gain tube?

I could swap an op amp no problem, depends where it is and how easy to get to it.  I've done it before.  It's just like this right?

http://i.ebayimg.com/images/i/260751535896-0-1/s-l1000.jpg (http://i.ebayimg.com/images/i/260751535896-0-1/s-l1000.jpg)

Here is an internal of the Hafler

(http://i177.photobucket.com/albums/w204/borislol/00001-6.jpg) (http://s177.photobucket.com/user/borislol/media/00001-6.jpg.html)
image of the whole thing
http://medias.audiofanzine.com/images/normal/hafler-t2-254403.jpg (http://medias.audiofanzine.com/images/normal/hafler-t2-254403.jpg)
Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: MarshallJMP on February 13, 2017, 02:20:23 PM
Is that a pic of yours? Because I see some differences with the pic in the link? For one they removed the small tranny after the tubes and put some resistors in it's place.
Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: rabidgerry on February 14, 2017, 02:10:57 AM
Is that a pic of yours? Because I see some differences with the pic in the link? For one they removed the small tranny after the tubes and put some resistors in it's place.

Ok perhaps this was lazy of my, but then how was I to know????  :facepalm:

I did not take a photo of my own preamp.  I used one from online. 

So that leads a question wide open about this, what has the person done to the tranny and what effect has this modification done to the tone?

I recorded last night and there is definitley a range where this preamp can currently be used.  When pushed hard though it turns to squash fest.  And if you use an external boost you have other realms of possibilities.

Before I read MJMP's post I was about to say "ok so if I was an electronic wiz I would turn this preamp into a three tube preamp and lighten the load of T1 by having another tube"

and since I could never dream this up that will remain a pipe dream.  But this find that MJMP has noticed is very interesting and purely accidental on my part.  So the picture of that preamp above has had some sort of modification done to it.  But what?
Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: MarshallJMP on February 14, 2017, 02:39:20 AM
Could be a factory mod, that at one point they decided to ditch the tranny. :dunno:
Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: rabidgerry on February 15, 2017, 01:25:37 AM
If only I could swap the op amp for a tube  :)

Haven't had time to check the tubes yet or swap, but recorded a little bit using a lighter setting and I still like the sound.  Not as much squash as well.

Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: Systematic Chaos on February 15, 2017, 03:35:06 PM
If only I could swap the op amp for a tube  :)

Haven't had time to check the tubes yet or swap, but recorded a little bit using a lighter setting and I still like the sound.  Not as much squash as well.

Is there a TL072 dual OpAmp in the signal path before, between or after the tube stages? if so, I bet that OpAmp gets fed with too much input it can't handle (sonically) and thus results in that squashy sound. Replace that/those with a BurrBrown OPA2134. These OpAmps are the most clean and transparent sounding and can handle more input (<<this is not the scientifically correct statement....just my own and other peoples findings, e.g. in TS circuits, in the tube driven DV circuit of a preamp,...).
Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: Harley Hexxe on February 15, 2017, 05:01:05 PM
Is there a TL072 dual OpAmp in the signal path before, between or after the tube stages? if so, I bet that OpAmp gets fed with too much input it can't handle (sonically) and thus results in that squashy sound. Replace that/those with a BurrBrown OPA2134 or 2234. These OpAmps are the most clean and transparent sounding and can handle more input (<<this is not the scientifically correct statement....just my own and other peoples findings, e.g. in TS circuits, in the tube driven DV circuit of a preamp,...).

    This is a very interesting subject to me. Are these OpAmps and sockets available through Mauser?
Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: Systematic Chaos on February 15, 2017, 08:52:24 PM
Is there a TL072 dual OpAmp in the signal path before, between or after the tube stages? if so, I bet that OpAmp gets fed with too much input it can't handle (sonically) and thus results in that squashy sound. Replace that/those with a BurrBrown OPA2134 or 2234. These OpAmps are the most clean and transparent sounding and can handle more input (<<this is not the scientifically correct statement....just my own and other peoples findings, e.g. in TS circuits, in the tube driven DV circuit of a preamp,...).

