Revisiting the TR-7

ricmon · « **on:** 7 Nov 2011, 06:59 pm »

Recently I got the tweak itch and decided to try some new tubes in the TR-7's phono stage. In short this turn out to be an futile effort as I have a very nice set of tubes in the thing all ready (I'll get to that latter). So back in go the current tubes. I forgot about all the time and research I put into getting the current set of tubes. Here's the thing, with the right tubes the TR-7 is still and out standing preamp. For any one looking for a really great bargain in a true Hi-end, musical sounding pre get a TR-7 and a pair of Telfunken ECC83/12AX7 for the phone section and a pair of Telefunken ECC801S/12AT/7 for the line stage and you will not be disappointed. This combination of design and execution are a testament to the staying power and understanding of the science of sound amplification and the obscurity of constantly changing out components to find the "next step" in audio nirvana. Because here we have the critical link of tube choice that move the TR-7 from the category of "the next thing to be upgraded" to "dam that thing still servers up the music in a BIG way.

Ric

avahifi · « **Reply #1 on:** 7 Nov 2011, 10:01 pm »

Thanks for the "revisit" to this fine hybrid preamplifier.

We do have a new major upgrade for any Transcendence SL or EC preamp built since 2002. It is the Ultra II upgrade.

This consists of new Exicon power mos-fets replacing all the existing Hitachi mos-fets on the audio boards, both phono and line along with circuit adjustments for their use as necessary. This makes a huge improvement in musicality.

The price is $300 for those without phono circuits or $500 for units with both line and phono circuits.

Regards,

Frank Van Alstine

mark funk · « **Reply #2 on:** 7 Nov 2011, 10:11 pm »

ricmon and anyone eles,
Save some money and get some Telefunken ECC81 and ECC83s. They sound the same, I have both. 801 and 803 and 802s last for 10,000 hours. They sound the same too me! Yes the T-7 is still a great pre, I am still running a T-5 (that is an all tube).

ricmon · « **Reply #3 on:** 8 Nov 2011, 02:04 am »

Frank, I'll have to check my invoice but I think my T-7 falls in that post 2002 group. If so whats the turn around time on the upgrade? Given the demand for the new amp.

thanks
Ric

budyog · « **Reply #4 on:** 8 Nov 2011, 03:05 am »

Speaking of the TR-7 & tubes, I have a TR-7 and a 350EXR-6?, I have no idea how long tubes can last, my luck, my friends and I will be having a

evening with the babes, well maybe not he babes

and poof, there goes a tube!

So maybe I would like to have a set of tubes on hand for each or replace them all soon.
What do I need and how many?
Thanks!

Lefty052347 · « **Reply #5 on:** 8 Nov 2011, 02:06 pm »

T-7 with phono:
2 12ax7 for phono
2 12at7 for line

350ex:
2 12at7

Regards,
Dean

aln · « **Reply #6 on:** 8 Nov 2011, 03:20 pm »

Does this upgrade work with the small chassis preamp's?

jmc207 · « **Reply #7 on:** 8 Nov 2011, 04:01 pm »

Quote from: aln on 8 Nov 2011, 03:20 pm

Does this upgrade work with the small chassis preamp's?

I'd like to know about this as well.

avahifi · « **Reply #8 on:** 8 Nov 2011, 04:09 pm »

"Does this upgrade work in the small chassis?"

Yes indeed it does. Dean just finished one here with both line and phono circuits and it works amazingly well. Another way to decide if your unit can be upgraded; count the number of mos-fets in each location.

Our oldest hybrid designs had two very close to each other. These had either green or black bodies with a metal tab protruding up on top - - basically a TO-220 case device. If your unit has a total of four of these devices per function, phono and or line, in pairs of two, then we could upgrade it, but it would probably not be cost effective as the labor costs would be a whole lot more.

The units with only one TO-220 Hitachi device near each tube are the ones we can work on economically.

The results are really very special.

