7c vs & 7t Listening testing. Which one Wins...

[jstang]

I don't know..... :scratch2:


Today I retubed the 7c with some NOS Sylvanias and then some NOS Telefunkens... Otherwise it is 100% stock and all voltages/caps check out fine.


The 7t is recapped and modified....

Dang its close... some pluses for each.


Stock worn cap 7t would not stand up to the test.


jk

 

[rab32chevell]

7c vs 7t listening testing. Which one wins

In what ways do they differ in sound quality? Is the 7t as open and airy as the 7c?

 

[jstang]

The 7t is recapped with Silmic IIs and film bypasses too. It has the edge in bass & highs definition. You can hear if the bass player bends a note...and the difference between a tambourine and cymbals....

7c has clean forward defined mids. The horns, strings and vocals are featured with greater detail.

jk

 

[JuanPabloCue]

7t price?

 

[rab32chevell]

7c vs 7t listening testing. Which one wins.

Here's hoping all you Marantz 7 owners are aware that when using a Marantz 7 with a solid state amp, you should modify them. The Marantz 500 has an input impedence of 33k so, the pre-amps will not function properly into that load. According to Saul Marantz : "If the pre-amp is used to drive 100k or less, there will be a loss in low bass response due to the relatively small value of the .22 microfarad output coupling cap from the cathode follower circuit. This can be increased by adding 1 microfarad, 100v mylars in parallel with it, resulting in better bass response. Example: if used to drive a 10k load, the pre-amp would result in a bass roll below 70hz where it would already be down 3db. The increased output capacitance would restore the response at low frequencies". This information from an early Absolute Sound letter to the editor about how to modify/update a Marantz 7. Since the 7t also has an output impedence of 100,000 ohms, I would assume this would also be true on the solid state unit. Just guessing. I would also assume other types of caps other than MYLAR could be used. It's my understanding that coupling caps make a big difference in sound so here may be a good place to splurge a little. He also says any leaky caps should be replaced with similar mylars or polycarbonate types and the small electolytics in the phono stage should be replaced preferably with tantalum types of the same value. I don't know if these cap type recommendations still holds true today since there are many new types of caps, but that was his choice back in the 1980s.

 

[jstang]

Might give that try...although I really don't feel the need to modify a C.. The gain control on the 500 does give some increase above the 33k as you turn down the gain.

The t can drive very low loads Without any roll off.

Jk

 

[onemug]

" Since the 7t also has an output impedence of 100,000 ohms"

I think you need to edit this.

 

[jstang]

Also, I added/changed some cap values and many other items on the 7t. It will remain my daily driver preamp. I really don't want to use the 7c every day nor modify it, strictly restore in a 100% stock fashion. It really only needed tubes and is mainly a hanger queen.... Modified units simple don't carry the same value as stickers in good shape with Telefunkens...

With that said I will temporally add a large good film to one channel on C and give it a try...longer range plan to is setup a Marantz tube amp second system that would be used Very sparingly. There are down sides to adding coupling cap value, besides the "Modification Snowball rolls down hill...and catches me up...."

I wish I could find a reasonable priced re-issue 7c....they were going for under 2k just a few years back, no more... The kid gloves would come off....and the "Modification Snowball" would roar gloriously.....

Jk

 

[jstang]

Yea that is not exactly the correct issue... That is a line matching / bleeding resistor...not the actual output impedance.

The 7t can drive headphone loads of 600 ohms or two ss Amps at the same time without losing feq response....

Adding some capacitance to the output coupling of a 7c is reasonable engineering approach to see the results...problem is, I never plan to use the C a lot and with the 500.

48 year old Stock C to 47 year old stock T.... The C would win.... Even with the 500. Modified 7t vs the stock retubed 7c with a 500..... Hmmmmmm.... Moded T with the 500 is hard to beat overal....

Jk

" Since the 7t also has an output impedence of 100,000 ohms"

I think you need to edit this.

 

[rab32chevell]

7c vs 7t listening testing, which one wins

" Since the 7t also has an output impedence of 100,000 ohms"

I think you need to edit this.

Maybe I should have said the 7t also likes to see 100k. I'm not very technically inclined. Hope this corrects my mistake.

