[tjkurita]

Hey all! Just picked this up and looking for some tube recommendations. I have the stock Sovteks and JJ SY3S rectifier.

ACORNIC did an excellent review of this amp in this thread with meticulous detail regarding tubes. I found similar results to his with tube rolling. The general consensus is that this amp benefits from tube rolling. His review will provide general impressions of different tubes in both driver and rectifier positions. I strongly recommend you check it out and get some cheap tubes to drop in there. Then when you start to notice the difference, you can search for your "best sound" tubes. I use relatively recent Tung-Sol US made 6SN7s and an RCA coke bottle 5R4 and I am happy with it. Electro Harmonix 6SN7s sound good in it too.

 

[audiofest2018]

Have been experimenting on several different types of tube for the past few months from the motivation of following Glenn OTL thread. This is by far my favor combo for IHA-1

Rectifier tube: WE 422A
Output tubes: two pairs of L63 GEC

When use ZMF Verite Open headphone, in general SQ characteristics are warm, deep and well defined bass yet not overpowering. The mid-range is where I thought the best of its presentation. Treble is smooth not harsh nor dark to me either. With this combo I tend to enjoy more on the music more than analyze the sound. This tube amp is, IMHO, one of the overlooked head-fi gear I think.

Hope to hear other IHA-1 user's impression of using other tubes if you can share. Thank you!

 

[Xcalibur255]

This is one of those rare amps where you truly do not need to buy crazy exotic tubes to get it sounding great in my opinion. My Inspire sounds very much to me the way you are describing yours whilst running a pair of Sylvania 6BX7 and a Sylvania 5Y3G. Total cost: $35. I've come to prefer this combo over much more expensive tubes I have tried in the amp. Perhaps not coincidentally the 6BX7 and 5Y3 are the native tubes the designer meant for those sockets too. Without the input transformer option it can feel a little short on gain though, something to keep in mind.

I should dig this poor amp out of the closet and listen to it again. When I re-designed my listening area I lost space and something had to go sadly, but I couldn't bear to sell it because it's such a good little amp.

 

[audiofest2018]

It is a wonderful amp and also happened to be my first tube amp as well. I love it immediately and was able to appreciate the SQ difference between tube amp sound and SS amp. Perhaps like what you (@Xcalibur255 ) said, it is such a great unit, I have not been interested in any SS amp since then until GS-X Mini . It is interested you mentioned about the native design for this amp. I was going to try 6BX7 as well since I got some for my upcoming GOTL amp. But figured I should ask Drew first as my unit was built in 2017. He was able to confirm my built version does take 6BXL but he mentioned in his response that the built I own is truly designed for 6SN7 so I kind of stop trying.... Maybe I should give it a try after all.

 

[comzee]

but I couldn't bear to sell it because it's such a good little amp.

Same here, even tho I spent thousands more upgrading to bespoke stuff, it's one of those audio devices that I just couldn't bare to sell.
It's just that good. I eventually sold it to my friend for $500 just to keep it local if I ever wanted to listen to it again.

6BX7.... Maybe I should give it a try after all.

It really comes down to preference at the end. I agree with @Xcalibur255 that you don't need expensive tubes, sometimes it's just finding what you personally like.
For me, I rolled a few different types of both 6BX7 and 6BL7, never really liked them as much as standard 6sn7. But they do have a unique tonal signature one could like more.
Iha-1 can also take 6SL7, but again never preferred those, they have extra sparkle in the treble, but wasn't a fan.

One of my favorites was 6f8g Tung-Sol black round plate. I also have the square plate Tung-Sol 6f8g as well.
The black round plate 6f8g doesn't have a lot of bass tho, so I could see many people not liking it.

If you want to spend a stupid amount of money, you can get the Tung-Sol 6sn7 black round plate, they go for around $500 a pair if you can even find them.
They are similar to the 6f8g black round plate, but much better lower end impact and tightness.
I'd say 100% skip tho, not worth the money, stay cheap like @Xcalibur255 mentioned.


The amp is slept on for two reasons. #1 Planars sound like trash from it, and planars are a big trend right now. #2 Even with dynamics like hd800, or Verite, it's a bass light amp compared to SS counterparts. Many people will immediately dismiss the iha-1 because of that.

What the Iha-1 does better than most any other amp at it's price point, is giving that pure SET OTC class A no feedback sound.
It comes from higher levels of second-order harmonic distortion. One might read "distortion" oh no, screw that, gimme the THX 789. Thing is, the second-order harmonic for me, and other tube lovers, is what gives music life and emotional impact. It sounds real, compared to an extremely detailed representation of what music should sound like. That's my take on it.

