There is two ways in improving the bass, change the Elect-Cap , currently you are using RIFA (330U) and BHC, Try to change the RIFA 330U to BHC, You can also change all 0.22U (WIma to other brand) and also change 2.2U to other brand. Personal, I do not like WIMA on tube amp as they will sound "thin" You can try auricap but I do suggest to change 2.2U to at least 3U. Since I only got the photo, it is only a guess and you should post the circuit.
I have attached the schematics for this Marantz 7C. Please take a look and give me some of your valuable advice.
This time, I am doing it for my colleague. He said he is willing to spend around HK$ 2K or so for the capacitors. So please advise him on what BRAND of caps he can use as well.
I know this schematics, I have done it for my friend but I have change the value as follows :
B+ is too low, M7 is running at +280V in order to sound good.
Add a 3.3K resistor per channel between B+ and R2
Change C3 to a larger value capacitor say 2u to 3U.
Try not to use WIMA, it sound terrible on tube amp.
There are a lot of Marantz 7 circuit but this one definitely is not a good one as B+ voltage is too run. +240V should just be the voltage for T1 before the load resistor.No wonder it sound bad without bass.
The value that i suggest to you is not marantz as the value use by Marantz is too small for modern capacitors. The schematic is based on Sid Smith 7.
Alfcat you must replace C1,2,3,7,8,11 0,22 uF for 0,33 or 0,47 uf and C14,15 2,2 uF for 4,7 uF or 10 uF. Use brands you used for the MHZS mod or if this is to expensive i like to use Clarity Caps SA serie.
I haven't seen this Clarity Cap before. The Marantz 7 is in the hands of my colleague now. He wants to buy it from me but asked me to help him solve the problem of "loosey" base. He wants more SOLID bass.
For the B+, yes, there is nothing you can do unless there is significant changes. I do not like DIYZONE's kit as they always change a lot and lost the original spirit. At the moment, you can change the caps and this will improve the tone and the bass. However, "好低音難求", sometimes, it is just a little bit of bass and cost you an arm and a leg.
You can use one EH 5751 goldpin tube,i like this tube because of his solid bass.
The 5751 has lower gain as the 12ax7( about 20% ), mostly this is not a problem. You get a better range of your volumepotmeter to.
Thanks for the advice. I wise 10 years from now, I could be as good as you are ... ha..ha...
For the time being, we can only stick to KITs .... and learn by trial & error.
I took your advice and changed the Caps inside the Matisse to Auricap. Indeed, they sound VERY different. The Matisse now is much much better and natural. Just run it for around 5 hours and both me and my wife are very satisfied.
Enclosed is the photo of the Matisse after changing to Auricaps.
Since you are already using RMG (or RMA?), It will sound very good if you are using the right caps. You next upgrade will proper cost you more as the elec-caps are worth upgrading but it is really expensive as you can only upgrade to BHC or Blackgate.
Oh, BTW, Auricap needs about 50-100 hours run in before really give the best performance....
The last tube is a cathay follower ( 陰極輸出), The original design is that it should work at 280V, the two tubes in front, it is design to work at lower voltage (240V), so the 3.3K resistor is to reduce the operating voltage from 280V to 240V.
Dear Cat Sir and Accphoto,
Your Matisse is Reference or Fantasy ? What are the sound performance different from Reference and Fantasy ? Which one is better ?
Do you have the schematics ? If yes, would you post it for my reference .
Thank you very much .
This one is reference as using 2 tubes, Fantasy is using 4 tubes but each tubes are run in parallel . If you look at the circuit, they are essential the same but two tubes in parallel means more problem on matching the tube. So I think reference sound better. For circuit, you should search the forum as it was posted before.
Alfcat, this problem i had also. I just send a email with the parts i needed and ask for the amount i must pay to them inclusive the shipmentcost and paymentconditions. If you still have problems contact me. I can phone them and place your order.
Dear CAT,
Shit, I must quote you the wrong number, It should be C2 which will affect most, it should be 3U, The Sid Smith circuit has corresponding value as follows :
C3 & C11 0.33u 400V
C1 & C7 0.33u 400V
C2 & C8 2-3U 400V
C14 & C15 3.3U 200V
Since you are trial without knowing the result, I suggest that you go for Aruircap first. I still have reservation on the power supply.
C14 & C15 is also important, i suggest that you should change it too.
Jensen is certainly good but it will be quite expensive as for a trial.
You need to change both as it is for left and right channel.
