[wilfredt]

Hello Wilfred,
I have same setup with LS/PS combo. I have updated the 6H30 with the DR version, and the RCAs with Mullard GZ34 Fat base. There was a great improvement from the factory tubes, especially the Mullards. But more than tubes, the LS/PS combo needs LOTS of break-in time to express his full potential. And I have to tanks AB for his precious suggestions.
Just to share with you my experience.
Initially I was very excited about the two box unit, but when I have connected my Bel Canto CD2 directly to the KWA 150 the sound was more transparent and brilliant. At that time the unit was about 200/250 hours. You can understand my surprise and my … sadness.   
So I started rolling tubes; but in the meantime the unit was breaking in very well. A month after I had for an audition the Bel Canto DAC3VB with Virtual Battery module. This unit is far away better than the CD2 alone, not only from a sound quality point of view, but also from his enhanced driving capabilities. At the end of the audition my friend (he is a dealer also) ask me to bypass the preamp and go directly to power amp. Well, I was scared, also because I had no more excuses like tubes, break-in, etc., but I accepted.
The music starts, and only a few seconds was enough (for both my friend and me) to clearly classifies the sound as less natural, less sweet and with reduced dynamics and soundstage.
We put again the LS/PS in the loop and all was back again into the right place. At the end of the day my friend, with a very fair statement, said that it was the first time he “fails” on this test.     
For sure, the synergy between the KWA150 and the LS/PS combo can be one of the reasons of this success, but I believe there is more.
Believe me, give the LS/PS combo the right time (and the right GZ34 tubes), and you will not be disappointed.   

Ciao
Giuseppe

Hello Giuseppe,

Thanks a lot for sharing your experience which is very similar to mine. I had the initial excitement and then disappointment when I compared CD direct into Amps. In fact, after few tests, I somehow concluded that there is some synergy mismatch with my Nuforce amps since everyone else were raving about the LS36.5. Hence I must admit I was a bit impatient and listed my units on Audiogon for sale ! Little did I know that these units had such a long break-in time !

Thank you for suggesting Mullard GZ34 Fat base. Are there any recommended sources for these tubes ? Pardon my ignorance, but this is just my second tube preamp and I have hardly done any tube rolling before...

Many thanks
Wilfred

[wilfredt]

Wilfredt,
it is not imperative that the rectifier tubes be true matched pairs due to the way Dan has the power supply set up, but they need to be of similar power output (and of course same model).  I swap TS 5U4GB's all the time with no real impact, but I had the tubes tested and know they are darn close.

Other than the dual EML's I agree that dual fat bases are real nice.  I found dual metal bases to be too much of a good thing, especially combined with the aggressive 6H30DR supertube signal tubes (too much of a midbass hump, like a "loudness" button was pushed).  Fat bases and DR's is very nice synergy in my system.

ted_b,

Thank you very much for your inputs.

My TS 5U4GBs have different numbers on them like 322RJ-3 and 322PR3. Could these possibly be different models ?

Going through this thread I understand that dual EMLs require larger holes on the chassis. How about the other fat bases - do they need larger holes too ? Which fat base models would you recommend ?

Also I am assuming that the main tubes - 6H30DRs they need to be truly matched pair, correct ?

Many thanks
Wilfred

[wilfredt]

Hi Wilfred,
It's been my experience that the 36.5+ requires somewhere between 300 and 500 hours of break in to sound its best. That seems like a crazy amount but I swear it's true. The sound really expands and deepens in every way as it breaks in and it is not subtle.
For me in my system the 5U4GB tubes are the smoothest and most polite option in the PSU. I have tried several versions of NOS GZ34 and all offer better PRAT than the TS 5U4GB. They tend to offer greater frequency extension too.
Which NOS GZ34 is best? Metal based tubes ( Philips) are pretty much considered the best, then the oldest non metal base Mullards then the Fat Black base tubes and then the 4 notch and then the 7 notch. Then there is the EML 5U4G mesh plate. Are the EMLs better than the Metal base? I think that depends on the system.
I also have played around with isolating the preamp ( not the PSU as much) from vibration. With the external PSU the preamp chassis is pretty much 1/2 empty. I noticed a nice improvement when I added some closed cell foam to the left, empty portion of the preamps chassis. I also suspended the chassis with some sorbathane hemispheres. This has been hit or miss and required a bit of experimentation to get the loading right but eventually I did get a nice improvement in focus this way.