 

[Xcalibur255]

It is a wonderful amp and also happened to be my first tube amp as well. I love it immediately and was able to appreciate the SQ difference between tube amp sound and SS amp. Perhaps like what you (@Xcalibur255 ) said, it is such a great unit, I have not been interested in any SS amp since then until GS-X Mini . It is interested you mentioned about the native design for this amp. I was going to try 6BX7 as well since I got some for my upcoming GOTL amp. But figured I should ask Drew first as my unit was built in 2017. He was able to confirm my built version does take 6BXL but he mentioned in his response that the built I own is truly designed for 6SN7 so I kind of stop trying.... Maybe I should give it a try after all.

They must have made a change to the circuit after I bought one then. Dennis Had himself said the circuit is designed for the 6BX7 first and that 6SN7 tubes are perfectly fine but will net you a little more distortion because the bias isn't quite ideal for it. It makes sense for them to shift the circuit in favor of a 6SN7 though given it is a popular and known tube, but the 6BX7 is wildly underrated and sounds really good. People shouldn't overlook it. It will save you from spending hundreds of dollars on exotic 6SN7s.

 

[Xcalibur255]

@comzee

I agree with your sentiments for sure. I actually don't mind listening to my LCD-2 on the amp. It's not the most dynamic sound for sure but it doesn't totally lose the better qualities of the LCD-2. The biggest weakness of the IHA-1, IMO, is bass definition. I can forgive a smallish tube amp not having a strong sense of slam in the bass, but the Inspire combines the lightness with a lack of control and pitch defintion too. It's just soft and limp all around. The gorgeous midrange and sweet gentle high end buys a lot of forgiveness though.

 

[audiofest2018]

I have to admit that when I first pick up this hobby back in 2016, my SQ taste is very different than what I like today... Not sure this is due to self-evolution or influenced by following other peoples opinions but probably both I think. Anyway, I wasn't very particular focused on the bass back then but feel like now I do just a little bit. Still today I would prefer solid mid and sweet high note than strong bass (Maybe this is due to my music taste). This is especially true when the unit can reproduce the true sound musically even if there are defects in it.

This reminded me of how I used to appreciate perfect SQ until I attended a classical music concert. It is not until then I realize that "Gee! This is what true violins, cello or other instruments sound like in a concert hall!" From that moment it totally changes my perspective of how stereo unit should represent sound and music... A true re-production of sound and music is what I want... Just my 2 cents.

One thing I do notice about my HPA-1 unit is that for certain tubes and headphone with low impedence I can still hear a faint hum sound from the right channel. But you can't hear it most of the time when the music is on though...

 

[ScornDefeat]

How do you guys generally find this amp for low-z phones i.e. planars? With an output impedence of 4.4 ohms, I'm a bit skeptical (as well as not a ton of extra headroom from an output power perspective), but I'm looking for an option to complement an Ampsandsound/ZMF Pendant (great for high-z, OK for planars, no balanced out) and a solid state JDS Labs EL II (good power all around, but no balanced out).

 

[comzee]

How do you guys generally find this amp for low-z phones i.e. planars? With an output impedence of 4.4 ohms,

You'd find your answer if you scrolled up in the thread a bit. To make easy for you, absolutely do not buy iha-1 for planar headphones.

 

[ScornDefeat]

You'd find your answer if you scrolled up in the thread a bit. To make easy for you, absolutely do not buy iha-1 for planar headphones.

Thank you, have noted your response now on the above post. I read many responses on this thread praising the amp with Audeze, so despite my skepticism on this performing with planars, there were notes in that direction. Tough finding a good, balanced-out tube amp for low-z!

 

[comzee]

Thank you, have noted your response now on the above post. I read many responses on this thread praising the amp with Audeze, so despite my skepticism on this performing with planars, there were notes in that direction. Tough finding a good, balanced-out tube amp for low-z!

iha-1 isn't balanced, the 4pin xlr port is still SE.

If you want a super solid balanced choice for planars, check out Bryston BHA-1.

 

[Laines]

Hello I just joined the family of IHA-1 owners. I got a unit with the Lundahl transformer update.
As my technical knowledge is very limited I thought I ask here.

One of the transformers (the biggest one, on the right looking at the front of the unit) is vibrating (would call it micro vibrations) at a very high frequency which also can be felt slightly at the whole unit. Also when I press my ear to the transformer or anywhere on the unit I can hear a loud electrical humming noise.

Is this a normal and an expected behavior?

 

[comzee]

One of the transformers (the biggest one, on the right looking at the front of the unit) is vibrating (would call it micro vibrations) at a very high frequency which also can be felt slightly at the whole unit. Also when I press my ear to the transformer or anywhere on the unit I can hear a loud electrical humming noise.

Is this a normal and an expected behavior?

That is not normal behavior. Check if any screws or anything is loose on the transformer mounting points, see if you can tighten them.

 

[Laines]

That is not normal behavior. Check if any screws or anything is loose on the transformer mounting points, see if you can tighten them.

All screws are properly tightened. Its also not a loud rattle what a loose screw would cause, its more a electrical humm. Do you have a unit on hand? When you press your ear on it can you hear the humm?