I changed all the caps of the Marantz 7C as the first trial. However, the Marantz 7 had been gone for too long and I can't exactly recall HOW it sound.
After upgrading, I "think" it gets closer to the Matisse but the Matisse seems to be a bit better. Unfortunately, my colleague is tooooo eager to get it back and I haven't got the chance to really compare the two.
I also changed the Volume switch as he doesn't like the Ladder one and I installed a TKD selector for him as well.
My colleague is now using the Marantz 7C but he said the Auricaps haven't yet run in. The sound is a bit dull for the time being.
I also changed some capacitors of my Antique Sound Lab amplifier. Will post the photos here later for sharing. However, the improvement is NOT good as expected. Maybe you can give me some advice as well.
What do you think about the "ladder" volume I DIYed? Assuming that there is NO cold soldering, is that a good one? For this type of Ladder Volume control, what makes it good? The design? The materials? I got the thing from DIY zone.
The problem with that Ladder volume control is, it is step by step. Turn to step 4 is too low the volume, turn to step 5 it is too loud .... There are 24 steps, I never use more than 5 .... just don't know what is the use of the rest ....
Ladder volume is certainly better than other volume as the sound signal only pass through one resistor. However, the type of resistor had significant influrence in the sound, normally , the best sounding resistor is RMG, than Holco, than Dale . AB had too much noise and is not suitable for such application. If you find the step is too loud, actually, you can modified the value of the resistor in the first few steps so that it suit you needs.Other volume like ALPS using carbon film, the sound is ok but in terms of music definition, those ladder volume will definitely win. One of the reason why Matisse sound so good is its volume is made of a pair of Holco Ladder Volume. the others are BHC caps .
The one I DIYed has 4 layers. Two Rin and Two Rg. That means the signal will go through TWO resistors for each channel, right?
So if I increase the Ohm value of the resistors, the sound will be lowered. Am I correct? If my logic is right, I should have the value (ohms) of the steps narrowed if I want small increment steps by steps.
Actually, one resistor is on the signal path and one resistor to the ground. Change the value of the resistor to the ground (Rg) in the daigram will affect the loudiness of the sound. The below web will certainly help you
I see. I will try to get some DALE resistors and change the values of probably third to six / seven stages.
The one from DIYzone has small holes. I think it is not very possible to use RMG resistors as their leads are quite thick.
Still waiting for the Matisse and the ASL amp to get to their Normal stage after changing the caps.
Too busy helping my daughter to prepare for her exam yesterday and no chance to post neither photos or schematics of the amp. Really would like to seek your advice on whether I replaced the right materials inside the ASL amp.
If u step volume control, u can actually save cost by using very good resistor (e.g RMG or tantalum resistor) at the range you often use. then other range use cheap resistor.
Or u can use different brand of resistor so that can enjoy different type of sound....
I managed to get the Antique Sound Labs 6L6 Mono Block Schematics and post it here. Hope that you can give me some advice on upgrading it.
Following another link by an American, I upgraded TWO capacitors as indicated in the photo. The person used Moundorg Supreme Gold / Silver but I used Jensen same value 0.22uf / 650V. I also changed the other one to an Auricap as the original one is a bit cheap.
For resistors R5 & R6 (I guess), that person used DALE / Vishay but I used RMG with same value.
Basically, i hatre those Japanese Electic-cap, If you really want a firm base, you should consider to upgrade those elect caps to black gate C1 and C2. If you do not want to spent a lot of money, consider Jensen elect caps. C9 is also important as it is for the -Ve, consider blackgate as this will not too expensive. The circuit is so small that i cannot really read. The feedback resistor (R11 or 13??? ) is also important, suggest to change to RMG 2W.
Thanks for your ultra fast response. I am not sure whether this is my 心理 problem or what ... the whole system does NOT sound as good as before after changing the caps.
I have thought of two possibilities: ONE, of course, is the capacitors need time to run in. I just run them in for 20 hours or less.
Second, a Mis-Match or need to upgrade some other components to match those newly installed.
I will seriously consider your suggestion and will enlarge the Schematics later today when I got home.
In my feeling, changing the resistors are better than caps.
i just replaced a lot of the resistors of dac and sound parts in my mhzs cd33.
sound become clear and solid.
low costs and got high gain.
I attached here a better schematics of the ASL AV-25. Hope this can help. I really would like to upgrade this Amp as I "think" this is a good amplifier at this price of HK$ 3K only.
[複製鏈接]
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