 

[rab32chevell]

The 7t is recapped with Silmic IIs and film bypasses too. It has the edge in bass & highs definition. You can hear if the bass player bends a note...and the difference between a tambourine and cymbals....

7c has clean forward defined mids. The horns, strings and vocals are featured with greater detail.

jk

What about transparency and soundstaging. I would love to hear the difference between the 7c and 7t. I've owned at least a dozen 7cs and know them very well. My newly purchased 7t still hasn't been repaired so I have no idea of what I have and how good it can be properly restored with high quality parts.

 

[PB_Audio]

7t or 7/7C...
Its a virtual tie. Depends on the relative condition, including any mods that may be in operation, and the resulting synergy with the rest of your system, especially including your speaker systems and the listening room acoustics.
In the end, between these two, it comes down to a question of personal sonic taste, and that's a very subjective consideration... comparing the BEST of the BEST.
One consideration... if you play mostly CDs, which are, of course, a digital source, either a good DAC or a tube preamp, such as the Marantz Model 7 will help give that 'liquid' quality that some find so seductive in the midrange and upper midrange in particular, to your listening experience. That quality is virtually impossible to achieve when listening to a digital music source, on an all solid state system. A DAC will help, but even that is not quite the same, as many tube devotees will tell you.
I'll take the 7T based on cost alone. Both are that good. So, cost wins out for me, not to mention some degree of reliability issues associated with tubes and the older Model 7.

 

[onemug]

Yea that is not exactly the correct issue... That is a line matching / bleeding resistor...not the actual output impedance.

The 7t can drive headphone loads of 600 ohms or two ss Amps at the same time without losing feq response....

Adding some capacitance to the output coupling of a 7c is reasonable engineering approach to see the results...problem is, I never plan to use the C a lot and with the 500.

48 year old Stock C to 47 year old stock T.... The C would win.... Even with the 500. Modified 7t vs the stock retubed 7c with a 500..... Hmmmmmm.... Moded T with the 500 is hard to beat overal....

Jk

Question: If you had a completely stock 7t but it met or exceeded all specs and there were no issues with it....What would you modify to bring it up to the 7c?

 

[JuanPabloCue]

if anyone knows the replacement transistors of the 7t, please contribute here:.
Marantz Equivalent Part Numbers

 

[jstang]

Question: If you had a completely stock 7t but it met or exceeded all specs and there were no issues with it....What would you modify to bring it up to the 7c?

Lots of recapping and good old fashion hard electronics work.... I do so many small things and some not so small things it's hard to explain them and then people tell me thats non-sense....

Send it on an all exspense paid vacation to NJ....and I will pamper it.....


Jk

 

[jstang]

Well that kind of depends.... A modded 7t can be so clean, detailed, wide/flat in freq response and sound stage.... But the mid range of a C is such a thing of bueaty....

Keep in mind that a well set up 7t has an insanely low noise floor....


6 of one....half dozen of another. :scratch2:

Jk

What about transparency and soundstaging. I would love to hear the difference between the 7c and 7t. I've owned at least a dozen 7cs and know them very well. My newly purchased 7t still hasn't been repaired so I have no idea of what I have and how good it can be properly restored with high quality parts.

 

[rab32chevell]

7t or 7/7C...
Its a virtual tie. Depends on the relative condition, including any mods that may be in operation, and the resulting synergy with the rest of your system, especially including your speaker systems and the listening room acoustics.
In the end, between these two, it comes down to a question of personal sonic taste, and that's a very subjective consideration... comparing the BEST of the BEST.
One consideration... if you play mostly CDs, which are, of course, a digital source, either a good DAC or a tube preamp, such as the Marantz Model 7 will help give that 'liquid' quality that some find so seductive in the midrange and upper midrange in particular, to your listening experience. That quality is virtually impossible to achieve when listening to a digital music source, on an all solid state system. A DAC will help, but even that is not quite the same, as many tube devotees will tell you.
I'll take the 7T based on cost alone. Both are that good. So, cost wins out for me, not to mention some degree of reliability issues associated with tubes and the older Model 7.

PB, don't you own a Mark Levinson ML1? I'm hoping to get the kind of clairity, low distortion, inner definition, detail and focus out of the 7t that I get with my Levinson. I'm using my Levinson right now with my Marantz 15s. I really don't want to use the Levinson. I need the versatility of the Marantz 7t. Does the 7t get to that level?

