Tube rolling in ModWright PS 36.5 - any thoughts?

rydenfan · « **Reply #60 on:** 20 May 2009, 07:32 pm »

You can absolutely use DR's in the 36.5 That is where I use mine

Philistine · « **Reply #61 on:** 21 May 2009, 12:54 pm »

Quote from: funkmonkey on 20 May 2009, 07:11 pm

Hey Phil, you can use the DRs in the 36.5 (or is that what you were implying?). Looking forward to hearing what you think of the 36.5.

Greg - thought you guys might find it ironic that the solution for dealing with spare 6H30DR's is to get a 36.5 to put them in! I've also got a few GZ34's around (including a metal base) but will jump in with both feet and have already ordered an EML from George. So, a big thanks to all the pioneers on the 36.5 tube rolling.
Phil

AB · « **Reply #62 on:** 12 Jun 2009, 10:28 pm »

Now that we have pic uploading abilities restored...

Pics of my 36.5's new holes.

Delrin Inserts

Still haven't tried the EMLs yet. I think I'll finally get to this this week.

ted_b · « **Reply #63 on:** 12 Jun 2009, 11:24 pm »

I had my MW Denon 3910 Platinum in for some updating this past week and sent my PS 36.5 lid along to be "EML'd". I should get it back next week.

Philistine · « **Reply #64 on:** 12 Jun 2009, 11:33 pm »

That looks cool AB.

I received my EML for the 36.5 yesterday, it's warming up as we speak.

I was going to take a look at the perspex route, a nice blue transparent sheet - it looks to be an expensive option though. I'm going to reconsider just drilling a hole as you did.

DTB300 · « **Reply #65 on:** 13 Jun 2009, 10:47 pm »

Quote from: AB on 12 Jun 2009, 10:28 pm

Now that we have pic uploading abilities restored...Pics of my 36.5's new holes.

How large - diameter - are the holes? You said you lined them with Delrin - why Delrin? Was anything else considered for the lining? Thanks.

AB · « **Reply #66 on:** 14 Jun 2009, 02:21 pm »

Quote from: DTB300 on 13 Jun 2009, 10:47 pm

Quote from: AB on 12 Jun 2009, 10:28 pm
Now that we have pic uploading abilities restored...Pics of my 36.5's new holes.
How large - diameter - are the holes? You said you lined them with Delrin - why Delrin? Was anything else considered for the lining? Thanks.

The holes are 2 3/8". Dan recommended this size as anything larger would interfere/overlap with the chassis side extrusions.

Regarding the delrin inserts, originally I had no intention of adding them but with the standard 5AR4 tubes in place the holes really look too large - like there's been a mistake. I wanted something that would "clean up" the look of the larger holes. It's really not that bad but initially I was surprised by the look.

We choose the Delrin mostly because it's such a nice plastic to machine - and it was available. It may be that the inserts add a bit of dampening to the lid.

Delrin does not have a very high melting point so it can't get too close to the tubes.

AB · « **Reply #67 on:** 14 Jun 2009, 02:27 pm »

Quote from: Philistine on 12 Jun 2009, 11:33 pm

That looks cool AB.
I received my EML for the 36.5 yesterday, it's warming up as we speak.

I was going to take a look at the perspex route, a nice blue transparent sheet - it looks to be an expensive option though. I'm going to reconsider just drilling a hole as you did.

Quote from: ted_b on 12 Jun 2009, 11:24 pm

I had my MW Denon 3910 Platinum in for some updating this past week and sent my PS 36.5 lid along to be "EML'd". I should get it back next week.

Cool. Post pics!

I AM going to try the EMLs this week. Trying them requires moving the gear around and I am loath to do that.

Also...
I have the Herbies dampeners in place on the 5AR4 tubes now. The new holes helped there too. The dampeners wouldn't have fit with the old ones.

DTB300 · « **Reply #68 on:** 15 Jun 2009, 05:16 pm »

Quote from: AB on 14 Jun 2009, 02:21 pm

The holes are 2 3/8". Dan recommended this size as anything larger would interfere/overlap with the chassis side extrusions.

