[comzee]

  You don't like your Melz tubes?

I'll have to give them a longer listen. Right now I'm using a Sophia 6sn7 pair + sophia mesh 274b.
I'm getting Psvane cv181 (6sn7) treasure mkii / shuguang natural sound series cv181-t (6sn7) / shuguang replica series we6sn7 pairs in the coming weeks.
 
Currently for pairs I have Sophia 6sn7 and 6sl7 / NOS "bad boy" 6sn7 / melz 5 hole anode 6sn7 / iha-1 stock raytheon 
 
I'll do a write up for all of my pairs, when I get my order from China. 

How it compared to the ZDS and stratus?


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I guess my memory of stratus is too old to really give specifics. I'll only say, it didn't personally blow me away like my Dennis Had fire-bottle did (and this why I bought iha-1). 
I only heard ZDS at a meet, so I'm giving only the aspects that really differentiate the two. 
 
ZDS is a dryer amp, in that it doesn't sound very tubey, almost thin... It's not a great pairing with hd800.
ZDS has much greater soundstage than iha-1, and that's not a knock on iha-1. ZDS soundstage is almost unnaturally big. Very airy!
 
iha-1 wins in microdetail (resolution), it has a more wet sound, instruments have weight and a liquid sense to them. Although, being liquid doesn't smooth anything out, it's still tac sharp.
I'd say it has above average soundstage, just shows how crazy ZDS is in that area. Iha-1 is a great pairing with hd800 / hd650, obviously not enough power for something like my he6.
 
For my personal tastes, and being an hd800 lover, the iha-1 is the no contest winner in my book.
 
Oh, and if you like tube rolling, iha-1 is better than ZDS in that regard.

 

[jelt2359]

Does yours have the lundahl input trafos?

 

[N15M0]

I see. Looks like the IHA-1 is a better choice. What about wa22? Have you tried the wa22?


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[comzee]

Does yours have the lundahl input trafos?

Yes, and the preamp, which I've been testing with the fire-bottle. 
 
Dennis makes a dedicated preamp, but spendy ($1600), I'm interested how the iha-1 compares to that... pretty different designs too. I know from my initial testing, I prefer my passive preamp (Axiom II). I guess this makes sense, tube preamping a tube amp is double warm, might be liking to some, but too much for me.
 
Also, the iha-1 isn't the end all be all, but I think it's one of the best $2k'ish amps out there, fantastic price v.s. performance. 
It does lack a bit of impact and dynamics, only in comparison to top deck amps.
 
I feel like I could be harsh tho, because I've heard so many good amps. In the general cesspool which is hifi products, the iha-1 is glimmer of light. Imo, it would be staggeringly hard to obtain a better sounding amp then iha-1 for under $3k, and it outperforms most of the junk out there regardless of price. It's unfortunate it has almost no exposure in the general hifi market.

 

[Xcalibur255]

They command pretty absurd prices, but if you can swing a pair of the black glass round plate Tung Sol 6SN7GT they sound better in this amp than in any other amp I've run a 6SN7 in.  Beautifully 3-dimensional and excellent tone from top to bottom.
 
The Sylvania "bad boy" GT from '52 is a nice sounding tube too.  It's rather overtly romantic sounding in the IHA-1 if you like that kind of thing.  But it doesn't make a bad showing for itself on technicals and is very easy to listen to.
 
I've found the rectifier choice to be very important for this amp.  Going for maximum transparency on rectifier side and then tuning the tone to your preference using the output tubes seems to be the best play for this amp.  The British made 5R4GY tubes are my personal favorites.  I really wanted to like the 5Y3, which is the rectifier the amp is designed for, but other rectifier tubes simply make the amp perform better IMO.  I have lovely little NOS 5Y3 from the late 40's with the older 5U4 style plates and hung filaments but it's just a decoration because the 5R4 tubes just sound way better.

 

[comzee]

 
I've found the rectifier choice to be very important for this amp.

I'm liking 274b currently, I had owned a 5r4gy, might have to buy another to try. 
I also have gz34/5u4/5y3/5v4, I've only tried 5y3/274b/5u4 so far. 
 
 
My fire-bottle uses a 6sn7 for the single input tube, so I've been rolling those for awhile now.
I own these 

Spoiler: tubes

as far as NOS goes. To my liking, the Psvane cv181 treasure mkii grey bottle is superior to any of those by a good margin. I'll see if the same is true for iha-1 once I get my order of psvane and shuguang pairs. might just be ymmv

 

[Xcalibur255]

I have yet to find a 6SN7 that sounds bad in the amp.  Some sound better than others, but never bad.  Rectifiers, on the other hand, it's possible to strike out I found.  Maybe there was something wrong with my particular example but I thought the 5V4G made the Inspire sound pretty awful, almost shockingly so.  5U4Gs are just kind of vanilla.  Nothing wrong but they don't bring the potential out of the amp.
 