Best regards,

Frank Van Alstine

budyog · « **Reply #9 on:** 8 Nov 2011, 10:24 pm »

Quote from: Lefty052347 on 8 Nov 2011, 02:06 pm

T-7 with phono:
2 12ax7 for phono
2 12at7 for line

350ex:
2 12at7

Regards,
Dean

If I do not use the "phono" in the TR-7, do I have to replace those tubes? What if I put high quality tubes in the "line" and lower quality tubes in the "phono"?

Tom Alverson · « **Reply #10 on:** 9 Nov 2011, 12:39 am »

Quote from: budyog on 8 Nov 2011, 10:24 pm

If I do not use the "phono" in the TR-7, do I have to replace those tubes? What if I put high quality tubes in the "line" and lower quality tubes in the "phono"?

If you don't use the Phono stage there is no reason to replace them. I would not remove them and operate the preamp without any phono tubes as this would cause higher than normal voltages on the phono board.

As for tube life, some very old tubes (40-50 year old tubes) still perform like new. I have seen chinese tubes get very weak after about 15 years of operation.

budyog · « **Reply #11 on:** 9 Nov 2011, 01:11 am »

Mt tubes in my TR-7 are original from 9/15/03 and my 350EXR 1/16/05, maybe they will last longer than me!

ricmon · « **Reply #12 on:** 17 Nov 2011, 06:50 pm »

Frank I shipped out the TR-7 today. I look forward to the upgrade.

Ric

coke · « **Reply #13 on:** 17 Nov 2011, 09:33 pm »

Quote from: ricmon on 17 Nov 2011, 06:50 pm

Frank I shipped out the TR-7 today. I look forward to the upgrade.

Ric

I noticed a nice improvement when he upgraded my ultra preamp to the ultra II. I haven't heard a TR-7 but i'm sure you'll like what you hear.

rcag_ils · « **Reply #14 on:** 17 Nov 2011, 11:47 pm »

Like I said before, I've lost track, I've never heard of a TR-7, I've heard of a T-7, the only TR-7 I know is a small British car.

What are the upgrade, I know that for the Amp, there are the "R" upgrade, Ultra preamp, there's the "+" upgrade, what about the Ultra DAC, is there an upgrade for that other than the DIY chip that came out awhile back?

Lefty052347 · « **Reply #15 on:** 18 Nov 2011, 12:21 am »

The Transcendence Seven is a hybrid pre-amp and pre-dates the Ultra. We can update the unit using the same Exicon 10P20 mosfet as we use in the Ultra II, with similar results. The upgrade works well with any of the tubes found in the various models.

Regards,
Dean

ricmon · « **Reply #16 on:** 13 Dec 2011, 04:05 am »

Hey Frank I got the TR-7 back. Well it's a nice step forward. All I can say at this point is that I'm going through the vinyl collection and enjoying the upgrade quite a bit. In a nut shell things are more flushed out, a slightly more real sound stage and more focus. One question. Where the Mos-Fet's upgraded in the line and phone section or just the line section?

thanks
Ric

avahifi · « **Reply #17 on:** 13 Dec 2011, 10:17 pm »

The Exicon mos-fet upgrade was done to both your line and phono sections.

I am glad you are happy with the upgrade.

Frank

ricmon · « **Reply #18 on:** 21 Dec 2011, 06:18 pm »

After listing to my “upgraded” TR-7 preamp I must say that it is very different sounding then the original. Now the sound field is more focused and I can follow the musician's performance (note articulation and technique) more closely. However this new sound does not suite me. To my ears what made the TR-7 such a unique product in it's price niche was it musicality. Mind you the sound field is much more focused and resolution is equally improved. But now it's more sterile and thin. No more meat on the bone so to speak. Gone is that wonderful “tube bloom”. To my humble ears it appears that the harmonics have changes. The sound does not provide the same emotional something. In closing I have seen this before. A well known reviewer had a similar response to the Aesthetix preamps, preferring the standard model over the SE for similar reasons. Maybe I'll try some Valvol tubes since they should have more bloom which is the sound I prefer. All this being very subjective of course.

Ric

avahifi · « **Reply #19 on:** 21 Dec 2011, 11:39 pm »

Ric, which tube type and brand do you have in your Ultra II preamp?

Frank