Thanks.

I guess I could have figured it out once I get an EML

Good to know what Dan suggested.

tomm · « **Reply #69 on:** 16 Jun 2009, 01:38 pm »

Dan,
My 36.5 has the PS board PS 9.0 VR V7.4. with all CAPS the same physical size. Is it the latest version for the unit and it will take the EML tube?
The 36.5 as is will take the 6SN7 tubes with an adapter?
Thanks.

modwright · « **Reply #70 on:** 16 Jun 2009, 02:52 pm »

No worries using the EML tube in the 36.5, either PS 36.5 or LS 36.5!

Thanks,

Dan

Eric · « **Reply #71 on:** 16 Jun 2009, 05:11 pm »

Quote from: ted_b on 12 Jun 2009, 11:24 pm

I had my MW Denon 3910 Platinum in for some updating this past week and sent my PS 36.5 lid along to be "EML'd". I should get it back next week.

Ted,

I have the same unit (3910). What updates are you having done?

ted_b · « **Reply #72 on:** 16 Jun 2009, 05:25 pm »

Just repairs to my specific unit...long time coming...my bad.

HumanMedia · « **Reply #73 on:** 18 Jun 2009, 03:14 am »

So for those who came in recently, the EML is the EML 5U4G-Mesh rectifier tube available from George at www.tubesusa.com

Is this correct?
And its the mesh variety as opposed to non-mesh?

ted_b · « **Reply #74 on:** 18 Jun 2009, 04:18 am »

Quote from: HumanMedia on 18 Jun 2009, 03:14 am

So for those who came in recently, the EML is the EML 5U4G-Mesh rectifier tube available from George at www.tubesusa.com

Is this correct?
And its the mesh variety as opposed to non-mesh?

You are correct, sir.

granosalis · « **Reply #75 on:** 15 Jan 2010, 05:00 pm »

AB, have you tried the EML?
could please someone explain how the sound will change from the NOS RCA included?

Thanks in advance.
Giuseppe

wilfredt · « **Reply #76 on:** 12 Mar 2010, 05:44 am »

I had recently purchased ModWright LS36.5 and PS36.5 and look forward to benefiting from the vast experience you all have in this forum.

While I really liked the soundstage and midrange of this preamp, I notice a loss of dynamics and PRAT "in my system" when compared against playing the CD direct into the amps.
Rest of my system is RA Opus 21 CD Player, Nuforce Ref9V3SE Amps and Dali MS5 amps and listen to CDs only.

LS 36.5 currently has the 6H30DRs and PS36.5 has the TungSol 5U4GBs. My questions are :

1. What other tube alternatives can be recommended to improve the dynamics, PRAT and punch ?
2. Is it important that both the 6H30DR pair and 5U4GBs need to be a matched pair ?

Any other recommendations also welcome.

Many thanks in advance
Wilfred

granosalis · « **Reply #77 on:** 12 Mar 2010, 01:44 pm »

Quote from: wilfredt on 12 Mar 2010, 05:44 am

I had recently purchased ModWright LS36.5 and PS36.5 and look forward to benefiting from the vast experience you all have in this forum.

While I really liked the soundstage and midrange of this preamp, I notice a loss of dynamics and PRAT "in my system" when compared against playing the CD direct into the amps.
Rest of my system is RA Opus 21 CD Player, Nuforce Ref9V3SE Amps and Dali MS5 amps and listen to CDs only.

LS 36.5 currently has the 6H30DRs and PS36.5 has the TungSol 5U4GBs. My questions are :

1. What other tube alternatives can be recommended to improve the dynamics, PRAT and punch ?
2. Is it important that both the 6H30DR pair and 5U4GBs need to be a matched pair ?

Any other recommendations also welcome.

Many thanks in advance
Wilfred

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

ted_b · « **Reply #78 on:** 12 Mar 2010, 03:07 pm »

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.

AB · « **Reply #79 on:** 12 Mar 2010, 04:04 pm »

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.