Latest King/Cello preamp
- Thread starter U47
- Start date
Good afternoon reel to reel enthusiasts,The latest King/Cello Pre Amp looks like a beautiful piece of electronics that extends the previous model. I note there is talk about low frequency bump in certain tape playback heads. Does anyone know if there has been any extensive research and which tape playback heads are the worse offenders? Finally, does the fact that a tape head pre amp which does not have a feature to control tape head low frequency bumps renders it outdated? This is interesting subject matter I hope someone has explored further. Thanks forum members for all imput.
jazzbo
Bruce B
WBF Founding Member, Pro Audio Production Member
jazzbo
So at what freq. are you going for? Nortronics, Flux, Studer, Ampex and all the others are different, so unless you have a parametric EQ with adjustable "Q", it's a crap shoot!
On my Ampex 350 I am using a Flux head designed for Bottlehead electronics with the King Cello preamp, I think it is on the darker side, maybe I would need EQ?
Or would it be easier to just get a new Head from Greg?
Or would it be easier to just get a new Head from Greg?
Bruce B
WBF Founding Member, Pro Audio Production Member
Have you run a sweep through it to see where the bump is? You're dealing with 3 brands, Ampex, Flux and Bottlehead. No telling where your curve is.
Good evening Mr. Brown,I believe my Tascam 42B has Nortronics tape heads. I've got to add that, although the tape heads are TEAC 53783023 i am wondering if they are really Nortronics with the TEAC name? At any rate they sound OK with the internal electronics. I'll have to see how it sounds with cables running directly from the playback heads. That will tell me a great deal. Thanks for your response.
jazzbo
Last edited:
Morning gentlemen,
The "new" K/C preamp pics that U47 posted are of a "one off" unit that I made for a customer in the Philippines. It is the original design in different clothing - what I refer to as the "Cello box". The only changes I've made throughout the "production run" of the pre are to bypass/eliminate the output capacitor and the type of one capacitor. The design won't change; I'm not capable of improving it and really don't think it has to be. It was originally unbalanced in and out and will remain so (tried balanced out and failed).
The VU meter panel was provided at the customer's request. Once you wire out a head you lose the capability of using the deck's built in meters. Problem with that concept is what size to make the enclosure - which kind of depends on / forces one to decide where you're going to put it. My latest two customers want it and we've agreed to try putting it in a box the same size as the pre itself. Found some really cute!!?? VU meters (only a few folks in the world make these anymore). Will post pics of the finished product. The panel helps provide some "focus" for those of us (including myself) who listen with our eyes.
Regarding head bumps - Nortronics published a "Design Guide" which discussed the various series of heads they built. Some quotes from that - "Premium heads.....pole tips are specially contoured to give smoother response for music reproduction plus thinner laminations for better high frequency response". "Studio series and PR professional series.....extra long pole pieces and window openings give extremely smooth and extended low frequency performance". The guide included some frequency response curves that illustrate the differences.
This got me thinking; we gotta get John French to join the forum. He is Mr. Tape Head; with the most knowledge and experience on the planet. Plus he's a swell guy.
Charles
The "new" K/C preamp pics that U47 posted are of a "one off" unit that I made for a customer in the Philippines. It is the original design in different clothing - what I refer to as the "Cello box". The only changes I've made throughout the "production run" of the pre are to bypass/eliminate the output capacitor and the type of one capacitor. The design won't change; I'm not capable of improving it and really don't think it has to be. It was originally unbalanced in and out and will remain so (tried balanced out and failed).
The VU meter panel was provided at the customer's request. Once you wire out a head you lose the capability of using the deck's built in meters. Problem with that concept is what size to make the enclosure - which kind of depends on / forces one to decide where you're going to put it. My latest two customers want it and we've agreed to try putting it in a box the same size as the pre itself. Found some really cute!!?? VU meters (only a few folks in the world make these anymore). Will post pics of the finished product. The panel helps provide some "focus" for those of us (including myself) who listen with our eyes.
Regarding head bumps - Nortronics published a "Design Guide" which discussed the various series of heads they built. Some quotes from that - "Premium heads.....pole tips are specially contoured to give smoother response for music reproduction plus thinner laminations for better high frequency response". "Studio series and PR professional series.....extra long pole pieces and window openings give extremely smooth and extended low frequency performance". The guide included some frequency response curves that illustrate the differences.