Are you running balanced cables out to your amps? I noticed an improvement with balanced cables running into my balanced BAT amp.

My recommendation would be to look for some NOS GZ34 tubes and let the 36.5+ break in. 

Hi AB,

Thank you very much for your detailed response.

Thanks for telling me about the break in period. 300 to 500 hours break in is really looong! But I hope it is definitely worth the wait ! Dan had converted the PS36.5 from 110 to 230 volts transformers and hence I am assuming my break-in count is just starting now and I have a long way to go ! But good to know that system will improve over time.

Sorry, I am new to tubes - what are the 4 notch and 7 notch types ? Also what are some good sources for NOS tubes. Appreciate your inputs.

Glad you mentioned vibration control. I definitely noticed improvement once I placed them on Sistrum SP-101s; in fact my impression was that the PS36.5 had more impact than the LS36.5 itself, but I did not do detailed comparison to confirm this though. Did you add the closed cell foam inside the chassis ? I shall read more about sorbothane hemispheres also.

I always used Balanced cables for input and output as well. I also wanted to try RCA cables but couldn't try them yet.

I shall get into some tube rolling and let the units break-in in the meantime.

Thank you
Wilfred

[AB]

Hi AB,

Thank you very much for your detailed response.

Thanks for telling me about the break in period. 300 to 500 hours break in is really looong! But I hope it is definitely worth the wait ! Dan had converted the PS36.5 from 110 to 230 volts transformers and hence I am assuming my break-in count is just starting now and I have a long way to go ! But good to know that system will improve over time.

Sorry, I am new to tubes - what are the 4 notch and 7 notch types ? Also what are some good sources for NOS tubes. Appreciate your inputs.

Glad you mentioned vibration control. I definitely noticed improvement once I placed them on Sistrum SP-101s; in fact my impression was that the PS36.5 had more impact than the LS36.5 itself, but I did not do detailed comparison to confirm this though. Did you add the closed cell foam inside the chassis ? I shall read more about sorbothane hemispheres also.

I always used Balanced cables for input and output as well. I also wanted to try RCA cables but couldn't try them yet.

I shall get into some tube rolling and let the units break-in in the meantime.

Thank you
Wilfred

The 4 notch or 7 notch  describes the plate style of the Mullard GZ34 tubes and, generally, their vintage. When you start looking for these you'll see this (and batch dates) used to approximately date the tubes.

Good sources? Andy at Vintage Tube Services and Brent Jesse Recording. There are others but these guys are tops.

I did add the closed cell foam to the interior of the chassis - I cut a block of the stuff to fit in the gaping maw on the left where the PS would sit in the standard 36.5.

The standard GZ34 tubes will fit without any changes to the chassis.

Almost sold it on A'gon?! Yow. Give it some time and get yourself some NOS GZ34 tubes and you will shocked at how awesome the 36.5+ really is. There's not much out there that beats it at any price.

[wilfredt]

Thanks a lot for your great inputs.

I will start my hunt for some good NOS Mullard GZ34 tubes as recommended and NOW I understand the units really need some good time to break-in !

I am also wondering if any of you found whether power conditioning / power cords had any significant impact on the LS36.5+.

Thanks a lot to you all for giving me the confidence !

[granosalis]

Hello Giuseppe,
...

Thank you for suggesting Mullard GZ34 Fat base. Are there any recommended sources for these tubes ? Pardon my ignorance, but this is just my second tube preamp and I have hardly done any tube rolling before...

Many thanks
Wilfred

Hello Wilfred,
I got tubes on ebay. There are many other sources, just google for GZ34 "FAT BASE" 1958 - 1962 (f31 series).
Good search! 

[Waters95bj]

Looking for NOS tubes for my PS/LS36.5 ...

Like to get a pair of vintage 6H30-DR, I found it on tubestore.com for $400 a pair. Another source available on ebay for $225 a pair, s Russia seller, both claimed to be NOS before 1990. Given the price difference, I am not sure if there is better DR from all the NOS, any advice? I don't want to get a pair of fake DR for sure.