 

[PB_Audio]

Funny you should ask... Since I moved from Chicage, over 20 years ago now, I've only breifly used the ML-1 in any system. I was burglarized 3 times back in Chicago, so unlike some on AK, I really don't like desplaying my stuff. What's not in use is literally kept 'out of sight'.
Now that I have a very aggressively refurbed and modded Marantz 7T, the Levinson will likely remain under wraps...(unless I find a Levinson Mk 3 Amp at a price I'm willing to pay... Pure Class A, and may even match my modded Marantz 500).
In any case, I feel that a properly prepared Marantz 7T preamp will not disappoint you compared to the ML-1. Both are extremely quiet and will provide all the detail, soundstage and punch you'll want to drive any world class amp. I even recently bought a second 7T to restore.
I definitely recommend the Marantz Model 7T, with one important reservation. When refurbing your Model 7T do not gloss over the details, if you want the best results.
Seems funny to have to even say that, especially when talking about equipment at that level; but some here still want to judge the character of a 35~40 year old piece of vintage audio genius with its original caps still in operation...
... go figure...

 

[rab32chevell]

Funny you should ask... Since I moved from Chicage, over 20 years ago now, I've only breifly used the ML-1 in any system. I was burglarized 3 times back in Chicago, so unlike some on AK, I really don't like desplaying my stuff. What's not in use is literally kept 'out of sight'.
Now that I have a very aggressively refurbed and modded Marantz 7T, the Levinson will likely remain under wraps...(unless I find a Levinson Mk 3 Amp at a price I'm willing to pay... Pure Class A, and may even match my modded Marantz 500).
In any case, I feel that a properly prepared Marantz 7T preamp will not disappoint you compared to the ML-1. Both are extremely quiet and will provide all the detail, soundstage and punch you'll want to drive any world class amp. I even recently bought a second 7T to restore.
I definitely recommend the Marantz Model 7T, with one important reservation. When refurbing your Model 7T do not gloss over the details, if you want the best results.
Seems funny to have to even say that, especially when talking about equipment at that level; but some here still want to judge the character of a 35~40 year old piece of vintage audio genius with its original caps still in operation...
... go figure...

You say "do not gloss over the details if you want the best results". I am a detail kind of guy and believe that the details are what seperates a good amp from a great amp. In the case of the Marantz 7t, what are the details you have discovered over the years in playing with the 7t that are not obvious like just replacing the caps?

 

[PB_Audio]

You say "do not gloss over the details if you want the best results". I am a detail kind of guy and believe that the details are what seperates a good amp from a great amp. In the case of the Marantz 7t, what are the details you have discovered over the years in playing with the 7t that are not obvious like just replacing the caps?

With my very limited tech experience, and that was mostly restoring Fender tube guitar combos over the last 30 years, it's all I can do to understand what my very talented tech, and EE of many years, explains to me when in the process of a serious restoration. I just sold this stuff through the mid 70s. Although, as store manager, I delt with the tech dept all the time. I took in all the repairs when I was in the store. So I had a lot of dialogue with the tech dept manager, who was also a friend. We talked about this stuff all the time. He was also an EE.
My personal Model 500 and 7T restorations were a mutual labor of love. Our goals just happen to perfectly align; and having experienced what he was able to accomplish with his own similar system, I had the confidence to just let him go for it. Which is exactly what he did. As good as my 500 was prior to the refurb, it is now virtually flawless, and yet Jk says there's still more that could be done.
With the Model 7T however, partly because John knew he was competing with my Mark Levinson ML-1, I suspect, it was no holds barred.
The recipe is all the regular improvements, including a very creative use of bypass caps where he felt the circuit would benefit. But all techs, it seems, like to maintain a few secrets. Here's a hint, specific to the Model 7T: think transistors and silver paste... When's the last time you heard mention of using silver paste?
Those familiar with the 7T will likely understand...
Many would call this needless overkill; but then, my 7T is virtually as quiet as the Levinson. The ML-1 achieves this with a completely separate housing for the power supply... just another example of over kill...
... OR, is it just good engineering??? There's your recipe.