This got me thinking; we gotta get John French to join the forum. He is Mr. Tape Head; with the most knowledge and experience on the planet. Plus he's a swell guy.
Charles
Good morning all,
I think I am going to take the advice of an expert, Mr. Stellavox himself and not worry about tape head low frequency bumps. Why be concerned about something i've not heard yet. That's my view at this point. Thanks all.
jazzbo
I think I am going to take the advice of an expert, Mr. Stellavox himself and not worry about tape head low frequency bumps. Why be concerned about something i've not heard yet. That's my view at this point. Thanks all.
jazzbo
OK,
"2016 UPDATE TIME"- here is the "latest" "Swiss Army Knife" K/C preamp. A combination of features I made individually for a few customers and retrofitted to an early customer's tape pre.
RIAA and Variable phono (for those toying with 78's and early LP's) and NAB/IEC Tape.
Will see how the customer likes it! Includes the separate VU meter panel that plugs into (and derives power from ) the pre itself.
Charles
"2016 UPDATE TIME"- here is the "latest" "Swiss Army Knife" K/C preamp. A combination of features I made individually for a few customers and retrofitted to an early customer's tape pre.
RIAA and Variable phono (for those toying with 78's and early LP's) and NAB/IEC Tape.
Will see how the customer likes it! Includes the separate VU meter panel that plugs into (and derives power from ) the pre itself.
Charles
Charles,
any performance upgrades relative to my early K/C unit? phono pre upgrades are not relevant for my use. I no longer have a tt in the vicinity of that side of my room.
still loving my King/Cello.....and the 'Zeel' 50 ohm interface really synergizes with my dart preamp.
Hi Mike,
Long time since we've communicated. Hope you and the family are well.
There have been a few internal pre parts changes mostly to replace older/original parts that are no longer available. Doubt that they make any sonic difference.
I believe you had Ki "jumper out" the output caps and install the Mundorf Gold/Silver/Foil input caps. Duelands as inputs are "slightly" better but are so physically big that I can't fit them in most pre's.
Certain customers have had me experience with various grades of better connectors - mainly Furutec RCA's and IEC connectors and in a few cases, Stillpoint PC board standoffs. Myles A. got some of the best Furutec's, had me retrofit them and raves about the results on the AudioNirvana blog. Email me separately if you'd like and we can discuss these.
Charles
Long time since we've communicated. Hope you and the family are well.
There have been a few internal pre parts changes mostly to replace older/original parts that are no longer available. Doubt that they make any sonic difference.
I believe you had Ki "jumper out" the output caps and install the Mundorf Gold/Silver/Foil input caps. Duelands as inputs are "slightly" better but are so physically big that I can't fit them in most pre's.
Certain customers have had me experience with various grades of better connectors - mainly Furutec RCA's and IEC connectors and in a few cases, Stillpoint PC board standoffs. Myles A. got some of the best Furutec's, had me retrofit them and raves about the results on the AudioNirvana blog. Email me separately if you'd like and we can discuss these.
Charles
Hey Charles,
If my pornographic (intended) memory serves me right... actually I had installed the mammoth Mundorfs in Mike's K/C preamp's outputs initially. Mike didn't think it was a good change. Maybe he could have let the caps ferment a bit longer but I ended up removing them and putting the outputs just the way you had shipped them. I believe there were three small caps in parallel at each channel.
One thing I would suggest for Mike's tape pre though... is to rewire the Phono/Tape switch into 1/4" and 1/2" selection switch so that he wouldn't have to swap cables every time. I know Mike has no need for the phono feature and do like his both Studer A820s playing through the K/C preamp. I think you had already done the same work for Dale V.
Ki
Hi Ki - and THANKS for the reply.
You did tweak my memory about the Mundorf's in Mike's pre. DO believe that more break-in may have "tipped the balance".
Have since supplied a number of "tape only" pre's and some with a two-position input switch - although I "intuitively" don't like putting ANY MORE components in this low-level application than ABSOLUTELY necessary.
Haven't gotten any complaints tho.
Charles
You did tweak my memory about the Mundorf's in Mike's pre. DO believe that more break-in may have "tipped the balance".
Have since supplied a number of "tape only" pre's and some with a two-position input switch - although I "intuitively" don't like putting ANY MORE components in this low-level application than ABSOLUTELY necessary.
Haven't gotten any complaints tho.
Charles
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