Looking into nad6300 and tandberg 3014 for inspiration for further mods I realised they both use 4052 and 4053 switches in thr signal path do they must be better than 4066.
Recording in a loop for hours...especially this for an entire hour in any possible setting:
I'm already thinking what to do with my 6 dolby S modules...where to hook them?
Inspired by the succes I had with the Denon I went to replace the belts on my Pioneer CT-S610.I wanted to listen to a recording made in dolby C with no component changed and I'm amazed by the little cxa1330 .The recording eq chip is a specialized one which I have in 3 different pioneer decks and to be honest, after 4 hours of continuous monitoring the rec function with or without dolby i can't find a weakness in it...
There's a thing that bothers me on this deck though.While on Denon with the new op amps I can't hear a differrence between monitoring the source or the tape, on stock Pioneer I hear higher noise from source than from tape when dolby is active.Which is good cause it means I can work on something 🙂
The most interesting thing is that I get lower by 2 ...3 db sound when listening a recorded tape than when monitoring it while recording ⁸which shows significant signal bleeding from rec to play section. Why is that interesting? Because this is what a real FX does, summing the input with some of the output....
Next thing should be my CT-777 to be put together cause it's utterly dismembered and I'm sure it would be a real pain in the a** to make it work again.It has the same transport as CT 610 AND shares the same BLE system, but I have a feeling i'll need to buy another ct 777 and use my bits and pieces as spare parts.
There's a thing that bothers me on this deck though.While on Denon with the new op amps I can't hear a differrence between monitoring the source or the tape, on stock Pioneer I hear higher noise from source than from tape when dolby is active.Which is good cause it means I can work on something 🙂
The most interesting thing is that I get lower by 2 ...3 db sound when listening a recorded tape than when monitoring it while recording ⁸which shows significant signal bleeding from rec to play section. Why is that interesting? Because this is what a real FX does, summing the input with some of the output....
Next thing should be my CT-777 to be put together cause it's utterly dismembered and I'm sure it would be a real pain in the a** to make it work again.It has the same transport as CT 610 AND shares the same BLE system, but I have a feeling i'll need to buy another ct 777 and use my bits and pieces as spare parts.
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Checking the motor drivers heat in the Pioneer CT-s610 made me think that maybe the drivers in Denon DRM 700A are ok...they're hot too.
Now the Pioneer is ready for renovation.I have analysed for a few good hours what can be done to improve it even further and I think there can still be done some good things about it.
Now the Pioneer is ready for renovation.I have analysed for a few good hours what can be done to improve it even further and I think there can still be done some good things about it.
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Finding the superior model of ct s610 in ct s830s gave me clear targets for modding and true motivation to spare nothing .So I know it's heresy to put Sanyo Oscons and Panasonic FC in such a slow equipment, but I couldn't help myself...
The headphones amp will be modified as in Yamaha kx990 as well, the transformer from CT777 might replace the actual transformer so that I get to build a ssfer regulation circuit for the 5 volts supply.
As i finished all the 10uf bipolar nichicon muse caps I started to use the 10u/50v Panasonic bipolars(black tall ones)...First mod day is over.
The headphones amp will be modified as in Yamaha kx990 as well, the transformer from CT777 might replace the actual transformer so that I get to build a ssfer regulation circuit for the 5 volts supply.
As i finished all the 10uf bipolar nichicon muse caps I started to use the 10u/50v Panasonic bipolars(black tall ones)...First mod day is over.
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On an even happier note I saw that the now defunct organ donor Pioneer CT-777 has identical motor drivers with my already moded Denon drm 700A so I can further investigate why Denon's reel driver works so hot.
Treating even the hx pro circuit and the bias trap with utmost respect as only the CT95 does, wiring the headphones amp as in Yamaha kx930, running separate grounds for signal and power in case the feedback fall to unity gain near clipping...replacing also the two 100uf decoupling caps to signal ground with only one from + to - rails ...just small things...that leaves me with two caps left to change on the display board and adding a new separate transformer for the +-8 V suplly which is an r-core and one more 12 V reg cause the +5V reg is simply put abused.I should shield that e+i transformer as in ct-777 but I'm seriously thinking of placing it out of the deck.
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I forgot to make the 20k log potentiometer into a 5k super log one...removed the monitor switch, going to replace it with a pan or bal potentiometer , add one more summing op-amp and pan between the direct signal and the played back signal.That's gonna make this deck a pure FX .
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The supply structure is wrong in the +5v regulator section as its input, unlike in better pioneers, is the same with the 12V reg input so a bit too much stress on the +5 reg and heatsink.Then the original unshielded power transformer which has 2 different outputs than lets say pioneer 777 transformer is also smaller and gets hot.
So I went mental and built a separate box where I split the power supply in 3 transformers : the main one that keeps the motors and lcd display supply , one for 5 v supply (r-core one) and one for the +-15 v regulator left in the box from the Transbridge box I scrapped last week and this new regulator is going to supply the deck's own +-6...8v regulator.Didn't measure it yet...some pioneers of that line has +-8, others +-6v for the analog processing side.
I wasn't thinking at the noise induced by the unshielded transformer inside the cassette deck as I did at a safety perspective and anyway.... maybe I'll use the unused space inside the deck left by the transformer removal to add a phono preamp to have a dedicated deck for vinyl tape duplication .Probably adding a power amp and a bigger transformer in the new power box might make this a complete system.
So I went mental and built a separate box where I split the power supply in 3 transformers : the main one that keeps the motors and lcd display supply , one for 5 v supply (r-core one) and one for the +-15 v regulator left in the box from the Transbridge box I scrapped last week and this new regulator is going to supply the deck's own +-6...8v regulator.Didn't measure it yet...some pioneers of that line has +-8, others +-6v for the analog processing side.
I wasn't thinking at the noise induced by the unshielded transformer inside the cassette deck as I did at a safety perspective and anyway.... maybe I'll use the unused space inside the deck left by the transformer removal to add a phono preamp to have a dedicated deck for vinyl tape duplication .Probably adding a power amp and a bigger transformer in the new power box might make this a complete system.
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Finally i could listen to the thing.When listening the recording in real time the Pioneer shows a bit more leakage between play and rec sections than the Denon and while the frequency range appear to be a bit more linear than in the Denon, i feel I need to shield the rec section from the play section to get a cleaner sound cause leakage in a three head system means delay over direct.All in all it sounds good, but using it as an effect in real time needs better separation between rec and play for maximum quality.I'm not sure if it's even possible if the leakage comes mainly from the tapeheads.A reel to reel can do it better having the tapeheads a few cm apart.
I removed the transformer from the deck to make some space for a phono preamp that will be placed inside so that I can use the machine to rip vinyl onto tape.
As I replaced all electrolitic caps in the dolby filter section with film and foil ones, the dolby is now more stable and I can work with dolby c on any type of music.
I removed the transformer from the deck to make some space for a phono preamp that will be placed inside so that I can use the machine to rip vinyl onto tape.
As I replaced all electrolitic caps in the dolby filter section with film and foil ones, the dolby is now more stable and I can work with dolby c on any type of music.
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Turned back to the headphones preamp and replaced njm4556 with opa2228 as I did in the Denon drm700 cause i have a gain of 6.2 available.Also going to shield the playback preamp with a heatsink that will be connected to ground too.I hope it will not make the circuit unstable .This is Sparta:
