Check traces to see if there’s any short circuit cause tweezers Pashka. Also check your soldering. Btw components that’s been replaced, comfirm pin outs are the same as originals.
Btw D601 did you check that its only functioning 1 way only with DVM. easuring resistance is not the correct way for zener diodes.
Btw D601 did you check that its only functioning 1 way only with DVM. easuring resistance is not the correct way for zener diodes.
The broken amplifier did not touch yet. Changed one capacitor uf C633 in the power amplifier MF, put Panasonic of FC. The sharpness and all charm of KZ disappeared. Panasonic sounds neutrally. Need time for Panasonic has to burn through but the difference is heard at once. The C603 capacitor seems to me has the greatest influence on a sound than other condensers as well as changes in the crossover is minimum. I do not understand the scheme that occurs, but here obviously the capacitor is involved as feedback and all sense of a sound in this piece. Also P635/636 resistors influence strongly. Likely it as that is calculated, there is no wish that the phase was turned or other negative changes happened, but on the scheme of the LF amplifier resistors 605/606 same as on MF of amp there are others. Attached the schematic On R605 amp MF the 620th, R606 the 560ohm On R635 Amp LF 1.5K ohm, R636 1.5Kohm
I removed on LF of the amplifier feedback the resistor R614 long ago, the sound on LF became with bigger information less pressed down. It is more than reality.
I want to understand that as well as that it is better to change to a sound to the best on this site of feedback schematic . As as influences and changes a sound changing resistors and capacity of the capacitor in this feedback. There are any ideas?
Do you mean increased capacity UF on LF amp ?
It is interesting whether it is possible to mix Panasonic in parallel with KZ.
With KZ the guitar sounds just super, all string instruments, the only thing sticks out bad top of mid frequencies. On the record Etypejazz - You Are the Sunshine of My Life (Album reference vocal) studio defect at the beginning heard noise of microphone with KZ distinctly, with Panasonic noise was gone.
I removed on LF of the amplifier feedback the resistor R614 long ago, the sound on LF became with bigger information less pressed down. It is more than reality.
I want to understand that as well as that it is better to change to a sound to the best on this site of feedback schematic . As as influences and changes a sound changing resistors and capacity of the capacitor in this feedback. There are any ideas?
Thanks for participation and interest. If not you I talk to yourself here>
Do you mean increased capacity UF on LF amp ?
It is interesting whether it is possible to mix Panasonic in parallel with KZ.
With KZ the guitar sounds just super, all string instruments, the only thing sticks out bad top of mid frequencies. On the record Etypejazz - You Are the Sunshine of My Life (Album reference vocal) studio defect at the beginning heard noise of microphone with KZ distinctly, with Panasonic noise was gone.
Attachments
Well, 10 dB louder at least.
With R614: Gv = 1 + (1k5||1k8)/39 ~= 22.0 dB
Without R614: Gv = 1 + 1k5/39 ~= 32.0 dB
*sigh*
Thanks sgrossklass this is very interesting .
What is 39 ? (With R614: Gv = 1 + (1k5||1k8)/39 ~= 22.0 dB
It is very interesting. But I noticed that the sound of LF changed not to much on loudness, without resistor feedback R614 began to sound corporally more, openly, with a big weight, more natural , realistic more bass. wight. All instrument have more body . Overall tonality ok
Connected back the R614 1.8kohm feedback resistor. The sound became with the cut-off bass, added power from LF crossover, the sounding not change , more compress then without R614 . I test how sounding one speaker without and with R614 . Big difference . On stereo then 2 speakers without R614 sound full and complete .
Yes sound LF speakers with KZ play looks like less information coming thru this capacitor . Compress sound on bass , soft 50-60hz no information upper bass , and ultra low .
Right now I'm increase capacity on C603 LF amp , and MF amp C633 from 220uf to 1500uf with Panasonic FC .
I dont know what is changes electrical , but after test with feedback resistor this sounding perfect and realistic .
What is 39 ? (With R614: Gv = 1 + (1k5||1k8)/39 ~= 22.0 dB
It is very interesting. But I noticed that the sound of LF changed not to much on loudness, without resistor feedback R614 began to sound corporally more, openly, with a big weight, more natural , realistic more bass. wight. All instrument have more body . Overall tonality ok
Connected back the R614 1.8kohm feedback resistor. The sound became with the cut-off bass, added power from LF crossover, the sounding not change , more compress then without R614 . I test how sounding one speaker without and with R614 . Big difference . On stereo then 2 speakers without R614 sound full and complete .