    This is a very interesting subject to me. Are these OpAmps and sockets available through Mauser?
OPA2134, Mouser Part#: 595-OPA2134PA

8Pin IC Socket, Mouser Part#: 575-113308
Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: rabidgerry on February 16, 2017, 02:43:05 AM
If only I could swap the op amp for a tube  :)

Haven't had time to check the tubes yet or swap, but recorded a little bit using a lighter setting and I still like the sound.  Not as much squash as well.

Is there a TL072 dual OpAmp in the signal path before, between or after the tube stages? if so, I bet that OpAmp gets fed with too much input it can't handle (sonically) and thus results in that squashy sound. Replace that/those with a BurrBrown OPA2134. These OpAmps are the most clean and transparent sounding and can handle more input (<<this is not the scientifically correct statement....just my own and other peoples findings, e.g. in TS circuits, in the tube driven DV circuit of a preamp,...).

I'm not sure if there is man, I have no idea about what kind there is (forgive my lack of knowledge).

What I will do is open it up myself and take some pics of my actual preamp.  And have a look and see what there is.

I reckon it's worth a shot trying to make some modification.  If it can't be helped well I shall sell it on.  Does the schematic tell us any of that information?

Busy recording these next few days however I will get a chance to get inside at the weekend.

Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: MarshallJMP on February 16, 2017, 09:32:53 AM
There is a NE5532 before the tube stages (and for clean) after the tubes there is a LF347 but this is a quad opamp which can be replaced with the OPA 4134
Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: rabidgerry on February 01, 2018, 01:45:41 AM
I've decided to try these mods

MJMP  is this the correct type of OP amp you suggest?

https://www.ebay.co.uk/itm/OPA4134PA-DIP-14-Integrated-Circuit-from-Texas-Instruments/292069205550?epid=1047485310&hash=item4400ae662e:g:n8wAAOSwax5Y2eGJ (https://www.ebay.co.uk/itm/OPA4134PA-DIP-14-Integrated-Circuit-from-Texas-Instruments/292069205550?epid=1047485310&hash=item4400ae662e:g:n8wAAOSwax5Y2eGJ)
Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: MarshallJMP on February 01, 2018, 09:50:09 PM
That looks okay  :thumb-up:
Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: rabidgerry on February 02, 2018, 03:48:52 AM
OK so I bought that chip,  don't suppose you now what Characteristic's of it are?

Also can I swap out NE5532 with the op amp SC suggested? I have a BurrBrown OPA2134 you see.
Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: MarshallJMP on February 02, 2018, 11:02:18 PM
yep the 2134 is pin compatible with the NE5532
Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: Chip Roberts on February 06, 2018, 10:34:42 AM
If I'm not mistaken, I think I remember reading this preamp was used by Marc Diglio from XYZ on the first record?  I think he switched to an MP1 for the second album, which was much heavier.
Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: rabidgerry on February 07, 2018, 06:02:20 AM
If I'm not mistaken, I think I remember reading this preamp was used by Marc Diglio from XYZ on the first record?  I think he switched to an MP1 for the second album, which was much heavier.

Chip, I would be so grateful if you could get that verified for me, I had a search myself but couldn't find Marc Diglio and Hafler T2 mentioned anywhere else in the same vein.  But it would be cool to know.

As for heaviness, the Hafler has shit loads of gain.  I like the tone, but just not this super "pumpy" compressed feel like when you turn the gain up too much and then hit the strings quite firmly and the sound pumps like a compressor with it's threshold set too low.  I get the same thing on the SS clean on the ADA MP1 I have to dial back the compressor (OD2) right back to about 2 to get it to work for me otherwise I end up with super pumpiness unless I play super light which is not my style.

I shall mod the Hafler and see what happens after that.  Still waiting on the OPA4134PA arriving.

I think the Hafler would be worth keeping if I could get rid of that.  Also works well with a boost and has a stereo FX loop.
Title: Re: Hafler T2 - Anyone heard of this or had any experience??
Post by: Chip Roberts on February 08, 2018, 12:12:19 PM
Apologies.  I was mistaken.  Marc Diglio used a Morin preamp, which is even more rare.