For Tung Sol 5U4GB, any specific mark or code to look for? If you have a reliable source of these tubes, please share with me, thank you very much.

[Philistine]

Here's a link to a reliable source of 6H30DR's $80 each:

http://www.partsconnexion.com/tube_nos_6h30.html

I have these in my 36.5, and a back up pair in reserve

[Waters95bj]

Thanks Philistine ... this is very helpful 

[Waters95bj]

Hi Philistine,
Just checked the web site, and found the tube. 

Is this the vintage tube before 1990 from REFLEKTOR? They did not specify ... 

[Philistine]

Good question - I would email them and ask.
You also might want to start a Want To Buy post here on AC - I'm sure a few MW Transporter owners have excess 6H30DR's they don't need, at one point in time, before the 6SN7 discovery, the 6H30DR was the optimum signal tube in the TP.

[Waters95bj]

good idea ... 

I have just sent an email to ask pcX, thanks.

[zeke]

I was wondering how important "matching" is to the 6H30 pair in the 36.5 ?


I see nothing about being able to buy a matched pair of these tubes from parts connection.

zeke

[Waters95bj]

Just got reply from Chris of pcX, the DR tubes are either 86 or 88

Any idea if 86 is better than 88, or just to ensure they are before 1992 production? 

[mikel51]

I think the deal is that they are old production for the military )(while still top secret and) before Sovtek retooled them into production to accommodate the popularity caused by BAT and other modern audio manufacturers. 

[Waters95bj]

I think the deal is that they are old production for the military )(while still top secret and) before Sovtek retooled them into production to accommodate the popularity caused by BAT and other modern audio manufacturers.

I see, so anything with a production date in the 80's should be the good sounding 6H30 DR tubes, right? Will there be fake vintage DR tubes in the market that need to watch out?   

[Waters95bj]

I was wondering how important "matching" is to the 6H30 pair in the 36.5 ?


I see nothing about being able to buy a matched pair of these tubes from parts connection.

zeke

Parts ConnecXion can provide matched pair, just specify this requirement in the comment section when going through the check out screens. Additional $5 will be added for selecting a matched pair for you. They are now having a 20% off sales, good time to buy. I just ordered a pair of DRs.

[edorr]

Guys, I just bought the 36.5 LS/PS combo and  I'm new to the tube rolling game. Apparently the tubes to get are Mullard Fat Base. Unfortuntaley they appear to be very rare and insanely priced as matched pairs. You can do a lot better buying two singles on eBay. Would there be any potential matching problems if I bought 2 singles from independent sellers?

[AB]

Apparently the tubes to get are Mullard Fat Base.

Maybe, maybe not. I replaced the Mullard Fat Black bases in my 36.5+ with a pair of strong testing NOS RCA 5U4GB. IMO they sound better than the Mullards. Well, at least the Mullards that were in there.
I sourced the 5U4GB tubes from Andy at Vintage Tube.

[Fork]

So far I've tried the RCA/Mullard GZ-34, Tungsol 5U4gb, RCA 5V4g and Synergy Hifi 5AR4.

The GZ-34 are labeled RCA, but they were actually made by Mullard.  These are rare, but not the extremely rare first version.  They're labeled F-32.  I've not been really taken with these in my system (First Watt F5, Druids, ASI cables, 36.5DM and Wyred DAC2).  They sound kind of plain jane.

The Tungsol 5u4gb are not that expensive and sound quite different from the others.  A lot more bass, but it's not as well controlled bass as the others, so it doesn't sound as tight.  Not my favorite in my system, but a change of pace from the others.

I've found the Synergy HiFi to be the best for me.  Full disclosure, I'm a dealer for the Synergy tubes, but I decided to use them myself, long before that.  They have a very even response throughout the frequency spectrum and are the best at detail retrieval, harmonics and ambient nuance.  Absolutely brilliant.

The Synergy are not that expensive at $160 per set, but for a really nice tube on a budget, the RCA 5v4g are similar in character and deliver 80% of the performance of the Synergy.  These can be found for $30-40 pair and are excellent for the money. 

Also, don't get caught up in whether the tubes are closely matched, as long as they're the same exact tube (meaning made by the same company, during the same period of time) and still strong, exact matching is not going to make them sound any better.