Yes sound LF speakers with KZ play looks like less information coming thru this capacitor . Compress sound on bass , soft 50-60hz no information upper bass , and ultra low .
Right now I'm increase capacity on C603 LF amp , and MF amp C633 from 220uf to 1500uf with Panasonic FC .
I dont know what is changes electrical , but after test with feedback resistor this sounding perfect and realistic .
While you are trying caps, why not change the bootstrap cap also? It is the 47uF (C605@LF). Going higher capacitance theoretically will lower distortion (but with small capacitance you can get good quality cap).
BTW, 39 Ohm is the gain setting resistor (Rg). Feedback usually consists of two resistors (Rf=1k5 & Rg=39) and a cap (220uF). I have never used the extra feedback resistor (1k8@LF) with this topology. I expect it will make better control of the woofer but you don't seem to like it.
It will be interesting also to try different input transistor. The original BC157 is not good.
BTW, 39 Ohm is the gain setting resistor (Rg). Feedback usually consists of two resistors (Rf=1k5 & Rg=39) and a cap (220uF). I have never used the extra feedback resistor (1k8@LF) with this topology. I expect it will make better control of the woofer but you don't seem to like it.
It will be interesting also to try different input transistor. The original BC157 is not good.
Thanks for help and magic words: "bootstrap cap" I make research and funded a lot good info .
BC157 I can replays with BC557 or better transistor with very low noise BC560. What you things ??? All ready got it
I read on German website Braun , BC157 make a lot of problem . feedback resistor (1k8@LF) , today I make my last test with resistor and without , I can tell 200% this resistor make sound on LF very bad , like chip Hi-FI . I remove this resistor long time ego.
C605 / 47uf I replays with 220uf today , but not report here . Can I try higher capacity like 1500uf Pan FC ???
How much capacity best for C605 , C603 , C 601 ????
C606 I put 3300uf .
johnego what did you mean?
It is the 47uF (C605@LF). Going higher capacitance theoretically will lower distortion (but with small capacitance you can get good quality cap).
Thanks
notes for everybody :
NOW I TRY IMPROVE BRAUN LV1020 higher serial number 11500. THIS IS FIRST GENERATION . FROM serial number 11501 second Gen. Between this two generations, the same only amplifiers and PS, crossover was changed.
Right now sound much better . In the evening, at a small loudness I can hear also everything well as well as at a big loudness. Was gone fake surround effect (wide soundstage)of KZ which it . Images of instruments from each speakers separately are very well heard. It became much cleaner sound. Instruments kind of were better shown, began to sound more particularly with FC and more capacity power amp LF and MF . C
I had no many time to listen today many records, but the fact that now there is it much better than was.
Other problem was it a lot of mid bass (150 Hz) . All time I make correction with EQ . It can be problem with BC157 transistor. Tomorrow will see
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With LF amp, power supply is 59V, the transistor should be capable of handling such high voltage, candidate transistor should have specified Vceo at least 50V.
The only problem with BC157 is that it has Vceo=45V. It is not low noise and gain is low so the sound is not 'special'.
The original BC157 has current gain (hfe) of no more than 150. If you replace with high hfe device like BC560C (BC560B is lower hfe), it will be a 'different' design, tho without adjustment it might sound better.
All of the caps above (input cap, feedback cap, bootstrap) has something to do with LF roll-off. Higher capacitance will bring lower frequency roll-off. When you tweak them you want to hear the bass quality. If the capacitance is too high/big, there will be diminishing return, no more improvement. There could even be degradation due to lower quality cap (more reactance/inductance).
Bootstrap cap, usually is no more than 470uF. In your case, you don't need high value to drive the driver-transistor output. You just need to choose big enough capacitance to allow low LF roll-off. Your 220uF is already much bigger than the 'calculated/designed' 47uF. My prediction is that 1500uF could be worse but I don't know. If you have 220uF/100uF why not try those.
Input cap is 1uF for HF but 10uF for LF because you want lower LF roll-off with LF amp. Best value is (1) Big enough such that LF roll-off and thus phase is flat to as low frequency as possible. (2) Small enough so you can buy exotic cap with small size. (3) Not too big where cap performance starts to degrade.
The bootstrap cap is the 47uF one (C605 at the LF amp).
Bigger/higher capacitance (100uF, 220uF, 470uF) will improve LF theoretically, in term of low frequency roll-off. And probably steadier VAS current.