I used to have an Emission Labs 274B meshplate, now sold (for a time I had no amp that could use it).  I kind of wish I could have it back now to see what it would have sounded like in the Inspire.
 
5R4 tubes are usually a good go-to if you want to make an amp sound more laid-back, but in the Inspire they're really balanced and open.  They also bring out the best level of resolution of any of the tubes I tried, but I have to admit my collection of compatible rectifiers is limited and not what it once was so my sample size here is small.

 

[jelt2359]

I love my 6sn7w sylvania tall bottle metal base with this amp. At least pre lundahl. Post, who knows!

 

[drubrew]

For rectification, we recommend 5Y3, 5U4 and 5R4 along with the 274B.  Oh, and don’t forget about a 5AR4 as well. We had some issues with quality control of the Sophia Princes 274B so stop offering, but no doubt the Emissions Labs should be wonderful. I have used their 300Bs but not 274B yet. Thank you for the reminder as I plan to get one for my unit.

 

[Xcalibur255]

I love my 6sn7w sylvania tall bottle metal base with this amp. At least pre lundahl. Post, who knows!

 
I've come close to buying a pair of these, but since I had the BGRP TS I couldn't justify the prices since it would likely be a side-grade.

 

[comzee]

@Xcalibur255 I took your advice, and purchased some rectifiers. 
NOS RCA JAN CRC 5r4gy (I guess super rare + good 5r4 ?)
NOS RCA 5r4gy ST shape (maybe the most common 5r4gy NOS variant)
GE 5r4gya (visually looks like a 5u4, not ST shape)
 
I also picked up a Bendix 6106 (5y3).
 
I just got my shipment in of 6sn7 pairs, and also my psvane 274B.
I now have three types of 274B, Sophia mesh / Preferred Series / Psvane.
 
Along with my various 5u4/gz34 I'm liking my NOS 5y3 the best. 
 
It seems the iha-1 likes rectifiers with high DCV drop. From my perspective, 5u4 and above start blowing out details.
This is initial impressions, I have many more hours of listening to get definitive info.
 
 
EDIT:
 

Spoiler: Quick pic of IHA-1 we6sn7 + 274b

 

[Xcalibur255]

I think the European 5R4 tubes are substantially better than the US made ones personally.  Upscale Audio is still selling their NOS Philips 5R4GYS tubes, which is what I run in my IHA-1 currently.  They're pretty reasonably priced for what they are.  The Brimar 5R4GY with hanging filaments is also lovely sounding, very refined and open sounding but not boring.
 
The US tubes do sound different from a 5U4G.  The voltage drop is different for sure, but the B+ requirements of the IHA-1 are very modest so the differences shouldn't really be as pronounced as they can be in other amps.  Voltage drop is probably the biggest factor that makes different rectifiers sound different, but the drop is dependent on load.  6SN7 tubes draw 9mA of current per plate maximum which is nothing.  The higher the draw the more the voltage will sag/drop.  At the rated maximum a 5R4 has a lot of Vdrop, but in this specific amp the difference between it and a 5U4 tube is smaller because the tube has such an easy job to do.
 
I don't mean to discourage your new purchases of course.  They may sound lovely.  I haven't tried the US flavor 5R4s in the Inspire.  Some years back I thinned out my tube collection big time and kept only my favorites so while I have experience with a lot of different tubes I don't have that experience specifically with them in the Inspire since they're all long gone.

 

[comzee]

  I think the European 5R4 tubes are substantially better than the US made ones personally.  Upscale Audio is still selling their NOS Philips 5R4GYS tubes, which is what I run in my IHA-1 currently.  They're pretty reasonably priced for what they are.
 
I don't mean to discourage your new purchases of course.

Pretty spendy, more than those four other rectifiers combined, but I can't not know.
I have one on order, I'll know soon enough how they compare. 
 
Got my Bendix 6106 in today, immediately loving that.
 

Spoiler: Pic

 

[Xcalibur255]

Okay Drew I have a new OPT guess to throw out:  Sowter.

 

[sdwong]

Can someone share their experience of IHA-1 driving the Utopia? I have read in Soundstage review that this amp aren't suited for high sensitive HP and the Utopia is very sensitve!
 
Thanks.