If you opt to use minimal capacitance, you can opt to buy non-elco type (MKP, etc) which is better than elco in general.
Nothing to do with input transistor. 150Hz is in the domain of room response and speaker design. Stuff the box with more foam if it is sealed and the bass is too boomy, otherwise just equalize like what you have done.
Thanks a lot, I’ll try.
I listened to music, and I understand between two channels a certain shift of a phase. As though the head was twisted to me. Pulled out amplifiers and compared between two amps what wrong, it turned out that on one capacitor LF ХО 10uf there was KZ, replays with KEMET. a stereo the picture became normal.
I forgot to replace one LF XO capacitor with old KAMET. KEMET 10uf 63v was recapped before i get this Braun. Interesting compare KEMET with MKP.
Yes sumotan I'm increase UF capacity but not with KZ , it work .
So why my first Id was add independent power PS for Lf and Mf amps.
KZ are very aggressive at Mid high frequencies (will not get rid even with EQ ), and spoils stage the smearing. KZ only in the amplifier for a guitar is good , perfect this KZ.
Listened to Panasonic, a neutral capacitor , even very neutral and good . Long could not understand time why everything sounds tonalno correctly but does not sound well. A conclusion a sounds dead , generally look like as from cheap stereo.
Now turned on in parallel Panasonic and Silmic II on amp MF. Let will be fried together. I don't have other Caps . I need get more info what next I need to buy .
Thanks .
Yesterday rechecked all details in not the working amplifier. Everything is OK. And in my head your words, "Is the orientation of T604/605 soldered back correctly Pashka ? ".
Now looked and saw that mixed two transistors in places. BD139/140. Now I will correct, it is sure that will work.
Sorry , I was wrong . still the same problem burning BD139/140 . Is it little bit crazy .
I listened to music, and I understand between two channels a certain shift of a phase. As though the head was twisted to me
. Pulled out amplifiers and compared between two amps what wrong, it turned out that on one capacitor LF ХО 10uf there was KZ, replays with KEMET. a stereo the picture became normal. I forgot to replace one LF XO capacitor with old KAMET. KEMET 10uf 63v was recapped before i get this Braun. Interesting compare KEMET with MKP.
Yes sumotan I'm increase UF capacity but not with KZ , it work .
So why my first Id was add independent power PS for Lf and Mf amps.
KZ are very aggressive at Mid high frequencies (will not get rid even with EQ ), and spoils stage the smearing. KZ only in the amplifier for a guitar is good , perfect this KZ.
Listened to Panasonic, a neutral capacitor , even very neutral and good . Long could not understand time why everything sounds tonalno correctly but does not sound well. A conclusion a sounds dead , generally look like as from cheap stereo.
Now turned on in parallel Panasonic and Silmic II on amp MF. Let will be fried together. I don't have other Caps . I need get more info what next I need to buy .
Thanks .
Yesterday rechecked all details in not the working amplifier. Everything is OK. And in my head your words, "Is the orientation of T604/605 soldered back correctly Pashka ? ".
Now looked and saw that mixed two transistors in places. BD139/140. Now I will correct, it is sure that will work.
Sorry , I was wrong . still the same problem burning BD139/140 . Is it little bit crazy .
I will write just remarks.
My main amplifier TRI AMPs before purchase was рecap in New York. I can tell with confidence this amp recap is a master of a sound.
Tried some KZ,FW, Panasonic FC, Silmic II capacitors .
KZ at all not for audio.
Silmik dim cuts all peaks, soft on bass , for full disclosure big loudness is necessary.
Any capacitors is the filter with an addiction badly to pass some frequencies.
I think that all tests of capacitors which are on the Internet this full delusion.
Listened long enough to different capacitors , SILMIC II with above the specified shortcomings the one of those which tried from many , not bed for audio.
Panasonic FC the dead sounding capacitor , I heard it even when put in parallel with other capacitor. Sounding is equal, without color but also without life, absolutely dead sound.
What I'm changed in my Braun :
In the crossover put old capacitors.....
Greater influence of capacitors on a sound in the amplifier but not in the crossover.
Crossover:
Left new WIMA MKS2 in in out coupling (It will be necessary to pick up from expensive something real good one)
Crossover:
put back KEMET old electrolytic capacitors . 10uf 63v
Power amplifier:
MF amplifier
2x 47uf 160v SECON Best of the best capacitor
220uf 63v Nichikon ???
LF amps of the 2x47uf 160v SECON
220v 63v Silmic II Give less mid bass bump .
HF AMP left a mix silmic II, FS KZ , XO cut frequency high and especially do not influence a sound. I'm not play a lot with HF testing capacitors , I will perhaps put old Chemi -Con so what before
SECON unique capacitor, open sound super sounds it is realistic.
Everything is learned in comparison.
If there is at anybody what ideas a capacitor I can try LF 220uf I will be grateful.
Interconnect cable also very strongly influence a sound.
If are test capacitors the interconnect cable has to be on the ball and is checked by time.
Where I can buy SECON the capacitors ?
In the photo blue capacitor is it Nichicon ? if yes that what type?
The sound returned to my stereo , the equalizer is switched off, the sound is balanced live, full presence. real good . I miss my best sound for this period of time and now coming back .
As earlier I wrote changes on my Braun :
preamp disconnected (T501/502), the signal is going straight to 3 crossovers through a coupling capacitor from DAC (50 ohms output)
The resistor R614 on LF the amplifier of feedback is switched also-off. (tried to connect, the sound degraded very strongly)
Tantalum coupling Capacitors Vs WIMA MKS2 (AMP board) look like sounding the same .
One amplifier from second set still not working .
Burning all time BD139/140 T604/605 .
Transistors output 2N3055 OK .
I don't know why . Stock .
Then I fix second set of amps , I w'll make video as show how different can be sounding the same amp.
//////
forgot , I make small changes in XO .
MF XO I make the same frequency cut like on new generation Braun ,
and on LF I change two 6db cuts on the same frequency , before low cut was 187hz +340hz , now both around 340hz .
My main amplifier TRI AMPs before purchase was рecap in New York. I can tell with confidence this amp recap is a master of a sound.
Tried some KZ,FW, Panasonic FC, Silmic II capacitors .
KZ at all not for audio.
Silmik dim cuts all peaks, soft on bass , for full disclosure big loudness is necessary.
Any capacitors is the filter with an addiction badly to pass some frequencies.
I think that all tests of capacitors which are on the Internet this full delusion.
Listened long enough to different capacitors , SILMIC II with above the specified shortcomings the one of those which tried from many , not bed for audio.
Panasonic FC the dead sounding capacitor , I heard it even when put in parallel with other capacitor. Sounding is equal, without color but also without life, absolutely dead sound.
What I'm changed in my Braun :
In the crossover put old capacitors.....
Greater influence of capacitors on a sound in the amplifier but not in the crossover.
Crossover:
Left new WIMA MKS2 in in out coupling (It will be necessary to pick up from expensive something real good one)
Crossover:
put back KEMET old electrolytic capacitors . 10uf 63v
Power amplifier:
MF amplifier
2x 47uf 160v SECON Best of the best capacitor
220uf 63v Nichikon ???
LF amps of the 2x47uf 160v SECON
220v 63v Silmic II Give less mid bass bump .
HF AMP left a mix silmic II, FS KZ , XO cut frequency high and especially do not influence a sound. I'm not play a lot with HF testing capacitors , I will perhaps put old Chemi -Con so what before
SECON unique capacitor, open sound super sounds it is realistic.
Everything is learned in comparison.
If there is at anybody what ideas a capacitor I can try LF 220uf I will be grateful.
Interconnect cable also very strongly influence a sound.
If are test capacitors the interconnect cable has to be on the ball and is checked by time.
Where I can buy SECON the capacitors ?
In the photo blue capacitor is it Nichicon ? if yes that what type?
The sound returned to my stereo , the equalizer is switched off, the sound is balanced live, full presence. real good . I miss my best sound for this period of time and now coming back .
As earlier I wrote changes on my Braun :
preamp disconnected (T501/502), the signal is going straight to 3 crossovers through a coupling capacitor from DAC (50 ohms output)
The resistor R614 on LF the amplifier of feedback is switched also-off. (tried to connect, the sound degraded very strongly)
Tantalum coupling Capacitors Vs WIMA MKS2 (AMP board) look like sounding the same .
One amplifier from second set still not working .
Burning all time BD139/140 T604/605 .
Transistors output 2N3055 OK .
I don't know why . Stock .
Then I fix second set of amps , I w'll make video as show how different can be sounding the same amp.
//////
forgot , I make small changes in XO .
MF XO I make the same frequency cut like on new generation Braun ,
and on LF I change two 6db cuts on the same frequency , before low cut was 187hz +340hz , now both around 340hz .
Attachments
Last edited:
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